JP2019216431A - Display - Google Patents

Abstract

To achieve further improvement.SOLUTION: A display 510 according to an aspect of the present disclosure is connected to a playback unit, and comprises: a transmission unit that transmits, to the playback unit, information indicating a luminance conversion method designed for the display 510; a receiving unit that receives a video signal from the playback unit; and a display unit that displays the video signal. For example, when the video signal received by the receiving unit is a signal in which the luminance can be converted with the luminance conversion method designed for the display 510, the display unit may convert the luminance with the conversion method and display the video signal.SELECTED DRAWING: Figure 13

Description

  The present disclosure relates to a data output device, a data output method, and a data generation method.

  2. Description of the Related Art Conventionally, an image signal processing device for improving a displayable luminance level has been disclosed (for example, see Patent Document 1).

JP 2008-167418 A

  A display device according to an aspect of the present disclosure is a display device connected to a playback device, and a transmission unit that transmits, to the playback device, information indicating a luminance conversion method supported by the display device. A receiving unit that receives a video signal from the playback device; and a display unit that displays the video signal.

  Note that these comprehensive or specific aspects may be realized by a recording medium such as a system, a method, an integrated circuit, a computer program or a computer-readable CD-ROM, and the system, the method, the integrated circuit, and the computer program. Alternatively, it may be realized by an arbitrary combination of recording media.

FIG. 1 is a diagram for explaining the evolution of the video technology. FIG. 2 is a diagram for explaining the relationship between the master, the distribution method, and the display device when HDR is introduced. FIG. 3 is an explanatory diagram of a method of determining a code value of a luminance signal stored in a content, and a process of restoring a luminance value from the code value during reproduction. FIG. 4 is a diagram illustrating an example of HDR metadata. FIG. 5 is a diagram illustrating a storage example of static HDR metadata. FIG. 6 is a diagram illustrating a storage example of dynamic HDR metadata. FIG. 7 is a flowchart of a method for transmitting static HDR metadata. FIG. 8 is a flowchart of a method for processing HDR metadata. FIG. 9 is a block diagram illustrating a configuration of the data output device. FIG. 10 is a diagram illustrating an example of a data structure of an SEI message storing HDR metadata. FIG. 11 is a diagram illustrating an example of a data structure of an SEI message storing HDR metadata. FIG. 12 is a diagram illustrating an example of a data structure of an SEI message storing HDR metadata. FIG. 13 is a block diagram illustrating a configuration example of a data output device. FIG. 14 is a block diagram illustrating a configuration example of the DR conversion unit. FIG. 15 is a block diagram illustrating a configuration example of the DR conversion unit. FIG. 16 is a diagram illustrating an example of the instruction content of the HDR meta-interpretation unit. FIG. 17 is a diagram illustrating an example of the instruction content of the HDR meta-interpretation unit. FIG. 18 is a diagram illustrating an example of the instruction content of the HDR meta-interpretation unit. FIG. 19 is a block diagram illustrating a configuration example of a data output device. FIG. 20 is a diagram illustrating a combination example of the characteristics of the video signal and the display device and the output signal of the data output device. FIG. 21 is a diagram showing an example of an operation model when reproducing various signals and outputting signals to various TVs. FIG. 22 is a diagram illustrating an example of a user guidance display method. FIG. 23 is a diagram illustrating an example of a user guidance display method. FIG. 24 is a diagram illustrating an example of a method of displaying the user guidance. FIG. 25 is a diagram illustrating an example of a user guidance display method. FIG. 26 is a diagram for explaining the reproducing operation of the dual disc. FIG. 27 is a flowchart showing the operation of reproducing a dual disc. FIG. 28 is a diagram illustrating types of BDs. FIG. 29 is a diagram illustrating the types of BDs in more detail. FIG. 30 is a first diagram illustrating a data capacity recorded on the BD. FIG. 31 is a second diagram illustrating the data capacity recorded on the BD. FIG. 32 is a diagram illustrating an example of a combination of a video stream and a graphic stream recorded on each of a BD and a dual stream disc. FIG. 33 is a diagram illustrating another example of the combination of the video stream and the graphic stream recorded on each of the BD and the dual stream disc. FIG. 34 is a diagram showing still another example of a combination of a video stream and a graphic stream recorded on each of a BD and a dual stream disc. FIG. 35A is a diagram illustrating an example of a display process of performing HDR display by converting an HDR signal in an HDRTV. FIG. 35B is a diagram illustrating an example of a display process of performing HDR display using an HDR-compatible playback device and SDRTV. FIG. 35C is a diagram illustrating an example of a display process of performing HDR display on an HDR-compatible playback device and an SDRTV connected to each other via a standard interface. FIG. 36 is a diagram for describing the conversion processing from HDR to pseudo HDR. FIG. 37A is a diagram illustrating an example of an EOTF (Electro-Optical Transfer Function) corresponding to each of HDR and SDR. FIG. 37B is a diagram showing an example of inverse EOTF corresponding to each of HDR and SDR. FIG. 38 is a block diagram illustrating a configuration of a conversion device and a display device according to an embodiment. FIG. 39 is a flowchart illustrating a conversion method and a display method performed by the conversion device and the display device according to the embodiment. FIG. 40A is a diagram for describing the first luminance conversion. FIG. 40B is a diagram for describing another example of the first luminance conversion. FIG. 41 is a diagram for describing the second luminance conversion. FIG. 42 is a diagram for describing the third luminance conversion. FIG. 43 is a flowchart showing the detailed processing of the display setting.

  A data output device according to an aspect of the present disclosure is a data output device, and includes a decoding unit that generates a first video signal by decoding a video stream, and one or more first output units that convert a luminance range of the video signal. An acquisition unit that acquires one or more pieces of metadata corresponding to a conversion mode; a characteristic data indicating a luminance range of the first image signal by interpreting one of the one or more pieces of metadata; A conversion auxiliary data for converting a luminance range of a signal, an interpretation unit for acquiring the characteristic data, a control information generation unit for converting the characteristic data into control information according to a predetermined transmission protocol, and a luminance range of a video signal. And performing conversion processing of the luminance range of the first video signal in one of the one or more second conversion modes based on the conversion auxiliary data. In front Comprising a conversion unit for generating a second video signal of a narrow luminance range than the luminance range of the first video signal, and an output unit which outputs the second image signal and the control information to the display device in the transmission protocol.

  According to this, the data output device can change the luminance range of the video signal based on one or more pieces of metadata, and can output the converted video signal and control information.

  For example, the interpretation unit may further include the one or more first conversion modes, the one or more second conversion modes, and one or more first conversion modes for converting a luminance range of a video signal corresponding to the display device. Based on the three conversion modes, it may be determined which of the data output device and the display device performs the conversion process.

  According to this, the data output device has a first conversion mode corresponding to one or more metadata, a second conversion mode corresponding to the data output device, and a third conversion mode corresponding to the display device. , It is possible to determine which of the data output device and the display device performs the conversion process. Thus, the data output device can determine a device that performs the conversion process appropriately.

  For example, the conversion unit corresponds to a plurality of second conversion modes including the one or more second conversion modes, each corresponding to each of the plurality of second conversion modes, and a corresponding second conversion mode. May be provided.

  For example, the conversion unit includes a basic processing unit that performs common processing in the one or more second conversion modes, and a processing unit in the second conversion mode corresponding to each of the one or more second conversion modes. May be provided.

  For example, the interpreter further determines a conversion mode included in the one or more first conversion modes and included in the one or more second conversion modes as a conversion mode of a conversion process performed by the data output device. You may.

  According to this, the data output device can determine the conversion mode to be used based on the first conversion mode corresponding to one or more metadata and the second conversion mode corresponding to the data output device.

  For example, the interpretation unit may further include a conversion mode included in the one or more first conversion modes and a conversion mode included in at least one of the one or more second conversion modes and the third conversion mode. The conversion mode of the conversion process performed by the display device may be determined.

  According to this, the data output device has a first conversion mode corresponding to one or more metadata, a second conversion mode corresponding to the data output device, and a third conversion mode corresponding to the display device. The conversion mode to be used can be determined based on

  For example, the acquisition unit acquires a plurality of metadata corresponding to a plurality of first conversion modes including the one or more first conversion modes, and the conversion unit includes a plurality of metadata including the one or more second conversion modes. And the interpretation unit includes a plurality of conversions included in the plurality of first conversion modes and included in at least one of the plurality of second conversion modes and the third conversion mode. Among the modes, a conversion mode having the highest reproducibility with respect to a master image which is an image output without converting the luminance range may be determined as a conversion mode of a conversion process performed by the data output device or the display device.

  According to this, the data output device can select the conversion mode having the highest reproducibility with respect to the master image, so that the quality of the displayed video can be improved.

  For example, when the conversion mode of the determined conversion process is included in the second conversion mode and not included in the third conversion mode, the interpretation unit performs the conversion process on the data output device. You may decide to do it.

  For example, when the conversion mode of the determined conversion process is included in the third conversion mode and is not included in the second conversion mode, the interpretation unit performs the conversion process on the display device. May be determined.

  For example, the interpretation unit may further determine whether or not a parameter for each of the plurality of first conversion modes can be obtained from the display device, and perform the conversion process performed by the data output device or the display device. The conversion mode may be determined.

  According to this, the data output device determines the conversion mode to be used depending on whether or not the parameters of the display device can be acquired, so that a more appropriate conversion mode can be selected.

  For example, the interpretation unit is included in the plurality of first conversion modes, is included in at least one of the plurality of second conversion modes, and the third conversion mode, and can acquire the parameter from the display device. The conversion mode may be determined as a conversion mode of a conversion process performed by the data output device or the display device.

  For example, the parameter may indicate a maximum value of a luminance range that can be displayed by the display device or a display mode in which the display device can display.

  For example, the data output device further includes a down-converting unit that generates a third video signal by reducing the resolution of the first video signal, and the output unit further outputs the third video signal to the display device. May be output to

  According to this, the data output device can change the resolution of the video signal to a resolution suitable for, for example, a display device.

  For example, the conversion unit may further perform a conversion process of a luminance range of the third video signal in one of the one or more second conversion modes based on the conversion auxiliary data, so that the third video signal is converted. May generate a fourth video signal having a luminance range narrower than the luminance range, and the output unit may further output the fourth video signal to the display device.

  According to this, the data output device can change the resolution and the luminance range of the video signal to a resolution and a luminance range suitable for, for example, a display device.

  For example, when the display device does not support displaying a video having the resolution of the first video signal, (1) the down-converter generates the third video signal, and (2) the output unit And outputting the third video signal to the display device.

  For example, when the display device does not support display of an image in the luminance range of the first image signal, (1) the conversion unit generates the second image signal, and (2) the output unit And outputting the second video signal and the control information to the display device.

  Further, a data output method according to an aspect of the present disclosure is a data output method in a data output device, wherein a decoding step of generating a first video signal by decoding a video stream, and converting a luminance range of the video signal. Acquiring one or more pieces of metadata corresponding to one or more first conversion modes, and interpreting one of the one or more pieces of metadata to obtain characteristic data indicating a luminance range of the first video signal. An interpretation step of acquiring conversion auxiliary data for converting a luminance range of the first video signal, and a control information generation step of converting the characteristic data into control information according to a predetermined transmission protocol; A conversion unit corresponding to one or more second conversion modes for converting a luminance range of a video signal, based on the conversion auxiliary data, converts any one of the one or more second conversion modes. Converting the luminance range of the first video signal to generate a second video signal having a luminance range narrower than the luminance range of the first video signal, and the second video signal and the control information. Outputting to the display device using the transmission protocol.

  According to this, the data output method includes a first conversion mode corresponding to a plurality of metadata, a second conversion mode corresponding to the data output device, and a third conversion mode corresponding to the display device. , It can be determined which of the data output device and the display device performs the conversion process. Thus, the data output method can determine a device that performs the conversion process appropriately.

  A program according to an embodiment of the present disclosure causes a computer to execute the data output method.

  Further, a data generation method according to an aspect of the present disclosure is a data generation method performed by a data generation device, and generates one or more metadata corresponding to one or more conversion modes for converting a luminance range of a video signal. A first generation step; and a second generation step of generating a video stream including the video signal, the one or more metadata, and a conversion mode number indicating the number of the one or more conversion modes.

  According to this, the data generation method can generate a video stream including metadata corresponding to one or more conversion modes. Thus, an appropriate conversion mode can be selected in a playback device or the like that plays back the video stream.

  Note that these comprehensive or specific aspects may be realized by a recording medium such as a system, a method, an integrated circuit, a computer program or a computer-readable CD-ROM, and the system, the method, the integrated circuit, and the computer program. Alternatively, it may be realized by an arbitrary combination of recording media.

  Regarding the above features, mainly [10. Example of storage of multiple HDR metadata] to [13. Configuration Example 2 of Data Output Device].

  Each of the embodiments described below shows a specific example of the present disclosure. Numerical values, shapes, materials, and components shown in the following embodiments. The arrangement positions and connection forms of components, the steps, the order of the steps, and the like are merely examples, and do not limit the present disclosure. In addition, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims indicating the highest concept are described as optional constituent elements.

(Embodiment)
[1. background]
An HDR (High Dynamic Range) signal, which is an image signal having a higher luminance range than a conventional image signal, is a package medium such as a Blu-ray (registered trademark, hereinafter the same) disk storing the HDR signal, a broadcast, or an OTT (Over The Theme). Top) and other distribution media. Here, the OTT means a Web site provided on the Internet, a content or service such as a moving image or a voice, or a business entity that provides them. The delivered HDR signal is decoded by a Blu-ray device or the like. Further, the decoded HDR signal is sent to an HDR-compatible display device (TV, projector, tablet, smartphone, or the like), and the HDR-compatible display device reproduces an HDR video.

  HDR technology is still in its infancy, and it is assumed that a new HDR scheme will be developed after the first introduced HDR technology is adopted. In this case, the new HDR method can be adopted by storing the newly created HDR signal (and metadata) in the HDR distribution medium. According to the present disclosure, a distribution medium storing a new HDR signal format (metadata) can be used in the original technology without changing a decoding device (for example, a Blu-ray device) designed for the original distribution medium. An HDR decoding device (for example, a Blu-ray device) which supports HDR reproduction by guaranteeing compatibility by guaranteeing the HDR reproduction realizes a method and an apparatus which can support processing of a new HDR method. .

  First, the transition of the video technology will be described with reference to FIG. FIG. 1 is a diagram for explaining the evolution of the video technology.

  Up to now, emphasis has been placed on increasing the number of display pixels in order to improve the image quality of video, and from 720 × 480 pixel video of Standard Definition (SD) to 1920 × 1080 pixel of High Definition (HD), so-called 2K. Video is widespread.

  In recent years, the introduction of a so-called 4K video of 3840 × 1920 pixels of Ultra High Definition (UHD) or 4096 × 1920 pixels of 4K has been started in order to further improve the image quality of the video.

  In addition to increasing the resolution of an image by introducing 4K, it is also being studied to enhance the image quality by expanding the dynamic range, expanding the color gamut, or adding or improving the frame rate.

  Among them, as for the dynamic range, the maximum luminance is used to express bright light such as specular reflection light, which cannot be expressed by the current TV signal, with more realistic brightness while maintaining the dark part gradation in the conventional video. Attention has been paid to HDR (High Dynamic Range) as a method corresponding to a luminance range in which the value is enlarged. Specifically, the method of the luminance range to which the TV signal corresponds so far is called SDR (Standard Dynamic Range), and the maximum luminance value is 100 nit, whereas the maximum luminance value is 1000 nit or more in HDR. It is assumed that the brightness value is increased. HDR is being standardized in SMPTE (Society of Motion Picture & Television Engineers) and ITU-R (International Telecommunications Union Radiocommunications Sector).

  As a specific application destination of HDR, similarly to HD and UHD, it is assumed that the HDR is used for broadcasting, package media (Blu-ray Disc, etc.), Internet distribution, and the like.

  Hereinafter, in a video corresponding to HDR, the luminance of the video includes a luminance value in a luminance range of HDR, and a luminance signal obtained by quantizing the luminance value of the video is referred to as an HDR signal. . In an image corresponding to SDR, the luminance of the image includes luminance values in a luminance range of the SDR, and a luminance signal obtained by quantizing the luminance value of the image is referred to as an SDR signal.

[2. Relationship between master, distribution method, and display device when HDR is introduced]
FIG. 2 is a diagram showing a flow of producing a master for home entertainment of SDR and HDR, and a relationship between a distribution medium and a display device.

  The concept of HDR has been proposed, and its effectiveness at the concept level has been confirmed. Also, a first method of implementing HDR has been proposed. However, HDR content was produced in large quantities using this method, and the first implementation method was not demonstrated. For this reason, if the production of HDR content is started in earnest in the future, there is a possibility that the current HDR production method, particularly the metadata, will change.

[3. How to use EOTF]
FIG. 3 is an explanatory diagram of a method of determining a code value of a luminance signal stored in a content and a process of restoring a 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 graded image is quantized by the inverse EOTF of HDR, and a code value corresponding to the luminance value of the image is determined. Image coding and the like are 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 the HDR EOTF, and the luminance value of each pixel is restored. Hereinafter, quantization using inverse HDR EOTF is referred to as “inverse HDR EOTF conversion”. Inverse quantization using HDR EOTF is referred to as “HDR EOTF conversion”. Similarly, quantization using SDR inverse EOTF is referred to as “inverse SDR EOTF conversion”. Inverse quantization using SDR EOTF is referred to as “SDR EOTF conversion”.

  Using the luminance value and the metadata, the video conversion processing unit converts the luminance value into a luminance value that can be displayed on the video display unit, so that the HDR video can be displayed on the video display unit. For example, when the peak brightness of the original HDR video is 2000 nit and the peak brightness of the video display unit is 800 nit, the conversion can be performed to reduce the brightness.

  As described above, the HDR master system is realized by a combination of the EOTF, the metadata, and the HDR signal. Therefore, more efficient EOTFs and metadata may be developed, and it may be time to adopt the HDR scheme using such EOTFs and metadata.

  However, it is not known at this time what the new scheme will be, but it is possible to imagine the possibility that the EOTF will be changed and the possibility that metadata will be added. In this case, the HDR signal itself changes.

  The present disclosure aims to spread HDR by reducing the risk that a customer who has purchased an HDR-compatible device will buy a new device even when the HDR transmission format is changed in this way.

[4. Metadata]
FIG. 4 is a diagram illustrating an example of HDR metadata. The HDR metadata includes conversion auxiliary information used for changing (DR conversion) the luminance range of the video signal and HDR control information. Each piece of information is, for example, either static HDR metadata provided for each title or dynamic HDR metadata provided for each frame. The static HDR metadata is classified into one of essential metadata (basic data) and selected metadata (extended data), and the dynamic HDR metadata is classified as selected metadata. The details of each information will be described later.

[5. HDR metadata]
As parameters indicating characteristics at the time of mastering in HDR content, there are static HDR metadata that is fixed for each title or playlist and dynamic HDR metadata that is variable for each scene. Here, the title and the playlist are information indicating a video signal that is continuously reproduced. Hereinafter, a video signal that is continuously reproduced is referred to as a continuous reproduction unit.

  For example, the static HDR metadata includes at least one of the type of the EOTF function (curve), the 18% Gray value, the Diffuse White value, the Knee point, and the Clip point. EOTF is information that associates a plurality of luminance values with a plurality of code values, and is information for changing the luminance range of a video signal. Since the other information is attribute information relating to the luminance of the video signal, the static HDR metadata is information relating to the luminance range of the video signal, and can be said to be information for specifying the luminance range of the video signal.

  Specifically, the 18% Gray value and the Diffuse White value indicate a luminance value (nit) in an image having a predetermined reference brightness, in other words, indicate a reference brightness in the image. More specifically, the 18% Gray value indicates a luminance value (nit) after mastering of an object having a brightness of 18 nit before mastering. The Diffuse White value indicates a luminance value (nit) corresponding to white.

  Further, Knee point and Clip point are parameters of the EOTF function, and indicate points at which characteristics in the EOTF change. Specifically, the Knee point is different from the one-to-one increase in the luminance value (output luminance) mapped to the EOTF as the luminance of the video signal with respect to the increase in the original luminance value (input luminance) at the time of shooting. Indicates a change point as a value. For example, Knee point is information for specifying a point deviating from a linear change in FIG. 30A described later. Clip point indicates the point at which clipping starts in the EOTF function. Here, clip means to convert an input luminance value equal to or greater than a certain value into the same output luminance value. For example, Clip point indicates a point at which the output luminance value does not change in FIG. 30B described later.

  The types of the EOTF function (curve) are, for example, the HDR EOTF and the SDR EOTF shown in FIG. 27A.

  As described above, the content data generation method according to the present embodiment is a content data generation method for generating content data, in which a video signal and a plurality of images (the continuous A first generation step of generating static HDR metadata (first metadata), which is information used in common with respect to a video signal constituting the video signal and includes information on a luminance range of the video signal, And generating static content data by associating the content data with the static HDR metadata. For example, the information on the luminance range of the video signal is information for converting the luminance range of the video signal.

  The static HDR metadata includes information for specifying an EOTF that associates a plurality of luminance values with a plurality of code values. The luminance value in the video signal is encoded as a code value.

  Further, the static HDR metadata further includes information indicating a luminance value in a video signal having a predetermined reference brightness or information indicating a point at which a characteristic in the EOTF changes. For example, the static HDR metadata includes information (Diffuse White value) indicating a luminance value corresponding to white in a video signal.

  Further, in the first generation step, dynamic HDR metadata (second metadata) which is information commonly used for a unit finer than the continuous reproduction unit and which is information regarding a luminance range of a video signal is further generated. . For example, the information on the luminance range of the video signal is information for converting the luminance range of the video signal.

  The dynamic HDR metadata is a parameter indicating a mastering characteristic that differs for each scene. Here, the mastering characteristic indicates a relationship between the original (before mastering) luminance and the luminance after mastering. For example, the parameter indicating the mastering characteristic is the same information as the static HDR metadata described above, in other words, at least one of the information included in the static HDR metadata.

  FIG. 5 is a diagram illustrating a storage example of static HDR metadata. In this example, static HDR metadata is stored in a playlist on a package medium such as a Blu-ray disc.

  Static HDR metadata is stored as one piece of metadata for each stream referenced from the playlist. In this case, the static HDR metadata is fixed for each playlist. That is, the static HDR metadata is stored in association with each playlist.

  In the OTT, static HDR metadata may be stored in a manifest file that is referred to before acquiring a stream. That is, in the content data generation method according to the present embodiment, a video signal may be generated as a video stream, and the static HDR metadata may be stored in a manifest file referred to before the video stream is obtained.

  In broadcasting, static HDR metadata may be stored in a descriptor indicating an attribute of a stream. That is, the content data generation method according to the present embodiment may generate content data as a video stream and store the static HDR metadata as an identifier indicating the attribute of the video stream independently of the video stream. . For example, static HDR metadata can be stored as a descriptor (descriptor) in MPEG2-TS.

  If the static HDR metadata is fixed for each title, the static HDR metadata may be stored as management information indicating the attribute of the title.

  FIG. 6 is a diagram illustrating an example of storing dynamic HDR metadata in a video stream. In MPEG-4 AVC or HEVC (High Efficiency Video Coding), information related to stream reproduction control is stored using a data structure called SEI (Supplemental Enhancement Information). Therefore, for example, dynamic HDR metadata is stored in SEI.

  It is assumed that the dynamic HDR metadata is updated for each scene. The head of a scene is the first access unit (AU) of a random access unit such as a GOP (Group Of Pictures). Therefore, the dynamic HDR metadata may be stored in the first access unit in the decoding order in the random access unit. The head access unit of the random access unit is an IDR picture or a non-IDR I picture to which an SPS (Sequence Parameter Set) is added. Therefore, the device on the receiving side can acquire the dynamic HDR metadata by detecting the NAL (Network Abstraction Layer) unit constituting the head access unit of the random access unit. Alternatively, a unique type may be given to the SEI that stores the dynamic HDR metadata.

  The type of the EOTF function may be stored as stream attribute information in the SPS. That is, in the content data generation method according to the present embodiment, content data may be generated as a video stream encoded by HEVC, and information for specifying the EOTF may be stored in the SPS included in the video stream.

[6. Transmission method of static HDR metadata]
FIG. 7 is a diagram illustrating a method of transmitting static HDR metadata, which is transmitted to a display device through a transmission protocol such as HDMI (registered trademark, hereinafter the same) in a playback device such as a BD player (Blu-ray device) or a recorder. 6 is a flowchart illustrating an operation example when transmitting an HDR signal.

  As described above, the static HDR metadata is fixed in title units or playlist units. Accordingly, when the setting of the static HDR metadata is necessary (Yes in S401), the playback device acquires the static HDR metadata from the management information of the content at the time of starting the playback of the title or the playlist and obtains the static HDR metadata. The static HDR metadata is stored and transmitted as HDMI control information. In other words, the playback device acquires the static HDR metadata corresponding to the title or the playlist before starting transmission of the video signal forming the title or the playlist, and controls the acquired static HDR metadata to control the HDMI. The information is transmitted as information (S402). More generally, the playback device may transmit static HDR metadata as initialization information when performing the HDMI initialization process between the playback device and the display device.

  Thereafter, the playback device transmits a video stream corresponding to the static HDR metadata (S403). Note that the transmitted static HDR metadata is valid for this video stream.

  As described above, the video stream transmission method according to the present embodiment is a video stream transmission method for transmitting a video stream (video stream), and is common to a video signal and a plurality of images included in a continuous playback unit. Acquiring content data including static HDR metadata (first metadata) related to a luminance range of a video signal, a video stream corresponding to the video signal, and a static HDR meta data. And transmitting the data.

  For example, in the transmission step, the video stream and the static HDR metadata are transmitted according to the HDMI communication protocol.

  Also, the dynamic HDR metadata is transmitted as a part of a video stream.

  Note that the playback device may transmit the dynamic HDR metadata as an HDMI control signal at a timing when the dynamic HDR metadata is valid. At this time, the playback device provides an identifier or the like to the static HDR metadata and the dynamic HDR metadata and transmits the static HDR metadata and the dynamic HDR metadata so that they can be distinguished from each other.

  In the control signal, only the data structure of the container for storing the dynamic HDR metadata may be defined, and the content of the SEI may be directly copied as the payload data of the container. Thereby, even if the syntax of the dynamic HDR metadata included in the SEI is updated, it can be dealt with without changing the implementation of a playback device such as a BD player.

  Similarly, if the static HDR metadata in the content management information can be copied and transmitted so that the static HDR metadata can be transmitted, even if the syntax of the static HDR metadata is changed, It can be handled without changing the implementation. That is, the data structure of the container for storing the static HDR metadata is defined. In the transmission step, the static HDR metadata included in the content data is copied to the payload of the container, and the container is transmitted. You may.

[7. HDR metadata processing method]
FIG. 8 is a flowchart illustrating an example of a method of processing HDR metadata when an HDR signal is displayed on a display device. First, the display device acquires static HDR metadata from HDMI control information (S411), and determines a display method of an HDR signal based on the acquired static HDR metadata (S412).

  When the control information does not include the static HDR metadata, the display device determines a display method of the HDR signal based on a value predetermined in an application standard or a default setting of the display device. . In other words, the video display method according to the present embodiment determines a video display method corresponding to a video signal based on a predetermined value or setting when static HDR metadata cannot be acquired.

  When detecting dynamic HDR metadata in SEI or the like in the video stream (Yes in S413), the display device updates the display method of the HDR signal based on the dynamic HDR metadata (S414). That is, when the static HDR metadata is acquired, the video display method according to the present embodiment determines the display method based on the acquired static HDR metadata, displays the video, and acquires the dynamic HDR metadata. In this case, the display method determined based on the static HDR metadata is updated to the display method determined based on the dynamic HDR metadata, and the video is displayed. Alternatively, the display method may be determined based on both the static HDR metadata and the dynamic HDR metadata.

  When the display device does not support acquisition of dynamic HDR metadata, the display device may operate based on only static HDR metadata. Further, even when the display device supports acquisition of dynamic HDR metadata, the display device displays the HDR signal in synchronization with the display time (PTS: Presentation Time Stamp) of the access unit in which the metadata is stored. Sometimes the method cannot be updated. In this case, after acquiring the metadata, the display device may update the display method from the access unit displayed after the earliest time at which the display method can be updated.

  By adding version information and the like to the HDR metadata, updating and addition of parameters can be handled. Accordingly, the display device can determine whether the metadata can be interpreted based on the version information of the HDR metadata. Alternatively, the HDR metadata may be composed of a basic part and an extended part, and updating or adding a parameter may be performed by changing the extended part, and the basic part may not be updated. That is, each of the static HDR metadata and the dynamic HDR metadata has a plurality of versions, and may include a basic part commonly used in a plurality of versions and an extended part different for each version. By doing so, backward compatibility in the display device can be ensured based on the HDR metadata of the basic part.

  As described above, the video display method according to the present embodiment is a video display method for displaying video based on a video stream, and includes a video stream corresponding to a video signal and static HDR metadata (first metadata). And a display step of determining and displaying a video display method corresponding to the video signal based on the static HDR metadata.

  In addition, the luminance value in the video signal is encoded as a code value, and the static HDR metadata includes information for specifying an EOTF that associates a plurality of luminance values with a plurality of code values. In the step, a video is generated by converting a code value represented by the video signal into a luminance value using the EOTF specified by the static HDR metadata.

[8. Data output device]
FIG. 9 is a block diagram illustrating a configuration of a data output device 400 that outputs an HDR signal, such as a BD player. The HDR metadata input to the data output device 400 indicates characteristic data indicating a mastering characteristic of the HDR signal and a tone mapping method for converting the HDR signal into an SDR signal or converting a dynamic range of the HDR signal. And conversion auxiliary data. These two types of metadata are stored as static HDR metadata or dynamic HDR metadata, as described in FIGS. Further, the static HDR metadata is stored in at least one of the content management information and the video stream.

  The data output device 400 includes a video decoding unit 401, an external meta acquisition unit 402, an HDR meta interpretation unit 403, an HDR control information generation unit 404, a DR conversion unit 405, and an HDMI output unit 406.

  The video decoding unit 401 generates a video signal (first video signal) by decoding a video stream that is an encoded stream of video, and outputs the obtained video signal to the DR conversion unit 405. Also, the video decoding unit 401 acquires HDR metadata (second metadata) (static HDR metadata or dynamic HDR metadata) in the video stream. Specifically, the video decoding unit 401 outputs the HDR metadata stored in an MPEG-4 AVC or HEVC SEI message or the like to the HDR meta interpreting unit 403.

  The external meta acquisition unit 402 acquires static HDR metadata (first metadata) stored in content management information such as a playlist, and outputs the acquired static HDR metadata to the HDR meta interpretation unit 403. . Here, dynamic HDR metadata that can be changed in a predetermined unit that can be randomly accessed, such as a play item, may be stored in the content management information. In this case, the external meta acquisition unit 402 acquires dynamic HDR metadata from the management information of the content, and outputs the acquired dynamic HDR metadata to the HDR meta interpretation unit 403.

  The HDR meta-interpretation unit 403 determines the type of HDR metadata output from the video decoding unit 401 or the external meta acquisition unit 402, outputs characteristic data to the HDR control information generation unit 404, and converts the conversion auxiliary data into a DR conversion unit. 405.

  When static HDR metadata is acquired by both the video decoding unit 401 and the external metadata acquisition unit 402, only the static HDR metadata output from the external metadata acquisition unit 402 is used as valid metadata. You may be. That is, the first metadata acquired by the external meta acquisition unit 402 and the second metadata acquired by the video decoding unit 401 are commonly used for a plurality of images included in a continuous reproduction unit of the first video signal. In the case where the HDR meta-interpretation unit 403 obtains both the first metadata and the second metadata in the case of the static HDR metadata to be obtained, the HDR meta-interpretation unit 403 obtains the characteristic data and the conversion auxiliary data by analyzing the first metadata. I do.

  Alternatively, when static HDR metadata is acquired by the external meta acquiring unit 402, the HDR meta interpreting unit 403 uses the static HDR metadata as valid metadata. When the metadata is obtained, valid metadata may be overwritten with the static HDR metadata. That is, the first metadata acquired by the external meta acquisition unit 402 and the second metadata acquired by the video decoding unit 401 are commonly used for a plurality of images included in a continuous reproduction unit of the first video signal. In the case where the static HDR metadata is obtained, the HDR meta-interpreting unit 403 analyzes the first metadata when only the first metadata among the first metadata and the second metadata is acquired. When the data and the conversion auxiliary data are acquired and the second metadata is acquired, the metadata to be used is switched from the first metadata to the second metadata.

  The HDR control information generation unit 404 generates HDR control information in HDMI based on the characteristic data, and outputs the generated HDR control information to the HDMI output unit 406. Here, regarding the dynamic HDR metadata, the output timing of the HDR control information in the HDMI output unit 406 is determined so that the HDR control information can be output in synchronization with the video signal for which the metadata is valid. That is, the HDMI output unit 406 outputs HDR control information in synchronization with a video signal (video signal) for which metadata is valid.

  The DR conversion unit 405 converts the decoded video signal into an SDR signal or converts a dynamic range based on the conversion auxiliary data. Here, when the display device connected to the data output device 400 supports the input of the HDR signal, the conversion by the DR conversion unit 405 is unnecessary. Therefore, the data output device 400 determines whether or not the conversion process is necessary by checking whether or not the connected display device supports the input of the HDR signal in the HDMI initialization process or the like. Good. When it is determined that the conversion process is unnecessary, the first video signal obtained by the video decoding unit 401 is input to the HDMI output unit 406 without passing through the DR conversion unit 405.

  That is, when the display device connected to the data output device 400 supports video output in the luminance range of the HDR signal (first video signal), the HDMI output unit 406 outputs the first video signal and the HDR control information. Output to the display device. In addition, when the display device connected to the data output device 400 does not support video output in the luminance range of the HDR signal (first video signal), the HDMI output unit 406 outputs the second video obtained by converting HDR to SDR. The signal and the HDR control information are output to a display device. Also, the HDMI output unit 406 determines whether or not the display device supports video output in the luminance range of the HDR signal (first video signal) in a transmission protocol (for example, HDMI) initialization process.

  The HDMI output unit 406 outputs the video signal and the HDR control information output from the DR conversion unit 405 or the video decoding unit 401 according to the HDMI protocol.

  Note that the same configuration can be used when the data output device 400 receives and outputs broadcast or OTT content. When the data output device 400 and the display device are included in a single device, the HDMI output unit 406 is not required.

  In the above description, the data output device 400 includes the external metadata acquisition unit 402 that acquires metadata from management information and the like, and the video decoding unit 401 has a function of acquiring metadata from a video stream. The output device 400 may have only one of them.

  Also, in the above description, an example has been described in which the data output device 400 outputs data (video signal and HDR control information) according to HDMI, but the data output device 400 may output data according to an arbitrary transmission protocol. Good.

  As described above, the data output device 400 relates to the decoding unit (the video decoding unit 401) that generates the first video signal of the first luminance range (HDR) by decoding the video stream, and relates to the luminance range of the first video signal. An acquisition unit that acquires the first metadata (at least one of the video decoding unit 401 and the external metadata acquisition unit 402), and interprets the first metadata to acquire characteristic data indicating a luminance range of the first video signal. An interpretation unit (HDR meta-interpretation unit 403), a control information generation unit (HDR control information generation unit 404) for converting characteristic data into HDR control information according to a predetermined transmission protocol (for example, HDMI), and an HDR control information An output unit (HDMI output unit 406) for outputting data using a predetermined transmission protocol.

  According to this, the data output device 400 can generate control information based on the characteristic data included in the metadata.

  Further, the interpretation unit (HDR meta interpretation unit 403) further obtains conversion auxiliary data for converting the luminance range of the first video signal by interpreting the first metadata, and the data output device 400 Furthermore, a conversion unit (DR conversion unit 405) is provided that converts the luminance range of the first video signal based on the conversion auxiliary data to generate a second video signal having a luminance range narrower than the luminance range of the first video signal. The output unit (HDMI output unit 406) further outputs at least one of the first video signal and the second video signal using a predetermined transmission protocol.

  According to this, the data output device 400 can change the luminance range of the first video signal using the conversion auxiliary data included in the metadata.

  The decoding unit (video decoding unit 401) further obtains second metadata (HDR metadata) related to the luminance range of the first video signal from the video stream, and the interpretation unit (HDR meta interpretation unit 403) Characteristic data and conversion auxiliary data are acquired by analyzing at least one of the first metadata and the second metadata.

  Also, as shown in FIG. 4, the static HDR metadata includes essential metadata and selected metadata, and the dynamic HDR metadata includes only selected metadata. That is, static HDR metadata is always used, and dynamic HDR metadata is selectively used. As described above, the first metadata acquired by the external meta-acquisition unit 402 or the second metadata acquired by the video decoding unit 401 is commonly used for a plurality of images included in a continuous reproduction unit of a video signal. And static HDR metadata (static metadata) including characteristic data. The HDR control information generation unit 404 converts the characteristic data included in the static HDR metadata into HDR control information according to a predetermined transmission protocol. When outputting the first video signal (HDR signal), the HDMI output unit 406 outputs HDR control information based on static HDR metadata.

  Further, the first metadata acquired by the external meta acquisition unit 402 or the second metadata acquired by the video decoding unit 401 are further commonly used for a unit finer than a continuous reproduction unit of a video signal, and Includes dynamic HDR metadata (dynamic metadata) including data. The HDR control information generation unit 404 converts the characteristic data included in the static HDR metadata and the specific data included in the dynamic HDR metadata into HDR control information according to a predetermined transmission protocol. When outputting the first video signal (HDR signal), the HDMI output unit 406 outputs HDR control information based on static HDR metadata and dynamic HDR metadata.

  Further, a data generation method according to the present disclosure is a data generation method performed by a data generation device, wherein a first generation step of generating metadata relating to a luminance range of a video signal, and a video stream including the video signal and the metadata And a second generation step of generating The metadata includes characteristic data indicating a luminance range of the video signal, and conversion auxiliary data for converting the luminance range of the video signal.

[9. Example of storing HDR metadata]
FIG. 10 is a diagram illustrating an example of a data structure of an SEI message storing HDR metadata. As shown in FIG. 10, an SEI message dedicated to HDR metadata may be defined. That is, the metadata may be stored in a message dedicated to the metadata.

  Alternatively, the HDR metadata is stored in a general-purpose SEI message for storing user data, and information (HDR extension identification information to be described later) indicating that the HDR metadata is stored in the message is included in a payload portion of the message. May be provided.

  HDR metadata includes static HDR metadata and dynamic HDR metadata. Further, flag information indicating whether static HDR metadata is stored and flag information indicating whether dynamic HDR metadata is stored may be provided. Thereby, there are three types of storage: a method of storing only static HDR metadata, a method of storing only dynamic HDR metadata, and a method of storing both static HDR metadata and dynamic HDR metadata. A method can be used.

  Further, for each piece of metadata, basic data (basic part) whose interpretation is essential and extended data (extended part) whose interpretation is optional (interpretation is optional) may be defined. For example, type information indicating the type of metadata (basic data or extended data) and the size are included in the header information, and the format of the container in which the metadata is stored in the payload is defined. That is, the metadata includes the payload, information indicating whether the data of the payload is basic data or extension data, and information indicating the data size of the payload. In other words, the metadata includes type information indicating the type of the metadata. For example, a container whose type value is 0 stores basic data. In addition, one or more values are assigned to the extension data as the type value, and the value indicates the type of the extension data.

  The data output device and the display device acquire the container data that can be interpreted by themselves by referring to the type value. That is, the data output device (or display device) determines whether the data output device (or display device) can interpret the metadata using the type information, and If the data can be interpreted, characteristic data and conversion auxiliary data are obtained by interpreting the metadata.

  Also, the maximum size of the HDR metadata may be set in advance, and the metadata may be generated such that the sum of the sizes of the basic data and the extension data is equal to or less than the maximum size. That is, the maximum value of the data size of the metadata is defined, and the data generation method according to the present disclosure generates the metadata such that the total data size of the basic data and the extension data is equal to or less than the maximum value.

  Since the data output device and the display device include the memory of the maximum size, it is possible to guarantee that all the HDR metadata can be stored in the memory. Alternatively, it is also possible to secure a data area of a fixed size for the static HDR metadata or the dynamic HDR metadata, and to reserve the area other than the area for storing the basic data for future expansion.

  Such a data structure may be used for storing HDR metadata in content management information.

  FIG. 11 is a diagram illustrating an example of a data structure when HDR metadata is stored in the SEI message for storing user data. It is the same as the data structure in FIG. 11 except that the message includes HDR extension identification information and extension type ID. The HDR extension identification information indicates that the message includes HDR metadata. The extension type ID indicates a version or the like of the HDR metadata. That is, the metadata is stored in the HEC SEI message, and the SEI message includes HDR extension identification information indicating whether the SEI message includes metadata.

  In this case, the data output device receives the SEI message for storing the user data including the HDR extended identification information, and the display device connected to the data output device supports the input of the HDR signal and the HDR control information. In this case, the received SEI message is copied and output as it is in accordance with the protocol of the output I / F to the display device such as HDMI. That is, the data output device obtains the SEI message including the HDR extension identification information indicating that the metadata is included in the SEI message, and the data output destination display device corresponds to the input of the HDR control information. In this case, the SEI message is output as it is according to a predetermined transmission protocol (for example, HDMI).

  Thus, the data output device can output the HDR metadata to the display device regardless of the content of the metadata. With such a configuration, a new DR conversion process is developed in the future, new HDR metadata is defined, and a display device corresponding to the new HDR metadata is connected to a data output device that does not support the new HDR metadata. Even in this case, the new HDR metadata can be output from the data output device to the display device. In addition, the display device can perform the DR conversion process according to the new HDR metadata.

[10. Storage example of multiple HDR metadata]
FIG. 12 is a diagram illustrating an example of a data structure when a plurality of HDR metadata is stored in one SEI message for storing user data. This SEI message stores a plurality of HDR metadata for a plurality of conversion modes (methods) related to the conversion of the dynamic range (luminance range).

  The data structure shown in FIG. 12 is different from the data structure shown in FIG. 11 in that a field (the number of conversion modes) indicating the number of conversion modes in which HDR metadata is provided is added. After the number of conversion modes, a plurality of HDR metadata corresponding to each conversion mode is sequentially stored.

  That is, the data generation method according to the present embodiment is a data generation method performed by the data generation device, and includes one or more metadata (HDR metadata) corresponding to one or more conversion modes for converting a luminance range of a video signal. ) And a second generation step of generating a video stream including a video signal, one or more metadata, and a conversion mode number indicating the number of one or more conversion modes.

[11. Configuration of data output device and DR conversion unit]
FIG. 13 is a block diagram illustrating a configuration example of a data output device 500 according to the present embodiment. The data output device 500 includes a video decoding unit 501, an external meta acquisition unit 502, an HDR meta interpretation unit 503, an HDR control information generation unit 504, a DR conversion unit 505, and an HDMI output unit 506. Note that the operations of the HDR meta-interpreter 503 and the DR converter 505 are different from those of the data output device 400 shown in FIG. That is, the operations of the video decoding unit 501, the external meta acquisition unit 502, the HDR control information generation unit 504, and the HDMI output unit 506 are different from those of the video decoding unit 401, the external meta acquisition unit 402, the HDR control information generation unit 404, and the HDMI output unit 406. The operation is the same as

  The data output device 500 is connected to the display device 510 (display unit), and outputs the generated video signal and HDR control information to the display device 510 via a predetermined transmission protocol such as HDMI.

  The DR conversion unit 505 and the display device 510 each correspond to a conversion mode (conversion method) of a plurality of dynamic ranges. Here, “corresponding” means having a function of performing the process in the conversion mode. First, the HDR meta interpretation unit 503 acquires static HDR metadata and dynamic HDR metadata from the external meta acquisition unit 502 and the video decoding unit 501. A plurality of HDR metadata for a plurality of conversion modes is stored in the content management information or the encoded video stream. The HDR meta-interpreting unit 503 determines a plurality of conversion modes corresponding to the plurality of HDR metadata as a plurality of usable conversion modes.

  The HDR meta-interpretation unit 503 acquires information on the conversion mode of the HDR signal supported by the display device 510 by communicating with the display device 510 or via a separate network. The HDR meta-interpreting unit 503 converts (1) a conversion mode corresponding to the HDR metadata, (2) a conversion mode corresponding to the DR conversion unit 505, and (3) a conversion mode corresponding to the display device 510. Based on the mode, (1) which of the data output device 500 and the display device 510 performs the conversion process of the dynamic range and (2) the conversion mode to be used are determined.

  When it is determined that the conversion process is to be performed by the data output device 500, the DR conversion unit 505 converts the HDR signal into an SDR signal according to the conversion mode instructed by the HDR meta-interpretation unit 503. When it is determined that the conversion process is to be performed by the display device 510, the data output device 500 transmits the video signal (HDR signal) to the display device 510, and converts the HDR metadata necessary for the conversion into an HDMI control signal (HDD control signal). HDR control information).

  In the above description, the DR conversion unit 505 supports a plurality of conversion modes, but it is sufficient that the DR conversion unit 505 supports one or more conversion modes. In this case, the data output device 500 may acquire one or more HDR metadata corresponding to one or more conversion modes.

  As described above, the data output device 500 switches between the decoding unit (the video decoding unit 501) that generates the first video signal by decoding the video stream and the one or more first conversion modes that convert the luminance range of the video signal. An acquisition unit (at least one of the video decoding unit 501 and the external metadata acquisition unit 502) for acquiring one or more corresponding metadata, and a luminance range of the first video signal by interpreting one of the one or more metadata. (HDR meta-interpretation unit 503) for acquiring characteristic data indicating the characteristic data and the conversion auxiliary data for converting the luminance range of the first video signal; and converting the characteristic data to a predetermined transmission protocol (for example, HDMI). It supports a control information generation unit (HDR control information generation unit 504) for converting to the HDR control information according to the above and one or more second conversion modes for converting the luminance range of the video signal. A second video signal having a luminance range smaller than the luminance range of the first video signal is generated by performing a conversion process of the luminance range of the first video signal in one or more second conversion modes based on the auxiliary data. And an output unit (HDMI output unit 506) that outputs the second video signal and HDR control information to the display device 510 using a predetermined transmission protocol. The interpretation unit (HDR meta-interpretation unit 503) further converts one or more first conversion modes, one or more second conversion modes, and a third luminance range of the video signal corresponding to the display device 510. Based on the conversion mode, it is determined which of the data output device 500 and the display device 510 performs the conversion process.

  According to this, the data output device 500 has a first conversion mode corresponding to one or more metadata, a second conversion mode corresponding to the data output device 500, and a third conversion mode corresponding to the display device 510. Based on the conversion mode, it is possible to determine which of the data output device 500 and the display device 510 performs the conversion process. Thus, the data output device 500 can determine a device that appropriately performs the conversion process.

  Note that the one or more second conversion modes supported by the data output device 500 may include at least a part of a plurality of first conversion modes corresponding to one or more metadata, or one or more first conversion modes. Neither of the modes may be included. Similarly, the third conversion mode supported by the display device 510 may include at least a part of the one or more first conversion modes, or may not include any of the one or more first conversion modes. The third conversion mode may include at least a part of one or more second conversion modes, or may not include any of the one or more second conversion modes.

  Hereinafter, a configuration example of the DR conversion unit 505 will be described. FIG. 14 is a block diagram illustrating a configuration example of the DR conversion unit 505. The DR conversion unit 505 includes a mode determination unit 511, N number of mode processing units 512, and a conversion result output unit 513. The N mode processing units 512 correspond to each of the N conversion modes (processing methods), and perform the processing of the corresponding conversion mode. The mode determination unit 511 acquires the conversion mode specified by the HDR meta-interpretation unit 503, and determines the mode processing unit 512 that performs the conversion process. That is, the mode determination unit 511 selects the mode processing unit 512 corresponding to the conversion mode specified by the HDR meta-interpretation unit 503. The determined mode processing unit 512 performs a conversion process on the HDR signal (video signal) to generate an SDR signal (converted video signal). Conversion result output section 513 outputs the converted SDR signal.

  FIG. 15 is a block diagram illustrating a configuration example of a DR conversion unit 505A that is another example of the DR conversion unit 505. The DR conversion unit 505 includes a mode determination unit 521, a basic processing unit 522, N extended mode processing units 523, and a conversion result output unit 524.

  The basic processing unit 522 performs a default conversion process that is a process common to the N conversion modes. The N extension mode processing units 523 perform extension processing such as dynamically controlling parameters of conversion processing using dynamic HDR metadata in addition to the processing of the basic processing unit 522. The N extension mode processing units 523 correspond to each of the N conversion modes, and perform extension processing of the corresponding conversion mode. For example, the basic processing unit 522 operates using only static HDR metadata, and the extended mode processing unit 523 operates using dynamic HDR metadata in addition to static HDR metadata.

[12. Example of operation of HDR meta interpreter]
FIGS. 16 and 17 show an instruction of the HDR meta-interpreting unit 503 based on a conversion mode in which HDR metadata is provided, whether or not each mode is supported by the data output device 500, and whether or not each mode is supported by the display device 510. It is a figure showing an example of contents. The HDR meta-interpretation unit 503 basically selects an operation having the highest reproducibility for the master image from the selectable combinations. Here, the master image is an image output without changing the luminance range.

  For example, in the example shown in FIG. 16, the data output device 500 corresponds to mode 1 and mode 2, and the display device 510 does not correspond to any conversion mode. In addition, in mode 1 and mode 2, reproducibility with respect to the master image is higher in mode 2. The HDR meta-interpretation unit 503 knows in advance the reproducibility of each mode with respect to the master image. In this case, the HDR meta-interpretation unit 503 determines that the data output device 500 performs the conversion process, and selects the mode 2 having high reproducibility from the modes 1 and 2.

  In the example shown in FIG. 17, the data output device 500 corresponds to mode 1, and the display device 510 corresponds to mode 1 and mode 2. In this case, the HDR meta-interpretation unit 503 determines that the conversion process is to be performed on the display device 510, and selects Mode 2 with high reproducibility from Mode 1 and Mode 2. The data output device 500 outputs the HDR metadata corresponding to the mode 2 conversion process to the display device 510 as HDMI control information (HDR control information). The display device 510 performs a mode 2 conversion process using the control information.

  As described above, the HDR meta-interpreting unit 503 is further included in one or more first conversion modes respectively corresponding to one or more metadata, and included in one or more second conversion modes corresponding to the data output device 500. Is determined as the conversion mode of the conversion process performed by the data output device 500. Specifically, the HDR meta-interpretation unit 503 further includes one or more second conversion modes included in one or more first conversion modes respectively corresponding to one or more metadata, and The conversion mode included in at least one of the third conversion modes corresponding to the display device 510 is determined as the conversion mode of the conversion process performed by the data output device 500 or the display device 510.

  More specifically, the HDR meta-interpretation unit 503 includes the master image among the plurality of conversion modes included in the plurality of first conversion modes and at least one of the plurality of second conversion modes and the third conversion mode. Is determined as the conversion mode of the conversion process performed by the data output device 500 or the display device 510.

  In other words, the data output device 500 selects the mode with the highest reproducibility among the conversion modes supported by the data output device 500 and the display device 510, and sets the selected mode among the data output device 500 and the display device 510 to the selected mode. It is determined that the conversion process is to be performed by a compatible device.

  More specifically, as illustrated in FIG. 16, the HDR meta-interpreting unit 503 determines that the conversion mode of the determined conversion process is included in the second conversion mode and is not included in the third conversion mode. It is determined that the data output device 500 performs the conversion process. Also, as shown in FIG. 17, when the conversion mode of the determined conversion process is included in the third conversion mode and is not included in the second conversion mode, HDR meta-interpreting section 503 displays on display device 510. It is determined that the conversion process will be performed.

  Thereby, the data output device 500 can be configured based on the first conversion mode corresponding to the plurality of metadata, the second conversion mode corresponding to the data output device, and the third conversion mode corresponding to the display device. , The conversion mode to be used can be determined. Further, the data output device 500 can select the conversion mode having the highest reproducibility for the master image, so that the quality of the displayed video can be improved.

  FIG. 18 is a diagram illustrating an example in which the data output device 500 determines a conversion process according to whether the parameters of the display device 510 can be acquired. The parameters of the display device 510 include the peak luminance of the display device 510 (the maximum value of the luminance range that can be displayed by the display device 510), the display mode in which the display device 510 can display, and the like. Specifically, this parameter indicates the display mode currently being viewed as the display mode. For example, the display mode includes a normal mode, a dynamic mode, a cinema mode, and the like.

  In the example shown in FIG. 18, the data output device 500 corresponds to mode 1, mode 2, and mode 3, and the display device 510 corresponds to mode 1. In addition, the data output device 500 can acquire the parameters of the display device 510 for mode 1 and mode 2, and cannot acquire the parameters of the display device 510 for mode 3. Mode 2 has higher reproducibility than mode 1, and mode 3 has higher reproducibility than mode 2.

  In this case, the mode with the highest reproducibility among the modes supported by the data output device 500 and the display device 510 is the mode 3, but the data output device 500 cannot acquire the parameters of the display device 510 for the mode 3. Therefore, mode 3 is excluded. Then, the data output device 500 selects the conversion mode using the mode 2 having the second highest reproducibility after the mode 3 and capable of acquiring parameters. Then, the data output device 500 acquires the parameters necessary for the mode 2 from the display device 510, and performs the mode 2 conversion process using the acquired parameters.

  As described above, the HDR meta-interpretation unit 503 further determines whether or not the parameters for each of the plurality of first conversion modes corresponding to the plurality of metadata can be obtained from the display device 510. Alternatively, the conversion mode of the conversion process performed by the display device 510 is determined. More specifically, the HDR meta-interpreting unit 503 is included in the plurality of first conversion modes, is included in at least one of the plurality of second conversion modes, and the third conversion mode, and acquires the parameter from the display device 510. The possible conversion mode is determined as the conversion mode of the conversion process performed by the data output device 500 or the display device 510.

  That is, the data output device 500 selects the mode with the highest reproducibility among the conversion modes supported by the data output device 500 and the display device 510, and only the data output device 500 supports the selected mode. Then, it is determined whether or not the parameters of the display device 510 for the mode can be acquired. If the parameters can be obtained, the data output device 500 selects the mode. On the other hand, if the parameters cannot be obtained, the data output device 500 selects another mode (the next mode with the highest reproducibility).

  Accordingly, the data output device 500 determines the conversion mode to be used depending on whether or not the parameters of the display device 510 can be acquired, so that a more appropriate conversion mode can be selected.

[13. Configuration example 2 of data output device]
Hereinafter, another configuration example of the data output device will be described. FIG. 19 is a block diagram showing a configuration of the data output device 500A. This data output device 500A further includes a DC unit 507 in addition to the data output device 500 shown in FIG. The DC unit 507 down-converts the resolution of the video signal obtained by the video decoding unit 501. For example, when the video signal is 4K, the DC unit 507 down-converts the 4K video signal into a 2K video signal.

  With this configuration, the data output device 500A converts (1) a 4K HDR signal into a 2K HDR signal and outputs it according to the resolution and dynamic range supported by the display device 510. (2) 4K HDR signal Is converted into a 2K HDR signal and then output after changing the dynamic range in the DR converter 505, and (3) the 4K SDR signal is converted to a 2K SDR signal and output. Can be done. That is, the operation of the data output device 500A can be switched according to the resolution of the display device 510, whether or not the HDR signal is supported, and the like.

  FIG. 20 is a diagram illustrating a combination example of the characteristics (resolution and dynamic range (luminance range)) of the video signal in the content, the characteristics of the display device 510, and the output signal of the data output device 500A. The data output device 500A selects a format of the output signal so as to match the resolution of the display device 510 and whether or not the HDR signal is supported, and the DC unit 507 and the DR conversion unit 505 so as to generate an output signal of the selected format. Control.

  For example, if the video signal in the content is a 4K resolution HDR signal, and the display device 510 does not support the display of the 4K resolution HDR signal and supports the display of the 2K resolution HDR signal, The output device 500A converts the video signal of the content into an HDR signal having a resolution of 2K and outputs the HDR signal (see the combination example described in the second row of FIG. 20). At this time, the conversion of the resolution of the video signal is performed in the DC unit 507.

  Also, the video signal in the content is a 4K resolution HDR signal, and the display device 510 does not support the display of the 4K resolution HDR signal and the 2K resolution HDR signal, and does not support the display of the 2K SDR signal. In this case, the data output device 500A converts the video signal of the content into an SDR signal having a resolution of 2K and outputs the converted signal (see the combination example described in the third row of FIG. 20). At this time, the conversion of the resolution of the video signal is performed by the DC unit 507, and the conversion of the luminance range is performed by the DR conversion unit 505.

  This allows the display device 510 to more faithfully reproduce the video signal of the content. Note that the data output device 500A may operate so that the display device 510 performs resolution conversion or dynamic range conversion as described with reference to FIG.

  As described above, the data output device 500A includes the down-converting unit (DC unit 507) that generates the third video signal by reducing the resolution of the first video signal obtained by the video decoding unit 501. The conversion unit (DR conversion unit 505) further performs a conversion process on the brightness range of the third video signal in one of the plurality of second conversion modes based on the conversion auxiliary data, thereby obtaining the brightness of the third video signal. A fourth video signal having a luminance range smaller than the range is generated. The output unit (HDMI output unit 506) further outputs the third video signal or the fourth video signal to the display device 510.

  Thereby, the data output device 500A can change the resolution of the video signal to a resolution suitable for the display device 510 or the like, for example.

  Specifically, when the display device 510 does not support the display of the video having the resolution of the first video signal, (1) the down-converting unit (DC unit 507) generates the third video signal, and ) The output unit (HDMI output unit 506) outputs the third video signal to the display device 510. For example, as shown in FIG. 20, when the resolution of the video signal is 4K and the resolution of the display device 510 is 2K, an output signal of 2K is output.

  When the display device 510 does not support displaying a video in the luminance range (HDR) of the first video signal, (1) the conversion unit (DR conversion unit 505) outputs the luminance range (HDR) of the first video signal. (2) Generate a second video signal in a narrower luminance range (SDR), and (2) output unit (HDMI output unit 506) outputs the second video signal and HDR control information to display device 510. For example, as shown in FIG. 20, when the dynamic range (luminance range) of the video signal is HDR and the display device 510 does not support HDR (in the case of SDR), the HDR video signal is changed to an SDR video signal. It is converted and an SDR video signal (output signal) is output.

  In addition, when the display device 510 does not support the display of the video of the resolution of the first video signal and does not support the display of the video in the luminance range (HDR) of the first video signal, (1) The down-conversion unit (DC unit 507) generates the third video signal, and (2) the conversion unit (DR conversion unit 505) generates the third video signal in the luminance range (SDR) smaller than the luminance range (HDR) of the third video signal. Four video signals are generated, and (3) the output unit (HDMI output unit 506) outputs the fourth video signal to the display device 510. For example, as shown in FIG. 20, the resolution of the video signal is 4K, the dynamic range (luminance range) of the video signal is HDR, the resolution of the display device 510 is 2K, and the display device 510 supports HDR. Otherwise (in the case of SDR), 2K and SDR output signals are output.

[14. Operation model for reproducing HDR signal and 4K signal]
FIG. 21 shows a 4K HDR signal, a 2K HDR signal, and a 4K SDR signal reproduced by a next-generation Blu-ray reproducing apparatus, and the reproduced signal is converted to an HDR-compatible 4KTV, an HDR-non-compatible 4KTV, and It is a figure showing an example of an operation model at the time of outputting to any of 2KTV corresponding to SDR.

  The Blu-ray playback device acquires static HDR metadata stored in the content management information and dynamic HDR metadata stored in a coded video stream. The Blu-ray playback device converts the video HDR signal into an SDR signal and outputs the SDR signal according to the characteristics of an output TV connected by HDMI using the HDR metadata, or outputs the HDR metadata. As an HDMI control signal.

  It is assumed that the conversion process from the HDR signal to the SDR signal and the conversion process from the HDR signal to a video signal in a luminance range suitable for the display device can be implemented by selecting from a plurality of methods. By storing the HDR metadata corresponding to the implemented conversion process in the content management information or the encoded video stream at the time of content creation, the effect of the conversion process can be enhanced. A plurality of HDR metadata can be stored in the content management information or the coded stream for each conversion method.

  Note that the Blu-ray playback device may include a plurality of conversion processing units, such as an option conversion module B (option conversion module B) or an option conversion module D (option conversion module D) in the drawing, and may include a device. In view of the balance between cost and performance, only one conversion processing unit may be provided, or no conversion processing unit may be provided. Similarly, an HDR-compatible TV may include a plurality of conversion processing units, may include only one conversion processing unit, or may not include the conversion processing unit.

  HDR metadata is stored in a predetermined container in which the format or the input operation is determined in advance, such as the SEI message for storing user data shown in FIG. 11 or FIG. Accordingly, even if a new conversion process is developed in the future and new HDR metadata is defined, and a display device corresponding to the new HDR metadata is connected to a Blu-ray playback device that does not support the new HDR metadata, , New HDR metadata can be output from the Blu-ray playback device to the display device. In addition, the display device can execute a conversion process according to the new HDR metadata. Accordingly, when a new technology is developed, it is possible to respond to the new technology by a simple procedure such as assigning an ID to the new HDR metadata. Therefore, it is possible to enhance the competitiveness of package media standards such as Blu-ray for applications with rapid technological evolution such as OTT. Note that the Blu-ray playback device that supports the new HDR metadata may perform the above-described new conversion processing on the video data in the playback device and output the processed video data to the display device. .

  Whether the conversion process is performed by the Blu-ray playback device or the TV is determined based on the method shown in FIGS. The playback device may down-convert the 4K signal into a 2K signal and output the down-converted signal according to the resolution of the TV.

[15. User guidance display method 1]
FIG. 22 is a diagram illustrating a method of displaying a user guidance on a Blu-ray device that executes a conversion process from HDR to SDR.

  At present, accurate conversion from HDR to SDR is difficult because an algorithm for conversion processing from HDR to SDR has not been established. It is also possible to implement a plurality of HDR to SDR conversion processing algorithms.

  Therefore, when a user inserts an HDR-compatible disc into an HDR-compatible Blu-ray device connected to an HDR non-compatible TV, it is necessary to perform an appropriate user guide.

  If the HDR compatible Blu-ray device connected to the HDR non-compatible TV detects the start of the conversion process from HDR to SDR, for example, "The disc is an HDR-compatible disc. Therefore, instead of the HDR video, the Blu-ray device reproduces the SDR video that has been converted from the HDR to the SDR. "

  Thus, the data output device (Blu-ray device) converts the first luminance range to the second luminance range when the display device does not support the video output in the luminance range of the first video signal (HDR signal). The second video signal (SDR signal) and the HDR control information are output to the display device, and the display device is informed that the second video signal converted from the first luminance range to the second luminance range is displayed.

[16. User guidance display method 2]
FIG. 23 is a diagram illustrating a method of displaying the user guidance at the time of executing the conversion processing from HDR stored in the disc to SDR.

  When a conversion process from HDR to SDR is performed, a message (menu) to be displayed by the Blu-ray device is stored in the HDR disk or a nonvolatile memory in the Blu-ray device. This allows the Blu-ray device to display a message when performing the conversion process from HDR to SDR. In this case, for example, "The disc is an HDR-compatible disc. Since your TV is not an HDR-compatible TV, Blu-ray devices will play SDR video that has been converted from HDR to SDR instead of HDR video. . "Is displayed.

[17. User guidance display method 3]
FIG. 24 is a diagram illustrating a method of displaying a user guidance menu when performing a conversion process from HDR stored in a disc to SDR.

  Blu-ray devices use the Blu-ray menu to say, "The disc is an HDR-compatible disc. Since your TV is not an HDR-compatible TV, it is not an HDR video but a Blu-ray device from HDR to SDR. A message such as "Is the SDR video that has been subjected to the conversion process reproduced? When the user selects the “play” button, the Blu-ray device starts displaying the converted image. If the user selects “do not play”, the Blu-ray device stops the playback and displays a message urging the user to insert a non-HDR compatible Blu-ray disc.

  Thus, the data output device (Blu-ray device) converts the first luminance range to the second luminance range when the display device does not support the video output in the luminance range of the first video signal (HDR signal). The display device displays a message for the user to select whether to display the second video signal (SDR signal).

[18. User guidance display method 4]
FIG. 25 is a diagram showing a display method of a user guidance menu from which a processing method at the time of executing the conversion processing from HDR stored in the disc to SDR can be selected.

  If the Blu-ray device stores metadata for conversion processing from HDR to SDR in the Blu-ray, the Blu-ray device displays that fact. When the user selects the designated conversion method, the Blu-ray device displays a message prompting that more beautiful conversion is possible. In other words, it is determined what kind of HDR-to-SDR conversion processing is implemented in the Blu-ray device by using a Java (registered trademark) command or the like in the disk. As a result, the Blu-ray device displays, "The disc is an HDR-compatible disc. Since your TV is not an HDR-compatible TV, it is not an HDR video, but an SDR that the Blu-ray device has converted from HDR to SDR. Display the menu for selecting the HDR-to-SDR conversion processing method, such as "Play a video, which method do you choose? (Play in process 1), (Play in process 3), (Do not play)" be able to. Here, processing 1 and processing 3 are different conversion processing from HDR to SDR.

  As described above, the data output device (Blu-ray device) converts the first luminance range to the second luminance range when the display device does not support the video output in the luminance range of the first video signal (HDR signal). A message for the user to select one of a plurality of conversion methods for performing the conversion is displayed on the display device.

[19. User guidance display method 5]
A similar message can be displayed in broadcasting. For example, a TV or a playback device that does not support an HDR signal displays a message indicating that a broadcast program is an HDR signal and may not be displayed correctly when viewed using a data broadcast application or the like. I do. Also, the TV or the playback device that supports the HDR signal need not display the message. The tag value indicating the attribute of the message indicates that the message is a warning message for the HDR signal. The TV or the playback device corresponding to the HDR signal determines that the display of the message is unnecessary by referring to the tag value.

[20. Dual disc playback operation 1]
The operation of reproducing an HDR disc storing only HDR signals has been described above.

  Next, multiplexed data stored on a dual disc storing both the HDR signal and the SDR signal will be described with reference to FIG. FIG. 26 is a diagram for describing multiplexed data stored on a dual disk.

  In the dual disk, as shown in FIG. 26, the HDR signal and the SDR signal are stored as different multiplexed streams. For example, in an optical disc such as a Blu-ray, data of a plurality of media such as video, audio, subtitles, and graphics is stored as one multiplexed stream by an MPEG-2 TS-based multiplexing method called M2TS. These multiplexed streams are referred to from playback control metadata such as a playlist, and at the time of playback, a multiplexed stream reproduced by a player by analyzing the metadata, or a separate language stored in the multiplexed stream. Select the data of. This example shows a case where playlists for HDR and SDR are individually stored, and each playlist refers to an HDR signal or an SDR signal. Also, identification information indicating that both the HDR signal and the SDR signal are stored may be separately indicated.

  Although it is possible to multiplex both the HDR signal and the SDR signal in the same multiplexed stream, the multiplexing is performed so as to satisfy a buffer model such as T-STD (System Target Decoder) defined in MPEG-2 TS. In particular, it is difficult to multiplex two videos with a high bit rate within a predetermined data read rate range. For this reason, it is desirable to separate the multiplexed stream.

  Data such as audio, subtitles, and graphics need to be stored for each multiplexed stream, and the data amount increases as compared to the case of multiplexing into one stream. However, an increase in the amount of data can reduce the amount of video data by using a video encoding scheme with a high compression rate. For example, by changing MPEG-4 AVC used in the conventional Blu-ray to HEVC (High Efficiency Video Coding), a 1.6 to 2 times improvement in compression ratio is expected. In addition, to store data on a dual disk, a combination of 2K HDR and SDR, a combination of 4K SDR and 2K HDR, such as two 2K or a combination of 2K and 4K, By prohibiting the storage of two, only combinations that fit in the capacity of the optical disk may be allowed.

[21. Dual disc playback operation 2]
FIG. 27 is a flowchart showing the operation of reproducing a dual disc.

  First, the reproducing device determines whether the optical disk to be reproduced is a dual disk (S301). If it is determined that the disc is a dual disc (Yes in S301), it is determined whether the output destination TV is HDRTV or SDRTV (S302). If it is determined that it is HDRTV (Yes in S302), the process proceeds to step S303, and if it is determined that it is SDRTV (No in S302), the process proceeds to step S304. In step S303, an HDR video signal is obtained from the multiplexed stream including the HDR signal in the dual disc, decoded, and output to HDRTV. In step S304, an SDR video signal is obtained from the multiplexed stream including the SDR signal in the dual disc, decoded, and output to the SDRTV. If it is determined in step S301 that the reproduction target is not a dual disk (No in S301), the reproduction is determined by a predetermined method, and the reproduction method is determined based on the determination result (S305).

[22. Disc type]
As described above, a plurality of types of Blu-ray Discs (hereinafter, referred to as BDs) corresponding to the specifications of the display device are provided by increasing the resolution and the luminance range of the display device. FIG. 28 is a diagram illustrating types of BDs. As shown in FIG. 28, hereinafter, a BD on which a video signal whose resolution is the first resolution and whose luminance range is the first luminance range is described as a 2K_SDR-compatible BD. A video signal whose resolution is the first resolution and whose luminance range is the first luminance range is stored as a stream on the BD. This stream is described as a 2K_SDR stream. The 2K_SDR compatible BD is a conventional BD.

  A BD on which a video signal whose resolution is the second resolution and whose luminance range is the first luminance range is recorded is referred to as a 4K_SDR compatible BD. A video signal whose resolution is the second resolution and whose luminance range is the first luminance range is stored as a stream on the BD. This stream is described as a 4K_SDR stream.

  Similarly, a BD on which a video signal whose resolution is the first resolution and whose luminance range is the second luminance range is described as a 2K_HDR compliant BD. A video signal whose resolution is the first resolution and whose luminance range is the second luminance range is stored as a stream on the BD. This stream is described as a 2K_HDR stream.

  A BD on which a video signal whose resolution is the second resolution and whose luminance range is the second luminance range is recorded is referred to as a 4K_HDR-compatible BD. A video signal whose resolution is the second resolution and whose luminance range is the second luminance range is stored as a stream on the BD. This stream is described as a 4K_HDR stream.

  The first resolution is, for example, a so-called 2K (1920 × 1080, 2048 × 1080) resolution, but may be any resolution including such a resolution. Hereinafter, the first resolution may be simply described as 2K.

  Further, the second resolution is a so-called 4K (3840 × 2160, 4096 × 2160) resolution, but may be any resolution including such a resolution. The second resolution is a resolution having a larger number of pixels than the first resolution.

  The first luminance range is, for example, the SDR (luminance range with a peak luminance of 100 nit) described above. The second luminance range is, for example, the HDR described above (a luminance range in which the peak luminance exceeds 100 nit). The second luminance range includes the entire first luminance range, and the peak luminance of the second luminance range is higher than the peak luminance of the first luminance range.

  FIG. 29 is a diagram illustrating the types of BDs in more detail.

  As shown in (c), (f), (g), and (h) of FIG. 29, a dual stream disc corresponding to a plurality of video expressions with one BD is conceivable. The dual stream disc is a BD in which a plurality of video signals for reproducing the same content and a plurality of video signals having at least one of a different resolution and a different luminance range are recorded.

  Specifically, the dual stream disc shown in FIG. 29C is a BD on which a 4K_SDR stream and a 2K_SDR stream are recorded. The dual stream disc shown in (f) of FIG. 29 is a BD on which a 2K_HDR stream and a 2K_SDR stream are recorded.

  The dual stream disc shown in (g) of FIG. 29 is a BD on which a 4K_HDR stream and a 4K_SDR stream are recorded. The dual stream disc shown in (h) of FIG. 29 is a BD on which a 4K_HDR stream and a 2K_SDR stream are recorded.

  Note that the dual stream disc shown in FIG. 29C is not essential because the Blu-ray device can perform down-conversion (hereinafter, also referred to as down-conversion) with a resolution of 4K to 2K.

[23. Disk capacity 1]
Here, each BD as described above will be supplemented with reference to FIGS. 30 and 31. FIG. 30 and FIG. 31 are diagrams showing the data capacity recorded on the BD.

  FIGS. 30 and 31 exemplify the data capacity of the stream actually used in each BD and the dual stream disc.

  FIG. 30 illustrates a case where streams having a resolution of 2K (2K_SDR stream and 2K_HDR stream) are compressed using MPEG-4 AVC. The bit rates of Movie length, lossless Audio, and Compressed Audio are as follows. The BD records audio streams (Lossless Audio and Compressed Audio) for the number of languages.

Movie length: 150min (14 -18 mbps)
Lossless Audio: 0 -2 language (4.5mbps)
Compressed Audio: 3 -5 language (1.5mbps)

  In this case, the maximum value (A), intermediate value (B), and minimum value (C) of the required disk capacity are as follows.

(A) (18 + 4.5 * 2 + 1.5 * 5) mbps * (150 * 60) s / 8 = 38.8 GB
(B) (16 + 4.5 * 1 + 1.5 * 3) mbps * (150 * 60) s / 8 = 28.1 GB
(C) (14 + 4.5 * 0 + 1.5 * 3) mbps * (150 * 60) s / 8 = 20.8 GB

  In addition, the case where streams with a resolution of 4K (4K_SDR stream and 4K_HDR stream) are compressed using HEVC is illustrated. The bit rates of Movie length, lossless Audio, and Compressed Audio are as follows.

Movie length: 150min (35 -40mbps)
Lossless Audio: 0 -2 language (4.5mbps)
Compressed Audio: 3 -6 language (1.5mbps)

  In this case, the maximum value (a), the intermediate value (b), and the minimum value (c) of the required disk capacity are as follows.

(A) (40 + 4.5 * 2 + 1.5 * 5) mbps * (150 * 60) s / 8 = 63.6 GB
(B) (37 + 4.5 * 0 + 1.5 * 4) mbps * (150 * 60) s / 8 = 48.4 GB
(C) (35 + 4.5 * 0 + 1.5 * 3) mbps * (150 * 60) s / 8 = 44.4 GB

  Here, the disk capacity required for a dual stream disk on which both a 2K_HDR stream compressed using MPEG-4 AVC and a 2K_SDR stream compressed using MPEG-4 AVC are recorded is the above (A) + (A), (B) + (B), and (C) + (C). Specifically, the maximum value is 77.6 GB, the intermediate value is 56.2 GB, and the minimum value is 41.6 GB.

  Since a disk of 66 GB and 100 GB is targeted in addition to the conventional 50 GB, the dual stream disk as described above can be realized in terms of capacity.

  Note that the disk capacity required for a dual stream disk in which both a 4K_HDR stream compressed using HEVC and a 2K_HDR stream compressed using HEVC are recorded is based on (b) + (b) above. 96.8 GB and 88.8 GB based on the above (c) + (c). Therefore, such a dual stream disc can be realized by a disc having a capacity of 100 GB.

  Similarly, the disk capacity required for a dual stream disk on which both a 4K_HDR stream compressed using HEVC and a 2K_SDR stream compressed using MPEG-4 AVC are recorded is (a) + (B ) Is 91.7 GB, and based on (c) + (C), it is 65.2 GB. Therefore, such a dual stream disk can be realized by a disk having a capacity of 100 GB or a disk having a capacity of 66 GB.

[24. Disk capacity 2]
Further, another example will be described with reference to FIG. FIG. 31 illustrates a case where streams with a resolution of 2K (2K_SDR stream and 2K_HDR stream) are compressed using HEVC. The bit rates of Movie length, lossless Audio, and Compressed Audio are as follows.

Movie length: 150min (7-9 mbps)
Lossless Audio: 0-2 language (4.5mbps)
Compressed Audio: 3-5 language (1.5mbps)

  In this case, the maximum value (A), intermediate value (B), and minimum value (C) of the required disk capacity are as follows.

(Α) (9 + 4.5 * 2 + 1.5 * 5) mbps * (150 * 60) s / 8 = 25.3 GB
(Β) (8 + 4.5 * 1 + 1.5 * 3) mbps * (150 * 60) s / 8 = 19.1 GB
(Γ) (7 + 4.5 * 0 + 1.5 * 3) mbps * (150 * 60) s / 8 = 12.9 GB

  Here, the disk capacity required for a dual stream disk in which both a 2K_HDR stream compressed using HEVC and a 2K_SDR stream compressed using HEVC are recorded is (α) + (α), ( β) + (β) and (γ) + (γ). Specifically, the maximum value is 50.6 GB, the type value is 38.2 GB, and the minimum value is 25.8 GB.

  Since a disk of 66 GB and 100 GB is targeted in addition to the conventional 50 GB, the dual stream disk as described above can be realized in terms of capacity.

  Similarly, the disk capacity required for a dual stream disk in which both a 4K_HDR stream compressed using HEVC and a 2K_SDR stream compressed using HEVC are recorded is based on (a) + (α) above. 88.9 GB, 67.5 GB based on (b) + (β), 61.3 GB based on (b) + (γ), and (c) + (γ) Based on this, it is 57.3 GB. Therefore, such a dual stream disk can be realized by a disk having a capacity of 100 GB or a disk having a capacity of 66 GB.

[25. Details of disc type 1]
More specifically, a video stream and a graphic stream (the graphics stream of the first embodiment) are recorded on the BD. Here, FIG. 32 is a diagram illustrating an example of a combination of a video stream and a graphic stream recorded on each BD including a dual stream disc.

  FIG. 32 shows that a graphic stream is recorded at a resolution of 2K irrespective of the resolution of the corresponding video stream in consideration of the trouble of producing the content (BD). A graphic stream can be shared between the 2K_SDR stream and the 4K_SDR stream. However, the graphic stream is recorded in a luminance range that matches the luminance range of the corresponding video stream. If the video stream is HDR, an HDR graphics stream is recorded. If the video stream is SDR, a graphics stream of SDR is recorded. The conversion of the graphic stream from SDR to HDR is performed when the content is created.

[26. Disc type details 2]
FIG. 33 is a diagram showing another example of a combination of a video stream and a graphic stream recorded on each BD including a dual stream disc.

  In FIG. 33, the graphic stream is recorded in the resolution of 2K and the luminance range is SDR irrespective of the resolution and luminance range of the corresponding video stream in consideration of the trouble of producing the content. The graphic stream can be shared by all of the 2K_SDR stream, the 4K_SDR stream, the 2K_HDR stream, and the 4K_HDR stream. In this case, the conversion of the resolution of the graphic stream from 2K to 4K and the conversion of the luminance range of the graphic stream from SDR to HDR are all performed by the Blu-ray device.

[27. Disc type details 3]
FIG. 34 is a diagram showing still another example of a combination of a video stream and a graphic stream recorded on each BD including a dual stream disc.

  FIG. 34 shows that when a content is created, the resolution and luminance range of the graphic stream are matched with the resolution and luminance range of the corresponding video stream so that conversion of the graphic stream is not required in the Blu-ray device.

[28. Summary]
A Blu-ray device that plays back a 4K-compatible BD or an HDR-compatible BD needs to support four TVs: 2K_SDR-compatible TV, 2K_HDR-compatible TV, 4K_SDR-compatible TV, and 4K_HDR-compatible TV. Specifically, the Blu-ray device needs to support three sets of HDMI / HDCP standards (HDMI 1.4 / HDCP 1.4, HDMI 2.0 / HDCP 2.1, HDMI 2.1 / HDCP 2.2).

  Further, when playing Blu-ray discs of four types (2K_SDR-compatible BD, 2K_HDR-compatible BD, 4K_SDR-compatible BD, and 4K_HDR-compatible BD), the Blu-ray device performs each BD (content) connection and connection. It is necessary to select appropriate processing and HDMI / HDCP for each of the display devices (TVs) that are being used. Furthermore, when combining graphics with video, it is necessary to change the processing depending on the type of BD and the type of display device (TV) connected.

  For this reason, the internal processing of the Blu-ray device becomes very complicated. In the third embodiment, various methods for relatively simplifying the internal processing of the Blu-ray device are provided.

  [1] When displaying an HDR signal on a TV that does not support HDR, conversion from HDR to SDR is required. On the other hand, in the third embodiment, in order to make this conversion optional in a Blu-ray device, a BD configuration called a dual stream disc has been proposed.

  [2] In the third embodiment, the graphic stream is restricted, and the types of combinations of the video stream and the graphic stream are reduced.

  [3] In the third embodiment, the number of complex processing combinations in the Blu-ray device is greatly reduced due to the dual stream disk and the restriction on the graphic stream.

  [4] In the third embodiment, the internal processing and the HDMI processing that do not cause inconsistency with the processing of the dual stream disc even when the pseudo HDR conversion is introduced are presented.

  According to the conversion method of the present disclosure, when displaying an HDR video in SDRTV, the HDR video is converted into an SDR video of 100 nit or less by using the fact that the peak luminance of the displayed SDRTV exceeds 100 nit (normally 200 nit or more). Instead, the “HDR → pseudo HDR conversion processing” that can be converted so as to maintain the gradation of an area exceeding 100 nit to some extent, converted to a pseudo HDR video close to the original HDR, and displayed on the SDRTV is realized.

  In the conversion method, the conversion method of “HDR → pseudo HDR conversion processing” may be switched according to the display characteristics (the highest luminance, the input / output characteristics, and the display mode) of the SDRTV.

  The display characteristic information can be acquired by (1) automatically acquiring the information through HDMI or a network, (2) generating the information by allowing the user to input information such as a manufacturer name and a product number, and (3) producing a manufacturer name and a product number. It is conceivable that the information is obtained from the cloud or the like using the information of the cloud.

  In addition, the acquisition timing of the display characteristic information of the conversion device 100 includes (1) acquisition immediately before pseudo HDR conversion, and (2) when the display device 200 is first connected to the display device 200 (such as SDRTV) (when connection is established). ).

  In the conversion method, the conversion method may be switched according to the luminance information (CAL, CPL) of the HDR video.

  For example, as a 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 inputting the title information of the content to the user, And (3) It is conceivable to acquire from a cloud or the like using input information that is influential to the user.

  The details of the conversion method include (1) conversion so as not to exceed DPL, (2) conversion so that CPL becomes DPL, and (3) brightness not changing CAL and its surroundings. 4) Conversion is performed using natural logarithm, and (5) clip processing is performed by DPL.

  Further, in the conversion method, in order to enhance the effect of the pseudo HDR, display settings such as the display mode of SDRTV and display parameters can be transmitted to the display device 200 and switched, for example, prompting the user to perform the display settings. The message may be displayed on the screen.

[29. Necessity of pseudo HDR 1]
Next, the necessity of the pseudo HDR will be described with reference to FIGS. 35A to 35C.

  FIG. 35A is a diagram illustrating an example of a display process of performing HDR display by converting an HDR signal in an HDRTV.

  As shown in FIG. 35A, when displaying an HDR image, the maximum value of the HDR luminance range (HPL (HDR Peak Luminance: example: 1500 nit)) is displayed as it is even when the display device is an HDRTV. May not be possible. In this case, the linear signal after the inverse quantization using the HDR EOTF is adjusted to the maximum value of the luminance range of the display device (peak luminance (DPL (Display Peak Immunity): example 750 nit)). Performs luminance conversion. Then, by inputting the video signal obtained by performing the brightness conversion to the display device, it is possible to display an HDR video that matches the maximum brightness range which is the limit of the display device.

  FIG. 35B is a diagram illustrating an example of a display process of performing HDR display using an HDR-compatible playback device and SDRTV.

  As shown in FIG. 35B, when displaying an HDR video, if the display device is an SDRTV, the maximum value of the luminance range of the SDRTV to be displayed (peak luminance (DPL: example 300 nit)) exceeds 100 nits. 35B is the maximum value of the “HDR EOTF conversion” and the luminance range of the SDRTV performed in the HDRTV in the “HDR → pseudo HDR conversion process” in the HDR-compatible playback device (Blu-ray device) in FIG. 35B. If the signal obtained by performing "brightness conversion" using DPL (eg, 300 nit) and performing "brightness conversion" can be directly input to the "display device" of SDRTV, the same effect as that of HDRTV can be obtained by using SDRTV. Can be realized.

  However, SDRTV cannot be realized because there is no means for directly inputting such a signal from outside.

  FIG. 35C is a diagram illustrating an example of a display process of performing HDR display using an HDR-compatible playback device and an SDRTV connected to each other via a standard interface.

  As shown in FIG. 35C, it is usually necessary to input a signal capable of obtaining the effect of FIG. 35B to the SDRTV by using an input interface (HDMI or the like) provided in the SDRTV. In SDRTV, a signal input via an input interface sequentially passes through “EODR conversion of SDR”, “luminance conversion for each mode”, and “display device”, and an image matched to the maximum luminance range of the display device. Is displayed. For this reason, in the HDR-compatible Blu-ray device, a signal (pseudo HDR signal) that passes immediately after the input interface by SDRTV and that can cancel “EODR conversion of SDR” and “luminance conversion for each mode” is output. Generate. In other words, in the HDR-compatible Blu-ray device, immediately after “HDR EOTF conversion” and “luminance conversion” using SDRTV peak luminance (DPL), “inverse luminance conversion for each mode” and “inverse SDR EOTF conversion ", the same effect as when the signal immediately after the" luminance conversion "is input to the" display device "(dashed arrow in FIG. 35C) is realized in a pseudo manner.

[30. Necessity of pseudo HDR 2]
A normal SDRTV has an input signal of 100 nits, but has a capability of expressing a video of 200 nits or more in accordance with a viewing environment (dark room: cinema mode, bright room: dynamic mode, etc.). However, since the upper limit of the luminance of the input signal to the SDRTV was set to 100 nit, the ability could not be used directly.

  When displaying an HDR video in SDRTV, the HDR video is converted to an SDR video of 100 nit or less by utilizing the fact that the peak luminance of the displayed SDRTV exceeds 100 nit (usually 200 nit or more). The “HDR → pseudo HDR conversion process” is performed so as to maintain the range of gradations to some extent. For this reason, it is possible to display the pseudo HDR video close to the original HDR on the SDRTV.

  When this “HDR → pseudo HDR conversion” technology is applied to Blu-ray, as shown in FIG. 36, only HDR signals are stored in an HDR disc, and when a SDRTV is connected to a Blu-ray device, The -ray device performs “HDR → pseudo HDR conversion processing”, converts the HDR signal into a pseudo HDR signal, and sends the signal to SDRTV. Accordingly, the SDRTV can display a video having a pseudo HDR effect by converting the received pseudo HDR signal into a luminance value. As described above, even when there is no HDR-compatible TV, if a HDR-compatible BD and an HDR-compatible Blu-ray device are prepared, a pseudo HDR video with higher image quality than an SDR video can be displayed even with an SDRTV. it can.

  Therefore, it has been considered that an HDR-compatible TV is required to watch an HDR video, but a pseudo HDR video that can realize an HDR-like effect can be viewed on an existing SDRTV. As a result, the spread of HDR-compatible Blu-ray can be expected.

[31. Effect]
The HDR signal transmitted by broadcast, package media such as Blu-ray, or Internet distribution such as OTT is converted into a pseudo HDR signal by performing an HDR-pseudo HDR conversion process. As a result, the HDR signal can be displayed as a pseudo HDR video on an existing SDRTV.

[32. About EOTF]
Here, the EOTF will be described with reference to FIGS. 37A and 37B.

  FIG. 37A is a diagram illustrating an example of an EOTF (Electro-Optical Transfer Function) corresponding to each of HDR and SDR.

  The EOTF is generally called a gamma curve, indicates a correspondence between a code value and a luminance value, and converts a code value into a luminance value. That is, the EOTF is relationship information indicating a correspondence between a plurality of code values and a luminance value.

  FIG. 37B is a diagram illustrating an example of inverse EOTF corresponding to each of HDR and SDR.

  The inverse EOTF indicates the correspondence between the luminance value and the code value. The inverse EOTF quantizes the luminance value and converts it into a code value, contrary to EOTF. That is, the inverse EOTF is relationship information indicating the correspondence between the luminance value and the plurality of code values. For example, when a luminance value of an image corresponding to HDR is expressed by a code value of a 10-bit gradation, luminance values in an HDR luminance range of up to 10,000 nits are quantized to 1024 luminance values of 0 to 1023. Is mapped to an integer value. That is, by performing quantization based on the inverse EOTF, a luminance value (luminance value of a video corresponding to HDR) in a luminance range up to 10,000 nit is converted into an HDR signal which is a 10-bit code value. In the EOTF corresponding to HDR (hereinafter, referred to as “HDR EOTF”) or the inverse EOTF corresponding to HDR (hereinafter, referred to as “HDR inverse EOTF”), the EOTF corresponding to SDR (hereinafter, “SDR EOTF”) is used. ) Or an inverse EOTF corresponding to SDR (hereinafter referred to as “inverse EOTF of SDR”). For example, in FIG. 37A and FIG. The value (peak luminance) is 10,000 nit. 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.

  For example, the HDR EOTF and the HDR inverse EOTF are, for example, SMPTE 2084 standardized by the American Society of Motion Picture and Television Engineers (SMPTE).

  In the following description, a luminance range from 0 nit to 100 nit which is the peak luminance described in FIGS. 37A and 37B may be described as a first luminance range. Similarly, a luminance range from 0 nit to 10,000 nit which is the peak luminance described in FIGS. 37A and 37B may be described as a second luminance range.

[33. Conversion device and display device]
FIG. 38 is a block diagram illustrating a configuration of a conversion device and a display device according to an embodiment. FIG. 39 is a flowchart illustrating a conversion method and a display method performed by the conversion device and the display device according to the embodiment.

  As shown in FIG. 38, the conversion apparatus 100 includes an HDR EOTF converter 101, a luminance converter 102, an inverse luminance converter 103, and an inverse SDR EOTF converter 104. The display device 200 includes a display setting unit 201, an EOTF conversion unit 202 for SDR, a luminance conversion unit 203, and a display unit 204.

  A detailed description of each component of the conversion device 100 and the display device 200 will be given in the description of the conversion method and the display method.

[34. Conversion Method and Display Method]
A conversion method performed by the conversion device 100 will be described with reference to FIG. The conversion method includes steps S101 to S104 described below.

  First, the HDR EOTF conversion unit 101 of the conversion device 100 acquires an HDR video on which inverse HDR EOTF conversion has been performed. The HDR EOTF conversion unit 101 of the conversion device 100 performs HDR EOTF conversion on the obtained HDR video HDR signal (S101). Thereby, HDR EOTF conversion section 101 converts the obtained HDR signal into a linear signal indicating a luminance value. The HDR EOTF is, for example, SMPTE 2084.

  Next, the brightness conversion unit 102 of the conversion device 100 performs a first brightness conversion for converting the linear signal converted by the HDR EOTF conversion unit 101 using the display characteristic information and the content brightness information (S102). . In the first luminance conversion, a luminance value corresponding to the HDR luminance range (hereinafter, referred to as “HDR luminance value”) is changed to a luminance value corresponding to the display luminance range (hereinafter, referred to as “display luminance value”). Convert. Details will be described later.

  From the above, the HDR EOTF conversion unit 101 functions as an acquisition unit that acquires an HDR signal as a first luminance signal indicating a code value obtained by quantizing a luminance value of a 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 for converting into a display luminance value corresponding to a display luminance range that is a maximum value (DPL) smaller than the value (HPL) and larger than 100 nit.

  More specifically, in step S101, the HDR EOTF conversion unit 101 uses the acquired HDR signal and the HDR EOTF to determine the HDR code value as the first code value indicated by the acquired HDR signal. The HDR luminance value associated with the HDR code value in the HDR EOTF is determined. Note that the HDR signal is obtained by quantizing the luminance value of a video (content) using an inverse EOTF of HDR that associates a luminance value in an HDR luminance range with a plurality of HDR code values. Shows the HDR code value.

  Also, in step S102, the luminance conversion unit 102 determines a display luminance value corresponding to the luminance range of the display, which is related to the luminance value of HDR determined in step S101 in advance, and The first brightness conversion is performed to convert the HDR brightness value corresponding to the brightness range of the display into a display brightness value corresponding to the brightness range of the display.

  Also, before step S102, the conversion apparatus 100 has content luminance information including at least one of a maximum value (Content Peak Luminance) of the video (content) and an average luminance value (CAL: Content Average Luminance) of the video. Is obtained as information on the HDR signal. The CPL (first maximum luminance value) is, for example, the maximum value of the luminance values for a plurality of images constituting the HDR video. CAL is, for example, an average luminance value that is an average of luminance values of a plurality of images constituting an HDR video.

  In addition, the conversion device 100 has acquired the display characteristic information of the display device 200 from the display device 200 before step S102. Note that the display characteristic information includes the maximum value (DPL) of the luminance that can be displayed by the display device 200, the display mode of the display device 200 (see below), and the input / output characteristics (EOTF corresponding to the display device). This is information indicating display characteristics.

  Further, conversion device 100 may transmit recommended display setting information (see below, also referred to as “setting information” hereinafter) to display device 200.

  Next, the inverse luminance conversion unit 103 of the conversion device 100 performs inverse luminance conversion according to the display mode of the display device 200. Thereby, the inverse luminance conversion unit 103 performs the second luminance conversion for converting the luminance value corresponding to the luminance range of the display into the luminance value corresponding to the luminance range of SDR (0 to 100 [nit]) (S103). . Details will be described later. That is, the inverse luminance conversion unit 103 sets the display luminance value obtained in step S102 as the third luminance value corresponding to the SDR luminance range having a maximum value of 100 nits, which is related to the display luminance value in advance. A luminance value corresponding to the SDR (hereinafter, referred to as “SDR luminance value”) is determined, and the display luminance value corresponding to the display luminance range is changed to the SDR luminance value corresponding to the SDR luminance range. A second luminance conversion is performed.

  Then, the inverse SDR EOTF conversion unit 104 of the conversion device 100 generates the pseudo HDR video by performing the inverse SDR EOTF conversion (S104). That is, the inverse SDR EOTF conversion unit 104 performs inverse EOTF (Electro-Optical) of SDR (Standard Dynamic Range), which is the third relation information that associates the luminance value in the HDR luminance range with a plurality of third code values. Using Transfer Function), the determined SDR luminance value is quantized, a third code value obtained by the quantization is determined, and the SDR luminance value corresponding to the SDR luminance range is indicated by the third code value. A pseudo HDR signal is generated by converting the signal into an SDR signal as a 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 inverse EOTF of the SDR that associates the luminance value in the luminance range of the SDR with the code values of the plurality of SDRs. It is represented by a code value. Then, conversion device 100 outputs the pseudo HDR signal (SDR signal) generated in step S104 to display device 200.

  The conversion device 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, an SDR signal corresponding to the pseudo HDR is generated by quantizing the SDR luminance value using the SDR EOTF. Note that the SDR luminance value is a numerical value within a luminance range of 0 to 100 nit corresponding to the SDR, but since the conversion based on the luminance range of the display is performed, the HDR EOTF and the SDR 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 the luminance conversion using the EOTF.

  Next, a display method performed by the display device 200 will be described with reference to FIG. The display method includes steps S105 to S108 described below.

  First, the display setting unit 201 of the display device 200 sets display settings of the display device 200 using the setting information acquired from the conversion device 100 (S105). Here, the display device 200 is an SDRTV. The setting information is information indicating a display setting recommended for the display device, and information indicating how to perform EOTF on the pseudo HDR image and display with which setting a beautiful image can be displayed (that is, This is information for switching the display setting of the display device 200 to the optimal display setting. The setting information includes, for example, gamma curve characteristics at the time of output on the display device, display modes such as a living mode (normal mode) and a dynamic mode, and numerical values of a backlight (brightness). Further, a message prompting 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.

  Note that the display device 200 acquires an SDR signal (pseudo HDR signal) and setting information indicating display settings recommended for the display device 200 when displaying an image before step S105.

  The display device 200 may acquire the SDR signal (pseudo HDR signal) before step S106, or may acquire it after step S105.

  Next, the SDR EOTF conversion unit 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. As a result, the SDR EOTF converter 202 converts the SDR code value indicated by the SDR signal into an SDR luminance value.

  Then, the brightness conversion unit 203 of the display device 200 performs brightness conversion according to the display mode set for the display device 200. Thereby, the brightness conversion unit 203 converts the SDR brightness value corresponding to the SDR brightness range (0 to 100 [nit]) into the display brightness value corresponding to the display brightness range (0 to DPL [nit]). Is performed (S107). Details will be described later.

  From the above, the display device 200 determines the third code value indicated by the acquired SDR signal (pseudo HDR signal) in step S106 and step S107 using the setting information acquired in step S105, using the display luminance range ( 0 to DPL [nit]).

  More specifically, in the conversion from the SDR signal (pseudo HDR signal) to the display luminance value, in step S106, an EOTF that associates the luminance value in the luminance range of the SDR with a plurality of third code values is used. For the SDR code value indicated by the acquired SDR signal, the luminance value of the SDR associated with the SDR code value by the EOTF of the SDR is determined.

  Then, in the conversion to the display brightness value, in step S107, a display brightness value corresponding to the display brightness range, which is related to the determined SDR brightness value in advance, is determined, and the SDR corresponding to the SDR brightness range is determined. A third luminance conversion is performed to convert the luminance value to a display luminance value corresponding to a luminance range of the display.

  Finally, 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).

[35. First luminance conversion]
Next, details of the first luminance conversion (HPL → DPL) in step S102 will be described with reference to FIG. 40A. FIG. 40A is a diagram for describing an example of the first luminance conversion.

  The brightness conversion unit 102 of the conversion device 100 performs first brightness conversion for converting the linear signal (HDR brightness value) obtained in step S101 using the display characteristic information and the content brightness information of the HDR video. . The first luminance conversion converts the HDR luminance value (input luminance value) into a display luminance value (output luminance value) that does not exceed the display peak luminance (DPL). The DPL is determined using the maximum brightness and the display mode of the SDR display, which are display characteristic information. The display mode is, for example, mode information such as a theater mode for displaying a dark image on the SDR display and a dynamic mode for displaying a bright image. When the display mode is, for example, the maximum brightness of the SDR display is 1,500 nit and the display mode is a mode in which the brightness is 50% of the maximum brightness, the DPL is 750 nit. Here, the DPL (second maximum luminance value) is the maximum value of the luminance that can be displayed in the currently set display mode of the SDR display. That is, in the first luminance conversion, the DPL as the second maximum luminance value is determined using display characteristic information that is information indicating the display characteristic of the SDR display.

  Also, in the first luminance conversion, CAL and CPL of the content luminance information are used, luminance values below CAL are the same before and after the conversion, and luminance values are changed only for luminance values above CPL. I do. That is, as shown in FIG. 40A, in the first luminance conversion, when the luminance value of the HDR is equal to or less than CAL, the luminance value of the HDR is not converted, and the luminance value of the HDR is determined as a display luminance value, When the luminance value of the HDR is equal to or higher than the CPL, DPL as the second maximum luminance value is determined as the display luminance value.

  In the first luminance conversion, the peak luminance (CPL) of the HDR video in the luminance information is used, and when the luminance value of the HDR is CPL, DPL is determined as the display luminance value.

  In the first luminance conversion, as shown in FIG. 40B, the linear signal (HDR luminance value) obtained in step S101 may be converted so as to be clipped to a value not exceeding DPL. By performing such luminance conversion, the processing in the conversion device 100 can be simplified, and the device can be reduced in size, the power consumption can be reduced, and the processing speed can be increased. FIG. 40B is a diagram for describing another example of the first luminance conversion.

[36-1. Second luminance conversion]
Next, details of the second luminance conversion (DPL → 100 [nit]) in step S103 will be described with reference to FIG. FIG. 41 is a diagram for describing the second luminance conversion.

  The inverse luminance conversion unit 103 of the conversion device 100 performs an inverse luminance conversion according to the display mode on the display luminance value of the display luminance range (0 to DPL [nit]) converted by the first luminance conversion in step S102. Apply. In the reverse brightness conversion, when the brightness conversion process (step S107) according to the display mode by the SDR display is performed, the display brightness value of the display brightness range (0 to DPL [nit]) after the process of step S102 is obtained. This is a process for making it possible. That is, the second luminance conversion is an inverse luminance conversion of the third luminance conversion.

  By the above processing, the second luminance conversion converts a display luminance value (input luminance value) in the display luminance range into an SDR luminance value (output luminance value) in the SDR luminance range.

  In the second luminance conversion, the conversion formula is switched according to 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. In the second luminance conversion, when the display mode of the SDR display is the dynamic mode in which the high luminance pixels are brighter and the low luminance pixels are darker than the normal mode, the inverse function is used to obtain the low luminance pixels. Is converted to a value higher than a directly proportional value directly proportional to the display luminance value, and the SDR luminance value of the high luminance pixel is converted to a value lower than a directly proportional value 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 the luminance relation information corresponding to the display characteristic information that is the information indicating the display characteristic of the SDR display. The luminance value is determined as the luminance value of the SDR, and the luminance conversion processing is switched according to the display characteristic information. Here, 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 and an SDR This is information relating a luminance value (output luminance value).

[36-2. Third luminance conversion]
Next, details of the third luminance conversion (100 → DPL [nit]) in step S107 will be described with reference to FIG. FIG. 42 is a diagram for describing the third luminance conversion.

  The brightness conversion unit 203 of the display device 200 converts the SDR brightness value in the SDR brightness range (0 to 100 [nit]) to (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 the inverse luminance conversion for each mode in S103.

  In the third brightness conversion, the conversion formula is switched according to 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 to a directly proportional value that is directly proportional to the SDR luminance value. . In the third luminance conversion, when the display mode of the SDR display is the dynamic mode in which the high-luminance pixels are brighter and the low-luminance pixels are darker than the normal mode, the display luminance value of the low-luminance pixels is equal to that of the SDR. The display luminance value of the high luminance pixel is converted into a value higher than the direct proportional value directly proportional to the SDR luminance value to a value lower than the direct proportional value directly proportional to the luminance value. In other words, in the third luminance conversion, the luminance value of the SDR determined in step S106 is determined by using the luminance relation information corresponding to the display parameter indicating the display setting of the SDR display, and the luminance value previously associated with the luminance value of the SDR. The value is determined as the display luminance value, and the luminance conversion processing is switched according to the display parameter. Here, the luminance-related information according to the display parameters includes, for example, an SDR luminance value (input luminance value) determined for each display parameter (display mode) of the SDR display and a display luminance as shown in FIG. This is information that is associated with a value (output luminance value).

[37. Display settings]
Next, details of the display setting in step S105 will be described with reference to FIG. FIG. 43 is a flowchart showing the detailed processing of the display setting.

  In step S105, the display setting unit 201 of the SDR display performs the following steps S201 to S208.

  First, the display setting unit 201 uses the setting information to determine whether the EOTF set for the SDR display (EODR for SDR display) matches the EOTF assumed when the pseudo HDR video (SDR signal) is generated. A determination is made (S201).

  If the display setting unit 201 determines that the EOTF set in the SDR display is different from the EOTF indicated by the setting information (the EOTF matching the pseudo HDR video) (Yes in S201), the display setting unit 201 sets the EOTF for the SDR display to the system. It is determined whether switching is possible on the side (S202).

  When determining that the display can be switched, the display setting unit 201 switches the EOTF for SDR display to an appropriate EOTF using the setting information (S203).

  From step S201 to step S203, in the display setting (S105), the EOTF set on the SDR display is set to the recommended EOTF according to the acquired setting information. In this way, in step S106 performed after step S105, the luminance value of SDR can be determined using the recommended EOTF.

  If the system determines that the switching is not possible (No in S202), a message prompting the user to manually change the EOTF 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 (EODR for SDR display) to the recommended EOTF. Is displayed on the SDR display.

  Next, on the SDR display, a pseudo HDR video (SDR signal) is displayed. Before displaying the pseudo HDR video, it is determined whether the display parameters of the SDR display match the setting information using the setting information (S205).

  When the display setting unit 201 determines that the display parameters set in the SDR display are different from the setting information (Yes in S205), the display setting unit 201 determines whether the display parameters of the SDR display can be switched (S206). .

  When determining that the display parameters of the SDR display can be switched (Yes in S206), the display setting unit 201 switches the display parameters of the SDR display in accordance with the setting information (S207).

  In steps S204 to S207, in the display setting (S105), the display parameters set in the SDR display are set to the recommended display parameters according to the acquired setting information.

  When the system determines that the switching is not possible (No in S206), a message is displayed on the screen prompting the user to manually change the display parameters set on the SDR display (S208). For example, a message “Please change the display mode to the dynamic mode and maximize the backlight” is displayed on the screen. That is, in the setting (S105), if the display parameters set on the SDR display cannot be switched, a message for prompting the user to switch the display parameters set on the SDR display to the recommended display parameters is displayed on the SDR display. To be displayed.

[38. Modification 1]
As described above, the embodiments have been described as examples of the technology disclosed in the present application. However, the technology in the present disclosure is not limited to this, and can be applied to the first embodiment in which changes, replacements, additions, omissions, and the like are made as appropriate. Further, it is also possible to form a new embodiment by combining the components described in the above embodiment.

  Therefore, other embodiments will be exemplified below.

  The HDR video is, for example, a Blu-ray Disc, a DVD, a video distribution site on the Internet, a broadcast, or a video in an HDD.

  The conversion device 100 (the HDR → pseudo HDR conversion processing unit) may exist inside a disk player, a disk recorder, a set-top box, a television, a personal computer, and 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, and a smartphone.

  The display characteristic information acquired by the conversion device 100 may be acquired from the display device 200 via an HDMI cable or a LAN cable using HDMI or another communication protocol. The display characteristic information acquired by the conversion device 100 may acquire the display characteristic information included in the model information of the display device 200 via the Internet. Alternatively, the user may perform a manual operation to set the display characteristic information in the conversion device 100. Further, the acquisition of the display characteristic information of the conversion apparatus 100 may be performed immediately before the generation of the pseudo HDR video (steps S101 to S104), or may be performed at the time of initial setting of the device or at the time of connecting the display. For example, the acquisition of the display characteristic information may be performed immediately before the conversion to the display luminance value, or may be performed at a timing when the conversion device 100 is first connected to the display device 200 via the HDMI cable.

  In addition, one HDR video CPL or CAL may be provided for one content, or may be present for each scene. That is, in the conversion method, the first maximum luminance value, which is luminance information corresponding to each of a plurality of scenes of a video and is the maximum value among luminance values for a plurality of images forming the scene, for each of the scenes And luminance information (CPL, CAL) including at least one of an average luminance value that is an average of luminance values for a plurality of images forming the scene. In the first luminance conversion, for each of the plurality of scenes, The display luminance value may be determined according to the luminance information corresponding to the scene.

  Further, the CPL and the CAL may be included in the same medium (Blu-ray Disc, DVD, etc.) as the HDR video, or may be obtained from a location different from the HDR video, such as the conversion device 100 obtaining from the Internet. May be. 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.

  Also, in the first luminance conversion (HPL → DPL) of the conversion device 100, a fixed value may be used without using CPL, CAL, and display peak luminance (DPL). Further, the fixed value may be externally changeable. Further, CPL, CAL, and DPL may be switched in several types. For example, DPL may be set to only three types, 200 nit, 400 nit, and 800 nit, and a value closest to the display characteristic information may be used. You may make it.

  Also, the HDR EOTF may not be SMPTE 2084, and another type of HDR EOTF may be used. Also, the maximum luminance (HPL) of the HDR video need not be 10,000 nits, but may be, for example, 4,000 nits or 1,000 nits.

  The bit width of the code value may be, for example, 16, 14, 12, 10, or 8 bits.

  In addition, although the inverse SDR EOTF conversion is determined from the display characteristic information, a fixed conversion function (which can be changed from outside) may be used. The inverse SDR EOTF conversion is performed, for example, in Rec. ITU-R BT. The function specified in 1886 may be used. Alternatively, the types of the inverse SDR EOTF conversion may be reduced to several types, and the type closest to the input / output characteristics of the display device 200 may be selected and used.

  The display mode may use a fixed mode, and may not be included in the display characteristic information.

  The conversion device 100 does not need to transmit the setting information, and the display device 200 may have a fixed display setting or may not change the display setting. In this case, the display setting unit 201 becomes unnecessary. The setting information may be flag information indicating whether or not the image is a pseudo HDR image. For example, if the image is a pseudo HDR image, the setting may be changed to a setting for displaying the brightest image. That is, in the setting of the display setting (S105), when the acquired setting information indicates a signal indicating the pseudo HDR video converted using the DPL, the brightness setting of the display device 200 is set to be the brightest. May be switched.

[39. Modification 2]
Further, the first luminance conversion (HPL → DPL) of the conversion device 100 is performed by, for example, the following equation.

  Here, L indicates a luminance value normalized to 0 to 1, and S1, S2, a, b, and M are values set based on CAL, CPL, and DPL. ln is the natural logarithm. V is the converted luminance value normalized to 0-1. As in the example of FIG. 40A, 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, and conversion is performed for 350 nits or more. It becomes such a value.

S1 = 350/10000
S2 = 2000 / 10,000
M = 750/10000
a = 0.023
b = S1−a * ln (S1) = 0.112105

  That is, in the first luminance conversion, when the luminance value of the SDR is between the average luminance value (CAL) and the first maximum luminance value (CPL), the luminance value of the HDR corresponds to the luminance value of the HDR using the natural logarithm. Determine the display brightness value.

[40. Effect]
By converting the HDR video using information such as the content peak luminance and the average content luminance of the HDR video, the conversion formula can be changed according to the content and the HDR video can be converted to keep the HDR gradation as much as possible. It becomes. Further, adverse effects such as too dark and too bright can be suppressed. Specifically, by mapping the content peak luminance of the HDR video to the display peak luminance, the gradation is kept as much as possible. In addition, by keeping the pixel values below the average luminance unchanged, the overall brightness is not changed.

  Also, by converting the HDR video using the peak luminance value and the display mode of the SDR display, the conversion formula can be changed according to the display environment of the SDR display, and the HDR image can be changed according to the performance of the SDR display. The video (pseudo HDR video) can be displayed with the same gradation and brightness as the original HDR video. Specifically, the display peak luminance is determined according to the maximum luminance and the display mode of the SDR display, and the HDR image is converted so as not to exceed the peak luminance value. The display is performed with almost no reduction in gradation, and the brightness value that cannot be displayed is reduced to a displayable brightness.

  As described above, undisplayable brightness information is reduced, and it is possible to display in a form close to the original HDR video without lowering the displayable brightness gradation. For example, for a display with a peak luminance of 1,000 nits, the overall brightness is maintained by converting to a pseudo HDR image 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 conversion formula of the luminance is changed according to the display mode of the display. If a luminance higher than the peak luminance of the display is allowed in the pseudo HDR image, the large luminance may be replaced with the peak luminance on the display side and displayed. In this case, the whole image is darker than the original HDR image. Become. Conversely, when a luminance smaller than the peak luminance of the display is converted as the maximum luminance, the small luminance is replaced with the peak luminance on the display side, and the whole becomes brighter than the original HDR video. Moreover, since the brightness is smaller than the peak brightness on the display side, the performance regarding the gradation of the display is not used to the utmost.

  On the display side, by switching the display setting using the setting information, it is possible to display the pseudo HDR video better. For example, when the brightness is set to be dark, high-luminance display cannot be performed, and the HDR feeling is impaired. In this case, by changing the display setting or displaying a message urging the user to change the display setting, the performance of the display is maximized and a high-gradation image can be displayed.

(Overall summary)
As described above, the reproducing method and the reproducing apparatus according to one or more aspects of the present disclosure have been described based on the embodiments. However, the present disclosure is not limited to the embodiments. Unless departing from the spirit of the present disclosure, various modifications conceived by those skilled in the art may be applied to the present embodiment, and a configuration constructed by combining components in different embodiments may be one or more of the present disclosure. It may be included within the scope of the embodiment.

  For example, in each of the above embodiments, each component may be configured by dedicated hardware such as a circuit, 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 can be applied to a content data generation device, a video stream transmission device such as a Blu-ray device, or a video display device such as a television.

Reference Signs List 100 conversion device 101 EOTF conversion unit 102 luminance conversion unit 103 inverse luminance conversion unit 104 inverse SDR EOTF conversion units 200, 510 display device 201 display setting unit 202 SDR EOTF conversion unit 203 luminance conversion unit 204 display units 400, 500, 500A Data output devices 401, 501 Video decoding units 402, 502 External meta acquisition units 403, 503 HDR meta interpretation units 404, 504 HDR control information generation units 405, 505, 505A DR conversion units 406, 506 HDMI output units 507 DC units

Claims (4)

A display device connected to the playback device,
A transmitting unit that transmits, to the playback device, information indicating a luminance conversion method supported by the display device,
A receiving unit that receives a video signal from the playback device,
A display unit for displaying the video signal,
A display device comprising: When the video signal received by the receiving unit is a signal that can convert the luminance by the luminance conversion method that the display device supports,
The display unit displays the video signal by converting the luminance in the conversion method.
The display device according to claim 1. When the video signal received by the receiving unit is a signal after converting the luminance in the playback device,
The display unit displays the video signal without performing luminance conversion,
The display device according to claim 2. The receiving unit, in addition to the video signal, receives metadata required to convert the brightness in the conversion method,
The display device according to claim 2.

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