WO2020048361A1 - Video decoding method and video decoder - Google Patents

Abstract

Disclosed are a video decoding method and a video decoder. Said method comprises: parsing coding tree partition information to obtain a current node; according to a division depth N of said current node, determining a region covered by a current quantization group; obtaining a quantization parameter (QP) difference value of a quantization parameter of a current coding unit (CU) in said region covered by the current quantization group; obtaining a reconstructed image of the current CU according to the QP difference value of the current CU. Using the present invention, it is possible to improve decoding efficiency.

Description

Video decoding method and video decoder

This application requires the submission of the State Intellectual Property Office of China on September 5, 2018, application number 201811032693.7, the invention name "Video Decoding Method and Video Decoder", and the submission of the State Intellectual Property Office of China, application on September 21, 2018 The priority of the Chinese patent application No. 201811104788.5 and the invention name is "Video Decoding Method and Video Decoder", the entire contents of which are incorporated herein by reference.

Technical field

The embodiments of the present application generally relate to the field of video coding, and more specifically, to a video decoding method and a video decoder.

Background technique

Video encoding (video encoding and decoding) is widely used in digital video applications, such as broadcast digital TV, video transmission on the Internet and mobile networks, real-time conversation applications such as video chat and video conferencing, DVD and Blu-ray discs, video content acquisition and editing systems And security applications for camcorders.

With the development of the block-based hybrid video coding method in the H.261 standard in 1990, new video coding technologies and tools have been developed and formed the basis for the new video coding standard. Other video coding standards include MPEG-1 video, MPEG-2 video, ITU-T H.262 / MPEG-2, ITU-T H.263, ITU-T H.264 / MPEG-4 Part 10 Advanced Video Coding ( Advanced Video Coding (AVC), ITU-T H.265 / High Efficiency Video Coding (HEVC) ... and extensions to such standards, such as scalability and / or three-dimensional (3D) extensions. As video creation and usage becomes more widespread, video traffic becomes the biggest burden on communication networks and data storage. Therefore, one of the goals of most video coding standards is to reduce the bit rate without sacrificing picture quality compared to previous standards. Even though the latest High Efficiency Video Coding (HEVC) can compress video about twice as much as AVC without sacrificing picture quality, new technologies are still needed to further compress video relative to HEVC.

Summary of the Invention

The embodiments of the present application provide a video decoding method and a video decoder, which can improve decoding efficiency.

The foregoing and other objects are achieved by the subject matter of the independent claims. Other implementations are apparent from the dependent claims, the description and the drawings.

In a first aspect, the invention relates to a video decoding method. The method is performed by a video decoder. The method includes: parsing coding tree partition information to obtain a current node; determining an area covered by a current quantization group according to a division depth N of the current node; obtaining a QP difference value of a current CU in an area covered by the current quantization group ; And acquiring a reconstructed image of the current CU according to a QP difference value of the current CU.

It can be seen that the video decoding method provided by the present invention can determine the area covered by the current quantization group according to the division depth N of the current node, can ensure that the QP can match the CU, thereby avoiding that one CU corresponds to two different QGs, and can improve decoding effectiveness.

According to the first aspect, in a possible implementation manner of the method, the partition depth N of the current node is the quadtree partition depth N of the current node; and the current quantization is determined according to the partition depth N of the current node. The area covered by the group includes: determining the area covered by the current quantization group according to the division depth N of the current node or determining the area covered by the current quantization group according to the multi-type division depth M of the current node; if the N is greater than the first threshold T1 or M is greater than 0, and the area covered by the current quantization group is the area covered by the K-th level quadtree node of the current node; where K is the smaller of N and T1 Value; the K-th level quadtree node is a quadtree node including the current node among the nodes generated by the quadtree partitioning K times from the coding tree unit CTU.

The K-layer quadtree node is the (M + N-K) -layer parent node of the current node.

It can be seen that the confirmation of QP coverage on the basis of CU can make the division of QP more accurate, thereby improving the decoding quality.

According to the first aspect, in a possible implementation manner of the method, the partition depth N of the current node is the quadtree partition depth N of the current node; and the current quantization is determined according to the partition depth N of the current node. The area covered by the group includes: determining the area covered by the current quantization group according to the quad-tree partition depth N of the current node and the multi-type tree partition depth M of the current node; if the N is less than or equal to the A threshold T1, and M is equal to 0, and the area covered by the current quantization group is the area covered by the current node.

It can be seen that the confirmation of QP coverage on the basis of CU can make the division of QP more accurate, thereby improving the decoding quality.

According to the first aspect, in a possible implementation manner of the method, the partition depth N of the current node is the quadtree partition depth N of the current node; and the current quantization is determined according to the partition depth N of the current node. The area covered by the group includes: determining the area covered by the current quantization group according to the quad tree partition depth N of the current node or the quad tree partition depth N of the current node and the multiple types of the current node The tree division depth M determines the area covered by the current quantization group; if the N is equal to the first threshold T1 and the M is 0, the area covered by the current quantization group is the area covered by the current node Or if the N is less than the first threshold T1, the area covered by the current quantization group is the area covered by the current node.

It can be seen that the confirmation of QP coverage on the basis of CU can make the division of QP more accurate, thereby improving the decoding quality.

According to the first aspect, in a possible implementation manner of the method, the partition depth N of the current node is the quadtree partition depth N of the current node; and the current quantization is determined according to the partition depth N of the current node. The area covered by the group includes: determining the area covered by the current quantization group according to the quad-tree partition depth N of the current node and the multi-type tree partition depth M of the current node; if the N is equal to a first threshold T1, and M is equal to 0, the area covered by the current quantization group is the area covered by the current node; or if N is less than a first threshold T1, and M is less than or equal to a fourth threshold T4 The area covered by the current quantization group is the area covered by the current node.

According to the first aspect, in a possible implementation manner of the method, the fourth threshold T4 may be a preset positive integer, for example, may be 1, 2, 3, or 4, and so on.

According to the first aspect, in a possible implementation manner of the method, the fourth threshold may be determined according to the first threshold T1 and a quadtree partition depth N of the current node, and may be, for example, T4 = T1-N.

It can be seen that confirming the QP coverage on the basis of the CU can make the QP division more accurate, thereby improving the decoding quality.

According to the first aspect, in a possible implementation manner of the method, the partition depth N of the current node is the quadtree partition depth N of the current node; and the current quantization is determined according to the partition depth N of the current node. The area covered by the group includes: determining the area covered by the current quantization group according to the quad-tree partition depth N of the current node and the multi-type tree partition depth M of the current node; if the N is less than or equal to the A threshold T1, and M is less than or equal to T1-N, and an area covered by the current quantization group is an area covered by the current node.

It can be seen that the confirmation of QP coverage on the basis of CU can make the division of QP more accurate, thereby improving the decoding quality.

According to the first aspect, in a possible implementation manner of the method, determining the area covered by the current quantization group according to the division depth N of the current node includes: if the division depth N of the current node is greater than a first threshold T1 Obtaining the (N-T1) -layer parent node of the current node; determining that the area covered by the current quantization group is the area covered by the (N-T1) -layer parent node.

It can be seen that the confirmation of QP coverage on the basis of CU can make the division of QP more accurate, thereby improving the decoding quality.

According to the first aspect, in a possible implementation manner of the method, the determining the area covered by the current quantization group according to the division depth N of the current node includes: if the division depth N of the current node is equal to a first threshold T1 , Determining that an area covered by the current quantization group is an area covered by the current node.

It can be seen that the division depth N of the current node is directly compared with the first threshold T1, so as to determine the area covered by the current quantization group, and the decoding speed is improved.

According to the first aspect, in a possible implementation manner of the method, the division depth of the current node is the QT depth of the current node; or the division depth of the current node is the QT depth of the current node and the Sum of the MTT depth of the current node.

It can be seen that using different methods of confirming the depth of division can balance the decoding speed and decoding quality, and improve the final decoding efficiency.

According to a first aspect, in a possible implementation manner of the method, the first threshold T1 is 0, 1, 2, or 3.

According to a first aspect, in a possible implementation manner of the method, the method further includes: obtaining a division manner of the current node; and determining the area covered by the current quantization group according to the division depth N of the current node includes: : If the division depth N of the current node is equal to the second threshold T2 minus 1, and the division mode of the current node is a tri-tree division manner, determine that the area covered by the current quantization group is covered by the current node Area; or if the current node's division depth N is equal to a second threshold T2, and the current node is divided into a binary tree or a quadtree, determining that the area covered by the current quantization group is the area The area covered by the current node; or, if the current node's division depth is less than or equal to a second threshold, and the current node is no longer divided, determining that the area covered by the current quantization group is covered by the current node Area.

It can be seen that, for different situations, determining the area covered by the current quantization group in different ways can improve the accuracy of QG partitioning and thus the decoding accuracy.

According to a first aspect, in a possible implementation manner of the method, the second threshold value is 2, 3, 4, 6, 8, or 9.

According to the first aspect, in a possible implementation manner of the method, the second threshold value may be set to be X times the first threshold value, and X is an integer greater than 1, for example, X is 2, 3, or 4, and so on.

According to a first aspect, in a possible implementation manner of the method, the method further includes: obtaining a division manner of the current node; and determining the area covered by the current quantization group according to the division depth N of the current node includes: : If the division depth N of the current node is equal to a third threshold T3 minus 1, and the division mode of the current node is a tri-tree division or a quad-tree division, determine that the area covered by the current quantization group is The area covered by the current node; if the current partition depth N of the current node is equal to a third threshold T3, and the current node is partitioned in a binary tree, determining that the area covered by the current quantization group is the current The area covered by the node; or if the current node's division depth N is equal to a third threshold T3 and the current node is no longer divided, determining that the area covered by the current quantization group is the area covered by the current node region.

It can be seen that, for different situations, determining the area covered by the current quantization group in different ways can improve the accuracy of QG partitioning and thus the decoding accuracy.

According to the first aspect, in a possible implementation manner of the method, the third threshold value is 3, or 5.

According to the first aspect, in a possible implementation manner of the method, the division depth N of the current node is determined according to the QT depth of the current node and the binary tree division depth Db of the current node.

According to the first aspect, in a possible implementation manner of the method, the division depth N of the current node is determined using the following calculation formula: N = Dq * 2 + Db; and Dq is the QT depth of the current node.

According to the first aspect, in a possible implementation manner of the method, if the current node is a MTT root node, the binary tree division depth Db of the current node is 0; if the current node is an MTT node and is not a MTT root node If the current node is a child node obtained by binary tree division, the binary tree division depth Db of the current node is the binary tree division depth of the immediate parent of the current node plus 1; if the current node is an MTT node and For non-MTT root nodes, if the current node is an intermediate child node obtained through tri-tree partitioning, the binary tree partition depth Db of the current node is the binary tree partition depth of the immediate parent of the current node plus 1; or if The current node is a MTT node and a non-MTT root node. If the current node is a non-intermediate child node obtained by a tri-tree partition, the binary tree division depth Db of the current node is a binary tree of the immediate parent of the current node Divide the depth by 2.

It can be seen that using different methods to determine the division depth for different situations can improve the division accuracy of QG, thereby improving the decoding accuracy.

According to the first aspect, in a possible implementation manner of the method, if the QP difference value of the first residual CU in the current quantization group is not equal to 0, the encoding order in the current quantization group is The brightness QP of all CUs before the first residual CU is modified to the brightness QP of the first residual CU;

If the current CU is a CU before the first residual CU in the current quantization group, obtaining the reconstructed image of the current CU according to the QP difference value of the current CU is specifically:

A reconstructed image of the current CU is obtained according to the brightness QP of the first residual CU.

In a second aspect, the invention relates to a video decoder. The video decoder includes: an entropy decoding unit configured to parse the coding tree partition information to obtain the current node; determine the area covered by the current quantization group according to the division depth N of the current node; and obtain the area covered by the current quantization group. The QP difference value of the current CU in the region; determining the brightness QP of the current CU according to the QP difference value of the current CU; an inverse quantization unit configured to obtain the inverse quantization coefficient of the current CU according to the brightness QP of the current CU An inverse transformation processing unit configured to obtain a reconstruction residual block of the current CU according to the inverse quantization coefficient of the current CU; and a reconstruction unit configured to obtain the current CU according to the reconstruction residual block of the current CU Reconstructed image.

According to a second aspect, in a possible implementation manner of the video decoder, a partition depth N of the current node is a quadtree partition depth N of the current node; and the entropy decoding unit is specifically configured to The division depth N of the current node determines the area covered by the current quantization group or the area covered by the current quantization group according to the multi-type division depth M of the current node; if the N is greater than the first threshold T1 or the M Greater than 0, the area covered by the current quantization group is the area covered by the K-level quadtree node of the current node; where K is the smaller of N and T1; the K-level quadtree The node is a quadtree node including the current node among the nodes generated by K tree quadtree partitioning starting from the coding tree unit CTU.

The K-layer quadtree node is the (M + N-K) -layer parent node of the current node.

According to a second aspect, in a possible implementation manner of the video decoder, a partition depth N of the current node is a quadtree partition depth N of the current node; and the entropy decoding unit is specifically configured to The quadtree partition depth N of the current node and the multi-type tree partition depth M of the current node determine the area covered by the current quantization group; if N is less than or equal to a first threshold T1, and M is 0 The area covered by the current quantization group is the area covered by the current node.

According to a second aspect, in a possible implementation manner of the video decoder, a partition depth N of the current node is a quadtree partition depth N of the current node; and the entropy decoding unit is specifically configured to The quadtree partition depth N of the current node determines the area covered by the current quantization group or the current quantization group is determined according to the quadtree partition depth N of the current node and the multi-type tree partition depth M of the current node. The area covered; if N is equal to the first threshold T1 and M is 0, the area covered by the current quantization group is the area covered by the current node; or if N is less than the first threshold T1, the area covered by the current quantization group is the area covered by the current node.

According to a second aspect, in a possible implementation manner of the video decoder, a partition depth N of the current node is a quadtree partition depth N of the current node; and the entropy decoding unit is specifically configured to The quadtree partition depth N of the current node and the multi-type tree partition depth M of the current node determine the area covered by the current quantization group; if N is equal to a first threshold T1, and M is equal to 0, all The area covered by the current quantization group is the area covered by the current node; or if the N is less than the first threshold T1 and the M is less than or equal to the fourth threshold T4, the area covered by the current quantization group Is the area covered by the current node.

According to a second aspect, in a possible implementation manner of the video decoder, the fourth threshold T4 may be a preset positive integer, for example, may be 1, 2, 3, or 4, and so on.

According to the second aspect, in a possible implementation manner of the video decoder, the fourth threshold may be determined according to the first threshold T1 and the quadtree partition depth N of the current node, for example, T4 = T1-N .

According to a second aspect, in a possible implementation manner of the video decoder, a partition depth N of the current node is a quadtree partition depth N of the current node; and the entropy decoding unit is specifically configured to The quadtree partition depth N of the current node and the multi-type tree partition depth M of the current node determine the area covered by the current quantization group; if N is less than or equal to a first threshold T1, and M is less than or Equal to T1-N, the area covered by the current quantization group is the area covered by the current node.

According to a second aspect, in a possible implementation manner of the video decoder, the entropy decoding unit is specifically configured to: if the division depth N of the current node is greater than a first threshold T1, obtain the (N -T1) layer parent node; determining that the area covered by the current quantization group is the area covered by the (N-T1) layer parent node.

According to a second aspect, in a possible implementation manner of the video decoder, the entropy decoding unit is specifically configured to: if the division depth N of the current node is equal to a first threshold value T1, determine a value covered by the current quantization group The area is the area covered by the current node.

According to a second aspect, in a possible implementation manner of the video decoder, the division depth of the current node is the QT depth of the current node; or the division depth of the current node is the QT depth of the current node and The sum of the MTT depth of the current node.

According to a second aspect, in a possible implementation manner of the video decoder, the first threshold T1 is 0, 1, 2, or 3.

According to a second aspect, in a possible implementation manner of the video decoder, the entropy decoding unit is further configured to obtain a division manner of the current node; if the division depth N of the current node is equal to a second threshold T2 minus 1, and the current node is partitioned in a tri-tree manner, and it is determined that the area covered by the current quantization group is the area covered by the current node; or if the current node's partition depth N is equal to a second threshold T2, and the current node is divided into a binary tree or a quadtree, and it is determined that the area covered by the current quantization group is the area covered by the current node; or if the current node is divided The depth is less than or equal to a second threshold, and the current node is no longer divided, and it is determined that an area covered by the current quantization group is an area covered by the current node.

According to a second aspect, in a possible implementation manner of the video decoder, the second threshold value is 2, 3, 4, 6, 8, or 9.

According to a second aspect, in a possible implementation manner of the video decoder, the entropy decoding unit is further configured to obtain a division manner of the current node; if the division depth N of the current node is equal to a third threshold T3 minus 1, and the current node is divided into a tri-tree or a quad-tree, determining that the area covered by the current quantization group is the area covered by the current node; if the current node has a division depth N is equal to a third threshold T3, and the current node is partitioned in a binary tree manner, and it is determined that the area covered by the current quantization group is the area covered by the current node; or if the current node has a partition depth N When it is equal to the third threshold T3 and the current node is no longer divided, it is determined that the area covered by the current quantization group is the area covered by the current node.

According to a second aspect, in a possible implementation manner of the video decoder, the third threshold value is 3, or 5.

According to a second aspect, in a possible implementation manner of the video decoder, the entropy decoding unit is specifically configured to determine the current node's QT depth according to the current node and the binary tree division depth Db of the current node. Divide the depth N.

According to a second aspect, in a possible implementation manner of the video decoder, the entropy decoding unit is specifically configured to determine a division depth N of the current node by using the following calculation formula: N = Dq * 2 + Db; the Dq is the QT depth of the current node.

According to a second aspect, in a possible implementation manner of the video decoder, if the current node is a MTT root node, the binary tree division depth Db of the current node is 0; if the current node is an MTT node and is not MTT Root node, if the current node is a child node obtained by binary tree division, the binary tree division depth Db of the current node is the binary tree division depth of the immediate parent of the current node plus 1; if the current node is MTT Nodes and non-MTT root nodes, if the current node is an intermediate child node obtained by tri-tree partitioning, the binary tree partition depth Db of the current node is the binary tree partition depth of the immediate parent of the current node plus 1; or If the current node is an MTT node and is not a MTT root node, and if the current node is a non-intermediate child node obtained by a tri-tree partition method, the binary tree division depth Db of the current node is a direct parent node of the current node The binary tree divides the depth plus 2.

According to a second aspect, in a possible implementation manner of the video decoder, the entropy decoding unit is further configured to, if the QP difference value of the first residual CU in the current quantization group is not equal to 0, then Modify the luminance QP of all CUs in the current quantization group whose coding order is before the first residual CU to the luminance QP of the first residual CU; if the current CU is the current The CU before the first residual CU in the quantization group, the inverse quantization unit is specifically configured to obtain the inverse quantization coefficient of the current CU according to the brightness QP of the first residual CU.

According to a third aspect, an embodiment of the present invention provides a video decoding method, including: parsing coding tree partition information to obtain a current node; and determining a coordinate of an upper left corner of an area covered by a current quantization group according to a partition depth N of the current node; Acquiring a QP difference value of a quantization parameter of a current coding unit CU in an area covered by the current quantization group; and obtaining a reconstructed image of the current CU according to the QP difference value of the current CU.

According to a third aspect, in a possible implementation manner of the method, the partition depth N of the current node is the quadtree partition depth N of the current node; and the current quantization is determined according to the partition depth N of the current node. The coordinates of the upper left corner of the area covered by the group include: determining the coordinates of the upper left corner of the area covered by the current quantization group according to the division depth N of the current node or determining the current quantization group according to the multi-type division depth M of the current node. The coordinates of the upper left corner of the area covered; if the N is greater than the first threshold T1 or the M is greater than 0, the coordinates of the upper left corner of the area covered by the current quantization group is the K-th level quadtree of the current node The coordinates of the upper-left corner of the area covered by the node; where K is the smaller value of N and T1; the K-level quadtree node is a node generated by the quadtree partition K times from the coding tree unit CTU The quadtree node of the current node.

According to a third aspect, in a possible implementation manner of the method, the partition depth N of the current node is the quadtree partition depth N of the current node; and the current quantization is determined according to the partition depth N of the current node. The upper-left corner coordinates of the area covered by the group include: determining the upper-left corner coordinates of the area covered by the current quantization group according to the quad-tree partition depth N of the current node and the multi-type tree partition depth M of the current node; If the N is less than or equal to the first threshold T1 and the M is 0, the coordinates of the upper left corner of the area covered by the current quantization group are the coordinates of the upper left corner of the area covered by the current node.

According to a third aspect, in a possible implementation manner of the method, the partition depth N of the current node is the quadtree partition depth N of the current node; and the current quantization is determined according to the partition depth N of the current node. The coordinates of the upper-left corner of the area covered by the group include: determining the coordinates of the upper-left corner of the area covered by the current quantization group according to the quad-tree partition depth N of the current node or the depth N of the quad-tree partition according to the current node And the multi-type tree partitioning depth M of the current node determines the coordinates of the upper left corner of the area covered by the current quantization group; if the N is equal to a first threshold T1 and the M is equal to 0, the current quantization group The coordinates of the upper left corner of the area covered are the coordinates of the upper left corner of the area covered by the current node; or if the N is less than the first threshold T1, the coordinates of the upper left corner of the area covered by the current quantization group are the current node The coordinates of the upper-left corner of the area covered.

According to a third aspect, in a possible implementation manner of the method, the partition depth N of the current node is the quadtree partition depth N of the current node; and the current quantization is determined according to the partition depth N of the current node. The upper-left corner coordinates of the area covered by the group include: determining the upper-left corner coordinates of the area covered by the current quantization group according to the quad-tree partition depth N of the current node and the multi-type tree partition depth M of the current node; If the N is equal to the first threshold T1, and the M is 0, the coordinates of the upper left corner of the area covered by the current quantization group are the coordinates of the upper left corner of the area covered by the current node; or if N is less than The first threshold T1 and the M are smaller than or equal to the fourth threshold T4. The coordinates of the upper left corner of the area covered by the current quantization group are the coordinates of the upper left corner of the area covered by the current node.

According to a third aspect, in a possible implementation manner of the method, the partition depth N of the current node is the quadtree partition depth N of the current node; and the current quantization is determined according to the partition depth N of the current node. The upper-left corner coordinates of the area covered by the group include: determining the upper-left corner coordinates of the area covered by the current quantization group according to the quad-tree partition depth N of the current node and the multi-type tree partition depth M of the current node; If the N is less than or equal to the first threshold T1 and the M is less than or equal to T1-N, the coordinates of the upper left corner of the area covered by the current quantization group are the coordinates of the upper left corner of the area covered by the current node.

According to a third aspect, in a possible implementation manner of the method, determining the upper-left corner coordinate of an area covered by the current quantization group according to the current partition depth N of the node includes: if the current partition depth N of the node is greater than The first threshold T1 is to obtain the (N-T1) -layer parent node of the current node; determining that the coordinates of the upper left corner of the area covered by the current quantization group are covered by the (N-T1) -layer parent node The coordinates of the upper-left corner of the area.

According to a third aspect, in a possible implementation manner of the method, determining the upper-left corner coordinate of the area covered by the current quantization group according to the current partition depth N of the node includes: if the current node partition depth N is equal to The first threshold T1 determines that the coordinates of the upper left corner of the area covered by the current quantization group are the coordinates of the upper left corner of the area covered by the current node.

According to a third aspect, in a possible implementation manner of the method, the first threshold T1 is a preset non-negative integer.

According to a third aspect, in a possible implementation manner of the method, the first threshold T1 is 0, 1, 2, or 3.

According to a third aspect, in a possible implementation manner of the method, the partition depth of the current node is a quad-tree partition depth QT depth of the current node.

According to a third aspect, in a possible implementation manner of the method, the partition depth of the current node is the sum of the QT depth of the current node and the multi-type tree partition depth MTT depth of the current node.

According to a third aspect, in a possible implementation manner of the method, the method further includes: obtaining a division manner of the current node; and determining the area covered by the current quantization group according to the division depth N of the current node. The upper-left corner coordinates include: if the current node's division depth N is equal to the second threshold T2 minus 1, and the current node is divided in a tri-tree manner, determining the upper-left corner coordinates of the area covered by the current quantization group Is the coordinate of the upper left corner of the area covered by the current node; or if the division depth N of the current node is equal to a second threshold T2, and the division mode of the current node is a binary tree division manner or a quadtree division manner, determine The coordinates of the upper left corner of the area covered by the current quantization group are the coordinates of the upper left corner of the area covered by the current node.

According to a third aspect, in a possible implementation manner of the method, the method further includes: obtaining a division manner of the current node; and determining the area covered by the current quantization group according to the division depth N of the current node. The upper left corner includes: if the current node's division depth N is equal to the third threshold T3 minus 1, and the current node's division mode is a tri-tree or quad-tree division, determining the coverage of the current quantization group The coordinates of the upper left corner of the region are the coordinates of the upper left corner of the region covered by the current node; or if the division depth N of the current node is equal to a third threshold T3, and the division manner of the current node is a binary tree division manner, determine The coordinates of the upper left corner of the area covered by the current quantization group are the coordinates of the upper left corner of the area covered by the current node.

According to a third aspect, in a possible implementation manner of the method, a partition depth N of the current node is determined according to a QT depth of the current node and a binary tree partition depth Db of the current node.

According to a third aspect, in a possible implementation manner of the method, the division depth N of the current node is determined using the following calculation formula: N = Dq * 2 + Db; and Dq is the QT depth of the current node.

According to a third aspect, in a possible implementation of the method, if the current node is a multi-type tree MTT partition root node, the binary tree partition depth Db of the current node is 0; if the current node is an MTT node and Non-MTT root node, if the current node is a child node obtained by binary tree division, the binary tree division depth Db of the current node is the binary tree division depth of the immediate parent of the current node plus 1; if the current node MTT node and non-MTT root node, if the current node is an intermediate child node obtained by tri-tree division, the binary tree division depth Db of the current node is the binary tree division depth of the immediate parent of the current node plus 1 Or if the current node is an MTT node and is not a MTT root node, if the current node is a non-intermediate child node obtained by a tri-tree partitioning method, the depth of the binary tree division Db of the current node is a direct value of the current node The binary tree partition depth of the parent node is increased by two.

According to a third aspect, in a possible implementation manner of the method, if the QP difference value of the first residual CU in the current quantization group is not equal to 0, the encoding order in the current quantization group is The brightness QP of all CUs before the first residual CU is modified to the brightness QP of the first residual CU; if the current CU is the first residual CU in the current quantization group For a previous CU, obtaining the reconstructed image of the current CU according to the QP difference value of the current CU is specifically: obtaining the reconstructed image of the current CU according to the brightness QP of the first residual CU. .

According to a fourth aspect, an embodiment of the present invention provides a video decoder, including: an entropy decoding unit, configured to parse coding tree partition information to obtain a current node; and determine a coverage area of a current quantization group according to the current partition depth N of the current node. The coordinates of the upper left corner of the area; obtaining the QP difference value of the quantization parameter of the current coding unit CU in the coordinates of the upper left corner of the area covered by the current quantization group; determining the brightness QP of the current CU according to the QP difference value of the current CU; An inverse quantization unit configured to obtain an inverse quantization coefficient of the current CU according to the brightness QP of the current CU; an inverse transform processing unit configured to obtain a reconstructed residual block of the current CU according to the inverse quantization coefficient of the current CU ; And a reconstruction unit, configured to obtain a reconstructed image of the current CU according to a reconstruction residual block of the current CU.

According to a fourth aspect, in a possible implementation manner of the video decoder, the partition depth N of the current node is the quadtree partition depth N of the current node; and the entropy decoding unit is specifically configured to The division depth N of the current node determines the upper-left corner coordinates of the area covered by the current quantization group or the multi-type division depth M of the current node determines the upper-left corner coordinates of the area covered by the current quantization group; if N is greater than The first threshold T1 or M is greater than 0, and the coordinates of the upper left corner of the area covered by the current quantization group are the coordinates of the upper left corner of the area covered by the K-level quadtree node of the current node; where K is N And the smaller value of T1; the K-th level quadtree node is a quadtree node including the current node among the nodes generated by the quadtree partitioning K times from the coding tree unit CTU.

According to a fourth aspect, in a possible implementation manner of the video decoder, the partition depth N of the current node is the quadtree partition depth N of the current node; and the entropy decoding unit is specifically configured to The quadtree partition depth N of the current node and the multi-type tree partition depth M of the current node determine the coordinates of the upper left corner of the area covered by the current quantization group; if the N is less than or equal to the first threshold T1, and The M is equal to 0, and the coordinates of the upper left corner of the area covered by the current quantization group are the coordinates of the upper left corner of the area covered by the current node.

According to a fourth aspect, in a possible implementation manner of the video decoder, the partition depth N of the current node is the quadtree partition depth N of the current node; and the entropy decoding unit is specifically configured to The quadtree partition depth N of the current node determines the coordinates of the upper left corner of the area covered by the current quantization group or the quadtree partition depth N of the current node and the multi-type tree partition depth M of the current node. The coordinates of the upper left corner of the area covered by the current quantization group; if the N is equal to the first threshold T1 and the M is 0, the coordinates of the upper left corner of the area covered by the current quantization group are covered by the current node The upper-left corner coordinate of the area covered by the current node; or if N is less than the first threshold T1, the upper-left corner coordinate of the area covered by the current quantization group is the upper-left corner coordinate of the area covered by the current node.

According to a fourth aspect, in a possible implementation manner of the video decoder, the partition depth N of the current node is the quadtree partition depth N of the current node; and the entropy decoding unit is specifically configured to The quadtree partition depth N of the current node and the multi-type tree partition depth M of the current node determine the coordinates of the upper left corner of the area covered by the current quantization group; if the N is equal to a first threshold T1, and the M Is equal to 0, the coordinates of the upper left corner of the area covered by the current quantization group are the coordinates of the upper left corner of the area covered by the current node; or if the N is less than the first threshold T1 and the M is less than or equal to the fourth Threshold T4, the coordinates of the upper left corner of the area covered by the current quantization group are the coordinates of the upper left corner of the area covered by the current node.

According to a fourth aspect, in a possible implementation manner of the video decoder, the partition depth N of the current node is the quadtree partition depth N of the current node; and the entropy decoding unit is specifically configured to The quadtree partition depth N of the current node and the multi-type tree partition depth M of the current node determine the coordinates of the upper left corner of the area covered by the current quantization group; if the N is less than or equal to the first threshold T1, and The M is less than or equal to T1-N, and the coordinates of the upper left corner of the area covered by the current quantization group are the coordinates of the upper left corner of the area covered by the current node.

According to a fourth aspect, in a possible implementation manner of the video decoder, the entropy decoding unit is specifically configured to: if the division depth N of the current node is greater than a first threshold T1, obtain the (N -T1) layer parent node; determining the coordinates of the upper left corner of the area covered by the current quantization group as the coordinates of the upper left corner of the area covered by the (N-T1) layer parent node.

According to a fourth aspect, in a possible implementation manner of the video decoder, the entropy decoding unit is specifically configured to: if the division depth N of the current node is equal to a first threshold value T1, determine a value covered by the current quantization group The coordinates of the upper left corner of the area are the coordinates of the upper left corner of the area covered by the current node.

According to a fourth aspect, in a possible implementation manner of the video decoder, the first threshold T1 is a non-negative integer set in advance.

According to a fourth aspect, in a possible implementation manner of the video decoder, the first threshold T1 is 0, 1, 2, or 3.

According to a fourth aspect, in a possible implementation manner of the video decoder, a partition depth of the current node is a quad-tree partition depth QT depth of the current node.

According to a fourth aspect, in a possible implementation manner of the video decoder, a partition depth of the current node is a sum of a QT depth of the current node and a multi-type tree partition depth MTT depth of the current node.

According to a fourth aspect, in a possible implementation manner of the video decoder, it is further configured to obtain a division manner of the current node; if the division depth N of the current node is equal to a second threshold T2 minus 1, and the current The division method of the nodes is a tri-tree division method, and it is determined that the coordinates of the upper left corner of the area covered by the current quantization group are the coordinates of the upper left corner of the area covered by the current node; A two-threshold value T2, and the current node is divided into a binary tree or a quadtree, and it is determined that the upper-left corner coordinate of the area covered by the current quantization group is the upper-left corner coordinate of the area covered by the current node .

According to a fourth aspect, in a possible implementation manner of the video decoder, the entropy decoding unit is further configured to obtain a division manner of the current node; if the division depth N of the current node is equal to a third threshold T3 minus 1, and the current node is divided into a tri-tree or a quad-tree, determining that the coordinates of the upper left corner of the area covered by the current quantization group are the coordinates of the upper left corner of the area covered by the current node; If the division depth N of the current node is equal to a third threshold T3, and the division manner of the current node is a binary tree division manner, it is determined that the coordinates of the upper left corner of the area covered by the current quantization group are covered by the current node. The coordinates of the upper-left corner of the area.

According to a fourth aspect, in a possible implementation manner of the video decoder, the entropy decoding unit is specifically configured to determine the current node's QT depth based on the current node's binary tree division depth Db Divide the depth N.

According to a fourth aspect, in a possible implementation manner of the video decoder, the entropy decoding unit is specifically configured to determine a division depth N of the current node by using the following calculation formula: N = Dq * 2 + Db; the Dq is the QT depth of the current node.

According to a fourth aspect, in a possible implementation manner of the video decoder, if the current node is a multi-type tree MTT partition root node, the binary tree partition depth Db of the current node is 0; if the current node is MTT Node and non-MTT root node, if the current node is a child node obtained by binary tree division, the binary tree division depth Db of the current node is the binary tree division depth of the immediate parent of the current node plus 1; if The current node is an MTT node and is not a MTT root node. If the current node is an intermediate child node obtained by a tri-tree partition, the binary tree partition depth Db of the current node is the binary tree partition depth of the immediate parent of the current node Increase by 1; or if the current node is an MTT node and is not a MTT root node, if the current node is a non-intermediate child node obtained by a tri-tree partitioning method, the binary tree division depth Db of the current node is the current node The binary tree partition depth of the immediate parent node is increased by two.

According to a fourth aspect, in a possible implementation manner of the video decoder, the entropy decoding unit is further configured to, if the QP difference value of the first residual CU in the current quantization group is not equal to 0, then Modify the luminance QP of all CUs in the current quantization group whose coding order is before the first residual CU to the luminance QP of the first residual CU; if the current CU is the current The CU before the first residual CU in the quantization group, the inverse quantization unit is specifically configured to obtain the inverse quantization coefficient of the current CU according to the brightness QP of the first residual CU.

In a fifth aspect, the present invention relates to a device for decoding a video stream, including a processor and a memory. The memory stores instructions that cause the processor to perform a method according to the first aspect or the third aspect or any possible embodiment of the first or the third aspect.

According to a sixth aspect, a computer-readable storage medium is provided, on which instructions are stored, which, when executed, cause one or more processors to encode video data. The instructions cause the one or more processors to perform a method according to the first or third aspect or any possible embodiment of the first or third aspect.

In a seventh aspect, the invention relates to a computer program comprising program code which, when run on a computer, performs a method according to the first or third aspect or any possible embodiment of the first or third aspect.

The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description, the drawings, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly explain the technical solutions in the embodiments of the present application or the background art, the drawings that are needed in the embodiments of the present application or the background art will be described below.

FIG. 1 is a block diagram of an example of a video encoding system for implementing an embodiment of the present invention;

2 is a block diagram showing an example structure of a video encoder for implementing an embodiment of the present invention;

3 is a block diagram showing an example structure of a video decoder for implementing an embodiment of the present invention;

FIG. 4 is a diagram showing the encoder 20 of FIG. 2 and the decoder 30 of FIG. 3.

5 is a block diagram illustrating another example of an encoding device or a decoding device;

FIG. 6 is a schematic diagram illustrating a division manner of a binary tree, a tri-tree and a quad-tree according to an embodiment; FIG.

7 is a schematic diagram illustrating QT-MTT division according to an embodiment;

8 is a schematic diagram illustrating QG partitioning according to an embodiment;

FIG. 9 is a flowchart illustrating a video decoding method according to an embodiment.

If there is no specific note about the same reference symbols below, the same reference symbols refer to the same or at least functionally equivalent features.

detailed description

In the following description, reference is made to the accompanying drawings, which form a part of this disclosure and illustrate, by way of illustration, specific aspects of embodiments of the invention or which may be used. It should be understood that embodiments of the present invention may be used in other aspects and may include structural or logical changes not depicted in the drawings. Therefore, the following detailed description should not be interpreted in a limiting sense, and the scope of the invention is defined by the appended claims.

For example, it should be understood that the disclosure in connection with the described method may be equally applicable to a corresponding device or system for performing the method, and vice versa. For example, if one or more specific method steps are described, the corresponding device may include one or more units such as functional units to perform the described one or more method steps (e.g., one unit performs one or more steps Or multiple units, each of which performs one or more of the multiple steps), even if such one or more units are not explicitly described or illustrated in the drawings. On the other hand, for example, if a specific device is described based on one or more units such as functional units, the corresponding method may include a step to perform the functionality of one or more units (e.g., a step performs one or more units Functionality, or multiple steps, where each performs the functionality of one or more of the multiple units), even if such one or more steps are not explicitly described or illustrated in the drawings. Further, it should be understood that the features of the various exemplary embodiments and / or aspects described herein may be combined with each other, unless explicitly stated otherwise.

Video coding generally refers to processing a sequence of pictures that form a video or a video sequence. In the field of video coding, the terms "picture", "frame" or "image" can be used as synonyms. Video encoding used in this application (or this disclosure) means video encoding or video decoding. Video encoding is performed on the source side and typically involves processing (e.g., by compressing) the original video picture to reduce the amount of data required to represent the video picture (thus storing and / or transmitting more efficiently). Video decoding is performed on the destination side and usually involves inverse processing relative to the encoder to reconstruct the video picture. The video pictures (or collectively referred to as pictures, which will be explained below) referred to in the embodiments should be understood as "encoding" or "decoding" related to a video sequence. The combination of the encoding part and the decoding part is also called codec (encoding and decoding).

In the case of lossless video coding, the original video picture can be reconstructed, that is, the reconstructed video picture has the same quality as the original video picture (assuming there is no transmission loss or other data loss during storage or transmission). In the case of lossy video coding, further compression is performed by, for example, quantization to reduce the amount of data required to represent the video picture, and the decoder side cannot completely reconstruct the video picture, that is, the quality of the reconstructed video picture is compared to the original video picture The quality is lower or worse.

Several video coding standards for H.261 belong to "lossy hybrid video codecs" (ie, combining spatial and temporal prediction in the sample domain with 2D transform coding for applying quantization in the transform domain). Each picture of a video sequence is usually partitioned into a set of non-overlapping blocks, usually encoded at the block level. In other words, the encoder side usually processes at the block (video block) level, that is, encodes the video. For example, the prediction block is generated by spatial (intra-picture) prediction and temporal (inter-picture) prediction. Processed blocks) minus the prediction block to obtain the residual block, transform the residual block in the transform domain and quantize the residual block to reduce the amount of data to be transmitted (compressed), and the decoder side will perform inverse processing relative to the encoder Partially applied to an encoded or compressed block to reconstruct the current block for representation. In addition, the encoder duplicates the decoder processing loop so that the encoder and decoder generate the same predictions (such as intra prediction and inter prediction) and / or reconstruction for processing, that is, encoding subsequent blocks.

As used herein, the term "block" may be part of a picture or frame. For ease of description, reference is made to Multi-purpose Video Coding (VVC: Versatile Video Coding) or the ITU-T Video Coding Experts Group (VCEG) and ISO / IEC Motion Picture Experts Group (MPEG). The High-Efficiency Video Coding (HEVC) developed by the Joint Working Group (Joint Collaboration, Video Coding, JCT-VC) describes embodiments of the present invention. Those skilled in the art understand that the embodiments of the present invention are not limited to HEVC or VVC. Can refer to CU, PU and TU. In HEVC, a CTU is split into multiple CUs by using a quad-tree structure represented as a coding tree. A decision is made at the CU level whether to use inter-picture (temporal) or intra-picture (spatial) prediction to encode a picture region. Each CU can be further split into one, two or four PUs according to the PU split type. The same prediction process is applied within a PU, and related information is transmitted to the decoder on the basis of the PU. After obtaining a residual block by applying a prediction process based on a PU split type, a CU may be partitioned into a transform unit (TU) according to other quad-tree structures similar to a coding tree for a CU. In the latest development of video compression technology, quad-tree and binary-tree (QTBT) split frames are used to split coded blocks. In the QTBT block structure, the CU may be a square or rectangular shape. In VVC, a coding tree unit (CTU) is first divided by a quad tree structure. The quad leaf nodes are further partitioned by a binary tree structure. Binary leaf nodes are called coding units (CUs), and the segments are used for prediction and transformation processing without any other segmentation. This means that the CU, PU, and TU have the same block size in the QTBT coded block structure. At the same time, it is also proposed to use multiple partitions with QTBT block structures, such as triple-tree partitioning.

Embodiments of the encoder 20, the decoder 30, and the encoding and decoding systems 10, 40 are described below based on Figs. 1 to 4 (before the embodiments of the present invention are described in more detail based on Fig. 9).

FIG. 1 is a conceptual or schematic block diagram illustrating an exemplary encoding system 10. For example, a video encoding system 10 that can use the technology of the present application (the present disclosure). The encoder 20 (e.g., video encoder 20) and decoder 30 (e.g., video decoder 30) of the video encoding system 10 represent that they can be used to perform for ... (segmentation / intra frame) according to various examples described in this application. Forecast / ...) As shown in FIG. 1, the encoding system 10 includes a source device 12 for providing the encoded data 13, such as the encoded picture 13, to a destination device 14 that decodes the encoded data 13, for example.

The source device 12 includes an encoder 20, and in addition, optionally, may include a picture source 16, such as a pre-processing unit 18 of a picture pre-processing unit 18, and a communication interface or communication unit 22.

The picture source 16 may include or may be any kind of picture capture device for, for example, capturing real-world pictures, and / or any kind of pictures or comments (for screen content encoding, some text on the screen is also considered to be a picture to be encoded Or a part of an image) generating device, for example, a computer graphics processor for generating computer animated pictures, or for obtaining and / or providing real world pictures, computer animated pictures (for example, screen content, virtual reality (VR) ) Pictures) of any type of device, and / or any combination thereof (eg, augmented reality (AR) pictures).

A (digital) picture is or can be regarded as a two-dimensional array or matrix of sampling points with luminance values. The sampling points in the array may also be called pixels (short for picture element) or pixels. The number of sampling points of the array or picture in the horizontal and vertical directions (or axes) defines the size and / or resolution of the picture. In order to represent color, three color components are usually used, that is, a picture can be represented as or contain three sampling arrays. In RBG format or color space, pictures include corresponding red, green, and blue sampling arrays. However, in video coding, each pixel is usually represented in a luma / chroma format or color space, for example, YCbCr, including the luma component indicated by Y (sometimes also indicated by L) and the two chroma indicated by Cb and Cr Weight. Luma (abbreviated as luma) component Y represents luminance or gray level intensity (for example, both are the same in a grayscale picture), while two chroma (abbreviated as chroma) components Cb and Cr represent chroma or color information components . Correspondingly, a picture in the YCbCr format includes a luminance sampling array of luminance sampling values (Y), and two chrominance sampling arrays of chrominance values (Cb and Cr). Pictures in RGB format can be converted or converted to YCbCr format, and vice versa. This process is also called color conversion or conversion. If the picture is black and white, the picture can include only an array of luminance samples.

The picture source 16 (e.g., the video source 16) may be, for example, a camera for capturing pictures, such as a memory of a picture memory, including or storing a previously captured or generated picture, and / or any category (internal) of obtaining or receiving a picture Or external) interface. The camera may be, for example, an integrated camera that is local or integrated in the source device, and the memory may be local or, for example, an integrated memory that is integrated in the source device. The interface may be, for example, an external interface for receiving pictures from an external video source. The external video source is, for example, an external picture capture device, such as a camera, external storage, or an external picture generation device. The external picture generation device is, for example, an external computer graphics processor, Or server. The interface may be any type of interface according to any proprietary or standardized interface protocol, such as a wired or wireless interface, an optical interface. The interface for acquiring the picture data 17 may be the same interface as the communication interface 22 or a part of the communication interface 22.

Different from the processing performed by the pre-processing unit 18 and the pre-processing unit 18, a picture or picture data 17 (for example, video data 16) may also be referred to as an original picture or original picture data 17.

The pre-processing unit 18 is configured to receive (original) picture data 17 and perform pre-processing on the picture data 17 to obtain pre-processed pictures 19 or pre-processed picture data 19. For example, the pre-processing performed by the pre-processing unit 18 may include trimming, color format conversion (for example, conversion from RGB to YCbCr), color correction, or denoising. It is understood that the pre-processing unit 18 may be an optional component.

An encoder 20 (eg, video encoder 20) is used to receive the pre-processed picture data 19 and provide the encoded picture data 21 (details will be further described below, for example, based on FIG. 2 or FIG. 4).

The communication interface 22 of the source device 12 can be used to receive the encoded picture data 21 and transmit it to other devices, such as the destination device 14 or any other device, for storage or direct reconstruction, or for correspondingly storing the The encoded data 13 and / or the encoded picture data 21 are processed before transmitting the encoded data 13 to other devices, such as the destination device 14 or any other device for decoding or storage.

The destination device 14 includes a decoder 30 (for example, a video decoder 30), and in addition, optionally, it may include a communication interface or communication unit 28, a post-processing unit 32, and a display device 34.

The communication interface 28 of the destination device 14 is used, for example, to receive the encoded picture data 21 or the encoded data 13 directly from the source device 12 or any other source. Any other source is, for example, a storage device, and the storage device is, for example, encoded picture data storage. device.

The communication interface 22 and the communication interface 28 can be used for direct communication through a direct communication link between the source device 12 and the destination device 14 or transmission or reception of encoded picture data 21 or encoded data 13 through any type of network The link is, for example, a direct wired or wireless connection, and any type of network is, for example, a wired or wireless network or any combination thereof, or any type of private and public network, or any combination thereof.

The communication interface 22 may be used, for example, to encapsulate the encoded picture data 21 into a suitable format, such as a packet, for transmission over a communication link or a communication network.

The communication interface 28 forming a corresponding part of the communication interface 22 may be used, for example, to decapsulate the encoded data 13 to obtain the encoded picture data 21.

Both the communication interface 22 and the communication interface 28 may be configured as unidirectional communication interfaces, as indicated by the arrows for the encoded picture data 13 from the source device 12 to the destination device 14 in FIG. 1, or configured as bidirectional communication interfaces, and It can be used, for example, to send and receive messages to establish a connection, acknowledge, and exchange any other information related to a communication link and / or data transmission such as encoded picture data transmission.

The decoder 30 is configured to receive the encoded picture data 21 and provide the decoded picture data 31 or the decoded picture 31 (details will be further described below, for example, based on FIG. 3 or FIG. 5).

The post-processor 32 of the destination device 14 is used to post-process decoded picture data 31 (also referred to as reconstructed picture data), for example, decoded picture 131 to obtain post-processed picture data 33, for example, post-processed Picture 33. The post-processing performed by the post-processing unit 32 may include, for example, color format conversion (e.g., conversion from YCbCr to RGB), color correction, retouching, or resampling, or any other processing, such as preparing the decoded picture data 31 to be processed by The display device 34 displays it.

The display device 34 of the destination device 14 is used to receive the post-processed picture data 33 to display a picture to, for example, a user or a viewer. The display device 34 may be or may include any kind of display for presenting a reconstructed picture, such as an integrated or external display or monitor. For example, the display may include a liquid crystal display (LCD), an organic light emitting diode (OLED) display, a plasma display, a projector, a micro LED display, a liquid crystal on silicon (LCoS), Digital light processor (DLP) or any other display of any kind.

Although FIG. 1 illustrates the source device 12 and the destination device 14 as separate devices, the device embodiment may also include the source device 12 and the destination device 14 or both, ie, the source device 12 or corresponding And the functionality of the destination device 14 or equivalent. In such embodiments, the same hardware and / or software, or separate hardware and / or software, or any combination thereof may be used to implement the source device 12 or corresponding functionality and the destination device 14 or corresponding functionality .

Those skilled in the art can clearly understand based on the description that the existence and (exact) division of the functionality of different units or the functionality of the source device 12 and / or the destination device 14 shown in FIG. 1 may differ according to the actual device and application.

Both the encoder 20 (e.g., video encoder 20) and decoder 30 (e.g., video decoder 30) may be implemented as any of a variety of suitable circuits, such as one or more microprocessors, digital signal processors (digital signal processor, DSP), application-specific integrated circuit (ASIC), field-programmable gate array (FPGA), discrete logic, hardware, or any combination thereof. If the technology is implemented partially in software, the device may store the software's instructions in a suitable non-transitory computer-readable storage medium, and may use one or more processors to execute the instructions in hardware to perform the techniques of the present disclosure. . Any one of the foregoing (including hardware, software, a combination of hardware and software, etc.) can be considered as one or more processors. Each of the video encoder 20 and the video decoder 30 may be included in one or more encoders or decoders, and any of the encoders or decoders may be integrated as a combined encoder / decoder in a corresponding device (Codec).

The source device 12 may be referred to as a video encoding device or a video encoding device. The destination device 14 may be referred to as a video decoding device or a video decoding device. The source device 12 and the destination device 14 may be examples of a video encoding device or a video encoding apparatus.

Source device 12 and destination device 14 may include any of a variety of devices, including any type of handheld or stationary device, such as a notebook or laptop computer, mobile phone, smartphone, tablet or tablet computer, video camera, desktop Computer, set-top box, TV, display device, digital media player, video game console, video streaming device (such as content service server or content distribution server), broadcast receiver device, broadcast transmitter device, etc., and may not be used Or use any kind of operating system.

In some cases, source device 12 and destination device 14 may be equipped for wireless communication. Therefore, the source device 12 and the destination device 14 may be wireless communication devices.

In some cases, the video encoding system 10 shown in FIG. 1 is merely an example, and the techniques of the present application may be applicable to a video encoding setting (eg, video encoding or video decoding) that does not necessarily include any data communication between encoding and decoding devices. . In other examples, data may be retrieved from local storage, streamed over a network, and the like. The video encoding device may encode the data and store the data to a memory, and / or the video decoding device may retrieve the data from the memory and decode the data. In some examples, encoding and decoding are performed by devices that do not communicate with each other, but only encode data to and / or retrieve data from memory and decode data.

It should be understood that for each of the examples described above with reference to video encoder 20, video decoder 30 may be used to perform the reverse process. Regarding signaling syntax elements, video decoder 30 may be used to receive and parse such syntax elements, and decode related video data accordingly. In some examples, video encoder 20 may entropy encode one or more syntax elements that define ... into an encoded video bitstream. In such examples, video decoder 30 may parse such syntax elements and decode related video data accordingly.

Encoder & encoding method

FIG. 2 shows a schematic / conceptual block diagram of an example of a video encoder 20 for implementing the technology of the present (disclosed) application. In the example of FIG. 2, the video encoder 20 includes a residual calculation unit 204, a transformation processing unit 206, a quantization unit 208, an inverse quantization unit 210, an inverse transformation processing unit 212, a reconstruction unit 214, a buffer 216, and a loop filter. A decoder unit 220, a decoded picture buffer (DPB) 230, a prediction processing unit 260, and an entropy encoding unit 270. The prediction processing unit 260 may include an inter prediction unit 244, an intra prediction unit 254, and a mode selection unit 262. The inter prediction unit 244 may include a motion estimation unit and a motion compensation unit (not shown). The video encoder 20 shown in FIG. 2 may also be referred to as a hybrid video encoder or a video encoder according to a hybrid video codec.

For example, the residual calculation unit 204, the transformation processing unit 206, the quantization unit 208, the prediction processing unit 260, and the entropy encoding unit 270 form the forward signal path of the encoder 20, while the inverse quantization unit 210, the inverse transformation processing unit 212, The constructing unit 214, the buffer 216, the loop filter 220, the decoded picture buffer (DPB) 230, and the prediction processing unit 260 form a backward signal path of the encoder, wherein the backward signal path of the encoder corresponds to To the decoder's signal path (see decoder 30 in Figure 3).

The encoder 20 receives a picture 201 or a block 203 of the picture 201 through, for example, an input 202, for example, a picture in a picture sequence forming a video or a video sequence. The picture block 203 can also be called the current picture block or the picture block to be encoded, and the picture 201 can be called the current picture or the picture to be encoded (especially when the current picture is distinguished from other pictures in video encoding, other pictures such as the same video sequence (Ie previously encoded and / or decoded pictures in the video sequence of the current picture).

segmentation

An embodiment of the encoder 20 may include a segmentation unit (not shown in FIG. 2) for segmenting the picture 201 into multiple blocks, such as the block 203, and generally into multiple non-overlapping blocks. The segmentation unit can be used to use the same block size and corresponding raster to define the block size for all pictures in the video sequence, or to change the block size between pictures or subsets or groups of pictures, and split each picture into Corresponding block.

In one example, the prediction processing unit 260 of the video encoder 20 may be used to perform any combination of the aforementioned segmentation techniques.

Like picture 201, block 203 is also or can be regarded as a two-dimensional array or matrix of sampling points with brightness values (sampling values), although its size is smaller than picture 201. In other words, the block 203 may include, for example, one sampling array (e.g., a luminance array in the case of a black and white picture 201) or three sampling arrays (e.g., one luminance array and two chroma arrays in the case of a color picture) or a basis An array of any other number and / or category of color formats applied. The number of sampling points in the horizontal and vertical directions (or axes) of the block 203 defines the size of the block 203.

The encoder 20 shown in FIG. 2 is used to encode a picture 201 block by block, for example, performing encoding and prediction on each block 203.

Residual calculation

The residual calculation unit 204 is configured to calculate the residual block 205 based on the picture block 203 and the prediction block 265 (the other details of the prediction block 265 are provided below). For example, the sample value of the picture block 203 is subtracted from the prediction by sample-by-sample (pixel-by-pixel). Sample values of block 265 to obtain residual block 205 in the sample domain.

Transform

The transform processing unit 206 is configured to apply a transform such as discrete cosine transform (DCT) or discrete sine transform (DST) on the sample values of the residual block 205 to obtain transform coefficients 207 in the transform domain. . The transform coefficient 207 may also be referred to as a transform residual coefficient, and represents a residual block 205 in a transform domain.

The transform processing unit 206 may be used to apply an integer approximation of DCT / DST, such as the transform specified for HEVC / H.265. Compared to an orthogonal DCT transform, this integer approximation is usually scaled by a factor. To maintain the norm of the residual blocks processed by the forward and inverse transforms, an additional scaling factor is applied as part of the transform process. The scaling factor is usually selected based on certain constraints, for example, the scaling factor is a power of two used for shift operations, the bit depth of the transform coefficients, the trade-off between accuracy, and implementation cost. For example, a specific scaling factor is specified on the decoder 30 side by, for example, the inverse transform processing unit 212 (and on the encoder 20 side by, for example, the inverse transform processing unit 212 as the corresponding inverse transform), and accordingly, the The 20 side specifies a corresponding scaling factor for the positive transformation through the transformation processing unit 206.

Quantify

The quantization unit 208 is used to quantize the transform coefficient 207, for example, by applying scalar quantization or vector quantization to obtain the quantized transform coefficient 209. The quantized transform coefficient 209 may also be referred to as a quantized residual coefficient 209. The quantization process can reduce the bit depth associated with some or all of the transform coefficients 207. For example, n-bit transform coefficients may be rounded down to m-bit transform coefficients during quantization, where n is greater than m. The degree of quantization can be modified by adjusting the quantization parameter (QP). For scalar quantization, for example, different scales can be applied to achieve finer or coarser quantization. A smaller quantization step size corresponds to a finer quantization, while a larger quantization step size corresponds to a coarser quantization. An appropriate quantization step size can be indicated by a quantization parameter (QP). For example, the quantization parameter may be an index of a predefined set of suitable quantization steps. For example, smaller quantization parameters may correspond to fine quantization (smaller quantization step size), larger quantization parameters may correspond to coarse quantization (larger quantization step size), and vice versa. Quantization may include division by a quantization step size and corresponding quantization or inverse quantization performed, for example, by inverse quantization 210, or may include multiplication by a quantization step size. Embodiments according to some standards such as HEVC may use quantization parameters to determine the quantization step size. In general, the quantization step size can be calculated using a fixed-point approximation using an equation containing division based on the quantization parameter. Additional scaling factors may be introduced for quantization and inverse quantization to restore the norm of the residual block that may be modified due to the scale used in the fixed-point approximation of the equation for the quantization step size and quantization parameter. In one example embodiment, inverse transform and inverse quantization scales can be combined. Alternatively, a custom quantization table can be used and signaled from the encoder to the decoder in, for example, a bitstream. Quantization is a lossy operation, where the larger the quantization step, the greater the loss.

The inverse quantization unit 210 is configured to apply the inverse quantization of the quantization unit 208 on the quantized coefficients to obtain the inverse quantized coefficients 211. For example, based on or using the same quantization step size as the quantization unit 208, apply the quantization scheme applied by the quantization unit 208 Inverse quantization scheme. The dequantized coefficient 211 may also be referred to as a dequantized residual coefficient 211, which corresponds to the transform coefficient 207, although the loss due to quantization is usually different from the transform coefficient.

The inverse transform processing unit 212 is used to apply an inverse transform of the transform applied by the transform processing unit 206, for example, an inverse discrete cosine transform (DCT) or an inverse discrete sine transform (DST), so that Obtain an inverse transform block 213. The inverse transform block 213 may also be referred to as an inverse transform inverse quantized block 213 or an inverse transform residual block 213.

The reconstruction unit 214 (for example, the summer 214) is used to add the inverse transform block 213 (that is, the reconstructed residual block 213) to the prediction block 265 to obtain the reconstructed block 215 in the sample domain. For example, The sample values of the reconstructed residual block 213 are added to the sample values of the prediction block 265.

Optionally, a buffer unit 216 (or simply "buffer" 216), such as a line buffer 216, is used to buffer or store the reconstructed block 215 and corresponding sample values, for example, for intra prediction. In other embodiments, the encoder may be used to use any unfiltered reconstructed block and / or corresponding sample values stored in the buffer unit 216 for any category of estimation and / or prediction, such as intra-frame prediction.

For example, an embodiment of the encoder 20 may be configured such that the buffer unit 216 is used not only for storing the reconstructed block 215 for intra prediction 254, but also for the loop filter unit 220 (not shown in FIG. 2). Out), and / or, for example, to make the buffer unit 216 and the decoded picture buffer unit 230 form a buffer. Other embodiments may be used to use the filtered block 221 and / or blocks or samples from the decoded picture buffer 230 (neither shown in FIG. 2) as the input or basis for the intra prediction 254.

The loop filter unit 220 (or "loop filter" 220 for short) is used to filter the reconstructed block 215 to obtain the filtered block 221, so as to smoothly perform pixel conversion or improve video quality. The loop filter unit 220 is intended to represent one or more loop filters, such as a deblocking filter, a sample-adaptive offset (SAO) filter, or other filters, such as a bilateral filter, Adaptive loop filters (adaptive loop filters, ALF), or sharpening or smoothing filters, or cooperative filters. Although the loop filter unit 220 is shown as an in-loop filter in FIG. 2, in other configurations, the loop filter unit 220 may be implemented as a post-loop filter. The filtered block 221 may also be referred to as a filtered reconstructed block 221. The decoded picture buffer 230 may store the reconstructed encoded block after the loop filter unit 220 performs a filtering operation on the reconstructed encoded block.

An embodiment of the encoder 20 (correspondingly, the loop filter unit 220) may be used to output loop filter parameters (e.g., sample adaptive offset information), for example, directly output or by the entropy coding unit 270 or any other The entropy coding unit outputs after entropy coding, for example, so that the decoder 30 can receive and apply the same loop filter parameters for decoding.

The decoded picture buffer (DPB) 230 may be a reference picture memory that stores reference picture data for the video encoder 20 to encode video data. DPB 230 can be formed by any of a variety of memory devices, such as dynamic random access (DRAM) (including synchronous DRAM (SDRAM), magnetoresistive RAM (MRAM), and resistive RAM (resistive RAM, RRAM)) or other types of memory devices. The DPB 230 and the buffer 216 may be provided by the same memory device or separate memory devices. In a certain example, a decoded picture buffer (DPB) 230 is used to store the filtered block 221. The decoded picture buffer 230 may be further used to store other previous filtered blocks of the same current picture or different pictures such as previously reconstructed pictures, such as the previously reconstructed and filtered block 221, and may provide a complete previous Reconstruction is the decoded picture (and corresponding reference blocks and samples) and / or part of the reconstructed current picture (and corresponding reference blocks and samples), for example for inter prediction. In a certain example, if the reconstructed block 215 is reconstructed without in-loop filtering, a decoded picture buffer (DPB) 230 is used to store the reconstructed block 215.

Prediction processing unit 260, also referred to as block prediction processing unit 260, is used to receive or obtain block 203 (current block 203 of current picture 201) and reconstructed picture data, such as a reference to the same (current) picture from buffer 216 Samples and / or reference picture data 231 from one or more previously decoded pictures from the decoded picture buffer 230, and used to process such data for prediction, i.e., may be provided as inter-predicted blocks 245 or intra- Prediction block 265 of prediction block 255.

The mode selection unit 262 may be used to select a prediction mode (such as an intra or inter prediction mode) and / or a corresponding prediction block 245 or 255 used as the prediction block 265 to calculate the residual block 205 and reconstruct the reconstructed block 215.

An embodiment of the mode selection unit 262 may be used to select a prediction mode (e.g., selected from those prediction modes supported by the prediction processing unit 260) that provides the best match or minimum residual (minimum residual means Better compression in transmission or storage), or provide minimal signaling overhead (minimum signaling overhead means better compression in transmission or storage), or consider or balance both. The mode selection unit 262 may be used to determine a prediction mode based on rate distortion optimization (RDO), that is, to select a prediction mode that provides the minimum code rate distortion optimization, or to select a prediction mode whose related code rate distortion meets the prediction mode selection criteria .

The prediction processing performed by an example of the encoder 20 (e.g., by the prediction processing unit 260) and mode selection (e.g., by the mode selection unit 262) will be explained in detail below.

As described above, the encoder 20 is used to determine or select the best or optimal prediction mode from a set of (predetermined) prediction modes. The prediction mode set may include, for example, an intra prediction mode and / or an inter prediction mode.

The set of intra prediction modes may include 35 different intra prediction modes, for example, non-directional modes such as DC (or average) mode and planar mode, or directional modes as defined in H.265, or may include 67 Different intra prediction modes, such as non-directional modes such as DC (or mean) mode and planar mode, or directional modes as defined in the developing H.266.

The set of (possible) inter-prediction modes depends on the available reference pictures (i.e., at least part of the decoded pictures previously stored in DBP 230) and other inter-prediction parameters, such as whether to use the entire reference picture or only the reference A part of the picture, such as a search window area surrounding the area of the current block, searches for the best matching reference block, and / or depends on, for example, whether pixel interpolation such as half-pixel and / or quarter-pixel interpolation is applied.

In addition to the above prediction modes, a skip mode and / or a direct mode can also be applied.

The prediction processing unit 260 may be further configured to divide the block 203 into smaller block partitions or sub-blocks, for example, using a quad-tree (QT) partition, a binary-tree (BT) partition, or a triple fork by iteration. Tree-triple-ternary-tree (TT) segmentation, or any combination thereof, and for performing predictions, for example, for each of block partitions or sub-blocks, where mode selection includes the tree structure and selection of the partitioned block 203 A prediction mode applied to each of a block partition or a sub-block.

The inter prediction unit 244 may include a motion estimation (ME) unit (not shown in FIG. 2) and a motion compensation (MC) unit (not shown in FIG. 2). The motion estimation unit is configured to receive or obtain picture block 203 (current picture block 203 of current picture 201) and decoded picture 231, or at least one or more previously reconstructed blocks, for example, one or more other / different previous The reconstructed block of picture 231 is decoded for motion estimation. For example, the video sequence may include the current picture and the previously decoded picture 31, or in other words, the current picture and the previously decoded picture 31 may be part of the picture sequence forming the video sequence or form the picture sequence.

For example, the encoder 20 may be used to select a reference block from multiple reference blocks of the same or different pictures in multiple other pictures, and provide a reference picture (or reference picture index) to a motion estimation unit (not shown in FIG. 2). ) And / or provide an offset (spatial offset) between the position (X, Y coordinates) of the reference block and the position of the current block as an inter prediction parameter. This offset is also called a motion vector (MV).

The motion compensation unit is used for obtaining, for example, receiving inter prediction parameters, and performing inter prediction based on or using the inter prediction parameters to obtain the inter prediction block 245. Motion compensation performed by a motion compensation unit (not shown in FIG. 2) may include taking out or generating a prediction block based on a motion / block vector determined through motion estimation (possibly performing interpolation on sub-pixel accuracy). Interpolation filtering can generate additional pixel samples from known pixel samples, potentially increasing the number of candidate prediction blocks that can be used to encode picture blocks. Upon receiving the motion vector of the PU for the current picture block, the motion compensation unit 246 may locate the prediction block pointed to by the motion vector in a reference picture list. Motion compensation unit 246 may also generate syntax elements associated with blocks and video slices for use by video decoder 30 when decoding picture blocks of video slices.

The intra prediction unit 254 is configured to obtain, for example, a picture block 203 (current picture block) and one or more previously reconstructed blocks, such as reconstructed neighboring blocks, that receive the same picture for intra estimation. For example, the encoder 20 may be used to select an intra prediction mode from a plurality of (predetermined) intra prediction modes.

Embodiments of the encoder 20 may be used to select an intra-prediction mode based on an optimization criterion, such as based on a minimum residual (eg, an intra-prediction mode that provides a prediction block 255 most similar to the current picture block 203) or a minimum code rate distortion.

The intra prediction unit 254 is further configured to determine the intra prediction block 255 based on the intra prediction parameters of the intra prediction mode as selected. In any case, after selecting the intra prediction mode for the block, the intra prediction unit 254 is further configured to provide the intra prediction parameters to the entropy encoding unit 270, that is, to provide an indication of the selected intra prediction mode for the block. Information. In one example, the intra prediction unit 254 may be used to perform any combination of intra prediction techniques described below.

The entropy coding unit 270 is configured to apply an entropy coding algorithm or scheme (for example, a variable length coding (VLC) scheme, a context adaptive VLC (context adaptive VLC, CAVLC) scheme, an arithmetic coding scheme, and a context adaptive binary arithmetic Coding (context, adaptive binary coding, CABAC), syntax-based context-adaptive binary arithmetic coding (SBAC), probability interval partitioning entropy (PIPE) coding, or other entropy Encoding method or technique) applied to one or all of the quantized residual coefficients 209, inter prediction parameters, intra prediction parameters, and / or loop filter parameters (or not applied) to obtain The encoded picture data 21 is output in the form of, for example, an encoded bit stream 21. The encoded bitstream may be transmitted to video decoder 30 or archived for later transmission or retrieval by video decoder 30. The entropy encoding unit 270 may also be used to entropy encode other syntax elements of the current video slice that is being encoded.

Other structural variations of video encoder 20 may be used to encode a video stream. For example, the non-transform-based encoder 20 may directly quantize the residual signal without a transform processing unit 206 for certain blocks or frames. In another embodiment, the encoder 20 may have a quantization unit 208 and an inverse quantization unit 210 combined into a single unit.

FIG. 3 illustrates an exemplary video decoder 30 for implementing the techniques of the present application. The video decoder 30 is configured to receive, for example, encoded picture data (eg, an encoded bit stream) 21 encoded by the encoder 20 to obtain a decoded picture 231. During the decoding process, video decoder 30 receives video data from video encoder 20, such as an encoded video bitstream and associated syntax elements representing picture blocks of encoded video slices.

In the example of FIG. 3, the decoder 30 includes an entropy decoding unit 304, an inverse quantization unit 310, an inverse transform processing unit 312, a reconstruction unit 314 (such as a summer 314), a buffer 316, a loop filter 320, The decoded picture buffer 330 and the prediction processing unit 360. The prediction processing unit 360 may include an inter prediction unit 344, an intra prediction unit 354, and a mode selection unit 362. In some examples, video decoder 30 may perform a decoding pass that is substantially inverse to the encoding pass described with reference to video encoder 20 of FIG. 2.

The entropy decoding unit 304 is configured to perform entropy decoding on the encoded picture data 21 to obtain, for example, quantized coefficients 309 and / or decoded encoding parameters (not shown in FIG. 3), for example, inter prediction, intra prediction parameters , (Filtered) any or all of the loop filter parameters and / or other syntax elements. The entropy decoding unit 304 is further configured to forward the inter prediction parameters, the intra prediction parameters, and / or other syntax elements to the prediction processing unit 360. Video decoder 30 may receive syntax elements at the video slice level and / or the video block level.

The inverse quantization unit 310 may be functionally the same as the inverse quantization unit 110, the inverse transformation processing unit 312 may be functionally the same as the inverse transformation processing unit 212, the reconstruction unit 314 may be functionally the same as the reconstruction unit 214, and the buffer 316 may be functionally Like the buffer 216, the loop filter 320 may be functionally the same as the loop filter 220, and the decoded picture buffer 330 may be functionally the same as the decoded picture buffer 230.

The prediction processing unit 360 may include an inter prediction unit 344 and an intra prediction unit 354. The inter prediction unit 344 may be functionally similar to the inter prediction unit 244 and the intra prediction unit 354 may be functionally similar to the intra prediction unit 254. . The prediction processing unit 360 is generally used to perform block prediction and / or obtain prediction blocks 365 from the encoded data 21, and to receive or obtain prediction-related parameters and / or Information about the selected prediction mode.

When a video slice is encoded as an intra-coded (I) slice, the intra-prediction unit 354 of the prediction processing unit 360 is used for the intra-prediction mode based on signal representation, Data to generate a prediction block 365 for a picture block of the current video slice. When a video frame is encoded as an inter-encoded (ie, B or P) slice, the inter-prediction unit 344 (e.g., a motion compensation unit) of the prediction processing unit 360 is based on the motion vector and received from the entropy decoding unit 304. The other syntax elements generate a prediction block 365 for a video block of the current video slice. For inter prediction, a prediction block may be generated from a reference picture in a reference picture list. The video decoder 30 may construct a reference frame list using a default construction technique based on the reference pictures stored in the DPB 330: List 0 and List 1.

The prediction processing unit 360 is configured to determine prediction information for a video block of a current video slice by analyzing a motion vector and other syntax elements, and use the prediction information to generate a prediction block for a current video block that is being decoded. For example, the prediction processing unit 360 uses some of the received syntax elements to determine a prediction mode (e.g., intra or inter prediction) of a video block used to encode a video slice, an inter prediction slice type (e.g., B slice, P slice or GPB slice), construction information for one or more of the reference picture lists for the slice, motion vectors for each inter-coded video block for the slice, each warp for the slice The inter-prediction status and other information of the inter-coded video block to decode the video block of the current video slice.

The inverse quantization unit 310 may be used for inverse quantization (ie, inverse quantization) of the quantized transform coefficients provided in the bitstream and decoded by the entropy decoding unit 304. The inverse quantization process may include using the quantization parameters calculated by video encoder 20 for each video block in the video slice to determine the degree of quantization that should be applied and also to determine the degree of inverse quantization that should be applied.

The inverse transform processing unit 312 is configured to apply an inverse transform (for example, an inverse DCT, an inverse integer transform, or a conceptually similar inverse transform process) to the transform coefficients to generate a residual block in the pixel domain.

Reconstruction unit 314 (e.g., summer 314) is used to add inverse transform block 313 (i.e., reconstructed residual block 313) to prediction block 365 to obtain reconstructed block 315 in the sample domain, such as by The sample values of the reconstructed residual block 313 are added to the sample values of the prediction block 365.

The loop filter unit 320 (during or after the encoding cycle) is used to filter the reconstructed block 315 to obtain the filtered block 321 so as to smoothly perform pixel conversion or improve video quality. In one example, the loop filter unit 320 may be used to perform any combination of filtering techniques described below. The loop filter unit 320 is intended to represent one or more loop filters, such as a deblocking filter, a sample-adaptive offset (SAO) filter, or other filters such as a bilateral filter, Adaptive loop filters (adaptive loop filters, ALF), or sharpening or smoothing filters, or cooperative filters. Although the loop filter unit 320 is shown as an in-loop filter in FIG. 3, in other configurations, the loop filter unit 320 may be implemented as a post-loop filter.

The decoded video block 321 in a given frame or picture is then stored in a decoded picture buffer 330 that stores reference pictures for subsequent motion compensation.

The decoder 30 is used, for example, to output a decoded picture 31 through an output 332 for presentation to or review by a user.

Other variations of video decoder 30 may be used to decode the compressed bitstream. For example, the decoder 30 may generate an output video stream without the loop filter unit 320. For example, the non-transform-based decoder 30 may directly inversely quantize the residual signal without the inverse transform processing unit 312 for certain blocks or frames. In another embodiment, the video decoder 30 may have an inverse quantization unit 310 and an inverse transform processing unit 312 combined into a single unit.

4 is an explanatory diagram of an example of a video encoding system 40 including the encoder 20 of FIG. 2 and / or the decoder 30 of FIG. 3 according to an exemplary embodiment. The system 40 may implement a combination of various techniques of the present application. In the illustrated embodiment, the video encoding system 40 may include an imaging device 41, a video encoder 20, a video decoder 30 (and / or a video encoder implemented by the logic circuit 47 of the processing unit 46), an antenna 42, One or more processors 43, one or more memories 44, and / or a display device 45.

As shown, the imaging device 41, antenna 42, processing unit 46, logic circuit 47, video encoder 20, video decoder 30, processor 43, memory 44, and / or display device 45 can communicate with each other. As discussed, although video encoding system 40 is shown with video encoder 20 and video decoder 30, in different examples, video encoding system 40 may include only video encoder 20 or only video decoder 30.

In some examples, as shown, the video encoding system 40 may include an antenna 42. For example, the antenna 42 may be used to transmit or receive an encoded bit stream of video data. In addition, in some examples, the video encoding system 40 may include a display device 45. The display device 45 may be used to present video data. In some examples, as shown, the logic circuit 47 may be implemented by the processing unit 46. The processing unit 46 may include application-specific integrated circuit (ASIC) logic, a graphics processor, a general-purpose processor, and the like. The video encoding system 40 may also include an optional processor 43, which may similarly include application-specific integrated circuit (ASIC) logic, a graphics processor, a general-purpose processor, and the like. In some examples, the logic circuit 47 may be implemented by hardware, such as dedicated hardware for video encoding, and the processor 43 may be implemented by general software, operating system, and the like. In addition, the memory 44 may be any type of memory, such as volatile memory (e.g., Static Random Access Memory (SRAM), Dynamic Random Access Memory (DRAM), etc.) or non-volatile memory Memory (for example, flash memory, etc.). In a non-limiting example, the memory 44 may be implemented by a cache memory. In some examples, the logic circuit 47 may access the memory 44 (eg, for implementing an image buffer). In other examples, the logic circuit 47 and / or the processing unit 46 may include a memory (eg, a cache, etc.) for implementing an image buffer or the like.

In some examples, video encoder 20 implemented by logic circuits may include an image buffer (eg, implemented by processing unit 46 or memory 44) and a graphics processing unit (eg, implemented by processing unit 46). The graphics processing unit may be communicatively coupled to the image buffer. The graphics processing unit may include a video encoder 20 implemented by a logic circuit 47 to implement the various modules discussed with reference to FIG. 2 and / or any other encoder system or subsystem described herein. Logic circuits can be used to perform various operations discussed herein.

Video decoder 30 may be implemented in a similar manner by logic circuit 47 to implement the various modules discussed with reference to decoder 30 of FIG. 3 and / or any other decoder system or subsystem described herein. In some examples, video decoder 30 implemented by a logic circuit may include an image buffer (implemented by processing unit 2820 or memory 44) and a graphics processing unit (eg, implemented by processing unit 46). The graphics processing unit may be communicatively coupled to the image buffer. The graphics processing unit may include a video decoder 30 implemented by a logic circuit 47 to implement various modules discussed with reference to FIG. 3 and / or any other decoder system or subsystem described herein.

In some examples, the antenna 42 of the video encoding system 40 may be used to receive an encoded bit stream of video data. As discussed, the encoded bitstream may contain data, indicators, index values, mode selection data, etc. related to encoded video frames discussed herein, such as data related to coded segmentation (e.g., transform coefficients or quantized transform coefficients) , (As discussed) optional indicators, and / or data defining code partitions). The video encoding system 40 may also include a video decoder 30 coupled to the antenna 42 and used to decode the encoded bitstream. The display device 45 is used to present video frames.

FIG. 5 is a simplified block diagram of an apparatus 500 that can be used as either or both of the source device 12 and the destination device 14 in FIG. 1 according to an exemplary embodiment. The device 500 may implement the technology of the present application. The device 500 may be in the form of a computing system including multiple computing devices, or in the form of a single computing device such as a mobile phone, tablet computer, laptop computer, notebook computer, desktop computer, and the like.

The processor 502 in the apparatus 500 may be a central processing unit. Alternatively, the processor 502 may be any other type of device or multiple devices capable of manipulating or processing information, existing or to be developed in the future. As shown, although a single processor such as the processor 502 can be used to practice the disclosed embodiments, speed and efficiency advantages can be achieved using more than one processor.

In one embodiment, the memory 504 in the device 500 may be a read-only memory (ROM) device or a random access memory (RAM) device. Any other suitable type of storage device can be used as the memory 504. The memory 504 may include code and data 506 accessed by the processor 502 using the bus 512. The memory 504 may further include an operating system 508 and an application program 510, which contains at least one program that permits the processor 502 to perform the methods described herein. For example, the application program 510 may include applications 1 to N, and applications 1 to N further include a video encoding application that performs the methods described herein. The device 500 may also include additional memory in the form of a slave memory 514, which may be, for example, a memory card for use with a mobile computing device. Because a video communication session may contain a large amount of information, this information may be stored in whole or in part in the slave memory 514 and loaded into the memory 504 for processing as needed.

The apparatus 500 may also include one or more output devices, such as a display 518. In one example, the display 518 may be a touch-sensitive display combining a display and a touch-sensitive element operable to sense a touch input. The display 518 may be coupled to the processor 502 through a bus 512. In addition to the display 518, other output devices may be provided that allow the user to program or otherwise use the device 500, or provide other output devices as an alternative to the display 518. When the output device is a display or contains a display, the display can be implemented in different ways, including through a liquid crystal display (LCD), a cathode-ray tube (CRT) display, a plasma display, or a light emitting diode diode (LED) displays, such as organic LED (OLED) displays.

The apparatus 500 may further include or be in communication with an image sensing device 520, such as a camera or any other image sensing device 520 that can or will be developed in the future to sense an image, such as An image of a user running the device 500. The image sensing device 520 may be placed directly facing a user of the running apparatus 500. In an example, the position and optical axis of the image sensing device 520 may be configured such that its field of view includes an area immediately adjacent to the display 518 and the display 518 is visible from the area.

The device 500 may also include or be in communication with a sound sensing device 522, such as a microphone or any other sound sensing device that can or will be developed in the future to sense the sound near the device 500. The sound sensing device 522 may be placed directly facing the user of the operating device 500 and may be used to receive a sound, such as a voice or other sound, emitted by the user when the device 500 is running.

Although the processor 502 and the memory 504 of the apparatus 500 are shown in FIG. 5 as being integrated in a single unit, other configurations may be used. The operation of the processor 502 may be distributed among multiple directly-coupled machines (each machine has one or more processors), or distributed in a local area or other network. The memory 504 may be distributed among multiple machines, such as a network-based memory or a memory among multiple machines running the apparatus 500. Although only a single bus is shown here, the bus 512 of the device 500 may be formed by multiple buses. Further, the slave memory 514 may be directly coupled to other components of the device 500 or may be accessed through a network, and may include a single integrated unit, such as one memory card, or multiple units, such as multiple memory cards. Therefore, the apparatus 500 can be implemented in various configurations.

Figure 6 describes the division of binary tree, tri-tree and quad-tree, where:

A quadtree is a tree-like structure, meaning that a node can be divided into four child nodes. The H265 video coding standard uses a quadtree-based CTU division method: the CTU serves as the root node, and each node corresponds to a square area; a node can no longer be divided (in this case, its corresponding area is a CU), or this The node is divided into four nodes at the next lower level, that is, the square area is divided into four square areas of the same size (the length and width are each half of the length and width of the area before division), and each area corresponds to a node. As shown in Figure 6 (a).

A binary tree is a tree-like structure, meaning that a node can be divided into two child nodes. In the existing encoding method using a binary tree, a node on a binary tree structure may not be divided, or this node may be divided into two nodes at a lower level. There are two ways to divide into two nodes: 1) Horizontal dichotomy, divide the area corresponding to the node into two areas of the same size, each area corresponds to a node, as shown in Figure 6 (b); Or 2) Divide vertically and divide the area corresponding to the node into two areas of the same size on the left and right, and each area corresponds to a node, as shown in Figure 6 (c).

A triple tree is a tree-like structure, meaning that a node can be divided into three child nodes. In the existing coding method using a tri-tree, the nodes on a tri-tree structure may not be divided, or this node may be divided into three lower-level nodes. There are two ways to divide into three nodes: 1) Horizontal three points, the area corresponding to the node is divided into three areas of upper, middle and lower, each area corresponds to a node, including three areas of upper, middle and lower The heights of the nodes are 1/4, 1/2, and 1/4 of the node height, respectively, as shown in Figure 6 (d); or 2) vertical three points, divide the area corresponding to the node into three left, middle, and right Area, each area corresponds to a node, where the widths of the left, middle, and right three areas are 1/4, 1/2, and 1/4 of the node height, respectively, as shown in Figure 6 (e).

The H.265 video coding standard divides a frame of image into non-overlapping coding tree units (CTU). The size of the CTU can be set to 64 × 64 (the size of the CTU can also be set to other values, such as the CTU in the JVET reference software JEM The size is increased to 128 × 128 or 256 × 256). A 64 × 64 CTU contains a rectangular pixel lattice of 64 columns with 64 pixels in each column, and each pixel contains a luminance component and / or a chrominance component.

H.265 uses a quad-tree (QT) -based CTU division method. The CTU is used as the root node of the quad tree, and the CTU is recursively divided into several leaves according to the quad tree division method. Node (leaf). A node corresponds to an image area. If the node is not divided, the node is called a leaf node, and its corresponding image area forms a CU. If the node continues to be divided, the image area corresponding to the node is divided into four regions of the same size (the (The length and width are each half of the divided area.) Each area corresponds to a node. You need to determine whether these nodes will be divided separately. Whether a node is divided is indicated by the split flag bit split_cu_flag corresponding to this node in the code stream. A node A is divided into four nodes Bi, i = 0, 1, 2, 3, Bi is called a child node of A, and A is called a parent node of Bi. The quadtree level (qtDepth) of the root node is 0, and the quadtree level of the node is the quadtree level of the parent node of the node plus 1. For brevity, the size and shape of the nodes in the following refers to the size and shape of the image area corresponding to the nodes.

More specifically, for a 64 × 64 CTU node (the quadtree level is 0), according to its corresponding split_cu_flag, you can choose not to divide it into one 64 × 64 CU, or choose to divide into four 32 × 32 Nodes (the quadtree level is 1). Each of these four 32 × 32 nodes can choose to continue to divide or not to divide according to its corresponding split_cu_flag; if a 32 × 32 node continues to divide, four 16 × 16 nodes (four The level of the fork tree is 2). And so on, until all nodes are no longer divided, such a CTU is divided into a group of CUs. The minimum size (size) of the CU is identified in the sequence parameter set (SPS: Sequence Parameter Set). For example, 8 × 8 is the smallest CU. In the above recursive division process, if the size of a node is equal to the minimum CU size, this node defaults to no longer divide, and it does not need to include its division flag in the code stream.

When a node is parsed as a leaf node, this leaf node is a CU, and further analyzes the coding information corresponding to the CU (including the prediction mode and transformation coefficients of the CU, such as the coding_unit () syntax structure in H.265). Then, the CU is subjected to decoding, prediction, inverse quantization, inverse transform, and loop filtering according to the encoded information to generate a reconstructed image corresponding to the CU. The quad-tree structure enables the CTU to be divided into a group of CUs of a suitable size according to the local characteristics of the image, for example, smooth regions are divided into larger CUs, and texture-rich regions are divided into smaller CUs.

Multi-purpose video coding test model (VTM: Versatile video coding Test Model) reference software adds a binary tree (BT) partition method and a ternary tree (TT) partition method based on the quadtree partition . Among them, VTM is a new codec reference software developed by JVET organization.

Binary tree partitioning divides a node into two sub-nodes. There are two specific binary tree partitioning methods:

1) Horizontal dichotomy: Divide the area corresponding to the node into two areas of the same size (that is, the width does not change, and the height becomes half of the area before division), and each area corresponds to a node; as shown in Figure 6 ( b) shown.

2) Vertical dichotomy: Divide the area corresponding to the node into two areas of the same size, that is, the height is unchanged, and the width becomes half of the area before division; as shown in (c) in FIG. 6.

Three-tree partitioning divides a node into three sub-nodes. There are two specific methods for three-tree partitioning:

1) Horizontal three points: divide the area corresponding to the node into three areas: upper, middle, and lower, each area corresponds to a node, where the height of the three areas is 1/4 of the height of the node, 1/2, 1/4, as shown in (d) of Figure 6;

2) Vertical three points: Dividing the area corresponding to the node into three areas: left, middle, and right, each area corresponds to a node, where the width of the three areas is 1/4 of the node height. , 1/2, 1/4, as shown in (e) of FIG. 6.

The division method of QT cascade BT / TT is used in VTM, referred to as QT-MTT (Quad Tree Plus Multi-Type Tree) division method. More specifically, the CTU generates QT leaf nodes through QT division. The nodes in the QT can be further divided into four QT child nodes using quad-tree division, or a QT leaf node can be generated without using quad-section division. The QT leaf node serves as the root node of the MTT. Nodes in MTT can be divided into sub-nodes using one of the four division methods: horizontal bisection, vertical bisection, horizontal trisection, and vertical trisection, or no longer be divided into an MTT leaf node. The leaf node of MTT is a coding unit CU.

Figure 7 shows an example of dividing a CTU into 16 CUs such as a to p using QT-MTT. Each endpoint on the right of Figure 7 represents a node, 4 nodes connected to a node represent quadtree partition, 2 nodes connected to a node represent binary tree partition, and 3 nodes connected to a node represent tritree partition. The solid line represents the QT division, the dashed line represents the first-level division of a Multi-Type Tree (MTT), and the dot-dash line represents the second-level division of the MTT. a to p are 16 MTT leaf nodes, and each MTT leaf node is 1 CU. A CTU obtains the CU division diagram shown in the left diagram of FIG. 7 according to the division manner in the right diagram of FIG. 7.

In the QT-MTT division method, each CU has a QT level (Quad-tree depth, QT depth, also called QT depth) and an MTT level (Multi-Type Tree depth, MTT depth, also called MTT depth). The QT level indicates the QT level of the QT leaf node to which the CU belongs, and the MTT level indicates the MTT level of the MTT leaf node to which the CU belongs. The root node of the coding tree has a QT level of 0 and an MTT level of 0. If a node on the coding tree is divided by QT, the QT level of the child node obtained by the division is the QT level of the node plus 1, and the MTT level is unchanged. Similarly, if a node on the coding tree is divided by MTT (that is, BT or TT One of the divisions), the MTT level of the child node obtained by the division is the MTT level of the node plus 1, and the QT level is unchanged. For example, in Figure 7, the QT level of a, b, c, d, e, f, g, i, and j is 1, and the MTT level is 2; the QT level of h is 1, and the MTT level is 1; for n, o, and p The QT level is 2 and the MTT level is 0; the QT level for l and m is 2 and the MTTT level is 1. If the CTU is divided into only one CU, the QT level of this CU is 0 and the MTT level is 0.

In HEVC, a CU includes a quantization parameter (QP) of luma block and two quantization parameters of chroma block, wherein the quantization parameter of chroma block is derived from the quantization parameter of luma block. The chrominance block quantization parameter is referred to as chrominance QP, and the luma block quantization parameter is referred to as luminance QP. The decoding of the luminance QP of a current CU (current CU) includes the following processing:

Obtain the diff_cu_qp_delta_depth syntax element from the Picture Parameter Set (PPS), and derive the Quantization Group (QG) from this syntax element, that is, the area of the quantization group is NxN, where N = CTUSize >> diff_cu_qp_delta_depth, and CTUSize is CTU The length of the side, such as a 64x64 CTU, has a CTUSize = 64. A 64x64 CTU is divided into Qs of M NxN regions, where M is a positive integer. For example, when diff_cu_qp_delta_depth = 2, the CTU is divided into 16 16x16 QGs, as shown in FIG. 8. Since only the QT partition is used in HEVC, if the QG obtained by the above-mentioned QG determination method includes multiple CUs smaller than the QG, the QG must include multiple complete CUs, that is, multiple CUs smaller than the QG are completely contained in one QG No CU with a size smaller than QG is included in multiple QGs at the same time. In addition, when only QT division is used, the QG obtained by the above QG determination method can also ensure that if a CU is the same size as the QG, the CU must be included in a QG. When a CU is larger than QG, it must contain a complete number of QGs.

A current quantization group (referred to as the current QG) in which the current CU is located is determined, where the current QG is a QG covering the coordinates of the upper left corner of the current CU. The upper left corner coordinate of the current CU is Pcu = (xCb, yCb), then the upper left corner coordinate of the current quantization group is Pqg = (xQg, yQg),

xQg = xCb- (xCb & ((1 << Log2MinCuQpDeltaSize) -1))

yQg = yCb- (yCb & ((1 << Log2MinCuQpDeltaSize) -1))

Among them, Log2MinCuQpDeltaSize = log2 (CTUSize) -diff_cu_qp_delta_depth, and log2 (x) is the logarithm of base 2 on x.

Get the QP difference value of the current CU, such as CuQpDeltaVal in the HEVC standard. If the current CU is the first residual CU in the QG (for example, the current CU's coding block flags cbf_luma, cbf_cb, and cbf_cr have a non-zero value indicating that the current CU has residuals), the current CU is parsed from the code stream. QP difference value. This QP difference is used as the QP difference value of all CUs whose coding order is located after the current CU in the current QG; the QP difference value of all CUs whose coding order is located before the current CU in the current QG is 0.

Obtain the predicted value of the quantization parameter of the luminance block of the current QG, such as qP _{Y_PRED} in the HEVC standard. qP _{Y_PRED} can be predicted from the left adjacent position luminance QP and the upper adjacent position luminance QP of the current QG. The left adjacent position of the current QG is (xQg-1, yQg), and the upper adjacent position is (xQg, yQg-1). The brightness QP of the upper neighboring position is the brightness QP of the coding unit covering the upper neighboring position; if the upper neighboring position is unavailable or the upper neighboring position does not belong to the same block (Tile) as the current block, the upper neighboring position The position brightness QP is set to the brightness QP of the last CU in the previous QG (such as qP _{Y_PREV} in the HEVC standard). Similarly, the brightness QP of the left neighboring position is the brightness QP of the coding unit covering the left neighboring position; if the left neighboring position is unavailable or the left neighboring position does not belong to the same block as the current block, the left neighboring position is The position brightness QP is set to the brightness QP of the last CU in the previous QG. Adjacent positions are unavailable. There are many ways to judge. For example, if adjacent positions are outside the current band, they are not available. For example, if adjacent positions are outside the current image, they are not available. Internally, it is not available; for example, pixels in adjacent positions are not available without reconstruction.

The predicted value of the quantization parameter of the luminance block of the current QG and the QP difference value (QP delta) of the current CU are added to obtain the luminance QP of the current CU.

It can be seen that in the QT-MTT division mode, using the above-mentioned QG division mode may cause a QG to include only a part of a certain CU, or a CU may also include multiple different QGs. Therefore, a new decoding (QG determination) method is needed to ensure the matching of QG and CU, that is, to ensure that one CU does not belong to two different QGs, thereby improving decoding efficiency.

FIG. 9 is a flowchart illustrating an example operation of a video decoder (for example, the video decoder 30 of FIG. 3) according to an embodiment of the present application. One or more structural elements of video decoder 30 may be used to perform the technique of FIG. 9. This embodiment includes:

901. Parse the coding tree partition information to obtain the current node.

The coding tree partition information is obtained by the video decoder 30 from the received code stream. Specifically, the entropy decoding unit in the video decoder 30 may perform this step.

The current node may be a CU, for example, it may be a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, and p in FIG. 7; It can be a node that needs to be further divided during the QT-MTT division of the CTU. Taking Figure 7 as an example, it can be the nodes corresponding to a and b, the nodes corresponding to c and d, and the nodes corresponding to e, f, and g. The nodes can be the nodes corresponding to i and j, the nodes corresponding to l, m, n, o, and p, the nodes corresponding to l and m, and the nodes a, b, c, d, e, f, and The node corresponding to g may be the node corresponding to h, i, and j.

902. Determine an area covered by the current quantization group according to the division depth N of the current node. In an implementation manner, determining the area covered by the current quantization group according to the division depth N of the current node includes determining coordinates of the upper left corner of the area covered by the current quantization group. After the coordinates of the upper left corner are determined, the specific area covered by the current quantization group can be determined. Therefore, in the following description, determining the area covered by the current quantization group can be understood as determining the coordinates of the upper left corner of the area covered by the current quantization group.

It can be understood that, according to different needs, there may be different determination manners of the division depth N of the current node.

The embodiments of the present invention provide the following four ways to determine the area covered by the current quantization group according to the division depth N of the current node.

Manner 1: Determine the area covered by the current quantization group according to the division depth N of the current node and a first threshold T1.

Specifically, it is first determined that the division depth N of the current node is greater than the first threshold T1, and if the division depth N of the current node is greater than the first threshold T1, the (N-T1) -th level parent node of the current node is obtained ; Then determine that the area covered by the current quantization group is the area covered by the (N-T1) -layer parent node. The first threshold T1 is a non-negative integer set in advance, and may be 0, 1, 2, or 3, for example.

There are two ways to determine the division depth N of the current node. One is to determine the division depth N of the current node as the QT depth of the current node, for example, nodes a, b, and c in FIG. 7. The QT depth of d, e, f, g, h, i, j, k is 1, and the QT depth of l, m, n, o, p is 2; the other is to divide the current node's depth N It is determined as the sum of the QT depth of the current node and the MTT depth of the current node, for example, the QT depth of the node k in FIG. 7 is 1, and the MTT depth is 0, so the partition depth N of the node k is 1; FIG. 7 The node a in the QT depth is 1, and the MTT depth is 2, so the partition depth N of the node a is 3. Among them, the QT depth of the root node of the coding tree is 0. If a node in the QT coding tree is divided by QT, the QT depth of the child nodes obtained by division is the QT depth of the node plus 1; if a node in the QT does not use QT division, this node is a MTT root node. The MTT root depth of the MTT root node is 0; if a node on the MTT coding tree is divided using MTT, the MTT depth of the child node obtained is the MTT depth of the node plus 1, and the QT depth of the child node is the QT depth of the node . That is to say, starting from the CTU root node, the current node is obtained after S1 QT partition and S2 MTT partition, then the QT depth of the current node is S1, and the MTT depth is S2. Taking Figure 7 as an example, the MTT node with a depth of 1 includes: nodes corresponding to a and b (that is, a node including the area where a and b are located), nodes corresponding to c and d, nodes corresponding to e, f, and g, h Corresponding nodes, nodes corresponding to i and j, and nodes corresponding to l and nodes corresponding to m. MTT depth of 1 indicates nodes that can be obtained by performing only one MTT division on the QT leaf nodes obtained after QT division of the CTU; MTT nodes with a depth of 2 include: a corresponding node, b corresponding node, c corresponding node, d corresponding node, e corresponding node, f corresponding node, g corresponding node, and j corresponding , The MTT depth of 2 indicates the node obtained by performing the second MTT division on the QT leaf nodes obtained after the QT division of the CTU. By analogy, there can also be nodes with an MTT depth of 3, 4, or 5, and so on (there are no nodes with an MTT depth greater than 2 in Figure 7).

Manner 2: Determine the area covered by the current quantization group according to the division depth N of the current node and a first threshold T1. In this embodiment, the division depth N of the current node is determined as the QT depth of the current node.

If the partition depth N of the current node is greater than a first threshold T1 or the multi-type tree partition depth M of the current node is greater than 0, a K-th level quadtree node of the current node is obtained, where K = min (N, T1 ), Min (a, b) means take the smaller of a and b; then determine that the area covered by the current quantization group is the area covered by the K-th level quadtree node. The first threshold T1 is a non-negative integer set in advance, and may be 0, 1, 2, or 3, for example.

The K-th layer quadtree node is a node that includes the current node among the nodes generated by K quadtree partitioning from the CTU, that is, the (M + N-K) layer parent node of the current node. The coordinates of the upper left corner (xK, yK) of the K-level quadtree node are:

xK = xCb- (xCb & ((1 << K1) -1))

yK = yCb- (yCb & ((1 << K1) -1))

Among them, xCb and yCb represent the horizontal and vertical coordinates of the upper left corner coordinate (xCb, yCb) of the current node, K1 = log2 (CTUSize) -K.

The width and height of the K-level quadtree node are equal to (1 << K1), where a << b represents the operation of shifting a to the left by b bits.

Manner 3: The area covered by the current quantization group is determined according to the division depth N of the current node and a first threshold T1. The current node is a node in the QT-MTT coding tree, and it may or may not be divided.

Specifically, first determine whether the division depth N of the current node is equal to the first threshold T1, and if the division depth N of the current node is equal to the first threshold T1, determine that the area covered by the current quantization group is the current node The area covered. Correspondingly, the coordinates of the upper left corner of this node can be saved, and the width and height of this node can also be saved. The CU in the current quantization group can read the above-mentioned saved information in processing such as brightness QP prediction.

For a manner of determining the division depth N and the value of the first threshold T1, refer to manner 1.

Manner 4: The area covered by the current quantization group is determined according to the division depth N of the current node and a first threshold T1. In this embodiment, the division depth N of the current node is determined as the QT depth of the current node.

If both condition one and condition two are true, determine that the area covered by the current quantization group is the area covered by the current node; where condition one is that the division depth N of the current node is less than or equal to the first threshold T1 The condition two is that the multi-type tree partition depth M of the current node is equal to zero.

Manner 5: The area covered by the current quantization group is determined according to the division depth N of the current node and a first threshold T1. In this embodiment, the division depth N of the current node is determined as the QT depth of the current node.

If both condition three and condition four are true, or if condition five is true, determine that the area covered by the current quantization group is the area covered by the current node; where condition three is that the division depth N of the current node is equal to The first threshold T1, the condition four is that the multi-type tree partition depth M of the current node is equal to 0, and the condition five is that the partition depth N of the current node is less than the first threshold T1.

Manner 6: The area covered by the current quantization group is determined according to the division depth N of the current node and a first threshold T1. In this embodiment, the division depth N of the current node is determined as the QT depth of the current node.

If both condition three and condition four are true, or if both condition five and condition six are true, determine that the area covered by the current quantization group is the area covered by the current node; where condition three is the current node's The partition depth N is equal to the first threshold T1, the condition four is that the multi-type tree partition depth M of the current node is equal to 0, the condition five is that the partition depth N of the current node is less than the first threshold T1, and the condition six is the multi-type tree of the current node The division depth M is less than or equal to the fourth threshold T4.

The fourth threshold T4 is a preset positive integer, for example, T4 may be 1, 2, or 3, and so on, and for example, T4 = T1-N.

Method 7: Determine the area covered by the current quantization group according to the division depth N of the current node and a first threshold T1. In this embodiment, the division depth N of the current node is determined as the QT depth of the current node.

If both condition one and condition seven are satisfied, it is determined that the area covered by the current quantization group is the area covered by the current node; wherein condition one is that the division depth N of the current node is less than or equal to the first threshold T1 , Condition 7 is that the multi-type tree partition depth M of the current node is less than or equal to T1-N.

Method 8: Determine the area covered by the current quantization group according to the division depth N of the current node, the division method of the current node, and the second threshold T2.

specifically:

1. If the division depth N of the current node is equal to the second threshold T2 minus 1, and the division mode of the current node is a tri-tree division manner, determine that the area covered by the current quantization group is the area covered by the current node. The area covered; or

2. If the division depth N of the current node is equal to a second threshold T2, and the division mode of the current node is a binary tree division mode or a quadtree division mode, determine that the area covered by the current quantization group is the current The area covered by the node; or

3. If the division depth of the current node is less than or equal to a second threshold, and the current node is no longer divided, determine that an area covered by the current quantization group is an area covered by the current node. In this case, the area covered by the current quantization group is the coverage area of one CU.

The second threshold value T2 is a preset positive integer. For example, the second threshold value T2 may be set to be X times the first threshold value T1, and X is an integer greater than 1, for example, X may be 2, 3, 4, or the like. You can also directly set T2 to 2, 3, 4, 6, 8, or 9 and so on.

The division depth N of the current node may be determined according to the QT depth of the current node and the binary tree division depth Db of the current node. For example, in one embodiment, N = Dq * 2 + Db, and in another embodiment, N = Dq + Db. Wherein, Dq is the QT depth of the current node.

Among them, since the MTT division can be a binary tree division, a tri-tree division, or a quad-tree division, under different division modes, the binary tree division depth Db of the current node can be determined in different ways. Specifically, the non-binary tree division needs to be divided. The partition depth is converted into a binary tree partition depth. For example, the conversion can be performed in the following manner:

If the current node is a MTT root node, the binary tree division depth Db of the current node is 0;

If the current node is an MTT node and the non-MTT root node (that is, the MTT depth of the current node is greater than 0), and if the current node is a child node obtained by binary tree division, the binary tree division depth Db of the current node is Describe the binary tree partition depth of the immediate parent of the current node plus 1;

If the current node is an MTT node and is not a MTT root node, and if the current node is an intermediate child node obtained through a tri-tree partition method (that is, a child node located in the middle among the three child nodes), the current node is a binary tree partition. The depth Db is the binary tree division depth of the immediate parent of the current node plus 1; or

If the current node is an MTT node and is not a MTT root node, and if the current node is a non-intermediate child node obtained by a tri-tree partition method, the binary tree division depth Db of the current node is a direct parent node of the current node The binary tree divides the depth plus 2.

It can be seen that the division depth determined in the manner of N = Dq * 2 + Db corresponds to the area of the node one by one. For example, when the CTU is 128x128, the division depth of the node is N, and the area of the node is (128x128) >> N .

Method Nine: Determine the area covered by the current quantization group according to the division depth N of the current node, the division method of the current node, and the second threshold T3.

specifically:

1. If the division depth N of the current node is equal to a third threshold T3 minus 1, and the division mode of the current node is a tri-tree division or a quad-tree division, determine that the area covered by the current quantization group is An area covered by the current node;

2. If the division depth N of the current node is equal to a third threshold T3, and the division manner of the current node is a binary tree division manner, determine that an area covered by the current quantization group is an area covered by the current node; or

3. If the division depth N of the current node is equal to a third threshold T3, and the current node is no longer divided, determine that an area covered by the current quantization group is an area covered by the current node. In this case, the area covered by the current quantization group is the coverage area of one CU.

The third threshold T3 may be a preset positive integer, for example, it may be 3, 4, or 5, and so on.

For a manner of determining the division depth N of the current node, refer to manner three.

903. Obtain a QP difference value of a current CU in an area covered by the current quantization group.

For specific implementation of this step, reference may be made to an existing implementation manner, for example, a CuQpDeltaVal manner in the HEVC standard may be referred to. More specifically, if the current CU is the first residual CU in the current QG, the QP difference value (for example, an absolute value and a sign) of the current CU is parsed from the code stream. If the current CU coding sequence is located after the first residual CU in the current QG, the QP differential value of the current CU is determined as the QP differential value of the first residual CU in the current QG. If the current CU coding order is before the first residual CU in the current QG, the QP differential value of the current CU is determined to be 0. Among them, at least one of the coded block flag (cbf) cbf_luma, cbf_cb, and cbf_cr of the current CU indicates that the current CU has a residual.

904. Obtain a reconstructed image of the current CU according to a QP difference value of the current CU.

For specific implementation of this step, reference may be made to an existing implementation manner, for example, a manner in the HEVC standard, and a manner in the H.264 / AVC standard, for example. For example, the inverse quantization coefficient of the current CU may be obtained according to the QP difference value of the current CU; the reconstruction residual block of the current CU is obtained according to the inverse quantization coefficient of the current CU; and then the reconstruction of the current CU The residual block obtains a reconstructed image of the current CU.

Specifically, the brightness QPA of the left adjacent position and the brightness QPB of the upper adjacent position may be obtained according to the coordinates of the upper left corner of the current quantization group, and the predicted brightness QP value of the current QG may be obtained from QPA and QPB. For specific implementation, refer to the method for calculating qP _{Y_PRED} in HEVC. Let the coordinates of the upper left corner of the current QG be Pqg = (xQg, yQg), the left adjacent position of the current QG is PA = (xQg-1, yQg), and the upper adjacent position is PB = (xQg, yQg-1). The brightness QP of the upper neighboring position is the brightness QP of the coding unit covering the upper neighboring position PB; if the upper neighboring position is unavailable (for example, the upper neighboring position is outside the current band or the upper neighboring position has not yet been reconstructed) Or when the upper neighboring position and the current block do not belong to the same block (Tile), the brightness QP of the upper neighboring position is set to the brightness QP of the last CU in the previous QG (such as qP _{Y_PREV} in the HEVC standard). Similarly, the brightness QP of the left neighboring position is the brightness QP of the coding unit covering the left neighboring position PA; if the left neighboring position is not available or the left neighboring position does not belong to the same block as the current block, the left phase The neighboring position luminance QP is set to the luminance QP of the last CU in the previous QG.

To obtain the current QG brightness QP prediction value from QPA and QPB, one of the following methods can be used:

Method 1: The average value of QPA and QPB is used as the brightness QP prediction value. This method is like the method in HEVC.

Method 2: The area of the current CU is R1, the area of the CU on the left adjacent position is R2, and the area of the CU on the upper adjacent position is R3; if max (R1, R2) / min (R1, R2) * Th <max (R1, R3) / min (R1, R3), then the brightness QP prediction value is set to QPA; max (R1, R2) / min (R1, R2)> max (R1, R3) / min (R1, R3) * Th, the brightness QP prediction value is set to QPB; otherwise, the brightness QP prediction value is set to the average of QPA and QPB. Where max (a, b) is the larger of a and b, min (a, b) is the smaller of a and b, and Th is a positive number greater than or equal to 1, for example, Th = 1, 2 or 4.

Since the calculation method of the brightness QP prediction values of all CUs in a QG is the same, as a simplified implementation, when decoding the first CU of a QG, the calculation process of the QG brightness QP prediction value is performed, and this The luminance QP prediction value is used for other CUs in the QG, thereby reducing calculations.

Then, the predicted value of the quantization parameter of the luminance block of the current QG and the QP delta value (QP delta) of the current CU are added to obtain the luminance QP of the current CU. Specifically, Qp _Y = ((qP _{Y_PRED} + CuQpDeltaVal + 52 + 2 * QpBdOffset _Y )% (52 + QpBdOffset _Y ))-QpBdOffset _Y , where qP _{Y_PRED} is the predicted value of the luminance block quantization parameter and CuQpDeltaVal is the QP difference of the current CU Value, QpBdOffsetY is a preset constant related to the luminance component bit width (eg, when the luminance component bit width is 8, QpBdOffsetY is 0; when the luminance component bit width is 10, QpBdOffsetY is 12).

Optionally, as an improved processing method, if the QP difference value of the first residual CU in the current QG is not equal to 0, the encoding order in the current QG is before the first residual CU. The brightness QP of all CUs is modified to the brightness QP of the first residual CU. That is, the QP difference values of all CUs in the current QG are set to the QP difference values of the current CU, and the QP values of all CUs in the current QG are set to the QP values of the current CU. The set QP value will be used for subsequent codec operations, such as deblocking filtering and QP prediction.

After obtaining the luminance QP and chrominance QP of the current CU, the transform coefficients of the current CU can be subjected to inverse quantization and inverse transform processing to obtain the residual image of the current CU.

Inter-prediction processing or intra-prediction processing is performed on the current CU according to the prediction mode of the current CU to obtain an inter-prediction image or an intra-prediction image of the current CU.

The residual image of the current CU is superimposed on the prediction image of the current CU to generate a reconstructed image of the current CU.

In one embodiment, after obtaining the luminance QP, the chrominance QP can also be obtained from the mapping relationship between the luminance QP and the chrominance QP and the offset value of the chrominance QP. The embodiment of the present invention does not limit the specific implementation manner.

Another embodiment of the present invention further provides a video decoder 30, including:

Entropy decoding unit 304 is configured to parse the coding tree partition information to obtain the current node determines the area covered by the current quantization group according to the current node's division depth N; obtain the QP difference of the current CU in the area covered by the current quantization group Value; determining the brightness QP of the current CU according to the QP difference value of the current CU.

In an implementation manner, determining the area covered by the current quantization group according to the division depth N of the current node includes determining coordinates of the upper left corner of the area covered by the current quantization group. After the coordinates of the upper left corner are determined, the specific area covered by the current quantization group can be determined. Therefore, in the following description, determining the area covered by the current quantization group can be understood as determining the coordinates of the upper left corner of the area covered by the current quantization group.

The inverse quantization unit 310 is configured to obtain an inverse quantization coefficient of the current CU according to the brightness QP of the current CU.

An inverse transform processing unit 312 is configured to obtain a reconstruction residual block of the current CU according to an inverse quantization coefficient of the current CU.

A reconstruction unit 314 is configured to obtain a reconstructed image of the current CU according to a reconstruction residual block of the current CU.

For specific implementation of the video decoder 30, reference may be made to the method described in FIG. 9, and details are not described herein again.

In an implementation manner, the division depth N of the current node is the quadtree division depth N of the current node; and the entropy decoding unit 304 is specifically configured to determine the current quantization according to the division depth N of the current node. The area covered by the group or the multi-type partition depth M of the current node determines the area covered by the current quantization group; if the N is greater than a first threshold T1 or the M is greater than 0, the current quantization group is The area covered is the area covered by the K-level quadtree node of the current node; where K is the smaller value of N and T1; the K-level quadtree node passes through from the coding tree unit CTU The nodes generated by K quadtree partitions include the quadtree nodes of the current node.

The K-layer quadtree node is the (M + N-K) -layer parent node of the current node.

In an implementation manner, the division depth N of the current node is the quadtree division depth N of the current node; the entropy decoding unit 304 is specifically configured to divide the depth N according to the quadtree division of the current node And the multi-type tree partition depth M of the current node determines the area covered by the current quantization group; if the N is less than or equal to a first threshold T1 and the M is equal to 0, the area covered by the current quantization group is The area is the area covered by the current node.

In an implementation manner, the division depth N of the current node is the quadtree division depth N of the current node; the entropy decoding unit 304 is specifically configured to divide the depth N according to the quadtree division of the current node Determine the area covered by the current quantization group or determine the area covered by the current quantization group according to the quad-tree partition depth N of the current node and the multi-type tree partition depth M of the current node; if the N Is equal to the first threshold T1, and M is 0, the area covered by the current quantization group is the area covered by the current node; or if N is less than the first threshold T1, the current quantization group covers The area is the area covered by the current node.

In an implementation manner, the division depth N of the current node is the quadtree division depth N of the current node; the entropy decoding unit 304 is specifically configured to divide the depth N according to the quadtree division of the current node And the multi-type tree partition depth M of the current node determines the area covered by the current quantization group; if the N is equal to a first threshold T1 and the M is equal to 0, the area covered by the current quantization group is The area covered by the current node; or if N is less than a first threshold T1 and M is less than or equal to a fourth threshold T4, the area covered by the current quantization group is the area covered by the current node .

In an implementation manner, the fourth threshold T4 may be a preset positive integer, for example, may be 1, 2, 3, or 4, and so on.

In an implementation manner, the fourth threshold may be determined according to the first threshold T1 and the quadtree partition depth N of the current node, and may be, for example, T4 = T1-N.

In an implementation manner, the division depth N of the current node is the quadtree division depth N of the current node; the entropy decoding unit 304 is specifically configured to divide the depth N according to the quadtree division of the current node And the multi-type tree partition depth M of the current node determines the area covered by the current quantization group; if N is less than or equal to a first threshold T1, and M is less than or equal to T1-N, the current quantization The area covered by the group is the area covered by the current node.

In an implementation manner, the entropy decoding unit 304 may be specifically configured to: if the current partition depth N of the current node is greater than a first threshold T1, obtain the (N-T1) -th level parent node of the current node; determine The area covered by the current quantization group is the area covered by the (N-T1) layer parent node.

In an implementation manner, the entropy decoding unit 304 may be specifically configured to: if the partition depth N of the current node is equal to a first threshold T1, determine that an area covered by the current quantization group is covered by the current node Area.

In an implementation manner, the division depth of the current node is the QT depth of the current node; or the division depth of the current node is the sum of the QT depth of the current node and the MTT depth of the current node.

In one embodiment, the first threshold T1 is 0, 1, 2, or 3.

In an implementation manner, the entropy decoding unit 304 may be further configured to obtain a division manner of the current node; if the division depth N of the current node is equal to a second threshold T2 minus 1, and the current node's The division method is a tri-tree division method, and it is determined that the area covered by the current quantization group is the area covered by the current node; or if the division depth N of the current node is equal to a second threshold T2, and the current node's The division manner is a binary tree division manner or a quadtree division manner, and it is determined that the area covered by the current quantization group is the area covered by the current node; or if the current node has a division depth less than or equal to a second threshold, And the current node is no longer divided, and it is determined that an area covered by the current quantization group is an area covered by the current node.

In one embodiment, the second threshold is 2, 3, 4, 6, 8, or 9.

In an implementation manner, the entropy decoding unit 304 may be further configured to obtain a division manner of the current node; if the division depth N of the current node is equal to a third threshold T3 minus 1, and the current node's The division method is a tri-tree division method or a quad-tree division method, and it is determined that the area covered by the current quantization group is the area covered by the current node; if the division depth N of the current node is equal to a third threshold T3, and The current node is partitioned in a binary tree, and it is determined that the area covered by the current quantization group is the area covered by the current node; or if the current node's partition depth N is equal to a third threshold T3, and When the current node is no longer divided, it is determined that an area covered by the current quantization group is an area covered by the current node.

In an embodiment, the third threshold may be 3, 4, or 5, and so on.

In an implementation manner, the entropy decoding unit 304 may be specifically configured to determine a partition depth N of the current node according to a QT depth of the current node and a binary tree partition depth Db of the current node.

In an implementation manner, the entropy decoding unit 304 may be specifically configured to determine the division depth N of the current node by using the following calculation formula: N = Dq * 2 + Db; where Dq is a value of the current node QT depth.

In one embodiment, if the current node is a MTT root node, the binary tree division depth Db of the current node is 0; if the current node is a MTT node and is not a MTT root node, if the current node is a pass For a child node obtained in a binary tree division mode, the binary tree division depth Db of the current node is the binary tree division depth of the immediate parent of the current node plus 1; if the current node is an MTT node and is not a MTT root node, if the The current node is an intermediate child node obtained through a tri-tree division method, and the binary tree division depth Db of the current node is the binary tree division depth of the immediate parent of the current node plus 1; or if the current node is an MTT node and is not For the MTT root node, if the current node is a non-intermediate child node obtained through a tri-tree partition, the binary tree partition depth Db of the current node is the binary tree partition depth of the immediate parent node of the current node plus two.

In an implementation manner, the entropy decoding unit 304 is further configured to: if the QP difference value of the first residual CU in the current quantization group is not equal to 0, then encode the encoding order in the current quantization group. The brightness QP of all CUs before the first residual CU is modified to the brightness QP of the first residual CU. Accordingly, if the current CU is a CU before the first residual CU in the current quantization group, the inverse quantization unit 310 is specifically configured to: according to the brightness of the first residual CU QP obtains the inverse quantization coefficient of the current CU.

An embodiment of the present invention further provides a video decoder, which includes an execution circuit for performing any one of the foregoing methods.

An embodiment of the present invention further provides a video decoder, including: at least one processor; and a non-volatile computer-readable storage medium coupled to the at least one processor, the non-volatile computer-readable storage The medium stores a computer program executable by the at least one processor, and when the computer program is executed by the at least one processor, causes the video decoder to perform any one of the methods described above.

An embodiment of the present invention further provides a computer-readable storage medium for storing a computer program executable by a processor, and when the computer program is executed by the at least one processor, performing any one of the foregoing methods. .

An embodiment of the present invention further provides a computer program, and when the computer program is executed, any one of the foregoing methods is performed.

In one or more examples, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored or transmitted as one or more instructions or code on a computer-readable medium and executed by a hardware-based processing unit. A computer-readable medium may include a computer-readable storage medium, which corresponds to a tangible medium such as a data storage medium or a communication medium including any medium that facilitates transfer of a computer program from one place to another according to a communication protocol . In this manner, computer-readable media generally may correspond to (1) tangible computer-readable storage media that is non-transitory, or (2) a communication medium such as a signal or carrier wave. A data storage medium may be any available medium that can be accessed by one or more computers or one or more processors to retrieve instructions, codes, and / or data structures used to implement the techniques described in this disclosure. The computer program product may include a computer-readable medium.

By way of example and not limitation, such computer-readable storage media may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, disk storage or other magnetic storage devices, flash memory, or may be used to store instructions or data structures Any other media that requires program code and is accessible by the computer. Also, any connection is properly termed a computer-readable medium. For example, if a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technology such as infrared, radio, and microwave is used to transmit instructions from a website, server, or other remote source, then Coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of the medium. It should be understood, however, that the computer-readable storage media and data storage media do not include connections, carrier waves, signals, or other temporary media, but are actually directed to non-transitory tangible storage media. As used herein, magnetic disks and compact discs include compact discs (CDs), laser discs, optical discs, digital versatile discs (DVDs), flexible discs and Blu-ray discs, where the discs are usually magnetic The data is reproduced, while the optical disk uses a laser to reproduce the data optically. Combinations of the above should also be included within the scope of computer-readable media.

The instructions may be executed by one or more processors, such as one or more digital signal processors (DSPs), general purpose microprocessors, application specific integrated circuits , ASIC), field programmable logic array (field programmable logic arrays, FPGA) or other equivalent integrated or discrete logic circuits. Accordingly, the term "processor" as used herein may refer to any of the above-described structures or any other structure suitable for implementing the techniques described herein. Additionally, in some aspects, the functionality described herein may be provided within dedicated hardware and / or software modules for encoding and decoding, or incorporated in a composite codec. Also, the techniques could be fully implemented in one or more circuits or logic elements.

The techniques of this disclosure may be implemented in a variety of devices or devices that include a wireless handset, an integrated circuit (IC), or a collection of ICs (eg, a chipset). The present disclosure describes various components, modules, or units to emphasize functional aspects of the device for performing the disclosed techniques, but does not necessarily need to be implemented by different hardware units. Specifically, as described above, the various units may be combined in a codec hardware unit in combination with suitable software and / or firmware, or provided by a collection of interoperable hardware units, which include as described above One or more processors.

Claims (39)

A video decoding method, comprising: Parse the coding tree partition information to obtain the current node; Determining the coordinates of the upper left corner of the area covered by the current quantization group according to the division depth N of the current node; Acquiring a quantization parameter QP difference value of a current coding unit CU in an area covered by the current quantization group; and Obtain a reconstructed image of the current CU according to the QP difference value of the current CU. The method according to claim 1, wherein the partition depth N of the current node is a quadtree partition depth N of the current node; The determining the coordinates of the upper left corner of the area covered by the current quantization group according to the division depth N of the current node includes: Determine the coordinates of the upper left corner of the area covered by the current quantization group according to the division depth N of the current node or determine the coordinates of the upper left corner of the area covered by the current quantization group according to the multi-type division depth M of the current node; If N is greater than the first threshold T1 or M is greater than 0, the coordinates of the upper left corner of the area covered by the current quantization group are the coordinates of the upper left corner of the area covered by the K-th level quadtree node of the current node; K is a smaller value of N and T1; the K-th level quadtree node is a quadtree node including the current node among the nodes generated by the quadtree partitioning K times from the coding tree unit CTU. The method according to claim 1, wherein the partition depth N of the current node is a quadtree partition depth N of the current node; The determining the coordinates of the upper left corner of the area covered by the current quantization group according to the division depth N of the current node includes: Determine the upper-left corner coordinates of the area covered by the current quantization group according to the quad-tree partition depth N of the current node and the multi-type tree partition depth M of the current node; if the N is less than or equal to a first threshold T1 And M is equal to 0, and the coordinates of the upper left corner of the area covered by the current quantization group are the coordinates of the upper left corner of the area covered by the current node. The method according to claim 1, wherein the partition depth N of the current node is a quadtree partition depth N of the current node; The determining the coordinates of the upper left corner of the area covered by the current quantization group according to the division depth N of the current node includes: Determine the coordinates of the upper left corner of the area covered by the current quantization group according to the quad tree partition depth N of the current node or the quad tree partition depth N of the current node and the multi-type tree partition depth of the current node M determines the coordinates of the upper left corner of the area covered by the current quantization group; if the N is equal to the first threshold T1 and M is 0, the coordinates of the upper left corner of the area covered by the current quantization group is the current The coordinates of the upper left corner of the area covered by the node; or if the N is less than the first threshold T1, the coordinates of the upper left corner of the area covered by the current quantization group are the coordinates of the upper left corner of the area covered by the current node. The method according to claim 1, wherein the division depth N of the current node is the quadtree division depth N of the current node; The determining the coordinates of the upper left corner of the area covered by the current quantization group according to the division depth N of the current node includes: Determine the upper-left corner coordinates of the area covered by the current quantization group according to the quad-tree partition depth N of the current node and the multi-type tree partition depth M of the current node; if the N is equal to a first threshold T1, and The M is equal to 0, and the coordinates of the upper left corner of the area covered by the current quantization group are the coordinates of the upper left corner of the area covered by the current node; It is equal to the fourth threshold T4, and the coordinates of the upper left corner of the area covered by the current quantization group are the coordinates of the upper left corner of the area covered by the current node. The method according to claim 1, wherein the partition depth N of the current node is a quadtree partition depth N of the current node; The determining the coordinates of the upper left corner of the area covered by the current quantization group according to the division depth N of the current node includes: Determine the upper-left corner coordinates of the area covered by the current quantization group according to the quad-tree partition depth N of the current node and the multi-type tree partition depth M of the current node; if the N is less than or equal to a first threshold T1 And M is less than or equal to T1-N, and the coordinates of the upper left corner of the area covered by the current quantization group are the coordinates of the upper left corner of the area covered by the current node. The method according to claim 1, wherein determining the coordinates of the upper left corner of the area covered by the current quantization group according to the division depth N of the current node comprises: If the division depth N of the current node is greater than a first threshold T1, obtaining a (N-T1) -layer parent node of the current node; It is determined that the coordinates of the upper left corner of the area covered by the current quantization group are the coordinates of the upper left corner of the area covered by the (N-T1) -layer parent node. The method according to claim 1, wherein determining the coordinates of the upper left corner of the area covered by the current quantization group according to the division depth N of the current node comprises: If the division depth N of the current node is equal to the first threshold T1, it is determined that the coordinates of the upper left corner of the area covered by the current quantization group are the coordinates of the upper left corner of the area covered by the current node. The method according to any one of claims 2 to 8, wherein the first threshold T1 is a non-negative integer set in advance. The method according to any one of claims 2-9, wherein the first threshold T1 is 0, 1, 2, or 3. The method according to any one of claims 7 to 10, wherein a partition depth of the current node is a quadtree partition depth QT depth of the current node. The method according to any one of claims 7 to 10, wherein a partition depth of the current node is a sum of a QT depth of the current node and a multi-type tree partition depth MTT of the current node. The method of claim 1, further comprising: Obtaining a division manner of the current node; The determining the coordinates of the upper left corner of the area covered by the current quantization group according to the division depth N of the current node includes: If the division depth N of the current node is equal to the second threshold T2 minus 1, and the division mode of the current node is a tri-tree division manner, it is determined that the upper-left corner coordinate of the area covered by the current quantization group is the current node. The coordinates of the upper-left corner of the area covered; or If the division depth N of the current node is equal to the second threshold T2, and the division mode of the current node is a binary tree division mode or a quadtree division mode, it is determined that the coordinates of the upper left corner of the area covered by the current quantization group The coordinates of the upper left corner of the area covered by the current node. The method of claim 1, further comprising: Obtaining a division manner of the current node; The determining the coordinates of the upper left corner of the area covered by the current quantization group according to the division depth N of the current node includes: If the current partition depth N of the current node is equal to the third threshold T3 minus 1, and the current node is divided into a tri-tree or quad-tree, determine the upper left corner of the area covered by the current quantization group. The coordinates are the coordinates of the upper left corner of the area covered by the current node; or If the division depth N of the current node is equal to a third threshold T3, and the division manner of the current node is a binary tree division manner, it is determined that the coordinates of the upper left corner of the area covered by the current quantization group are covered by the current node. The coordinates of the upper-left corner of the area. The method according to claim 13 or 14, wherein the division depth N of the current node is determined according to the QT depth of the current node and the binary tree division depth Db of the current node. The method according to claim 15, wherein the division depth N of the current node is determined using the following calculation formula: N = Dq * 2 + Db; The Dq is the QT depth of the current node. The method according to claim 15 or 16, wherein if the current node is a multi-type tree MTT partition root node, the binary tree partition depth Db of the current node is 0; If the current node is an MTT node and is not a MTT root node, and if the current node is a child node obtained by binary tree partitioning, the binary tree partition depth Db of the current node is the binary tree partition of the immediate parent of the current node Add 1 to the depth If the current node is an MTT node and is not a MTT root node, and if the current node is an intermediate child node obtained by a tri-tree partition, the binary tree division depth Db of the current node is a direct parent node of the current node. Binary tree partition depth plus 1; or If the current node is an MTT node and is not a MTT root node, and if the current node is a non-intermediate child node obtained by a tri-tree partition method, the binary tree division depth Db of the current node is a direct parent node of the current node The binary tree divides the depth plus 2. The method according to any one of claims 1 to 17, wherein if the QP difference value of the first residual CU in the current quantization group is not equal to 0, the coding order in the current quantization group is Modify the brightness QP of all CUs before the first residual CU to the brightness QP of the first residual CU; If the current CU is a CU before the first residual CU in the current quantization group, obtaining the reconstructed image of the current CU according to the QP difference value of the current CU is specifically: A reconstructed image of the current CU is obtained according to the brightness QP of the first residual CU. A video decoder, comprising: An entropy decoding unit, configured to parse the coding tree partition information to obtain the current node; determine the upper left coordinate of the area covered by the current quantization group according to the current node's division depth N; obtain the upper left corner of the area covered by the current quantization group The quantization parameter QP difference value of the current coding unit CU in angular coordinates; determining the brightness QP of the current CU according to the QP difference value of the current CU; An inverse quantization unit, configured to obtain an inverse quantization coefficient of the current CU according to the brightness QP of the current CU; An inverse transform processing unit, configured to obtain a reconstructed residual block of the current CU according to an inverse quantization coefficient of the current CU; and A reconstruction unit, configured to obtain a reconstructed image of the current CU according to a reconstruction residual block of the current CU. The video decoder according to claim 19, wherein the partition depth N of the current node is a quadtree partition depth N of the current node; The entropy decoding unit is specifically configured to determine the coordinates of the upper left corner of the area covered by the current quantization group according to the division depth N of the current node or determine the coverage of the current quantization group according to the multi-type division depth M of the current node. Coordinates of the upper left corner of the region; if the N is greater than the first threshold T1 or the M is greater than 0, the coordinates of the upper left corner of the region covered by the current quantization group are determined by the K-th level quadtree node of the current node Coordinates of the upper left corner of the area covered; where K is the smaller value of N and T1; the K-th level quadtree node is the node generated by the quadtree partition K times from the encoding tree unit CTU, including the current node Quadtree nodes. The video decoder according to claim 19, wherein the partition depth N of the current node is a quadtree partition depth N of the current node; The entropy decoding unit is specifically configured to determine the coordinates of the upper-left corner of the area covered by the current quantization group according to the quad-tree partition depth N of the current node and the multi-type tree partition depth M of the current node; N is less than or equal to the first threshold T1, and M is 0, and the coordinates of the upper left corner of the area covered by the current quantization group are the coordinates of the upper left corner of the area covered by the current node. The video decoder according to claim 19, wherein the partition depth N of the current node is a quadtree partition depth N of the current node; The entropy decoding unit is specifically configured to determine the upper left corner coordinate of the area covered by the current quantization group according to the quadtree partition depth N of the current node or the quadtree partition depth N and The multi-type tree partitioning depth M of the current node determines the upper-left corner coordinates of the area covered by the current quantization group; if the N is equal to the first threshold T1 and the M is 0, the The coordinates of the upper left corner of the region are the coordinates of the upper left corner of the region covered by the current node; or if the N is less than the first threshold T1, the coordinates of the upper left corner of the region covered by the current quantization group are covered by the current node The coordinates of the upper-left corner of the area. The video decoder according to claim 19, wherein the partition depth N of the current node is a quadtree partition depth N of the current node; The entropy decoding unit is specifically configured to determine the coordinates of the upper-left corner of the area covered by the current quantization group according to the quad-tree partition depth N of the current node and the multi-type tree partition depth M of the current node; N is equal to the first threshold T1, and M is 0, and the upper left corner coordinate of the area covered by the current quantization group is the upper left corner coordinate of the area covered by the current node; or if N is smaller than the first The threshold T1, and M is less than or equal to the fourth threshold T4, and the coordinates of the upper left corner of the area covered by the current quantization group are the coordinates of the upper left corner of the area covered by the current node. The video decoder according to claim 19, wherein the partition depth N of the current node is a quadtree partition depth N of the current node; The entropy decoding unit is specifically configured to determine the coordinates of the upper-left corner of the area covered by the current quantization group according to the quad-tree partition depth N of the current node and the multi-type tree partition depth M of the current node; Where N is less than or equal to the first threshold T1, and M is less than or equal to T1-N, the coordinates of the upper left corner of the area covered by the current quantization group are the coordinates of the upper left corner of the area covered by the current node. The video decoder according to claim 19, wherein the entropy decoding unit is specifically configured to: If the division depth N of the current node is greater than a first threshold T1, obtaining a (N-T1) -layer parent node of the current node; It is determined that the coordinates of the upper left corner of the area covered by the current quantization group are the coordinates of the upper left corner of the area covered by the (N-T1) -layer parent node. The video decoder according to claim 19, wherein the entropy decoding unit is specifically configured to: If the division depth N of the current node is equal to the first threshold T1, it is determined that the coordinates of the upper left corner of the area covered by the current quantization group are the coordinates of the upper left corner of the area covered by the current node. The video decoder according to any one of claims 20 to 26, wherein the first threshold T1 is a non-negative integer set in advance. The video decoder according to any one of claims 20 to 27, wherein the first threshold T1 is 0, 1, 2, or 3. The video decoder according to any one of claims 25 to 28, wherein a partition depth of the current node is a quad-tree partition depth QT depth of the current node. The video decoder according to any one of claims 25 to 28, wherein the partition depth of the current node is the sum of the QT depth of the current node and the multi-type tree partition depth MTT of the current node. The video decoder according to claim 19, wherein the entropy decoding unit is further configured to obtain a division manner of the current node; If the division depth N of the current node is equal to the second threshold T2 minus 1, and the division mode of the current node is a tri-tree division manner, it is determined that the upper-left corner coordinate of the area covered by the current quantization group is the current node. The coordinates of the upper-left corner of the area covered; or If the division depth N of the current node is equal to the second threshold T2, and the division mode of the current node is a binary tree division mode or a quadtree division mode, it is determined that the coordinates of the upper left corner of the area covered by the current quantization group The coordinates of the upper left corner of the area covered by the current node. The video decoder according to claim 19, wherein the entropy decoding unit is further configured to obtain a division manner of the current node; If the current partition depth N of the current node is equal to the third threshold T3 minus 1, and the current node is divided into a tri-tree or quad-tree, determine the upper left corner of the area covered by the current quantization group. The coordinates are the coordinates of the upper left corner of the area covered by the current node; If the division depth N of the current node is equal to a third threshold T3, and the division manner of the current node is a binary tree division manner, it is determined that the coordinates of the upper left corner of the area covered by the current quantization group are covered by the current node. The coordinates of the upper-left corner of the area. The video decoder according to claim 31 or 32, wherein the entropy decoding unit is specifically configured to determine the current node's QT depth according to the current node's QT depth and the binary tree partition depth Db of the current node. Divide the depth N. The video decoder according to claim 33, wherein the entropy decoding unit is specifically configured to: The following calculation formula is used to determine the division depth N of the current node: N = Dq * 2 + Db; The Dq is the QT depth of the current node. The video decoder according to claim 33 or 34, wherein if the current node is a multi-type tree MTT partition root node, the binary tree partition depth Db of the current node is 0; If the current node is an MTT node and is not a MTT root node, and if the current node is a child node obtained by binary tree partitioning, the binary tree partition depth Db of the current node is the binary tree partition of the immediate parent of the current node Add 1 to the depth If the current node is an MTT node and is not a MTT root node, and if the current node is an intermediate child node obtained by a tri-tree partition, the binary tree division depth Db of the current node is a direct parent node of the current node. Binary tree partition depth plus 1; or If the current node is an MTT node and is not a MTT root node, and if the current node is a non-intermediate child node obtained by a tri-tree partition method, the binary tree division depth Db of the current node is a direct parent node of the current node The binary tree divides the depth plus 2. The video decoder according to any one of claims 19 to 35, wherein the entropy decoding unit is further configured to: if the QP difference value of the first residual CU in the current quantization group is not equal to 0 , Modify the luminance QP of all CUs in the current quantization group whose coding order is before the first residual CU to the luminance QP of the first residual CU; If the current CU is a CU before the first residual CU in the current quantization group, the inverse quantization unit is specifically configured to obtain the CU according to the brightness QP of the first residual CU The inverse quantization coefficient of the current CU. A video decoder, comprising an execution circuit for performing the method according to any one of claims 1 to 18. A video decoder, comprising: At least one processor; and A non-volatile computer-readable storage medium coupled to the at least one processor, the non-volatile computer-readable storage medium storing a computer program executable by the at least one processor, and when the computer program When executed by the at least one processor, the video decoder is caused to perform the method according to any one of claims 1 to 18. A computer-readable storage medium for storing a computer program executable by a processor, and when the computer program is executed by the at least one processor, the method according to any one of claims 1 to 18 is executed.

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