WO2013056577A1 - Intra-frame prediction mode encoder and decoder, method thereof, and electronic device - Google Patents

Abstract

An intra-frame prediction mode encoder and decoder, a method thereof, and an electronic device. The encoding method comprises: according to availability of an intra-frame prediction reference pixel point in a block adjacent to a current block, removing, from all intra-frame prediction modes, an intra-frame prediction mode not used definitely by the current block in an encoding process, to obtain available intra-frame prediction modes; allocating index numbers to the available intra-frame prediction modes, and generating a mapping code table of the index numbers and code words; encoding the intra-frame prediction modes of the current block according to the generated mapping code table. Through the technical solution, the intra-frame prediction mode not used definitely is removed according to the availability of the reference pixel point in the adjacent block, thereby reducing the overhead of encoding the intra-frame prediction modes.

Description

 Intra prediction mode encoder, decoder, method and electronic device thereof

Technical field

 The present invention relates to the field of video communication technologies, and in particular, to an intra prediction mode encoder, a decoder, a method thereof, and an electronic device.

Background technique

 With the development of network technology and the growing demand for multimedia services, video communication is gradually becoming one of the main services of digital communication networks. In order to efficiently transmit video data over the network, it is often necessary to compress and encode the video.

 Currently, there are two main international organization groups for developing video coding standards: the International Telecommunication Union Telecommunication Standards (ITU-T, ITU Telecommunication Standardization Sector) and the International Organization for Standardization/International Electrotechnical Commission (ISO/IEC). H.264/AVC was developed in cooperation with these two standardization organizations. The purpose is to adapt to the ever-increasing demands of various business services for the compression ratio of moving images, and to enable the encoded video data to be used in various network environments. transmission.

 The intra prediction technique used by H.264/AVC can effectively improve the intra prediction coding efficiency. Among them, 16x16 blocks use 4 intra prediction modes, and 8x8 blocks and 4x4 blocks use 9 intra prediction modes. Among them, the four intra prediction modes of the 16x16 block use 2 bits for the equal length coding. The intra prediction direction coding of 8x8 blocks and 4x4 blocks uses the following method:

 Step 1: Obtain the most probable prediction mode (MPM) of the current block according to the intra prediction direction of the neighboring block.

Most Probable Mode ).

 Step 2: If the current block uses the same intra prediction mode as the MPM, use the 1 bit flag to identify "the current block uses the intra prediction mode of the MPM" and the encoding process ends; otherwise, skip to step 3.

 Step 3: Encode a 1-bit flag that identifies "the current block does not use MPM's intra prediction mode".

Step 4: Remove the MPM from the intra prediction mode list, then sort the remaining intra prediction modes and assign equal length code words to each mode, and correspond to the currently used intra prediction mode. The code word is written to the code stream and the encoding process ends. According to the related art, intra prediction calculates an intra prediction value of each pixel point in a current block using a restored value of a coded pixel point in a neighboring block. If some of the reference pixels in the neighboring block are not available, some of the corresponding intra prediction modes will inevitably not be used. For example, if adjacent pixels on a boundary are not available, the intra prediction mode using adjacent pixels on the boundary will not be used. However, in the related art, in the intra prediction coding, a mapping code table is generated for all intra prediction modes except for all or MPM, and is encoded, which results in a large coding overhead.

Summary of the invention

 The technical problem to be solved by the embodiments of the present invention is to provide an intra prediction mode encoder, a decoder, a method thereof, and an electronic device, which remove a prediction mode that is inevitably unavailable according to the availability of reference pixels of neighboring blocks, thereby reducing intra prediction. Mode encoding overhead.

 In order to solve the above technical problem, the following technical solutions are used in the embodiment of the present invention:

 An intra prediction mode coding method, the method comprising:

 According to the availability of the intra-predicted reference pixel in the neighboring block of the current block, the intra prediction mode that the current block is inevitably used in the encoding process is removed from all the intra prediction modes, and the available intra prediction mode is obtained;

 Allocating an index number to an available intra prediction mode, and generating a mapping code table between the index number and the code word;

 The intra prediction mode of the current block is encoded according to the generated mapping code table.

 Optionally, according to the availability of the intra-predicted reference pixel in the neighboring block of the current block, the intra prediction mode that the current block is inevitably not used in the encoding process is removed from all the intra prediction modes, and the available intra prediction is obtained. The steps of the pattern include:

When the neighboring block uses the restricted intra prediction mode, if the block in which the intra prediction reference pixel is located uses a non-intra prediction mode, or the intra prediction reference pixel is not in the same slice as the current block, Or if the intra prediction reference pixel does not exist, it is determined that the intra prediction reference pixel is not available; when the neighboring block does not use the restricted intra prediction mode, if the intra prediction reference pixel is not the same as the current block If the slice or the intra prediction reference pixel does not exist, then the intra prediction parameter is determined. The test pixel is not available.

 Optionally, the case where the intra prediction reference pixel does not exist includes: the current block is located at an image boundary.

An intra prediction mode decoding method, the method comprising:

 According to the availability of the intra-predicted reference pixel in the neighboring block of the current block, the intra prediction mode that the current block is inevitably used in the encoding process is removed from all the intra prediction modes, and the available intra prediction mode is obtained;

 Allocating an index sequence number to the available intra prediction mode, and generating a mapping code table between the index sequence number and the codeword;

 Determining, according to the generated mapping code table, an input codeword into an intra prediction mode index sequence, and determining an intra prediction mode used by the current block;

 The current block is decoded according to the determined intra prediction mode.

 Optionally, according to the availability of the intra-predicted reference pixel in the neighboring block of the current block, the intra prediction mode that the current block is inevitably not used in the encoding process is removed from all the intra prediction modes, and the available intra prediction is obtained. The steps of the pattern include:

 When the neighboring block uses the restricted intra prediction mode, if the block in which the intra prediction reference pixel is located uses a non-intra prediction mode, or the intra prediction reference pixel is not in the same slice as the current block, Or if the intra prediction reference pixel does not exist, it is determined that the intra prediction reference pixel is not available; when the neighboring block does not use the restricted intra prediction mode, if the intra prediction reference pixel is not the same as the current block If the slice, or the intra prediction reference pixel does not exist, it is determined that the intra prediction reference pixel is not available.

An encoder, the encoder includes a determining module, a generating module, and an encoding module, where: the determining module is configured to: determine, according to the availability of an intra-predicted reference pixel in a neighboring block, that the current block encoding process is inevitably Intra prediction mode used;

The generating module is configured to: according to the current block encoding process determined by the determining module However, the intra prediction mode that is not used removes the intra prediction mode that the current block must not use during the encoding process from all intra prediction modes, obtains an available intra prediction mode, and assigns an index number to the available intra prediction mode, and Generating a mapping code table between the index number and the codeword;

 The encoding module is configured to: encode the current block intra prediction mode according to the mapping code table generated by the generating module.

 Optionally, the determining module is configured to determine an intra prediction mode that is inevitably not used in the current block coding process according to the availability of the intra prediction reference pixel in the neighboring block in the following manner:

 When the neighboring block uses the restricted intra prediction mode, if the block in which the intra prediction reference pixel is located uses the non-intra prediction mode, or the intra prediction reference pixel is not in the same slice or frame as the current block, Determining that the reference pixel is not present, determining that the intra prediction reference pixel is not available;

 When the neighboring block does not use the restricted intra prediction mode, if the intra prediction reference pixel is not in the same slice as the current block, or the intra prediction reference pixel does not exist, the intra prediction reference pixel is determined. The point is not available.

A decoder, the decoder comprising a determining unit, a generating unit, a first decoding unit and a second decoding unit, wherein: the determining unit is configured to: determine according to availability of intra prediction reference pixel points in neighboring blocks An intra prediction mode that is inevitably not used in the current block encoding process;

 The generating unit is configured to: remove, according to the intra prediction mode that is not used in the current block coding process determined by the determining module, the intra prediction that the current block is inevitably not used in the encoding process from all the intra prediction modes. a mode, obtaining an available intra prediction mode, assigning an index number to an available intra prediction mode, and generating a mapping code table between the index number and the code word;

 The first decoding unit is configured to: convert the input codeword into an intra prediction mode index sequence according to the mapping code table generated by the generating unit, and determine an intra prediction mode used by the current block; the second decoding unit Set to: decode the current block according to the determined intra prediction mode.

Optionally, the determining unit is configured to determine an intra prediction mode that is inevitably not used in the current block coding process according to the availability of the intra prediction reference pixel in the neighboring block in the following manner: When the neighboring block uses the restricted intra prediction mode, if the block in which the intra prediction reference pixel is located uses the non-intra prediction mode, or the intra prediction reference pixel is not in the same slice or frame as the current block, Determining that the reference pixel is not present, determining that the intra prediction reference pixel is not available;

 When the neighboring block does not use the restricted intra prediction mode, if the intra prediction reference pixel is not in the same slice as the current block, or the intra prediction reference pixel does not exist, the intra prediction reference pixel is determined. The point is not available.

An electronic device comprising: any of the encoders described above, and/or any of the decoders described above.

In the embodiment of the present invention, according to the availability of reference pixel points in the current prediction block neighboring block, the intra prediction mode that is inevitably unavailable is removed from all intra prediction modes, the prediction mode index table is cropped, and the prediction mode index sequence number is adjusted. The prediction mode index number is encoded by using the unequal length code, thereby reducing the intra prediction mode coding overhead.

BRIEF abstract

 The drawings are intended to provide a further understanding of the invention, and are intended to be illustrative of the invention. In the drawing:

 1 is a schematic flowchart of an intra prediction mode encoding method according to an embodiment of the present invention; FIG. 2 is a schematic flowchart of an intra prediction mode decoding method according to an embodiment of the present invention; and FIG. 3 is a schematic diagram of an intra prediction mode of a 16x16 block;

 Figure 4 is a schematic diagram of the intra prediction modes of 8x8 blocks and 4x4 blocks. Preferred embodiment of the invention

The present embodiment provides an intra prediction mode coding method, which uses the following technical solution: According to the availability of intra prediction reference pixel points in neighboring blocks of the current block, all intra prediction is performed. In the mode, the intra prediction mode that the current block is inevitably not used in the encoding process is removed, and the available intra prediction mode is obtained;

 Allocating an index sequence number to the available intra prediction mode, and generating a mapping code table between the index sequence number and the codeword;

 The current block intra prediction mode is encoded according to the generated mapping code table.

 Optionally, determining the availability of the intra prediction reference pixel in the following manner: the neighboring block uses a restricted intra prediction mode (refer to an encoding mode of a reference block where an intra prediction reference pixel is located must be a specified frame) Intra prediction mode) (PPS::constrained_intra_pred_flag value is 1), if the block in which the intra prediction reference pixel is located uses a non-intra prediction mode (such as inter prediction mode, etc.), or an intra prediction reference pixel Determining that the intra prediction reference pixel is not available, if the current block is not in the same slice, or the intra prediction reference pixel does not exist (as in the case where the current block is located at the image boundary);

 When the neighboring block does not use the restricted intra prediction mode (PPS::constrained_intra_pred_flag value is 0), if the intra prediction reference pixel is not in the same slice as the current block, or the intra prediction reference If the pixel does not exist (as in the case where the current block is located at the edge of the image), it is determined that the intra-predicted reference pixel is not available.

 In addition, the embodiment further provides an intra prediction mode decoding method, which uses the following technical solutions:

 According to the availability of the intra-predicted reference pixel in the neighboring block of the current block, the intra prediction mode that the current block is inevitably used in the encoding process is removed from all the intra prediction modes, and the available intra prediction mode is obtained;

 Allocating an index sequence number to the available intra prediction mode, and generating a mapping code table between the index sequence number and the codeword;

 Determining, according to the generated mapping code table, an input codeword into an intra prediction mode index sequence, and determining an intra prediction mode used by the current block;

 The current block is decoded according to the determined intra prediction mode.

In order to make the objects, technical solutions and advantages of the present invention more clear, the following will be combined with the accompanying drawings. The embodiments of the present invention will be described in detail. It should be noted that, in the case of no conflict, the features in the embodiments and the embodiments in the present application may be arbitrarily combined with each other.

 Embodiment 1

 As shown in FIG. 1, the intra prediction mode coding method in this embodiment mainly includes the following steps: Step 1: Determine the availability of intra prediction reference pixel points in adjacent blocks;

 Step 2: removing an intra prediction mode that is inevitably not used according to the availability of the intra prediction reference pixel;

 According to the determined unavailable intra prediction reference pixel, the intra prediction mode that is inevitably not used in the encoding process can be obtained according to the relevant standard protocol.

 Step 3: assign an index sequence number to the available intra prediction mode, and generate a mapping code table between the index sequence number and the codeword;

 Step 4: encode the current block intra prediction mode according to the generated mapping code table.

Embodiment 2

 As shown in FIG. 2, the intra prediction mode decoding method in this embodiment mainly includes the following steps: Step 1: Determine the availability of an intra prediction reference pixel in a neighboring block;

 Step 2: removing an intra prediction mode that is inevitably not used according to the availability of the intra prediction reference pixel;

 Step 3: assign an index sequence number to the available intra prediction mode, and generate a mapping code table between the index sequence number and the codeword;

 Step 4: Convert the input codeword into an intra prediction mode index number according to the generated mapping code table, and determine an intra prediction mode used by the current block.

 Step 5: Decode the current block according to the determined intra prediction mode.

Embodiment 3

The embodiment provides an encoder, where the encoder includes: a determining module, a generating module, and an encoding module, where The determining module is configured to: determine, according to availability of intra prediction reference pixel points in the neighboring block, an intra prediction mode that is inevitably not used in the current block encoding process;

 The generating module is configured to: remove, according to the intra prediction mode that is not used in the current block coding process determined by the determining module, from all the intra prediction modes, remove the intra prediction that the current block is inevitably not used in the encoding process. Mode, obtaining an available intra prediction mode, assigning an index number to an available intra prediction mode, and generating a mapping code table between the index number and the code word;

 The encoding module is configured to: encode the current block intra prediction mode according to the mapping code table generated by the generating module.

 Optionally, the determining module is configured to determine the availability of the intra prediction reference pixel in the following manner:

 When the neighboring block uses the restricted intra prediction mode, if the block in which the intra prediction reference pixel is located uses the non-intra prediction mode, or the intra prediction reference pixel is not in the same slice or frame as the current block, Determining that the reference pixel is not present, determining that the intra prediction reference pixel is not available;

 When the neighboring block does not use the restricted intra prediction mode, if the intra prediction reference pixel is not in the same slice as the current block, or the intra prediction reference pixel does not exist, the intra prediction reference pixel is determined. The point is not available.

Embodiment 4

 The present embodiment provides a decoder, where the decoder includes: a determining unit, a generating unit, a first decoding unit, and a second decoding unit, where

 The determining unit is configured to: determine an intra prediction mode that is inevitably not used in the current block encoding process according to availability of intra prediction reference pixel points in the neighboring block;

 The generating unit is configured to: remove, according to the intra prediction mode that is not used in the current block coding process determined by the determining module, the intra prediction that the current block is inevitably not used in the encoding process from all the intra prediction modes. a mode, obtaining an available intra prediction mode, assigning an index number to an available intra prediction mode, and generating a mapping code table between the index number and the code word;

The first decoding unit is configured to: convert the input codeword into an intra prediction mode index sequence according to the mapping code table generated by the generating unit, and determine an intra prediction mode used by the current block; The second decoding unit is configured to: decode the current block according to the determined intra prediction mode.

 Optionally, the determining unit is configured to determine the availability of the intra prediction reference pixel in the following manner:

 When the neighboring block uses the restricted intra prediction mode, if the block in which the intra prediction reference pixel is located uses the non-intra prediction mode, or the intra prediction reference pixel is not in the same slice or frame as the current block, Determining that the reference pixel is not present, determining that the intra prediction reference pixel is not available;

 When the neighboring block does not use the restricted intra prediction mode, if the intra prediction reference pixel is not in the same slice as the current block, or the intra prediction reference pixel does not exist, the intra prediction reference pixel is determined. The point is not available.

Embodiment 5

 The embodiment provides an electronic device, where the electronic device includes an encoder in a transmitting end, and the encoder can encode an intra prediction mode by using a specific implementation process in the foregoing Embodiment 1, and the specific composition can be implemented by using the foregoing implementation. The description in the third example will not be repeated here.

 The electronic device may further include a decoder in the receiving end, and the decoding is implemented according to the method provided in the foregoing embodiment. The specific composition of the decoder may be described in the foregoing Embodiment 4, and details are not described herein again. .

 The electronic device of this embodiment may be a related code stream generating device and a receiving and playing device in a video communication application, for example, a mobile phone, a computer, a server, a set top box, a portable mobile terminal, a digital television, a digital camera, and the like.

 It should be noted that the sending end is configured to: send video information, and the receiving end is configured to: receive video information. The above embodiments may be used arbitrarily in combination or separately.

The implementation of the technical solution of the present invention will be further described in detail below for three specific manners of 16x16 block, 8x8 block and 4x4 block, respectively, in combination with several application examples.

Application example one This example mainly describes the intra prediction mode coding method of 16x16 blocks. The encoding process is as follows: As shown in Figure 3, there are four 16x16 intra prediction modes: 0 (Vertical), 1 (Horizontal), 2 (DC), 3 ( Plane ).

 If both pixels in H and V are available, the existing intra prediction mode coding method of H.264/AVC is used.

 If the H pixel is not available and the V pixel is available, the original mode 0 and mode 3 are inevitably unavailable. The intra mode code code table is as shown in Table 1 below:

 Table 1

 If the H pixel is available and the V pixel is not available, the original mode 1 and mode 3 are inevitably unavailable. The intra mode code code table is as shown in Table 2 below:

 Table 2

 If neither H pixel nor V pixel is available, only DC mode is available. In this case, if the macroblock uses intra prediction coding, the DC mode is inevitably used, so the intra prediction mode information may not be encoded.

 The encoder determines the used mapping code table according to the above situation, and encodes the intra prediction mode.

Application example two

 This example mainly describes the intra-pre-measurement mode coding method of 8x8 block and 4x4 block. The encoding process is as follows:

As shown in Figure 4, there are 9 16x16 intra prediction modes: 0 (Vertical), 1 (Horizontal), 2 ( DC ), 3 ( diagonal down-left ), 4 ( diagonal down-right ), 5 ( Vertical-right ), 6 ( Horizontal-down ), 7 ( Vertical-left ), 8 ( Horizontal-up ).

 Since the 8x8 intra prediction mode is the same as the intra prediction direction corresponding to the nine prediction modes used in the 4x4 intra prediction mode, 4x4 intra prediction is taken as an example here. The 8x8 intra prediction method is the same.

 Referring to FIG. 4, the pixel points eight, B, C, D, E, F, G, H, and M in the figure are referred to as upper adjacent intra prediction reference pixel points (referred to as "upper adjacent"), and pixels Points I, J, K, and L are called left adjacent intra prediction reference pixels (referred to as "left adjacent").

 If both upper and left neighbors are available, the existing intra prediction mode coding method of H.264/AVC is used.

 If the upper neighbor is unavailable and the left neighbor is available, the original mode 0, mode 3, mode 4, mode 5, mode 6, and mode 7 are inevitably unavailable. The intra mode code table is as shown in Table 3 below:

 table 3

 If the upper neighbor is available and the left neighbor is unavailable, the original mode 1, mode 4, mode 5, mode 6, and mode 8 are inevitably unavailable. When the unequal length encoding is used, the intra mode code table can be as shown in Table 4 below. : Table 4

 Or use equal length coding, the intra mode code table is as shown in Table 5 below:

table 5 Mode Mode Index Codeword

 Vertical 0 00

 DC 1 01

Diagonal Down-Left 2 10

 Vertical Left 3 11 If neither H pixels nor V pixels are available, only DC mode is available. In this case, if the macroblock uses intra prediction coding, the DC mode is inevitably used, so the intra prediction mode information may not be encoded.

 The encoder determines the used code table according to the above situation, and encodes the intra prediction mode.

Application example three

 This example mainly describes the intra-pre-measurement mode decoding method of 16x16 blocks. The decoding process is as follows: With reference to Figure 3, if both pixels in H and V are available, the existing intra prediction mode coding method of H.264/AVC is used.

 If the H pixel is not available and the V pixel is available, the original mode 0 and mode 3 are inevitably unavailable. The intra mode code code table is as shown in Table 6 below:

 Table 6

 If H pixel is available and V pixel is not available, the original mode 1 and mode 3 are inevitably unavailable. The intra mode code code table is shown in Table 7 below:

 Table 7

If neither H pixel nor V pixel is available, only DC mode is available. In this case, if the macroblock With intra prediction coding, the DC mode is inevitably used, so the intra prediction mode information may not be encoded.

 The decoder determines the used code table according to the above situation, maps the codeword obtained by analyzing the code stream into an intra mode index number, and further obtains the used intra mode according to the code table mapping. The decoder encodes the current block according to the resulting intra mode.

Application example four

 This example mainly describes the intra-pre-measurement mode decoding method for 8x8 and 4x4 blocks. Since the 8x8 intra prediction mode is the same as the intra prediction direction corresponding to the 9 prediction modes used in the 4x4 intra prediction mode, here, 4x4 The intra prediction is taken as an example to illustrate the decoding method of the intra mode. The intra mode decoding method of 8x8 intra prediction is the same. The decoding process is as follows:

 Referring to Fig. 4, if both the upper adjacent and the left adjacent are available, the existing intra prediction mode encoding method of H.264/AVC is used.

 If the upper neighbor is unavailable and the left neighbor is available, the original mode 0, mode 3, mode 4, mode 5, mode 6, and mode 7 are inevitably unavailable. The intra mode code table is as shown in Table 8 below:

 Table 8

 If the upper neighbor is available and the left neighbor is unavailable, the original mode 1, mode 4, mode 5, mode 6, and mode 8 are inevitably unavailable. When the unequal length encoding is used, the intra mode code table can be as shown in Table 9 below. : Table 9

 Or use the same length coding method, the intra mode code code table is as shown in Table 10 below:

 Table 10

 Mode Mode Index Codeword

 Vertical 0 00

DC 1 01

Diagonal Down-Left 2 10

 Vertical Left 3 11 If neither H pixels nor V pixels are available, only DC mode is available. In this case, if the macroblock uses intra prediction coding, the DC mode is inevitably used, so the intra prediction mode information may not be encoded.

 The decoder determines the used code table according to the above situation, maps the codeword obtained by analyzing the code stream into an intra mode index number, and further obtains the used intra mode according to the code table mapping. The decoder encodes the current block according to the resulting intra mode.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention. The present invention may be embodied in various other embodiments without departing from the spirit and scope of the invention. Various changes and modifications may be made to the invention, and such changes and modifications are intended to be included within the scope of the appended claims.

Obviously, those skilled in the art should understand that the above modules or steps of the present invention can be implemented by a general-purpose computing device, which can be concentrated on a single computing device or distributed over a network composed of multiple computing devices. Alternatively, they may be implemented by program code executable by the computing device, such that they may be stored in the storage device by the computing device and, in some cases, may be different from the order herein. The steps shown or described are performed, or they are separately fabricated into individual integrated circuit modules, or a plurality of modules or steps are fabricated as a single integrated circuit module. Thus, the invention is not limited to any specific combination of hardware and software. INDUSTRIAL APPLICABILITY According to the availability of reference pixel points in a neighboring block of a current prediction block, the embodiment of the present invention removes an intra prediction mode that is inevitably unavailable from all intra prediction modes, and performs clipping on the prediction mode index table to adjust the prediction mode. The sequence number is indexed, and the prediction mode index sequence number is encoded by using the unequal length code, thereby reducing the intra prediction mode coding overhead. Therefore, the present invention has strong industrial applicability.

Claims

Claim  1. An intra prediction mode coding method, the method comprising:  According to the availability of the intra-predicted reference pixel in the neighboring block of the current block, the intra prediction mode that the current block is inevitably used in the encoding process is removed from all the intra prediction modes, and the available intra prediction mode is obtained;  Allocating an index number to an available intra prediction mode, and generating a mapping code table between the index number and the code word;  The intra prediction mode of the current block is encoded according to the generated mapping code table.  The intra prediction mode encoding method according to claim 1, wherein, according to the availability of the intra prediction reference pixel in the neighboring block of the current block, removing the current block from all intra prediction modes is inevitable in the encoding process. The unused intra prediction mode, the steps to obtain the available intra prediction modes include:  When the neighboring block uses the restricted intra prediction mode, if the block in which the intra prediction reference pixel is located uses a non-intra prediction mode, or the intra prediction reference pixel is not in the same slice as the current block, Or if the intra prediction reference pixel does not exist, it is determined that the intra prediction reference pixel is not available; when the neighboring block does not use the restricted intra prediction mode, if the intra prediction reference pixel is not the same as the current block If the slice, or the intra prediction reference pixel does not exist, it is determined that the intra prediction reference pixel is not available.  The intra prediction mode encoding method according to claim 1, wherein the case where the intra prediction reference pixel does not exist comprises: the current block being located at an image boundary.  4. An intra prediction mode decoding method, the method comprising:  According to the availability of the intra-predicted reference pixel in the neighboring block of the current block, the intra prediction mode that the current block is inevitably used in the encoding process is removed from all the intra prediction modes, and the available intra prediction mode is obtained;  Allocating an index sequence number to the available intra prediction mode, and generating a mapping code table between the index sequence number and the codeword; Converting the input codeword into an intra prediction mode index number according to the generated mapping code table, Determining an intra prediction mode used by the current block;  The current block is decoded according to the determined intra prediction mode.  The intra prediction mode decoding method according to claim 4, wherein, according to the availability of the intra prediction reference pixel in the neighboring block of the current block, removing the current block from all intra prediction modes is inevitable in the encoding process. The unused intra prediction mode, the steps to obtain the available intra prediction modes include:  When the neighboring block uses the restricted intra prediction mode, if the block in which the intra prediction reference pixel is located uses a non-intra prediction mode, or the intra prediction reference pixel is not in the same slice as the current block, Or if the intra prediction reference pixel does not exist, it is determined that the intra prediction reference pixel is not available; when the neighboring block does not use the restricted intra prediction mode, if the intra prediction reference pixel is not the same as the current block If the slice, or the intra prediction reference pixel does not exist, it is determined that the intra prediction reference pixel is not available.  An encoder, the encoder comprising a determining module, a generating module and an encoding module, wherein: the determining module is configured to: determine the current block encoding process according to the availability of the intra-predicted reference pixel in the neighboring block Intra prediction mode that must not be used;  The generating module is configured to: remove, according to the intra prediction mode that is not used in the current block coding process determined by the determining module, from all the intra prediction modes, remove the intra prediction that the current block is inevitably not used in the encoding process. Mode, obtaining an available intra prediction mode, assigning an index number to the available intra prediction mode, and generating a mapping code table between the index number and the code word;  The encoding module is configured to: encode the current block intra prediction mode according to the mapping code table generated by the generating module.  The encoder according to claim 6, wherein the determining module is configured to determine, according to the availability of the intra-predicted reference pixel in the neighboring block, the intra prediction that is inevitably not used in the current block encoding process. Mode:  When the neighboring block uses the restricted intra prediction mode, if the block in which the intra prediction reference pixel is located uses the non-intra prediction mode, or the intra prediction reference pixel is not in the same slice or frame as the current block, Determining that the reference pixel is not present, determining that the intra prediction reference pixel is not available; When the neighboring block does not use the restricted intra prediction mode, if the intra prediction reference pixel is current and current If the block is not in the same slice, or the intra prediction reference pixel does not exist, it is determined that the intra prediction reference pixel is not available.  8. A decoder, the decoder comprising a determining unit, a generating unit, a first decoding unit, and a second decoding unit, wherein: the determining unit is configured to:: according to availability of intra prediction reference pixel points in neighboring blocks , determining an intra prediction mode that is inevitably not used in the current block encoding process;  The generating unit is configured to: remove, according to the intra prediction mode that is not used in the current block coding process determined by the determining module, the intra prediction that the current block is inevitably not used in the encoding process from all the intra prediction modes. a mode, obtaining an available intra prediction mode, assigning an index number to an available intra prediction mode, and generating a mapping code table between the index number and the code word;  The first decoding unit is configured to: convert the input codeword into an intra prediction mode index sequence according to the mapping code table generated by the generating unit, and determine an intra prediction mode used by the current block; the second decoding unit Set to: decode the current block according to the determined intra prediction mode.  The decoder according to claim 8, wherein the determining unit is configured to determine an intra prediction that is inevitably not used in the current block encoding process according to the availability of intra prediction reference pixel points in the neighboring block in the following manner Mode:  When the neighboring block uses the restricted intra prediction mode, if the block in which the intra prediction reference pixel is located uses the non-intra prediction mode, or the intra prediction reference pixel is not in the same slice or frame as the current block, Determining that the reference pixel is not present, determining that the intra prediction reference pixel is not available;  When the neighboring block does not use the restricted intra prediction mode, if the intra prediction reference pixel is not in the same slice as the current block, or the intra prediction reference pixel does not exist, the intra prediction reference pixel is determined. The point is not available.  An electronic device comprising: the encoder according to claim 6 or 7, and/or the decoder according to claim 8 or 9.