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WO2017037971A1 - Procédé et appareil de conversion - Google Patents

Procédé et appareil de conversion Download PDF

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Publication number
WO2017037971A1
WO2017037971A1 PCT/JP2016/002946 JP2016002946W WO2017037971A1 WO 2017037971 A1 WO2017037971 A1 WO 2017037971A1 JP 2016002946 W JP2016002946 W JP 2016002946W WO 2017037971 A1 WO2017037971 A1 WO 2017037971A1
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WIPO (PCT)
Prior art keywords
luminance
hdr
display
conversion
dynamic range
Prior art date
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Ceased
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PCT/JP2016/002946
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English (en)
Japanese (ja)
Inventor
和彦 甲野
小塚　雅之
遠間　正真
西　孝啓
健吾 寺田
美裕 森
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Panasonic Intellectual Property Corp of America
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Panasonic Intellectual Property Corp of America
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Priority claimed from JP2016096576A external-priority patent/JP2017050840A/ja
Application filed by Panasonic Intellectual Property Corp of America filed Critical Panasonic Intellectual Property Corp of America
Publication of WO2017037971A1 publication Critical patent/WO2017037971A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G5/00—Control arrangements or circuits for visual indicators common to cathode-ray tube indicators and other visual indicators
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G5/00—Control arrangements or circuits for visual indicators common to cathode-ray tube indicators and other visual indicators
    • G09G5/36—Control arrangements or circuits for visual indicators common to cathode-ray tube indicators and other visual indicators characterised by the display of a graphic pattern, e.g. using an all-points-addressable [APA] memory
    • G09G5/39—Control of the bit-mapped memory
    • G09G5/391—Resolution modifying circuits, e.g. variable screen formats
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/14—Picture signal circuitry for video frequency region
    • H04N5/20—Circuitry for controlling amplitude response

Definitions

  • the present disclosure relates to a conversion method and a conversion apparatus related to video luminance.
  • Patent Document 1 An image signal processing apparatus for improving the displayable luminance level has been disclosed (see, for example, Patent Document 1).
  • a conversion method is performed in a conversion device that converts luminance of a video whose luminance is defined by a first dynamic range into luminance defined by a second dynamic range that can be displayed by the display device.
  • the second dynamic range has a smaller maximum value and a narrow dynamic range than the first dynamic range, and the conversion method is connected to the conversion device.
  • the display device displays a UI (User Interface) for determining the second dynamic range, receives an input from the user for the UI displayed on the display device, and responds to the received input
  • the second dynamic range is determined, and the brightness of the video is determined by the determined second dynamic range. Converting the luminance is.
  • a recording medium such as a system, an apparatus, an integrated circuit, a computer program, or a computer-readable CD-ROM.
  • the system, the apparatus, the integrated circuit, and the computer program Also, any combination of recording media may be realized.
  • FIG. 11 is a diagram illustrating an example of display processing for performing HDR display using an HDR-compatible playback device and SDRTV. It is a figure which shows an example of the display process which performs HDR display with the reproducing
  • FIG. 3 is a diagram illustrating a configuration of an HDR-compatible device that performs pseudo-HDR conversion processing and displays user guidance for a user to set DPL in the HDR-compatible device.
  • FIG. 6 is a flowchart illustrating a conversion method by the conversion apparatus according to the second embodiment. It is a figure which shows an example of a message screen. It is a figure which shows an example of an image quality setting screen. It is a figure which shows an example of a dynamic range conversion adjustment screen. It is a figure which shows another example of a dynamic range conversion adjustment screen. It is a figure which shows another example of a dynamic range conversion adjustment screen. It is a figure for demonstrating the reproduction
  • linear luminance is calculated for each pixel based on the linear RGB value calculated from the pixels constituting the subject, and for each pixel based on the linear RGB value and the linear luminance.
  • the corrected linear luminance and the corrected linear RGB value of the combined pixel obtained by synthesizing a plurality of pixels including the pixel are calculated, and the corrected linear luminance and the corrected linear RGB value are respectively gamma corrected to calculate the display luminance and the display RGB value.
  • the number of gradations that can be displayed is increased by correcting the linear luminance based on the corrected linear RGB values.
  • the luminance correction (conversion) of the image signal processing device disclosed in Patent Document 1 the luminance is corrected (converted) to the second luminance range reduced from the first luminance range.
  • the brightness conversion method was not considered.
  • the present inventor examined the following improvement measures in order to solve the above-mentioned problems.
  • a conversion method is performed in a conversion device that converts luminance of a video whose luminance is defined by a first dynamic range into luminance defined by a second dynamic range that can be displayed by the display device.
  • the second dynamic range has a smaller maximum value and a narrow dynamic range than the first dynamic range, and the conversion method is connected to the conversion device.
  • the display device displays a UI (User Interface) for determining the second dynamic range, receives an input from the user for the UI displayed on the display device, and responds to the received input
  • the second dynamic range is determined, and the brightness of the video is determined by the determined second dynamic range. Converting the luminance is.
  • the input to the UI displayed on the display device is accepted, so that an appropriate value can be obtained according to the input.
  • the second dynamic range can be easily determined. For this reason, it is possible to easily appropriately convert the luminance of the video defined by the first dynamic range into the luminance of the second dynamic range that can be displayed by the display device.
  • a sample image in which luminance is defined in the second dynamic range determined in the determination may be displayed on the display device.
  • the user can confirm whether or not the second dynamic range determined according to the input to the UI is an appropriate dynamic range for the display device by looking at the sample image. For this reason, the user can intuitively determine the second dynamic range appropriate for the display device by performing input to the UI.
  • a slider for determining the maximum value of the second dynamic range is displayed on the display device as the UI.
  • a value corresponding to the position of the slider knob is received from the user. May be accepted as input.
  • each of the minimum value and the maximum value of the slider may be a predetermined fixed value.
  • the minimum value of the slider may be a predetermined fixed value
  • the maximum value of the slider may be a value determined based on metadata relating to the luminance of the video.
  • the metadata may be a peak luminance of the video.
  • the metadata may be an average luminance of the video.
  • the conversion device is connected to the display device via HDMI (registered trademark), the first dynamic range is HDR (High Dynamic Range), and the conversion method further includes the display Information indicating whether or not the device can display a video corresponding to HDR is acquired, and if the acquired information indicates that the display device cannot display a video corresponding to HDR, the conversion is performed. A message may be displayed on the display device.
  • HDMI registered trademark
  • HDR High Dynamic Range
  • the UI may be displayed.
  • a recording medium such as a device, a system, an integrated circuit, a computer program, or a computer-readable CD-ROM.
  • the device, system, integrated circuit, computer You may implement
  • the present disclosure relates to an HDR (High Dynamic Range) signal, which is a high luminance signal having a high luminance range, and a TV or projector corresponding to an SDR (Standard Dynamic Range) signal, which is a normal luminance signal having a maximum luminance value of 100 nits.
  • the present invention relates to an image conversion / playback method and apparatus for displaying on a display device such as a tablet or a smartphone.
  • FIG. 1 is a diagram for explaining the evolution of video technology.
  • SD Standard Definition
  • HD high definition 1920 x 1080 pixels
  • the dynamic range is the maximum brightness to express bright light such as specular reflection light that cannot be expressed by the current TV signal with more realistic brightness while maintaining the dark gradation in the conventional video.
  • HDR High Dynamic Range
  • SDR Standard Dynamic Range
  • the maximum luminance value was 100 nits, whereas in HDR the maximum is 1000 nits or more. It is assumed that the luminance value is enlarged. Standardization of HDR is underway in SMPTE (Society of Motion Picture & Television Engineers) and ITU-R (International Telecommunications Union Radiocommunications Sector).
  • HDR high definition video recorder
  • package media Blu-ray (registered trademark) Disc, etc.
  • Internet distribution etc., like HD and UHD.
  • the luminance of the video is composed of luminance values in the HDR luminance range, and a luminance signal obtained by quantizing the luminance value of the video is referred to as an HDR signal.
  • the luminance of the video is composed of luminance values in the luminance range of SDR, and a luminance signal obtained by quantizing the luminance value of the video is called an SDR signal.
  • FIG. 2 is a diagram for explaining the relationship between video production, a distribution method, and a display device when a new video expression is introduced into content.
  • HDR display TV (hereinafter referred to as “HDR display”) compatible with HDR display (hereinafter referred to as “HDR display”). It is expected that replacement for “HDRTV” will be required.
  • SDRTV A TV (hereinafter referred to as “SDRTV”) that supports only video display corresponding to SDR (hereinafter referred to as “SDR display”) normally receives an input signal having a luminance value of up to 100 nits. For this reason, SDRTV is sufficient to represent the luminance value of the input signal if its display capability is 100 nits. However, SDRTV actually has a function of reproducing an image with an optimal luminance value in accordance with the viewing environment (dark room: cinema mode, bright room: dynamic mode, etc.), and the ability to express an image of 200 nits or more. There are many things that have. That is, such SDRTV can display video up to the maximum luminance (for example, 300 nits) of display capability by selecting a display mode according to the viewing environment.
  • the maximum luminance for example, 300 nits
  • the luminance upper limit of the input signal is determined to be 100 nits. Therefore, as long as the SDR input interface is used as usual, a high-intensity video exceeding 100 nits that SDRTV has. It is difficult to use the reproduction capability for reproducing the HDR signal (see FIGS. 4A and 4B).
  • HDR ⁇ SDR conversion High-brightness video content (hereinafter referred to as “HDR-compatible broadcasting”, “video distribution via communication network”, or “HDR-compatible Blu-ray (registered trademark) Disc”). “HDR content” or “HDR video” is also transmitted via SDRTV via an HDR-compatible playback device (for example, a communication STB (Set Top Box), Blu-ray (registered trademark) device, IPTV playback device). It is assumed that it will be output.
  • HDR-compatible playback device for example, a communication STB (Set Top Box), Blu-ray (registered trademark) device, IPTV playback device. It is assumed that it will be output.
  • HDR ⁇ SDR conversion is implemented to convert HDR signals corresponding to HDR into SDR luminance range SDR signals with a maximum value of 100 nits so that images can be displayed correctly with SDRTV. To do. Thereby, SDRTV can display the SDR video obtained by converting from the HDR video using the converted SDR signal (see
  • HDR-compatible content for example, Blu-ray (registered trademark) Disc, HDR IPTV content
  • HDR-compatible playback device for example, Blu-ray (registered trademark) device, HDR-compatible IPTV playback device.
  • SDR expression SDR video expression
  • HDR that is, superiority to SDR due to high image quality of HDR
  • the spread of HDR contents and HDR compatible distribution methods is determined according to the spread rate of HDRTV.
  • FIG. 6 is a diagram for explaining an example in which only an HDR signal corresponding to HDR is stored in an HDR-compatible BD.
  • HDRTV can display both HDR signals and SDR signals, it performs display processing according to the input luminance signal and displays HDR video or SDR video.
  • the Blu-ray (registered trademark) device converts the HDR signal to an SDR signal when playing the HDRBD.
  • the SDR signal obtained by the conversion process is output to SDRTV.
  • the Blu-ray (registered trademark) device outputs the SDR signal stored in the BD as it is to the SDRTV without conversion. Thereby, SDRTV displays an SDR video.
  • HDRTV is required for the user to view the HDR video, and it is expected that it will take time to spread the HDR-compatible Blu-ray (registered trademark) device or HDRBD.
  • HDR ⁇ pseudo HDR conversion From the above, it can be said that in order to promote the spread of HDR, it is important to be able to promote the commercialization of HDR contents and distribution methods without waiting for the spread of HDRTV. For this purpose, if the HDR signal can be viewed with existing SDRTV as HDR video or pseudo HDR video closer to HDR video than SDR video, instead of SDR video, the user can view HDRTV. Even if you don't buy it, you can watch a higher quality video that is clearly different from the SDR video and is close to the HDR video.
  • pseudo-HDR video can be a user's motive for purchasing HDR content and HDR distribution equipment (see FIG. 7A).
  • FIG. 7B is a diagram for describing another example in which only HDR signals corresponding to HDR are stored in an HDR-compatible BD.
  • FIG. 8A is a diagram showing an example of EOTF (Electro-Optical Transfer Function) corresponding to each of HDR and SDR.
  • EOTF Electro-Optical Transfer Function
  • EOTF is generally called a gamma curve, indicates the correspondence between code values and luminance values, and converts code values into luminance values. That is, EOTF is relationship information indicating a correspondence relationship between a plurality of code values and luminance values.
  • FIG. 8B is a diagram illustrating an example of reverse EOTF corresponding to each of HDR and SDR.
  • Inverse EOTF indicates the correspondence between the luminance value and the code value.
  • the luminance value is quantized and converted into a code value. That is, inverse EOTF is relationship information indicating a correspondence relationship between a luminance value and a plurality of code values. For example, when the luminance value of a video corresponding to HDR is expressed by a 10-bit gradation code value, the luminance values in the HDR luminance range up to 10,000 nits are quantized and 1024 from 0 to 1023 Mapped to the integer value of.
  • HDR EOTF an EOTF corresponding to HDR
  • HDR inverse EOTF an EOTF corresponding to HDR
  • SDR EOTF an EOTF corresponding to SDR
  • inverse EOTF of SDR an inverse EOTF corresponding to SDR
  • the value (peak luminance) is 10,000 nits. That is, the HDR luminance range includes the entire SDR luminance range, and the HDR peak luminance is larger than the SDR peak luminance.
  • the HDR luminance range is a luminance range obtained by expanding the maximum value from 100 nit, which is the maximum value of the SDR luminance range, to 10,000 nit.
  • HDR EOTF and HDR inverse EOTF are, for example, SMPTE 2084 standardized by the American Film and Television Engineers Association (SMPTE).
  • FIG. 9 is an explanatory diagram of a method for determining the code value of the luminance signal stored in the content and the process of restoring the luminance value from the code value during reproduction.
  • the luminance signal indicating the luminance in this example is an HDR signal corresponding to HDR.
  • the image after grading is quantized by the inverse EOTF of HDR, and the code value corresponding to the luminance value of the image is determined. Image coding or the like is performed based on this code value, and a video stream is generated. At the time of reproduction, the decoding result of the stream is converted into a linear signal by inverse quantization based on HDR EOTF, and the luminance value for each pixel is restored.
  • quantization using the inverse EOTF of HDR is referred to as “inverse HDR EOTF conversion”.
  • Inverse quantization using HDR EOTF is referred to as “HDR EOTF conversion”.
  • quantization using inverse SDR EOTF is referred to as “inverse SDR EOTF conversion”.
  • Inverse quantization using SDR EOTF is referred to as “SDR EOTF conversion”.
  • FIG. 10A is a diagram illustrating an example of a display process in which HDR display is performed by converting an HDR signal in HDRTV.
  • the maximum value of the HDR luminance range (peak luminance (HPL (HDR Peak Luminance): example 1500 nit)) is displayed as it is, even if the display device is HDRTV. May not be possible.
  • the linear signal after inverse quantization using HDR EOTF is adjusted to the maximum value of the luminance range of the display device (peak luminance (DPL (Display Peak Iluminance): example 750 nit)).
  • DPL Display Peak Iluminance
  • FIG. 10B is a diagram illustrating an example of display processing for performing HDR display using an HDR-compatible playback device and SDRTV.
  • the maximum value of the luminance range of the SDRTV to be displayed exceeds 100 nits.
  • “HDR to pseudo HDR conversion processing” in the HDR compatible playback device (Blu-ray (registered trademark) device) in FIG. 10B which is performed in HDRTV, “HDR EOTF conversion” and SDRTV luminance range
  • “luminance conversion” using the maximum value of DPL (eg 300 nit) is performed, and the signal obtained by performing “luminance conversion” can be directly input to the “display device” of SDRTV, The same effect as HDRTV can be realized.
  • FIG. 10C is a diagram showing an example of display processing for performing HDR display using an HDR-compatible playback device and SDRTV connected to each other via a standard interface.
  • a signal input via an input interface passes through “SDR EOTF conversion”, “brightness conversion for each mode”, and “display device” in order, and an image that matches the maximum luminance range of the display device. Is displayed. For this reason, a signal (pseudo) that can cancel “SDR EOTF conversion” and “brightness conversion for each mode” that passes immediately after the input interface in SDRTV in an HDR-compatible Blu-ray (registered trademark) device. HDR signal) is generated.
  • FIG. 11 is a block diagram illustrating configurations of the conversion device and the display device according to the embodiment.
  • FIG. 12 is a flowchart illustrating a conversion method and a display method performed by the conversion device and the display device according to the embodiment.
  • the conversion apparatus 100 includes an HDR EOTF conversion unit 101, a luminance conversion unit 102, an inverse luminance conversion unit 103, and an inverse SDR EOTF conversion unit 104.
  • the display device 200 includes a display setting unit 201, an SDR EOTF conversion unit 202, a luminance conversion unit 203, and a display unit 204.
  • the HDR luminance range (0 to HPL [nit]) is referred to as a “first luminance range”.
  • the luminance range (0 to DPL [nit]) of the display is indicated as “second luminance range”.
  • the SDR luminance range (0 to 100 [nit]) is referred to as a “third luminance range”.
  • the first luminance range is also referred to as “first dynamic range”
  • the second luminance range is also referred to as “second dynamic range”. That is, the second dynamic range is a narrow dynamic range having a maximum value smaller than that of the first dynamic range.
  • a conversion method performed by the conversion apparatus 100 will be described with reference to FIG.
  • the conversion method includes steps S101 to S104 described below.
  • the HDR EOTF conversion unit 101 of the conversion apparatus 100 acquires an HDR video that has been subjected to reverse HDR EOTF conversion.
  • the HDR EOTF conversion unit 101 of the conversion device 100 performs HDR EOTF conversion on the HDR signal of the acquired HDR video (S101).
  • the HDR EOTF converter 101 converts the acquired HDR signal into a linear signal indicating a luminance value.
  • HDR EOTF is, for example, SMPTE 2084.
  • the luminance conversion unit 102 of the conversion device 100 performs first luminance conversion that converts the linear signal converted by the HDR EOTF conversion unit 101 using display characteristic information and content luminance information (S102). .
  • the luminance value corresponding to the HDR luminance range which is the first luminance range (hereinafter referred to as “HDR luminance value”) is used as the luminance value corresponding to the luminance range of the display which is the second luminance range. (Hereinafter referred to as “display luminance value”). Details will be described later.
  • the HDR EOTF converter 101 functions as an acquisition unit that acquires the HDR signal as the first luminance signal indicating the code value obtained by quantizing the luminance value of the video.
  • the HDR EOTF conversion unit 101 and the luminance conversion unit 102 determine the code value indicated by the HDR signal acquired by the acquisition unit based on the luminance range of the display (display device 200). It functions as a conversion unit that converts a display luminance value corresponding to the luminance range of the display that is a maximum value (DPL) that is smaller than the value (HPL) and larger than 100 nits.
  • DPL maximum value
  • the HDR EOTF conversion unit 101 uses the acquired HDR signal and the HDR EOTF in step S101 to determine the HDR code value as the first code value indicated by the acquired HDR signal.
  • An HDR luminance value associated with the HDR code value in the HDR EOTF is determined.
  • the HDR signal is obtained by quantizing the luminance value of the video (content) using the HDR inverse EOTF that associates the luminance value in the HDR luminance range with a plurality of HDR code values.
  • the code value of HDR is shown.
  • step S102 the luminance conversion unit 102 determines a display luminance value corresponding to the luminance range of the display, which is associated with the HDR luminance value in advance in the HDR luminance value determined in step S101.
  • the first luminance conversion is performed to convert the HDR luminance value corresponding to the luminance range of the display into the display luminance value corresponding to the luminance range of the display.
  • the conversion device 100 includes content luminance information including at least one of a maximum luminance value (CPL: Content Peak Luminance) and an average luminance value (CAL: Content Average Luminance) of video (content) before step S102. Is acquired as information relating to the HDR signal.
  • CPL first maximum luminance value
  • CAL is an average luminance value that is an average of luminance values for a plurality of images constituting an HDR video, for example.
  • the conversion device 100 acquires the display characteristic information of the display device 200 from the display device 200 before step S102.
  • the display characteristic information refers to the maximum value (DPL) of luminance that can be displayed on the display device 200, the display mode of the display device 200 (see later), the input / output characteristics (EOTF corresponding to the display device), and the like. This is information indicating display characteristics.
  • the conversion apparatus 100 may transmit recommended display setting information (referred to below-mentioned, hereinafter also referred to as “setting information”) to the display apparatus 200.
  • recommended display setting information referred to below-mentioned, hereinafter also referred to as “setting information”.
  • the reverse luminance conversion unit 103 of the conversion device 100 performs reverse luminance conversion according to the display mode of the display device 200. Accordingly, the inverse luminance conversion unit 103 performs the second luminance conversion for converting the luminance value corresponding to the luminance range of the display that is the second luminance range into the luminance value corresponding to the luminance range of the SDR that is the third luminance range. Perform (S103). Details will be described later. That is, the inverse luminance conversion unit 103 uses the display luminance value obtained in step S102 as the third luminance value corresponding to the luminance range of SDR, which is associated with the display luminance value in advance and has a maximum value of 100 nits.
  • SDR luminance value Luminance value corresponding to SDR
  • the luminance value of SDR is determined, and the display luminance value corresponding to the luminance range of the display is changed to the luminance value of SDR corresponding to the luminance range of SDR.
  • a second luminance conversion for conversion is performed.
  • the inverse SDR EOTF converter 104 of the conversion device 100 performs pseudo SDR EOTF conversion to generate a pseudo HDR video (S104). That is, the inverse SDR EOTF conversion unit 104 performs the inverse dynamic EOTF (Electro-Optical) of SDR (Standard Dynamic Range), which is the third relational information that associates the luminance value in the HDR luminance range with a plurality of third code values.
  • the determined SDR brightness value is quantized using Transfer Function), the third code value obtained by the quantization is determined, and the SDR brightness value corresponding to the SDR brightness range is indicated as the third code value.
  • a pseudo HDR signal is generated by converting the SDR signal as the third luminance signal.
  • the third code value is a code value corresponding to SDR, and is hereinafter referred to as “SDR code value”. That is, the SDR signal is obtained by quantizing the luminance value of the video using the SDR inverse EOTF that associates the luminance value in the luminance range of the SDR and a plurality of SDR code values. Expressed as a code value. Then, conversion device 100 outputs the pseudo HDR signal (SDR signal) generated in step S104 to display device 200.
  • SDR code value a code value corresponding to SDR
  • the conversion apparatus 100 generates the SDR luminance value corresponding to the pseudo HDR by performing the first luminance conversion and the second luminance conversion on the HDR luminance value obtained by dequantizing the HDR signal. Then, the SDR luminance value is quantized using the SDR EOTF to generate an SDR signal corresponding to the pseudo HDR.
  • the SDR luminance value is a numerical value in the luminance range of 0 to 100 nits corresponding to the SDR.
  • the HDR EOTF and the SDR are converted to the HDR luminance value. This is a numerical value different from the luminance value in the luminance range of 0 to 100 nit corresponding to the SDR obtained by performing luminance conversion using the EOTF.
  • the display method includes steps S105 to S108 described below.
  • the display setting unit 201 of the display device 200 sets the display setting of the display device 200 using the setting information acquired from the conversion device 100 (S105).
  • the display device 200 is an SDRTV.
  • the setting information is information indicating display settings recommended for the display device, and information indicating how to perform pseudo-HDR video EOTF and display at which setting a beautiful video can be displayed (that is, Information for switching the display setting of the display device 200 to the optimal display setting).
  • the setting information includes, for example, a gamma curve characteristic at the time of output in the display device, a display mode such as a living mode (normal mode) and a dynamic mode, a numerical value of backlight (brightness), and the like.
  • a message that prompts the user to change the display setting of the display device 200 by a manual operation may be displayed on the display device 200 (hereinafter also referred to as “SDR display”). Details will be described later.
  • the display device 200 acquires an SDR signal (pseudo HDR signal) and setting information indicating display settings recommended for the display device 200 in displaying a video before step S105.
  • the display device 200 may acquire the SDR signal (pseudo HDR signal) before step S106, or after step S105.
  • the SDR EOTF converter 202 of the display device 200 performs SDR EOTF conversion on the acquired pseudo-HDR signal (S106). That is, the SDR EOTF converter 202 performs inverse quantization on the SDR signal (pseudo HDR signal) using the SDR EOTF. Accordingly, the SDR EOTF converter 202 converts the SDR code value indicated by the SDR signal into an SDR luminance value.
  • the luminance conversion unit 203 of the display device 200 performs luminance conversion according to the display mode set in the display device 200. Thereby, the luminance conversion unit 203 converts the SDR luminance value corresponding to the SDR luminance range (0 to 100 [nit]) into the display luminance value corresponding to the display luminance range (0 to DPL [nit]). The third luminance conversion is performed (S107). Details will be described later.
  • the display device 200 uses the setting information acquired in step S105 to obtain the third code value indicated by the acquired SDR signal (pseudo HDR signal) in step S106 and step S107. 0 to DPL [nit]).
  • step S106 in the conversion from the SDR signal (pseudo HDR signal) to the display luminance value, in step S106, using the EOTF that associates the luminance value in the luminance range of the SDR with a plurality of third code values. Then, for the SDR code value indicated by the acquired SDR signal, the SDR luminance value related to the SDR code value by the SDR EOTF is determined.
  • step S107 the display brightness value corresponding to the brightness range of the display, which is related in advance to the determined brightness value of the SDR, is determined, and the SDR value corresponding to the SDR brightness range is determined.
  • a third luminance conversion is performed for converting the luminance value into a display luminance value corresponding to the luminance range of the display.
  • the display unit 204 of the display device 200 displays the pseudo HDR video on the display device 200 based on the converted display luminance value (S108).
  • FIG. 13A is a diagram for describing an example of the first luminance conversion.
  • the luminance conversion unit 102 of the conversion device 100 performs first luminance conversion that converts the linear signal (HDR luminance value) obtained in step S101 using display characteristic information and content luminance information of the HDR video. .
  • the HDR luminance value input luminance value
  • the display luminance value output luminance value
  • DPL display peak luminance
  • DPL is determined using the maximum brightness and display mode of the SDR display, which is display characteristic information.
  • the display mode is, for example, mode information such as a theater mode that is displayed dark on the SDR display and a dynamic mode that is displayed brightly.
  • the display mode is a mode in which the maximum brightness of the SDR display is 1,500 nits and the display mode is a brightness that is 50% of the maximum brightness
  • the DPL is 750 nits.
  • DPL (second maximum luminance value) is the maximum luminance value that can be displayed in the display mode in which the SDR display is currently set. That is, in the first luminance conversion, DPL as the second maximum luminance value is determined using display characteristic information that is information indicating display characteristics of the SDR display.
  • the first luminance conversion CAL and CPL in the content luminance information are used, luminance values below the CAL are the same before and after the conversion, and the luminance value is changed only for luminance values near the CPL.
  • the first luminance conversion when the HDR luminance value is CAL or less, the HDR luminance value is not converted, and the HDR luminance value is determined as the display luminance value.
  • the DPL as the second maximum luminance value is determined as the display luminance value.
  • the peak luminance (CPL) of the HDR video in the luminance information is used, and when the HDR luminance value is CPL, DPL is determined as the display luminance value.
  • the linear signal (HDR luminance value) obtained in step S101 may be converted so as to be clipped to a value not exceeding DPL.
  • the processing in the conversion device 100 can be simplified, and the device can be reduced, the power consumption can be reduced, and the processing speed can be increased.
  • FIG. 13B is a diagram for describing another example of the first luminance conversion.
  • FIG. 14 is a diagram for describing the second luminance conversion.
  • the inverse luminance conversion unit 103 of the conversion device 100 performs inverse luminance conversion corresponding to the display mode on the display luminance value in the display luminance range (0 to DPL [nit]) converted by the first luminance conversion in step S102. Apply.
  • the reverse luminance conversion when the luminance conversion processing (step S107) according to the display mode by the SDR display is performed, the display luminance value of the display luminance range (0 to DPL [nit]) after the processing of step S102 is acquired. This is a process for making it possible. That is, the second luminance conversion is an inverse luminance conversion of the third luminance conversion.
  • the second luminance conversion is performed by converting the display luminance value (input luminance value) of the display luminance range which is the second luminance range into the SDR luminance value (output luminance) of the SDR luminance range which is the third luminance range. Value).
  • the conversion formula is switched depending on the display mode of the SDR display. For example, when the display mode of the SDR display is the normal mode, the luminance is converted to a directly proportional value that is directly proportional to the display luminance value.
  • the second luminance conversion when the display mode of the SDR display is a dynamic mode in which a high luminance pixel is brighter and a low luminance pixel is darker than in the normal mode, the inverse function is used to obtain the low luminance pixel.
  • the luminance value of the SDR is converted to a value higher than the direct proportional value that is directly proportional to the display luminance value, and the luminance value of the SDR of the high luminance pixel is converted to a value lower than the direct proportional value that is directly proportional to the display luminance value. That is, in the second luminance conversion, the display luminance value determined in step S102 is related to the display luminance value using luminance relationship information corresponding to the display characteristic information that is information indicating the display characteristic of the SDR display. The brightness value is determined as the brightness value of the SDR, and the brightness conversion process is switched according to the display characteristic information.
  • the luminance-related information according to the display characteristic information includes, for example, a display luminance value (input luminance value) determined for each display parameter (display mode) of the SDR display as shown in FIG. This is information relating brightness values (output brightness values).
  • FIG. 15 is a flowchart showing detailed processing for display setting.
  • the display setting unit 201 of the SDR display performs the following steps S201 to S208 in step S105.
  • the display setting unit 201 uses the setting information to determine whether the EOTF set for the SDR display (EOF for SDR display) matches the EOTF assumed when the pseudo HDR video (SDR signal) is generated. Determine (S201).
  • the display setting unit 201 determines that the EOTF set in the SDR display is different from the EOTF indicated by the setting information (EOTF matching the pseudo HDR video) (Yes in S201), the display setting unit 201 sets the EOTF for the SDR display in the system. It is determined whether switching is possible on the side (S202).
  • the display setting unit 201 determines that switching is possible, the setting information is used to switch the SDR display EOTF to an appropriate EOTF (S203).
  • step S105 in the display setting setting (S105), the EOTF set in the SDR display is set to the recommended EOTF corresponding to the acquired setting information. Accordingly, in step S106 performed after step S105, the luminance value of SDR can be determined using the recommended EOTF.
  • a message prompting the user to change the EOTF manually is displayed on the screen (S204). For example, a message “Please set the display gamma to 2.4” is displayed on the screen. That is, if the EOTF set for the SDR display cannot be switched in the display setting setting (S105), the display setting unit 201 switches the EOTF set for the SDR display (EOF for SDR display) to the recommended EOTF. A message for prompting the user to do so is displayed on the SDR display.
  • the pseudo-HDR image (SDR signal) is displayed on the SDR display, but it is determined whether or not the display parameters of the SDR display match the setting information using the setting information before display (S205).
  • the display setting unit 201 determines whether the display parameter of the SDR display can be switched (S206). .
  • the display setting unit 201 determines that the display parameter of the SDR display can be switched (Yes in S206)
  • the display setting unit 201 switches the display parameter of the SDR display according to the setting information (S207).
  • step S105 in the display setting setting (S105), the display parameter set in the SDR display is set to the recommended display parameter corresponding to the acquired setting information.
  • a message prompting the user to manually change the display parameters set in the SDR display is displayed on the screen (S208). For example, a message “Please set the display mode to dynamic mode and maximize the backlight” is displayed on the screen. That is, in the setting (S105), when the display parameter set in the SDR display cannot be switched, a message for prompting the user to switch the display parameter set in the SDR display to the recommended display parameter is displayed. To display.
  • FIG. 16 is a diagram for describing the third luminance conversion.
  • the luminance conversion unit 203 of the display device 200 converts the SDR luminance value in the SDR luminance range (0 to 100 [nit]) into (0 to DPL [nit]) according to the display mode set in step S105. .
  • This processing is performed so as to be an inverse function of inverse luminance conversion for each mode in S103.
  • the conversion formula is switched depending on the display mode of the SDR display. For example, when the display mode of the SDR display is the normal mode (that is, when the set display parameter is a parameter corresponding to the normal mode), the display luminance value is converted into a direct proportional value that is directly proportional to the luminance value of the SDR. .
  • the display mode of the SDR display is the dynamic mode in which the high luminance pixel is brighter and the low luminance pixel is darker than the normal mode, the display luminance value of the low luminance pixel is SDR.
  • the luminance value of the display luminance value of the high luminance pixel is converted to a value higher than the direct proportional value that is directly proportional to the luminance value of the SDR. That is, in the third luminance conversion, for the luminance value of the SDR determined in step S106, luminance related in advance to the luminance value of the SDR using luminance relationship information corresponding to the display parameter indicating the display setting of the SDR display. The value is determined as the display luminance value, and the luminance conversion processing is switched according to the display parameter.
  • the brightness-related information according to the display parameter is, for example, as shown in FIG. 16, the SDR brightness value (input brightness value) determined for each display parameter (display mode) of the SDR display, and the display brightness. This is information that relates values (output luminance values).
  • a normal SDRTV has an input signal of 100 nits, but has an ability to express an image of 200 nits or more according to the viewing environment (dark room: cinema mode, bright room: dynamic mode, etc.). However, since the upper limit of luminance of the input signal to SDRTV was determined to be 100 nits, it was not possible to directly use that capability.
  • HDR video in SDRTV When displaying HDR video in SDRTV, using the fact that the peak brightness of SDRTV to be displayed exceeds 100 nits (usually 200 nits or more), the HDR video is not converted to SDR video of 100 nits or less, but luminance exceeding 100 nits. “HDR ⁇ pseudo HDR conversion processing” is performed so as to maintain the gradation of the range to some extent. For this reason, it can be displayed on SDRTV as a pseudo HDR video close to the original HDR.
  • Blu-ray (registered trademark) and other package media, and HDR signals sent by Internet distribution such as OTT are converted into pseudo-HDR signals by performing HDR-pseudo HDR conversion processing.
  • OTT Internet distribution
  • HDR-pseudo HDR conversion processing it is possible to display the HDR signal as a pseudo HDR video with the existing SDRTV.
  • the display characteristic information of the display device 200 is acquired from the display device 200, and the first luminance conversion is performed based on the display peak luminance (DPL) of the display device 200 obtained from the display characteristic information.
  • DPL display peak luminance
  • the conversion apparatus does not need to acquire DPL from the display apparatus 200, for example, may acquire DPL of the display apparatus 200 by a user's input.
  • the user does not know the concept of HDR, how an HDR signal looks on a non-HDR compatible TV (SDRTV), and how a pseudo HDR signal looks on a non-HDR compatible TV (SDRTV).
  • SDRTV non-HDR compatible TV
  • SDRTV pseudo HDR signal looks on a non-HDR compatible TV
  • non-HDR compatible TVs owned by users vary from user to user, and their performance (maximum brightness, etc.) also varies. There is a high possibility that the user does not grasp the type of non-HDR compatible TV and its performance. Further, some non-HDR compatible TVs do not hold information indicating the maximum luminance that can be displayed by the non-HDR compatible TV, or do not have means for transmitting the information to an HDR compatible player.
  • the user needs to appropriately set the DPL of the display device in order to perform appropriate pseudo-HDR conversion in the HDR-compatible Blu-ray (registered trademark) device or HDR distribution device.
  • a conversion method in the case of causing a non-HDR compatible TV to output a pseudo HDR signal obtained by performing pseudo HDR conversion of an HDR signal to a Blu-ray (registered trademark) device or an HDR distribution device. explain.
  • the conversion method includes a simple setting method for causing a Blu-ray (registered trademark) device or an HDR distribution device to perform an appropriate pseudo-HDR conversion according to the display capability of the output destination non-HDR compatible TV.
  • FIG. 18 is a diagram illustrating a configuration of an HDR-compatible device that performs pseudo-HDR conversion processing and displays user guidance for the user to set DPL in the HDR-compatible device.
  • the conversion device 110 includes a UI display unit 111, an input reception unit 112, a determination unit 113, and a conversion unit 114.
  • Each of the UI display unit 111, the input reception unit 112, the determination unit 113, and the conversion unit 114 is realized by, for example, a microcomputer, a processor, or a dedicated circuit. That is, each processing unit constituting the conversion device 110 may be realized by software or hardware.
  • the UI display unit 111 causes the display device connected to the conversion device 110 to display a UI for determining the dynamic range of the video displayed on the display device. Specifically, the UI display unit 111 outputs UI data for displaying the UI on the display device to the display device via, for example, HDMI (registered trademark).
  • the input receiving unit 112 receives input from the user for the UI displayed on the display device. Specifically, the input receiving unit 112 receives, for example, an input signal transmitted from a remote controller when a remote controller (not shown) is operated by a user via an infrared communication interface.
  • a remote controller not shown
  • a mobile terminal such as a smartphone or a tablet terminal may be used instead of the remote control.
  • the determining unit 113 determines a second dynamic range having a smaller maximum value and a narrow dynamic range than the first dynamic range in accordance with the input received by the input receiving unit 112.
  • the conversion unit 114 converts the luminance of the video into luminance defined by the determined second dynamic range.
  • an HDR compatible device having the conversion device 110 is connected to an HDR non-compatible TV such as UHDTV or HDTV via HDMI (registered trademark).
  • HDMI registered trademark
  • the HDR compatible device detects the start of the HDR ⁇ pseudo HDR conversion processing in the conversion device 110, “The disc is an HDR compatible disc. Your TV is not compatible with HDR, so it is not an HDR video but an Ultra HD Blu.
  • -Ray registered trademark
  • -Ray may play back a video that has been subjected to the HDR ⁇ pseudo HDR conversion process. Please make settings for the conversion process.
  • the conversion device 110 acquires information indicating whether or not the TV (display device) can display a video corresponding to HDR, and the acquired information indicates that the TV cannot display a video corresponding to HDR. In this case, a message for performing the HDR ⁇ pseudo HDR conversion process may be displayed on the TV.
  • FIG. 19 is a diagram illustrating an example of a DPL setting method for an HDR-compatible device that executes HDR ⁇ pseudo HDR conversion processing.
  • an HDR-compatible device having the conversion device 110 may display a UI for determining a DPL value on a non-HDR compatible TV together with a sample image. That is, the UI display unit 111 of the conversion apparatus 110 may display a sample image whose luminance is defined in the second dynamic range determined by the determination unit 113 on the non-HDR compatible TV.
  • the UI display unit 111 of the conversion apparatus 110 may display a UI when the information acquired from the TV indicates that the TV cannot display an image corresponding to HDR. That is, in this case, the display unit 111 of the conversion device 110 may automatically transition to a UI display screen. For this reason, the user can adjust the second dynamic range, and can cause the conversion apparatus to appropriately convert the dynamic range.
  • the UI is, for example, a slider for determining the DPL that is the maximum value of the second dynamic range in the conversion device 110.
  • a value corresponding to the position of the slider knob is accepted as an input value from the user. For this reason, the user can easily adjust the maximum value of the second dynamic range.
  • a sample image in which the luminance is defined in the second dynamic range determined according to the position of the slider knob is displayed on the non-HDR compatible TV.
  • the sample image is, for example, an image showing a chart for adjusting luminance, an image having a wide range of luminance distribution in the content, or the like.
  • the minimum value of the slider is a predetermined fixed value, for example, 200 nit. That is, when the slider knob is positioned at the leftmost position of the slider, DPL is set to 200 nit, for example.
  • the maximum value of the slider is a predetermined fixed value, for example, 700 nit. That is, when the slider knob is positioned on the rightmost side of the slider, DPL is set to 700 nit, for example. Thus, since the minimum value and the maximum value of the slider are fixed values, the processing load can be reduced.
  • the maximum value of the slider may be a value determined based on metadata related to the brightness of the HDR content video. That is, when the slider knob is positioned on the rightmost side of the slider, the DPL is set to a value determined based on, for example, metadata relating to the luminance of the video.
  • the metadata relating to the luminance of the video may be, for example, MaxCLL (Maximum Content Light Level) or MaxFALL (Maximum Frame-Average Light Level).
  • MaxCLL is a value indicating the maximum luminance of the pixel in all frames in the content. That is, MaxCLL is the peak luminance of the video.
  • MaxFALL is a value indicating the maximum value of the average luminance in the frame in all frames in the content. That is, MaxFALL is the average luminance of the video.
  • FIG. 20 is a flowchart showing a conversion method by the conversion apparatus according to the second embodiment.
  • the UI display unit 111 of the conversion device 110 displays a UI for determining the maximum value (DPL) of the second dynamic range on the TV (S301).
  • the timing for displaying the UI may be when the conversion apparatus 110 determines that the content to be reproduced is HDR content and the connected TV is a non-HDR compatible TV.
  • FIG. 21 is a diagram illustrating an example of a message screen.
  • an image quality setting button 121 and a cancel button 122 are displayed together with a message. If the image quality setting button 121 is selected and determined by the user, the screen transitions to the next image quality setting screen 130. If the cancel button 122 is selected and determined by the user, the reproduction processing of the HDR compatible disc is stopped, and the home screen (not shown) is returned.
  • the conversion device 110 transitions to an image quality setting screen 130 as shown in FIG. 22, for example, when the “image quality setting” button 121 on the message screen 120 is selected and determined by an input to the user's remote control or the like.
  • FIG. 22 is a diagram illustrating an example of the image quality setting screen.
  • a dynamic range conversion adjustment button 131 for transitioning to a conversion adjustment screen 140 on which a UI for setting DPL is displayed. That is, the image quality setting screen 130 is a setting menu of the conversion device 110, and is an example of a guide screen to a menu for setting DPL.
  • the image quality setting screen 130 may include buttons for transitioning to a screen for performing resolution adjustment, noise reduction, and brightness / color adjustment, and buttons for returning the image quality setting to the standard. Good.
  • FIG. 23 is a diagram illustrating an example of a dynamic range conversion adjustment screen.
  • the slider 141 as a UI for setting the maximum value (DPL) of the second dynamic range, the message 142 explaining the dynamic range conversion adjustment, and the slider 141 are moved.
  • a message 143 for explaining the effect of the time, a sample image 144, an enter button 145, and an undo button 146 are displayed.
  • the UI is displayed on the TV by displaying the dynamic range conversion adjustment screen 140.
  • the dynamic range conversion adjustment screen 140 is a setting menu for the conversion device 110 and is a menu screen for setting DPL.
  • the dynamic range conversion adjustment screen 140 causes the user to set an appropriate DPL value by comparing brightening with a dynamic range feeling.
  • FIG. 24 is a diagram illustrating another example of the dynamic range conversion adjustment screen.
  • the dynamic range conversion adjustment screen 150 displays a message 151 that prompts the user to confirm whether the brightness setting of the non-HDR compatible TV is an appropriate setting, instead of the message 143 of the dynamic range conversion adjustment screen 140.
  • a message 151 that prompts the user to confirm whether the brightness setting of the non-HDR compatible TV is an appropriate setting, instead of the message 143 of the dynamic range conversion adjustment screen 140.
  • the display device is in an appropriate display mode and is not set to be set to output the maximum luminance, the image after pseudo HDR conversion does not function properly. For this reason, displaying the message 151 can prompt the user to check whether the brightness setting of the display device is an appropriate setting.
  • the input receiving unit 112 of the conversion apparatus 110 receives input from the user via the remote controller or the like (S302).
  • the determination unit 113 of the conversion device 110 determines the second dynamic range according to the input received by the input reception unit 112 (S303).
  • the conversion apparatus 110 changes the luminance of the sample image 144 to the luminance defined by the determined second dynamic range (S304).
  • the slider 141 is an example of the UI described above, and is a UI for changing the maximum value of the second dynamic range in accordance with the position of the knob.
  • the sample image 144 is an image in which, for example, 11 levels of luminance gradation are expressed.
  • the brightness of the sample image 144 is adjusted according to the position of the knob of the slider 141. Therefore, the user can set an appropriate DPL according to the position of the knob by moving the knob of the slider 141 so that all gradations can be distinguished.
  • FIG. 25 is a diagram illustrating another example of the dynamic range conversion adjustment screen.
  • the dynamic range conversion adjustment screen 160 has a luminance distribution in a wide range in the content, instead of the sample image 144 that is an image in which gradation levels of eleven levels of brightness are expressed in the dynamic range conversion adjustment screens 140 and 150.
  • a sample image 161 as an image is displayed.
  • the conversion apparatus 110 determines whether or not the determination button 145 is selected and determined (S305). If the determination button 145 is selected and determined (Yes in S305), the luminance of the content to be reproduced is converted to the luminance defined by the second dynamic range having the determined DPL value as the maximum value, Output to a non-HDR compatible TV (S306). If the determination button 145 is selected and not determined (No in S305), the process returns to step S302.
  • the enter button 145 is a button for determining the DPL value adjusted by the slider 141. If the enter button 145 is selected and determined, the value is changed to the DPL value adjusted by the slider 141. Is done.
  • the undo button 146 is a button for returning to the DPL value that was set before adjustment by the slider 141. If the undo button 146 is selected and determined, before the adjustment by the slider 141, Return to the DPL value that was set to.
  • the determination button 145 and the undo button 146 are not necessarily displayed, and the DPL value may be determined at the position where the slider 141 is moved. That is, in this case, when the adjustment by the slider 141 is finished and the home screen is returned, it is assumed that the DPL value is changed according to the position where the knob of the slider 141 is moved, and this value is set to the maximum value.
  • the second dynamic range may be determined.
  • the conversion device 110 guides the user to adjust visual effects such as whether the sample image is bright or dark as a whole and whether there is a sense of resolution as a whole while allowing the user to visually recognize the sample image. That is, the user determines that the user is preferable while viewing the visual effect reflected in the displayed sample image, instead of directly inputting the DPL value of the non-HDR compatible TV to the conversion device 110.
  • the conversion device 110 can set the DPL value corresponding to the position of the slider knob.
  • the user does not need to directly input a numerical value such as 700 nit, 500 nit, 350 nit, or 200 nit as the DPL value, and the visual effect that the user has determined is appropriate by visually recognizing the visual effect reflected in the sample image.
  • the degree can be specified, and the DPL value suitable for the HDR ⁇ pseudo HDR conversion process can be determined indirectly and intuitively.
  • the user can indirectly determine the value of DPL by adjusting the position of the knob of the slider 141 to a position that is appropriate in appearance rather than a numerical value.
  • the pseudo HDR conversion can be performed by the conversion device 110.
  • the dynamic range can be easily determined. For this reason, it is possible to easily appropriately convert the luminance of the video defined by the first dynamic range into the luminance of the second dynamic range that can be displayed by the display device.
  • a sample image whose luminance is defined in the second dynamic range determined in the determination is displayed on the display device. For this reason, the user can confirm whether the 2nd dynamic range determined according to the input with respect to UI is an appropriate dynamic range with respect to a display apparatus by seeing a sample image. For this reason, the user can intuitively determine the second dynamic range appropriate for the display device by performing input to the UI.
  • HDR video is, for example, video in Blu-ray (registered trademark) Disc, DVD, Internet video distribution site, broadcast, HDD.
  • the conversion device 100 may exist inside a disc player, a disc recorder, a set top box, a television, a personal computer, or a smartphone.
  • the conversion device 100 may exist inside a server device in the Internet.
  • the display device 200 (SDR display unit) is, for example, a television, a personal computer, or a smartphone.
  • the display characteristic information acquired by the conversion apparatus 100 may be acquired from the display apparatus 200 via an HDMI (registered trademark) cable or a LAN cable using HDMI (registered trademark) or another communication protocol.
  • the display characteristic information acquired by the conversion apparatus 100 may acquire display characteristic information included in the model information of the display apparatus 200 via the Internet.
  • the user may perform a manual operation to set display characteristic information in the conversion device 100.
  • the display characteristic information of the conversion device 100 may be acquired immediately before the pseudo HDR video generation (steps S101 to S104), or may be at the time of initial setting of the device or at the time of display connection.
  • the display characteristic information may be acquired immediately before the conversion to the display luminance value, or may be performed at the timing when the conversion device 100 is first connected to the display device 200 with an HDMI (registered trademark) cable.
  • HDR video CPL or CAL there may be one HDR video CPL or CAL per content, or there may be one for each scene. That is, in the conversion method, the luminance information corresponding to each of the plurality of scenes of the video, and for each scene, the first maximum luminance value that is the maximum value among the luminance values for the plurality of images constituting the scene. And luminance information (CPL, CAL) including at least one of average luminance values that are averages of luminance values for a plurality of images constituting the scene, and in the first luminance conversion, for each of the plurality of scenes, The display brightness value may be determined according to the brightness information corresponding to the scene.
  • CPL and CAL may be bundled with the same medium (Blu-ray (registered trademark) Disc, DVD, etc.) as the HDR video, or separately from the HDR video, such as the conversion device 100 obtaining from the Internet. You may get it from the place. That is, luminance information including at least one of CPL and CAL may be acquired as video meta information or may be acquired via a network.
  • medium Blu-ray (registered trademark) Disc, DVD, etc.
  • luminance information including at least one of CPL and CAL may be acquired as video meta information or may be acquired via a network.
  • a fixed value may be used without using CPL, CAL, and display peak luminance (DPL). Further, the fixed value may be changed from the outside.
  • CPL, CAL, and DPL may be switched in several types. For example, DPL may be set to only three types of 200 nit, 400 nit, and 800 nit, and the value closest to the display characteristic information is used. You may make it do.
  • the HDR EOTF may not be SMPTE 2084, but other types of HDR EOTF may be used.
  • the maximum luminance (HPL) of the HDR video may not be 10,000 nits, for example, 4,000 nits or 1,000 nits.
  • the bit width of the code value may be 16, 14, 12, 10, 8 bits, for example.
  • inverse SDR EOTF conversion is determined from the display characteristic information, a fixed conversion function (which can be changed from the outside) may be used. Inverse SDR EOTF conversion is performed in, for example, Rec. ITU-R BT. A function defined in 1886 may be used. Also, the types of inverse SDR EOTF conversion may be limited to several types, and the one closest to the input / output characteristics of the display device 200 may be selected and used.
  • the display mode may be a fixed mode and may not be included in the display characteristic information.
  • the conversion device 100 may not transmit the setting information, and the display device 200 may have a fixed display setting or may not change the display setting.
  • the display setting unit 201 is not necessary.
  • the setting information may be flag information indicating whether or not the image is a pseudo HDR video.
  • the setting information may be changed to a setting that displays the brightest image. That is, in the display setting setting (S105), when the acquired setting information indicates that the signal indicates a pseudo-HDR image converted using DPL, the brightness setting of the display device 200 is set to display the brightest. You may switch to.
  • the backlight maximum luminance for displaying the DPL value of TV 100 nit for SDR, and the maximum luminance value for pseudo-HDR depending on the type of content to be reproduced (HDR or SDR) It is also possible to set the TV appropriately depending on the type of content by sending the setting using an HDMI (registered trademark) CEC command.
  • the first luminance conversion (HPL ⁇ DPL) of the conversion device 100 is converted by the following formula, for example.
  • L indicates a luminance value normalized to 0 to 1
  • S1, S2, a, b, and M are values set based on CAL, CPL, and DPL.
  • V is a luminance value after conversion normalized to 0 to 1.
  • CAL is set to 300 nits
  • CPL is set to 2,000 nits
  • DPL is set to 750 nits
  • conversion is not performed up to CAL + 50 nits. It becomes a value like this.
  • the conversion formula can be changed according to the content, and conversion can be performed so as to keep the HDR gradation as much as possible. It becomes.
  • adverse effects such as being too dark and too bright can be suppressed.
  • the gradation is kept as much as possible by mapping the content peak luminance of the HDR video to the display peak luminance.
  • the overall brightness is prevented from changing by not changing the pixel values below the average luminance.
  • the conversion formula can be changed according to the display environment of the SDR display, and there is a sense of HDR according to the performance of the SDR display.
  • Video can be displayed with the same gradation and brightness as the original HDR video.
  • the display peak brightness is determined according to the maximum brightness of the SDR display and the display mode, and the HDR video is converted so as not to exceed the peak brightness value.
  • the display is performed with almost no gradation reduction, and the brightness that cannot be displayed is reduced to the displayable brightness.
  • the display can be displayed in a form close to the original HDR video without reducing the gradation of displayable brightness.
  • the overall brightness is maintained by converting to a pseudo HDR video with a peak luminance of 1,000 nits, and the luminance value changes depending on the display mode of the display. For this reason, the luminance conversion formula is changed according to the display mode of the display. If the pseudo-HDR image allows a luminance larger than the peak luminance of the display, the high luminance may be replaced with the peak luminance on the display side, and in that case, it is darker than the original HDR video. Become.
  • the performance relating to the gradation of the display is not used at the maximum.
  • the pseudo HDR video can be better displayed by switching the display setting using the setting information. For example, when the brightness is set to dark, high brightness display cannot be performed, so that the HDR feeling is impaired. In that case, by changing the display setting or displaying a message prompting the user to change the display setting, the display performance can be maximized and a high gradation video can be displayed.
  • video signals and graphics signals such as subtitles and menus are multiplexed as independent data. At the time of reproduction, each is decoded individually, and the decoded result is synthesized and displayed. Specifically, subtitles and menu planes are superimposed on the video plane.
  • graphics signals such as subtitles and menus may be SDR.
  • HPL ⁇ DPL conversion of the video signal the following two conversions (a) and (b) are possible.
  • the graphics peak luminance is 100 nits.
  • the DPL is high luminance such as 1000 nits
  • the graphics luminance remains 100 nits.
  • the luminance of graphics is lowered with respect to the video after the HPL ⁇ DPL conversion.
  • adverse effects such as darkening of subtitles superimposed on video are assumed. Therefore, the luminance of graphics may be converted according to the value of DPL.
  • the luminance of the caption may be preliminarily defined as what percentage of the DPL value is set, and may be converted based on the set value. Graphics other than subtitles such as menus can be processed similarly.
  • FIG. 18 is a diagram for explaining multiplexed data stored in a dual disk.
  • the HDR signal and the SDR signal are stored as different multiplexed streams.
  • an optical disc such as Blu-ray (registered trademark)
  • data of multiple media such as video, audio, subtitles, and graphics is made into one multiplexed stream by an MPEG-2 TS-based multiplexing method called M2TS.
  • M2TS MPEG-2 TS-based multiplexing method
  • These multiplexed streams are referred to from reproduction control metadata such as playlists, and are reproduced by the player analyzing the metadata at the time of reproduction, or individual languages stored in the multiplexed stream. Select the data.
  • playlists for HDR and SDR are individually stored, and each playlist refers to an HDR signal or an SDR signal. Further, identification information indicating that both the HDR signal and the SDR signal are stored may be separately indicated.
  • HDR and SDR signals are multiplexed to satisfy a buffer model such as T-STD (System Target Decoder) defined in MPEG-2 TS.
  • T-STD System Target Decoder
  • Data such as audio, subtitles, or graphics needs to be stored for each multiplexed stream, and the amount of data increases compared to the case of multiplexing to one.
  • the increase in the amount of data can reduce the amount of video data by using a video encoding method with a high compression rate.
  • MPEG-4 AVC used in the conventional Blu-ray (registered trademark) to HEVC (High Efficiency Video Coding)
  • the compression ratio can be improved by 1.6 to 2 times.
  • the dual disk is stored in a combination of 2K HDR and SDR, such as a combination of 4K SDR and 2K HDR, or 2K, or a combination of 2K and 4K. It is also possible to allow only combinations that fit within the capacity of the optical disk by prohibiting storing two.
  • FIG. 27 is a flowchart showing the dual disk playback operation.
  • the playback apparatus determines whether the playback target optical disk is a dual disk (S401). If it is determined that the disk is a dual disk (Yes in S401), it is determined whether the output TV is HDRTV or SDRTV (S402). If it is determined that it is HDRTV (Yes in S402), the process proceeds to step S403. If it is determined that it is SDRTV (No in S402), the process proceeds to step S404. In step S403, an HDR video signal is acquired from the multiplexed stream including the HDR signal in the dual disc, decoded, and output to HDRTV. In step S404, an SDR video signal is acquired from the multiplexed stream including the SDR signal in the dual disc, decoded, and output to SDRTV. If it is determined in step S401 that the playback target is not a dual disc (No in S401), whether or not playback is possible is determined by a predetermined method, and a playback method is determined based on the determination result (S405).
  • the HDR video when HDR video is displayed in SDRTV, the HDR video is converted to SDR video of 100 nit or less by using the peak brightness of SDRTV to be displayed exceeds 100 nit (usually 200 nit or more). Instead, it realizes a “HDR ⁇ pseudo HDR conversion process” that can be converted to maintain a certain level of gradation in a region exceeding 100 nits, converted into pseudo HDR video close to the original HDR, and displayed on SDRTV.
  • the conversion method of “HDR ⁇ pseudo HDR conversion processing” may be switched depending on the display characteristics (maximum luminance, input / output characteristics, and display mode) of SDRTV.
  • the display characteristic information can be acquired by (1) automatically acquiring it via HDMI (registered trademark) or a network, (2) generating it by allowing the user to input information such as manufacturer name and product number, and (3) manufacturer. It can be obtained from the cloud using information such as name and product number.
  • the display characteristic information acquisition timing of the conversion device 100 includes (1) acquisition immediately before pseudo-HDR conversion, and (2) when connecting to the display device 200 (such as SDRTV) for the first time (when connection is established). ) Can be considered.
  • the conversion method may be switched according to the luminance information (CAL, CPL) of the HDR video.
  • the method of acquiring the luminance information of the HDR video of the conversion device 100 (1) acquiring as meta information attached to the HDR video, (2) acquiring by causing the user to input content title information, And (3) It is conceivable to acquire from the cloud or the like using input information that has been instructed by the user.
  • the details of the conversion method are as follows: (1) Conversion so as not to exceed DPL; (2) Conversion so that CPL becomes DPL; (3) CAL and its surrounding luminance are not changed; 4) Conversion using natural logarithm, (5) Clip processing by DPL.
  • display settings such as the SDRTV display mode and display parameters can be transmitted to the display device 200 and switched. For example, the user is prompted to perform display settings. A message may be displayed on the screen.
  • each component may be configured by dedicated hardware or may be realized by executing a software program suitable for each component.
  • Each component may be realized by a program execution unit such as a CPU or a processor reading and executing a software program recorded on a recording medium such as a hard disk or a semiconductor memory.
  • the present disclosure is useful as a conversion method, a conversion device, and the like that can appropriately convert luminance from the first luminance range to the second luminance range in which the luminance range is reduced.
  • SYMBOLS 100 Conversion apparatus 101 Conversion part 102 Brightness conversion part 103 Reverse brightness conversion part 104 Inverse SDR EOTF conversion part 200 Display apparatus 201 Display setting part 202 SDR EOTF conversion part 203 Brightness conversion part 204 Display part

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Picture Signal Circuits (AREA)
  • Two-Way Televisions, Distribution Of Moving Picture Or The Like (AREA)
  • Controls And Circuits For Display Device (AREA)

Abstract

L'invention concerne un procédé de conversion qui est exécuté par un appareil de conversion pour convertir la luminosité d'une vidéo, la luminosité étant définie par une première gamme dynamique, en une luminosité qui est définie par une seconde gamme dynamique qu'un appareil d'affichage peut afficher. La seconde gamme dynamique possède une valeur maximale inférieure et est plus étroite que la première gamme dynamique. L'appareil d'affichage, connecté à l'appareil de conversion, est amené à afficher une interface utilisateur (UI) pour déterminer la gamme dynamique de la vidéo que l'appareil d'affichage doit être amené à afficher (S301), une entrée d'un utilisateur dans l'UI affichée par l'appareil d'affichage est reçue (S302), la seconde gamme dynamique est déterminée en fonction de l'entrée reçue (S303), et la luminosité de la vidéo est convertie en une luminosité définie par la seconde gamme dynamique déterminée (S306).
PCT/JP2016/002946 2015-09-01 2016-06-20 Procédé et appareil de conversion Ceased WO2017037971A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US201562212751P 2015-09-01 2015-09-01
US62/212,751 2015-09-01
JP2016096576A JP2017050840A (ja) 2015-09-01 2016-05-12 変換方法および変換装置
JP2016-096576 2016-05-12

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003230022A (ja) * 2002-02-01 2003-08-15 Sony Corp 画像処理装置および方法、並びに記録媒体
JP2010239610A (ja) * 2009-03-13 2010-10-21 Omron Corp 画像処理装置および画像処理方法
JP2014531821A (ja) * 2011-09-27 2014-11-27 コーニンクレッカ フィリップス エヌ ヴェ 画像のダイナミックレンジ変換のための装置及び方法

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003230022A (ja) * 2002-02-01 2003-08-15 Sony Corp 画像処理装置および方法、並びに記録媒体
JP2010239610A (ja) * 2009-03-13 2010-10-21 Omron Corp 画像処理装置および画像処理方法
JP2014531821A (ja) * 2011-09-27 2014-11-27 コーニンクレッカ フィリップス エヌ ヴェ 画像のダイナミックレンジ変換のための装置及び方法

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