Display energy reduction SL-HDR SEI message

Abstract

A method comprising: generating (111) a standard dynamic range video from a high dynamic range video; generating (112) energy-aware information by analyzing a distribution of tones of a first high dynamic range video; generating (113) first metadata allowing transforming the standard dynamic range video into a second high dynamic range video and second metadata representing the energy-aware information, the energy aware information allowing controlling an energy consumed for displaying a third high dynamic range video obtained from a reconstructed version of the second high dynamic range video, the second metadata comprising at least one set comprising an energy reduction rate and a peak luminance value; and encoding the standard dynamic range video and the first and second metadata in video data.

Description

[0001] DISPLAY ENERGY REDUCTION SL-HDR SEI MESSAGE

[0002] 1. CROSS REFERENCE TO RELATED APPLICATIONS

[0003] This application claims priority to European Application No. 24305299.0, filed February 23, 2024, which is incorporated herein by reference in its entirety.

[0004] 2. TECHNICAL FIELD

[0005] At least one of the present embodiments generally relates to the field of distribution and display of High Dynamic Range (HDR) video and more particularly to a method and a device for controlling an energy consumed for displaying HDR video.

[0006] 3. BACKGROUND

[0007] Recent advancements in display technologies allow for an extended dynamic range of color, luminance and contrast in images to be displayed. The term image refers here to an image content that can be for example a video or a still picture or image.

[0008] High-dynamic-range video (HDR video) describes video having a dynamic range greater than that of standard-dynamic-range video (SDR video). HDR-video based applications involve capture, production, content / encoding, and display. HDR capture and display devices are capable of brighter whites and deeper blacks. To accommodate this, HDR encoding standards allow for a higher maximum luminance and use at least a 10-bit dynamic range (compared to 8-bit (for non-professional) and 10-bit (for professional) dynamic ranges for SDR video) in order to maintain precision across this extended range.

[0009] HDR technology offers a better viewer experience (or Quality of Experience (QoE)) of video contents, but the energy consumption is much more significant than SDR. Indeed, the display of a HDR video consumes up to two times more energy than a SDR video. A current trend in many domains being to reduce the consumption of energy, it is desirable to overcome the above drawbacks.

[0010] It is particularly desirable to propose a solution allowing controlling or reducing the energy consumed by the display of HDR videos while preserving as much as possible the improvement of the QoE provided by the HDR technology and the artistic intent of the content creator. 4. BRIEF SUMMARY

[0011] In a first aspect, one or more of the present embodiments provide a method comprising: generating a standard dynamic range video from a high dynamic range video; generating energy-aware information by analyzing a distribution of tones of the first high dynamic range video; generating first metadata allowing transforming the standard dynamic range video into a second high dynamic range video and second metadata representing the energy-aware information, the energy aware information allowing controlling an energy consumed for displaying a third high dynamic range video obtained from a reconstructed version of the second high dynamic range video, the second metadata comprising at least one set comprising an energy reduction rate and a peak luminance value; and encoding the standard dynamic range video and the first and second metadata in video data.

[0012] In an embodiment, the second metadata further comprise a first information in each set indicating a quality metric considered to indicate a reduction of a video quality responsive to a peak luminance of the third high dynamic range video is decreased with respect to the first high dynamic range video.

[0013] In an embodiment, the second metadata further comprise a second information in each set indicating a percentage of reduction of the quality metric responsive to a maximal peak luminance of the second high dynamic range video is decreased with respect to the first high dynamic range video.

[0014] In an embodiment, the second metadata further comprise a flag indicating with a first value that the second metadata comprise a single set and with a second value that the second metadata comprise a list of sets.

[0015] In an embodiment, the flag further indicates with the first value that a display adaptation process to be applied to the reconstructed version of the second high dynamic range video uses the single set to determine a target peak luminance value and with the second value that the display adaptation process to be applied to a reconstructed version of the second high dynamic range video uses one set selected in the list to determine the peak luminance value.

[0016] In an embodiment, the second metadata further comprise and information indicating a number of sets in the list.

[0017] In an embodiment, the second metadata are encoded in a supplemental enhancement information message.

[0018] In a second aspect, one or more of the present embodiments provide a method comprising: obtaining a decoded version of a standard dynamic range video, first metadata allowing transforming the standard dynamic range video into a first high dynamic range video and second metadata representing energy-aware information and reconstructing the first high dynamic range video from the first metadata and the standard dynamic range video, the energy aware information allowing controlling an energy consumed for displaying a second high dynamic range video obtained from the first high dynamic range video, the second metadata comprising at least one set comprising an energy reduction rate and a peak luminance value; determining a target peak luminance value from the second metadata; and applying a display adaptation process to the first high dynamic range video based on the determined target peak luminance value to obtain the second high dynamic range video.

[0019] In an embodiment, the second metadata further comprise in each set a first information indicating a quality metric considered to indicate a reduction of a video quality responsive to a peak luminance of the second high dynamic range video is decreased with respect to the first high dynamic range video.

[0020] In an embodiment, the second metadata further comprise for each set a second information indicating a percentage of reduction of the quality metric responsive to a maximal peak luminance of the second high dynamic range video is decreased with respect to the first high dynamic range video. In an embodiment, the second metadata further comprise a flag indicating with a first value that the second metadata comprise a single set and with a second value that the second metadata comprise a list of sets.

[0021] In an embodiment, the flag further indicates with the first value that a display adaptation process to be applied to obtain the second high dynamic range video uses the single set to determine the target peak luminance value and with the second value that the display adaptation process to be applied to obtain the second high dynamic range video uses one set selected in the list to determine the target peak luminance value.

[0022] In an embodiment, the second metadata further comprise and information indicating a number of sets.

[0023] In an embodiment, the second metadata are decoded in a supplemental enhancement information message.

[0024] In a third aspect, one or more of the present embodiments provide a device comprising electronic circuitry configured for: generating a standard dynamic range video from a first high dynamic range video; generating energy-aware information by analyzing a distribution of tones of the first high dynamic range video; generating first metadata allowing transforming the standard dynamic range video into a second high dynamic range video and second metadata representing the energy-aware information, the energy aware information allowing controlling an energy consumed for displaying a third high dynamic range video obtained from a reconstructed version of the second high dynamic range video, the second metadata comprising at least one set comprising an energy reduction rate and a peak luminance value; and encoding the standard dynamic range video and the first and second metadata in video data.

[0025] In an embodiment, the second metadata further comprise a first information in each set indicating a quality metric considered to indicate a reduction of a video quality responsive to a peak luminance of the third high dynamic range video is decreased with respect to the first high dynamic range video.

[0026] In an embodiment, the second metadata further comprise a second information in each set indicating a percentage of reduction of the quality metric responsive to a maximal peak luminance of the second high dynamic range video is decreased with respect to the first high dynamic range video.

[0027] In an embodiment, the second metadata further comprise a flag indicating with a first value that the second metadata comprise a single set and with a second value that the second metadata comprise a list of sets.

[0028] In an embodiment, the flag further indicates with the first value that a display adaptation process to be applied to the reconstructed version of the second high dynamic range video uses the single set to determine a target peak luminance value and with the second value that the display adaptation process to be applied to a reconstructed version of the second high dynamic range video uses one set selected in the list to determine the peak luminance value.

[0029] In an embodiment, the second metadata further comprise and information indicating a number of sets in the list.

[0030] In an embodiment, the second metadata are encoded in a supplemental enhancement information message.

[0031] In a fourth aspect, one or more of the present embodiments provide a device comprising electronic circuitry configured for: obtaining a decoded version of a standard dynamic range video, first metadata allowing transforming the standard dynamic range video into a first high dynamic range video and second metadata representing energy-aware information and reconstructing the first high dynamic range video from the first metadata and the standard dynamic range video, the energy aware information allowing controlling an energy consumed for displaying a second high dynamic range video obtained from the first high dynamic range video, the second metadata comprising at least one set comprising an energy reduction rate and a peak luminance value; determining a target peak luminance value from the second metadata; and applying a display adaptation process to the first high dynamic range video based on the determined target peak luminance value to obtain the second high dynamic range video.

[0032] In an embodiment, the second metadata further comprise in each set a first information indicating a quality metric considered to indicate a reduction of a video quality responsive to a peak luminance of the second high dynamic range video is decreased with respect to the first high dynamic range video.

[0033] In an embodiment, the second metadata further comprise for each set a second information indicating a percentage of reduction of the quality metric responsive to a maximal peak luminance of the second high dynamic range video is decreased with respect to the first high dynamic range video.

[0034] In an embodiment, the second metadata further comprise a flag indicating with a first value that the second metadata comprise a single set and with a second value that the second metadata comprise a list of sets.

[0035] In an embodiment, the flag further indicates with the first value that a display adaptation process to be applied to obtain the second high dynamic range video uses the single set to determine the target peak luminance value and with the second value that the display adaptation process to be applied to obtain the second high dynamic range video uses one set selected in the list to determine the target peak luminance value.

[0036] In an embodiment, the second metadata further comprise and information indicating a number of sets.

[0037] In an embodiment, the second metadata are decoded in a supplemental enhancement information message.

[0038] In a fifth aspect, one or more of the present embodiments provide a signal representing energy aware information comprising at least one set comprising an energy reduction rate and a target peak luminance value generated by the method of the first aspect or by the device of third aspect. In a sixth aspect, one or more of the present embodiments provide a non- transitory information storage medium storing program code instructions for implementing the method according to the first or the second aspect.

[0039] In a seventh aspect, one or more of the present embodiments provide a computer program comprising program code instructions for implementing the method according to the first or the second aspect.

[0040] 5. BRIEF SUMMARY OF THE DRAWINGS

[0041] Fig. 1 illustrates schematically an example of context in which the various embodiments are implemented;

[0042] Fig. 2 details various modules of a video sender system and of a video receiver system; Fig. 3A illustrates schematically a process of generation of energy-aware information; Fig. 3B illustrates schematically a process of use of the energy-aware information for generating a HDR video;

[0043] Fig. 4A illustrates schematically an example of hardware architecture of a processing module able to implement various aspects and embodiments;

[0044] Fig. 4B illustrates a block diagram of an example of a first system in which various aspects and embodiments are implemented; and,

[0045] Fig. 4C illustrates a block diagram of an example of a second system in which various aspects and embodiments are implemented.

[0046] 6. DETAILED DESCRIPTION

[0047] The various embodiments proposed in the following relates to a global video chain (production, encoding, transmission, decoding and display rendering) in which a reduction of an overall energy consumption is applied. This video chain allows distributing a compressed HDR video in the form of one SDR video with a limited dynamic range and some dynamic metadata. Both are inserted in a same bitstream (i.e., in same video data) and are distributed to a receiver (i.e., Integrated Receiver Device). Using the dynamic metadata, the receiver reconstructs the original HDR video. In this context, a display adaptation feature HDR to HDR which takes place at the receiver side, is used to reduce a dynamic range of the displayed HDR video, relatively to a dynamic range of the original HDR video, to reduce the display energy consumption. More precisely, the display adaptation reduces a peak luminance of the displayed HDR video Lpdtsp so that it is between a peak luminance of the transmitted SDR video LSDRand the peak luminance of the original HDR video LHDR - SDR — pdtsp — HDR

[0048] Artistic intent friendly display adaptation methods were developed. When speaking about images, the artistic intent often relies on how tones, i.e., shadows, midtones, highlights, are distributed within the scenes. This is part of a color grading that an artist (i.e., a content creator) has to do in order to convey a desired emotion and / or to define a visual signature of the content.

[0049] Tonal zones can be defined as follows:

[0050] • Shadows: this corresponds to the lowest part of the color distribution (represented for example by an histogram of luminance values of an image) of a considered content;

[0051] • Midtones: this corresponds to the middle part of the color distribution of the considered content;

[0052] • Highlights: this corresponds to the highest part of the color distribution of a considered content.

[0053] In addition to these three tonal zones, it is common to define a black point as the pixel with the lowest sample value found within the shadows whereas the white point corresponds to the pixel with the lightest sample value found within the highlights.

[0054] Obviously, defining such black and white points is key during the color grading performed by artists. Increasing the black point leads to a scene in which areas darker than the black point are clipped. Similarly, decreasing the white point leads to a scene in which areas lighter than the white point are clipped. Clipping the highlights can result in a loss of valuable highlight details.

[0055] Artistic friendly display adaptation methods allow getting the highest QoE and preserving the artistic intent in the displayed HDR video. For instance, display adaptation adjusts tones to preserve highlights which cannot be clipped. To make possible a trade-off between energy consumption and QoE, various embodiments described in the following propose an adjustment of the peak luminance at a content production side and a transmission of peak luminance reduction information (i.e., energy-aware information) over the network up to the receiver in the form of metadata in order to use it during the reconstruction of the HDR video to be displayed.

[0056] Even if the luminance is decreased, the highest QoE (for the given targeted luminance) and the creator intent are kept by adjusting the tones to avoid clipping or burning the highlights.

[0057] Fig- 1 illustrates schematically an example of context in which the various embodiments are implemented.

[0058] In Fig. 1, a system 1 transmits video data to a system 3 via a network 2.

[0059] Fig- 2 details various modules of the system 1 (video sender system) and the system 2 (video receiver system).

[0060] The system 1 comprises a source device 10, such as a camera generating a video content or a streaming system providing a video content. The source device 10 is for instance a SDR or HDR camera generating respectively a SDR or HDR video content.

[0061] The video content is then provided to a pre-processing module 11 of the system 1. The pre-processing module 11, for example, adapts a content to a SL-HDRx standard. For instance, the SL-HDRx standard is SL-HDR1. Therefore, when the video content is a HDR video, the pre-processing module 11 applies atone mapping (TM) to the HDR video to generate a SDR video and generates metadata compatible with the standard SL-HDR1 (i.e., SL-HDR1 metadata). When the video content is a SDR video, the preprocessing module first estimates a HDR video and then applies a TM to the estimated HDR video to generate a SDR video. In this second case also, the pre-processing module 11 generates SL-HDR1 metadata. The HDR video inputted to the preprocessing module 11 has a peak of luminance called master display peak luminance corresponding generally to a peak luminance defined by a content creator. The master display peak luminance is called LHDRabove. The SL-HDR1 metadata comprise information representative of an inverse tone mapping function and of a color correction function allowing to obtain a HDR video from a SDR video. These metadata could be dynamic and adapted to each image or group of images. In addition, energy- aware additional metadata comprising energy-aware information detailed latter in relation to embodiments detailed in tables TAB1 to TAB9 are generated by the preprocessing module 11.

[0062] The SDR video, the SL-HDR1 metadata and the energy-aware additional metadata are then provided to an encoding module 12. The SDR video, the SL-HDR1 metadata and the energy-aware additional metadata are encoded by the encoding module 12 in a bitstream (i.e., in video data) using a video compression format such as AVC ((ISO / CEI 14496-10 / ITU-T H.264), HEVC (ISO / IEC 23008-2 - MPEG-H Part

[0063] 2, High Efficiency Video Coding / ITU-T H.265)), VVC (ISO / IEC 23090-3 - MPEG- I, Versatile Video Coding / ITU-T H.266), AV1,VP9, EVC (ISO / CEI 23094-1 Essential Video Coding) or any other video compression format adapted to encode a SDR video and SL-HDR1 metadata. For example, the SL-HDR1 metadata and the energy-aware additional metadata are encoded in the form of SEI (supplemental enhancement information) message. The output of the encoding module 12 is a bitstream (i.e., video data) representing the encoded SDR video, the SL-HDR1 metadata and the energy- aware additional metadata.

[0064] The bitstream is then provided to a transmitting module 13 comprised in the system 1. The transmitting module 13 transmits the bitstream to the system 3 via the network 2.

[0065] The system 3 comprises a receiving module 30 receiving the bitstream.

[0066] The bitstream is then provided to a decoding module 31 comprised in the system

[0067] 3. The decoding module 31 decodes the bitstream to obtain a decoded (i.e., reconstructed) version of the SDR video, the SL-HDR1 metadata and the energy-aware additional metadata.

[0068] The reconstructed SDR video is provided directly to a display device 34 adapted to display SDR contents.

[0069] The SDR video, the SL-HDR1 metadata and the energy-aware additional metadata are provided to a post-processing module 32. The post-processing module 32 applies an inverse tone mapping (ITM) step and a color correction step to the SDR video to obtain an output HDR video based on the SL-HDR1 metadata and applies a display adaptation process using the energy-aware additional metadata as detailed later in relation to Fig. 3B. The display adaptation process is for example the one described in Annex E of ETSI TS 103.433.

[0070] The color correction comprises a computation of a Look-Up-Table (LUT) lutCC() from the SL-HDR1 metadata. The LUT lutCC() is then used to reconstruct the HDR chrominance signal of the HDR video.

[0071] For both constant luminance (CL) and non-constant luminance (NCL) modes, lutCC(Y) =f(Y).(l / Y) with f(Y) = 1 / (R . sgf(l / Y)) and Y being a value representative of a luminance. Function sgf(l / Y) corresponds to the color correction function encoded in the SL-HDR1 metadata.

[0072] In NCL mode, f(Y) is a constant function, i.e., f(Y) = so that lutCC(Y) = Q.(l / Y).

[0073] In CL mode, / (%) is not a constant function.

[0074] The ITM step comprises a derivation of a LUT lutMapY() from the SL-HDR1 metadata. The LUT lutMapY() is then used to perform the inverse tone mapping of the luminance signal of the SDR video to reconstruct the HDR luminance signal of the HDR video.

[0075] When a display adaptation is required (i.e., responsive to the energy-aware additional metadata specify energy-aware information requesting a reduction of the energy consumption of the display), the energy-aware information is taken into account in the display adaptation process described later in a step 323 of Fig. 3B.

[0076] The output HDR video (eventually, on which had been applied the display adaption), is then provided to a HDR display 33 adapted to display HDR contents. As can be seen, the energy-aware information allows controlling an energy consumed for displaying the HDR video on the system 3 side.

[0077] Fig. 4A illustrates schematically an example of hardware architecture of a processing module 40 used for instance in the pre-processing module 11 or in the postprocessing module 32. The processing module 40 comprises, connected by a communication bus 405: a processor or CPU (central processing unit) 400 encompassing one or more microprocessors, general purpose computers, special purpose computers, and processors based on a multi-core architecture, as non-limiting examples; a random access memory (RAM) 401; a read only memory (ROM) 402; a storage unit 403, which can include non-volatile memory and / or volatile memory, including, but not limited to, Electrically Erasable Programmable Read-Only Memory (EEPROM), Read-Only Memory (ROM), Programmable Read-Only Memory (PROM), Random Access Memory (RAM), Dynamic Random Access Memory (DRAM), Static Random Access Memory (SRAM), flash, magnetic disk drive, and / or optical disk drive, or a storage medium reader, such as a SD (secure digital) card reader and / or a hard disc drive (HDD) and / or a network accessible storage device; at least one communication interface 404 for exchanging data with other modules, devices, systems or equipment. The communication interface 404 can include, but is not limited to, a transceiver configured to transmit and to receive data over a communication network, for example, the network 2. The communication interface 404 can include, but is not limited to, a modem or a network card.

[0078] For example, the communication interface 404 enables for instance the processing module 40 to receive the HDR or SDR data and to output HDR or SDR data along with SL-HDR1 metadata and energy-aware additional metadata.

[0079] The processor 400 is capable of executing instructions loaded into the RAM 401 from the ROM 402, from an external memory (not shown), from a storage medium, or from a communication network. When the processing module 40 is powered up, the processor 400 is capable of reading instructions from the RAM 401 and executing them. When the processing module 40 is comprised in the pre-processing module 11, these instructions form a computer program causing, for example, the implementation by the processor 400 of a TM process (when the source module generates a HDR video), of a process of generation of SL-HDR1 metadata and of energy-aware additional metadata (as described in Fig. 3A). When the processing module 40 is comprised in the postprocessing module 32, these instructions form a computer program causing, for example, the implementation by the processor 400 of an ITM process comprising a display adaptation according to embodiments described in the following of this document in relation with Fig. 3B.

[0080] All or some of the algorithms and steps of said processes may be implemented in software form by the execution of a set of instructions by a programmable machine such as a DSP (digital signal processor) or a microcontroller, or be implemented in hardware form by a machine or a dedicated component such as a FPGA (field- programmable gate array) or an ASIC (application-specific integrated circuit). Microprocessors, DSP, FPGA and ASIC are considered as electronic circuitry. Fig. 4C illustrates a block diagram of an example of a system 3 implementing a post processing module in which various aspects and embodiments are implemented.

[0081] System 3 can be embodied as a device including various components or modules and is configured to generate a HDR displayable video. Examples of such system include, but are not limited to, various electronic systems such as personal computers, laptop computers, smartphones, tablet, TV, or set top boxes. Components of system 3, singly or in combination, can be embodied in a single integrated circuit (IC), multiple ICs, and / or discrete components. For example, in at least one embodiment, the system 3 comprises one processing module 40 that implements the post-processing module 32. In various embodiments, the system 3 is communicatively coupled to one or more other systems, or other electronic devices, via, for example, a communication bus or through dedicated input and / or output ports.

[0082] The input to the processing module 40 can be provided through various input modules as indicated in a block 42. Such input modules include, but are not limited to, (i) a radio frequency (RF) module that receives an RF signal transmitted, for example, over the air by a broadcaster, (ii) a component (COMP) input module (or a set of COMP input modules), (iii) a Universal Serial Bus (USB) input module, and / or (iv) a High Definition Multimedia Interface (HDMI) input module. Other examples, not shown in FIG. 4C, include composite video.

[0083] In various embodiments, the input modules of block 42 have associated respective input processing elements as known in the art. For example, the RF module can be associated with elements suitable for (i) selecting a desired frequency (also referred to as selecting a signal, or band-limiting a signal to a band of frequencies), (ii) down-converting the selected signal, (iii) band-limiting again to a narrower band of frequencies to select (for example) a signal frequency band which can be referred to as a channel in certain embodiments, (iv) demodulating the down-converted and bandlimited signal, (v) performing error correction, and (vi) demultiplexing to select the desired stream of data packets. The RF module of various embodiments includes one or more elements to perform these functions, for example, frequency selectors, signal selectors, band-limiters, channel selectors, filters, downconverters, demodulators, error correctors, and demultiplexers. The RF portion can include a tuner that performs various of these functions, including, for example, down-converting the received signal to a lower frequency (for example, an intermediate frequency or a near-baseband frequency) or to baseband. Various embodiments rearrange the order of the abovedescribed (and other) elements, remove some of these elements, and / or add other elements performing similar or different functions. Adding elements can include inserting elements in between existing elements, such as, for example, inserting amplifiers and an analog-to-digital converter. In various embodiments, the RF module includes an antenna.

[0084] Additionally, the USB and / or HDMI modules can include respective interface processors for connecting system 3 to other electronic devices across USB and / or HDMI connections. It is to be understood that various aspects of input processing, for example, Reed-Solomon error correction, can be implemented, for example, within a separate input processing IC or within the processing module 40 as necessary. Similarly, aspects of USB or HDMI interface processing can be implemented within separate interface ICs or within the processing module 40 as necessary. The demodulated, error corrected, and demultiplexed stream is provided to the processing module 40.

[0085] Various elements of system 3 can be provided within an integrated housing. Within the integrated housing, the various elements can be interconnected and transmit data therebetween using suitable connection arrangements, for example, an internal bus as known in the art, including the Inter-IC (I2C) bus, wiring, and printed circuit boards. For example, in the system 3, the processing module 40 is interconnected to other elements of said system 3 by the bus 405.

[0086] The communication interface 404 of the processing module 40 allows the system 3 to communicate on the communication network 2. The communication network 2 can be implemented, for example, within a wired and / or a wireless medium.

[0087] Data is streamed, or otherwise provided, to the system 3, in various embodiments, using a wireless network such as a Wi-Fi network, for example IEEE 802.11 (IEEE refers to the Institute of Electrical and Electronics Engineers). The WiFi signal of these embodiments is received over the communications network 2 and the communications interface 404 which are adapted for Wi-Fi communications. The communications network 2 of these embodiments is typically connected to an access point or router that provides access to external networks including the Internet for allowing streaming applications and other over-the-top communications. Still other embodiments provide streamed data to the system 3 using the RF connection of the input block 42. As indicated above, various embodiments provide data in a nonstreaming manner, for example, when the system 3 is a smartphone or a tablet. Additionally, various embodiments use wireless networks other than Wi-Fi, for example a cellular network or a Bluetooth network.

[0088] The system 3 can provide an output signal to various output devices using the communication network 2 or the bus 405. For example, the system 3 can provide a reconstructed HDR video.

[0089] The system 3 can provide an output signal to various output devices, including the HDR display 33, speakers 46, and other peripheral devices 47. The HDR display 33 of various embodiments includes one or more of, for example, a touchscreen display, an organic light-emitting diode (OLED) display, a curved display, and / or a foldable display. The HDR display 33 can be for a television, a tablet, a laptop, a cell phone (mobile phone), or other devices. The HDR display 33 can also be integrated with other components (for example, as in a smart phone), or separate (for example, an external monitor for a laptop). The other peripheral devices 47 include, in various examples of embodiments, one or more of a stand-alone digital video disc (or digital versatile disc) (DVR, for both terms), a disk player, a stereo system, and / or a lighting system. Various embodiments use one or more peripheral devices 47 that provide a function based on the output of the system 3. For example, a disk player performs the function of playing the output of the system 3.

[0090] In various embodiments, control signals are communicated between the system 3 and the HDR display 33, speakers 46, or other peripheral devices 47 using signaling such as AV. Link, Consumer Electronics Control (CEC), or other communications protocols that enable device-to-device control with or without user intervention. The output devices can be communicatively coupled to system 3 via dedicated connections through respective interfaces 43, 44, and 45. Alternatively, the output devices can be connected to system 3 using the communication network 2 via the communication interface 404. The HDR display 33 and speakers 46 can be integrated in a single unit with the other components of system 3 in an electronic device such as, for example, a television. In various embodiments, the display interface 43 includes a display driver, such as, for example, a timing controller (T Con) chip.

[0091] The HDR display 33 and speakers 46 can alternatively be separate from one or more of the other components, for example, if the RF module of block 42 is part of a separate set-top box. In various embodiments in which the HDR display 33 and speakers 46 are external components, the output signal can be provided via dedicated output connections, including, for example, HDMI ports, USB ports, or COMP outputs.

[0092] Fig. 4B illustrates a block diagram of an example of the system 1 adapted to implement the pre-processing module 11 in which various aspects and embodiments are implemented.

[0093] System 1 can be embodied as a device including the various components and modules described above and is configured to perform one or more of the aspects and embodiments described in this document.

[0094] Examples of such devices include, but are not limited to, various electronic devices such as personal computers, laptop computers, a camera, a smartphone and a server. Elements or modules of system 1, singly or in combination, can be embodied in a single integrated circuit (IC), multiple ICs, and / or discrete components. For example, in at least one embodiment, the system 1 comprises one processing module 40 that implement the pre-processing module 11. In various embodiments, the system 1 is communicatively coupled to one or more other systems, or other electronic devices, via, for example, a communications bus or through dedicated input and / or output ports.

[0095] The input to the processing module 40 can be provided through various input modules as indicated in block 42 already described in relation to Fig. 4C.

[0096] Various elements of system 1 can be provided within an integrated housing. Within the integrated housing, the various elements can be interconnected and transmit data therebetween using suitable connection arrangements, for example, an internal bus as known in the art, including the Inter-IC (I2C) bus, wiring, and printed circuit boards. For example, in the system 1, the processing module 40 is interconnected to other elements of said system 1 by the bus 405.

[0097] The communication interface 404 of the processing module 40 allows the system 1 to communicate on the communication network 2. The communication network 2 can be implemented, for example, within a wired and / or a wireless medium.

[0098] Data is streamed, or otherwise provided, to the system 1, in various embodiments, using a wireless network such as a Wi-Fi network, for example IEEE 802.11 (IEEE refers to the Institute of Electrical and Electronics Engineers). The WiFi signal of these embodiments is received over the communications network 2 and the communications interface 404 which are adapted for Wi-Fi communications. The communications network 2 of these embodiments is typically connected to an access point or router that provides access to external networks including the Internet for allowing streaming applications and other over-the-top communications. Still other embodiments provide streamed data to the system 1 using the RF connection of the input block 42. As indicated above, various embodiments provide data in a nonstreaming manner.

[0099] When a figure is presented as a flow diagram, it should be understood that it also provides a block diagram of a corresponding apparatus. Similarly, when a figure is presented as a block diagram, it should be understood that it also provides a flow diagram of a corresponding method / process.

[0100] The implementations and aspects described herein can be implemented in, for example, a method or a process, an apparatus, a software program, a data stream, or a signal. Even if only discussed in the context of a single form of implementation (for example, discussed only as a method), the implementation of features discussed can also be implemented in other forms (for example, an apparatus or program). An apparatus can be implemented in, for example, appropriate hardware, software, and firmware. The methods can be implemented, for example, in a processor, which refers to processing devices in general, including, for example, a computer, a microprocessor, an integrated circuit, or a programmable logic device. Processors also include communication devices, such as, for example, computers, cell phones, portable / personal digital assistants ("PDAs"), smartphones, tablets, and other devices that facilitate communication of information between end-users.

[0101] Reference to “one embodiment” or “an embodiment” or “one implementation” or “an implementation”, as well as other variations thereof, means that a particular feature, structure, characteristic, and so forth described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrase “in one embodiment” or “in an embodiment” or “in one implementation” or “in an implementation”, as well any other variations, appearing in various places throughout this application are not necessarily all referring to the same embodiment.

[0102] Additionally, this application may refer to “determining” various pieces of information. Determining the information can include one or more of, for example, estimating the information, calculating the information, predicting the information, retrieving the information from memory or obtaining the information for example from another device, module or from user.

[0103] Further, this application may refer to “accessing” various pieces of information. Accessing the information can include one or more of, for example, receiving the information, retrieving the information (for example, from memory), storing the information, moving the information, copying the information, calculating the information, determining the information, predicting the information, or estimating the information.

[0104] Additionally, this application may refer to “receiving” various pieces of information. Receiving is, as with “accessing”, intended to be a broad term. Receiving the information can include one or more of, for example, accessing the information, or retrieving the information (for example, from memory). Further, “receiving” is typically involved, in one way or another, during operations such as, for example, storing the information, processing the information, transmitting the information, moving the information, copying the information, erasing the information, calculating the information, determining the information, predicting the information, or estimating the information.

[0105] It is to be appreciated that the use of any of the following “and / or”, and “at least one of’, “one or more of’ for example, in the cases of “A / B”, “A and / or B” and “at least one of A and B”, “one or more of A and B” is intended to encompass the selection of the first listed option (A) only, or the selection of the second listed option (B) only, or the selection of both options (A and B). As a further example, in the cases of “A, B, and / or C” and “at least one of A, B, and C”, “one or more of A, B and C” such phrasing is intended to encompass the selection of the first listed option (A) only, or the selection of the second listed option (B) only, or the selection of the third listed option (C) only, or the selection of the first and the second listed options (A and B) only, or the selection of the first and third listed options (A and C) only, or the selection of the second and third listed options (B and C) only, or the selection of all three options (A and B and C). This may be extended, as is clear to one of ordinary skill in this and related arts, for as many items as are listed.

[0106] As will be evident to one of ordinary skill in the art, implementations or embodiments can produce a variety of signals formatted to carry information that can be, for example, stored or transmitted. The information can include, for example, instructions for performing a method, or data produced by one of the described implementations or embodiments. For example, a signal can be formatted to carry a SDR image or video sequence, SL-HDRx metadata and energy-aware additional metadata of a described embodiment. Such a signal can be formatted, for example, as an electromagnetic wave (for example, using a radio frequency portion of spectrum) or as a baseband signal. The formatting can include, for example, encoding a SDR image or video sequence with SL-HDR1 metadata and energy-aware additional metadata in an encoded stream (i.e., in video data) and modulating a carrier with the encoded stream. The information that the signal carries can be, for example, analog or digital information. The signal can be transmitted over a variety of different wired or wireless links, as is known. The signal can be stored on a processor-readable medium.

[0107] As seen above, display adaptation allows displaying a HDR video compliant with energy-aware information while preserving the artistic intent of the content creator.

[0108] A common objective of the various embodiments described in the following is to decrease the consumption of the display device when displaying the HDR video.

[0109] Various embodiments described in the following propose to add additional energy-aware information in the current syntax of the signal reconstruction metadata and the SL-HDR information SEI message respectively defined in section 6.2 and annex A.2 of the ETSI TS 103.433 specification to support information relative to a reduction of the display energy consumption.

[0110] One can note that the energy-aware information can also be transported by other means such as the User data registered SEI message, defined by Recommendation ITU- T T.35 (02-2000): "Procedure for the allocation of ITU-T defined codes for nonstandard facilities" or in Metadata ITUT T35 OBU specified in AV 1 specification (AV 1 Bitstream & Decoding Process Specification) .

[0111] This additional energy aware information is added in an alternate tuning profile which is intended to be used by a display adaptation process to put more or less emphasis on desired areas of a HDR to HDR tone mapping curve in order to impact the display energy consumption while preserving the artist intent. Section 6.2 (Reconstruction metadata syntax) of ETSI TS 103.433 specifies a format abstraction layer implementing static and dynamic metadata used for signal reconstruction (i.e. SDR-to-HDR reconstruction) agnostically to a distribution format (i.e. independent of the SL-HDR Information SEI message syntax). This format supports two mutually exclusive carriage modes among a Parameter-based carriage mode and a Table-based carriage mode defined in section 6.3.2.5 of ETSI TS 103.433.

[0112] The SDR-to-HDR-reconstruction process, specified in section 7 of ETSI TS 103.433 for both carriage modes relies on luminance mapping and colour correction curves produced from dynamic reconstruction metadata associated with each mode. The reconstruction metadata are carried in HEVC, AVC, VVC, WebM or AVI video coding and transport specifications thanks to a mapping process respectively described in Annex A, Annex B, Annex J, Annex K and Annex L of ETSI TS 103.433.

[0113] In a first part of the present document, we show how the reconstruction metadata syntax is modified according to an embodiment. The additional energy aware information is added in the signal reconstruction metadata in the form of a syntax element hdr display energy reduction. Table TAB1 discloses an example modified syntax of the signal reconstruction metadata comprising the syntax element hdr display energy reduction.

[0114]

[0115] Table TAB 1

[0116] One can note that a number of bits used to represent kCoefficient

[0000] , kCoefflcient

[0001] , kCoefficient 2 ] is respectively “6”, “7” and “8” bits.

[0117] In table TAB1 the new syntax element is represented in bold. Table TAB2 below details the syntax element hdr display energy reduction.

[0118] From an Integrated Receiver Decoder (IRD) viewpoint, the sub-elements comprised in the syntax element hdr display energy reduction are mapped from the SL-HDR Information SEI message syntax element. In other words, the signal reconstruction metadata signal reconstruction infoQ is a data structure used by the display adaptation process on the system 3 side and, in the described embodiment, the values of the subelements of this data structure are transported in the SL-HDR information SEI message.

[0119] Table TAB2

[0120] In table TAB2 the new syntax element is represented in bold.

[0121] In the syntax element hdr display energy reduction, the number of sub- elements hdrDisplayEnergyReduction num val depends on the payload mode (indicated by the sub-element payloadMode).

[0122] The semantic of the sub-elements is the following: hdrDisplayEnergyReduction rate indicates a target energy reduction rate in percentage. hdrDisplayEnergyReduction MaxLuminancepml has the same semantics as specified in clause D.3.28 of HEVC specification (Recommendation ITU-T H.265 (04- 2015): "High efficiency video coding") for the syntax element max display master ing luminance, except that it represents a value coded in units of one candela per square meter. hdrDisplayEnergyReduction MaxLuminance val applies to a target picture, outputted by the display adaptation process. In bitstreams conforming to the present document, hdrDisplayEnergyReduction MaxLuminance val value shall be in the range “100” to original _picture_max_luminance or src_mdcv_max_mastering_luminance as defined in section A.2.2.4 of ETSI TS 103.433. hdrDisplayEnergyReduction VideoQualityMetric indicates a quality metric considered by the encoder to indicate the reduction of the video quality when a maximal value of the luminance is decreased to perform balancing between the QoE and the energy reduction rate as indicated in table TAB3. It allows the post-processing module 32 choosing a peak luminance value in a display adaptation process (applied in step 323 described in the following) which is, for a given quality metric, as close as possible to a target peak luminance (determined in step 322 described in the following) so that an acceptable QoE is provided to a user.

[0123] Table TAB3 hdrDisplayEnergyReduction VideoQualityReduction indicates a percentage of reduction of the selected quality metric when the maximal value of the luminance is decreased to perform balancing between the QoE and the energy reduction rate.

[0124] In case the sub-element payloadMode is set to “0”, a list of sets each comprising a Display Energy reduction rate hdrDisplayEnergyReduction_rate[i], a maximal luminance value hdrDisplayEnergyReduction_MaxLuminancepval[i], a quality metric value hdrDisplayEnergyReduction_VideoQualityMetric[i] and quality reduction value hdrDisplayEnergyReduction_VideoQualityReduction[i] is provided to the postprocessing module 32 to implement the display adaptation process. In that case, the post-processing module 32 uses the sets of this list to determine the best set consistent with its energy reduction strategy.

[0125] If a flag hdrReductionSupervisedMode is set to “0”, the post-processing module 32 uses the sets of the list to perform its own Display Energy reduction strategy.

[0126] If the flag hdrReductionSupervisedMode is set to “1”, the system 1 forces the post-processing module 32 to perform the display adaptation with a single set.

[0127] In case the sub-element payloadMode is set to “1”, the display Energy reduction rate hdrDisplayEnergyReduction rate, the maximal luminance value hdrDisplayEnergyReduction MaxLuminance val, the quality metric value hdrDisplayEnergyReduction VideoQualityMetric and the quality reduction value hdrDisplayEnergyReduction VideoQualityReduction are provided for information to indicate characteristics of look-up tables used to implement the display adaptation process as described in Fig. E.l of annex E of ETSI TS 103 433 in term of display energy reduction.

[0128] In the first embodiment, the additional energy aware information is added in the signal reconstruction metadata.

[0129] In a second part of this document, we propose several variants of a modification of the SL-HDR information SEI message to transport the additional energy-aware information. Table TAB4 proposes a first variant of the modification of the SL-HDR information SEI message.

[0130]

[0131] Table TAB4 In table TAB4 the new syntax element is represented in bold.

[0132] In this first variant, the field si _hdr extension of the SEI message is used to map the additional energy-aware information. It is also proposed to set the sl_hdr_extension_6bits to “1” instead of “0” as specified in section A.2.2.4 of ETSI TS 103.433, as this value is not used in version 1, 2 and 3 of ETSI TS 103 433. The field sl hdr extension data byte corresponds to Table TAB5 below.

[0133] Table TAB5

[0134] In table TAB5 the new syntax element is represented in bold.

[0135] This case is exclusive, i.e., it is not possible to have the field sl_hdr_extension_data_byte gathering the data for the sub-element sl hdr _extension_6bits set to “0” and “1” in the same SL-HDR SEI messages.

[0136] Thus, a possibility is to consider the sl_hdr_extension_6bits as a bit mask field. The value “0” for this field allows to keep compatibility with the current versions of the ETSI TS 103 433.

[0137] The other values of the sub-element sl hdr _extension_6bits (i.e., 1 to 63) allows enriching the field si _hdr extension data byte with additional bytes. As an example, if sl hdr extension 6bit =\ . the field sl hdr extension data byte contains the additional energy-aware information and other additional information represented by the sub-element si _hdr additional bytes () as shown in the Table TAB6.

[0138] Table TAB6

[0139] In a second variant of the modification of the SL-HDR information SEI message represented in table TAB7, it is proposed to create three new fields in the extension part of the syntax to separate the bytes of the display energy reduction information from the existing ones in the current versions of ETSI TS 103 433.

[0140]

[0141]

[0142] Table TAB7

[0143] In table TAB7 the new syntax element is represented in bold.

[0144] The sub-element sl hdr energy extension flag indicates that the SL-HDR information SEI message comprise additional energy-aware information. The sub-element sl hdr energy extension length indicates a number of subelement sl_hdr_energy_extension_data_byte[ i ] contained in the SL-HDR information SEI message.

[0145] The sub-element sl_hdr_energy_extension_data_byte[ i ] contains the energy- aware information corresponding to the field sl hdr extension data byte described in table TAB5.

[0146] A third variant of the modification of the SL-HDR information SEI message is represented in table TAB8.

[0147]

[0148] Table TAB 8 In table TAB8 the new syntax element is represented in bold.

[0149] The sub-element sl hdr display energy reduction present Jlag indicates if the SL-HDR SEI message comprise additional energy-aware information.

[0150] The third variant can be simplified as represented below in table TAB9.

[0151]

[0152]

[0153] Table TAB9

[0154] In table TAB9 the new syntax element is represented in bold.

[0155] In that variant of table TAB9, the flag sl hdr reduction supervised mode Jlag is forced to “1” when the sub-element si hdr _payload_mode equals to “1”.

[0156] When sl hdr reduction supervised mode Jlag is set to “1” or sl hdr _payload_mode is set to “1”, the field sl hdr display energy reduction num val is set to “1”. When sl hdr payload mode is set to “1” the fields values in the for(i=0 ;i < si hdr display energy reduction num val; i++) loop are just informative for the decoder.

[0157] The semantic of the sub-elements is the following: sl hdr reduction supervised mode flag equal to “1” specifies that a single set of display energy reduction rate hdrDisplayEnergyReduction rate, maximal luminance value hdrDisplayEnergyReduction MaxLuminance val, quality metric value hdrDisplayEnergyReduction VideoQualityMetric and quality reduction value hdrDisplayEnergyReduction VideoQualityReduction is provided and the post-processing module 32 shall use it in its display adaptation process to reduce the display energy consumption. If equal to “0”, a list of sets is provided allowing the post-processing module 32 to perform its display adaptation process depending on its own energy reduction strategy by selecting one of the set. sl hdr display energy reduction numval indicates the number of sets. When sl hdr reduction supervised mode flag is equal to “1”, the sl hdr display energy reduction num val equal to “1” to force a specific set .

[0158] The semantic of hdr display energy reduction rate is identical to the semantic of hdrDisplayEnergyReduction rate.

[0159] The semantic of hdr display energy reductionjnax luminancev^ is identical to the semantic of hdr Display Energy Reduction MaxLuminancepml-

[0160] The semantic of hdr display energy reduction video quality metric is identical to the semantic of hdrDisplayEnergyReduction VideoQualityMetric.

[0161] The semantic of hdr display energy reduction video quality reduction is identical to the semantic of hdrDisplayEnergyReduction VideoQualityReduction.

[0162] Fig. 3A illustrates schematically a process of generation of the additional energy-aware information.

[0163] The process of Fig. 3A is executed by the processing module 40 implementing the pre-processing module 11.

[0164] In a step 111, the processing module 40 generates the SDR video from the HDR video using a TM process.

[0165] In a step 112, the processing module 40 generates the additional energy-aware information by analyzing a distribution of tones of the HDR video, i.e. shadows, midtones, highlights and determining a suitable target peak luminance value Lpdispto ensure balancing between artist intent and energy reduction rates while rendering the video on a display. For example, a deep learning-based method can be used to perform such analysis. The processing module 40 outputs the energy-aware information, this information being intended to be mapped in the syntax element hdr display energy reduction, for example, in the SL-HDR information SEI message of table TAB4.

[0166] In a step 113, the processing module 40 generates the SL-HDR1 metadata (i.e., the HDR signal reconstruction dynamic metadata) and transmits the SL-HDR1 metadata and the energy-aware information to the encoding module 12. The SL-HDR1 metadata and the additional energy-aware information are intended to be embedded in a SL-HDR information SEI message modified according to the various embodiments of tables TAB4 to TAB9 by the encoding module 12 and to be transmitted in a bitstream along the SDR video by the transmitting module 13.

[0167] In an embodiment, during the distribution, the bitstream comprising SL-HDR information SEI message can pass through a node (e.g. edge entity) of the network 2 that modifies (i.e., updates) the energy-aware information comprised in the SL-HDR information SEI message or inserts energy-aware information in the SL-HDR information SEI message. The node then transmits the bitstream SL-HDR information SEI message in direction of the receiving system 3.

[0168] Fig. 3B illustrates schematically a process of use of the additional energy-aware information for generating a HDR video.

[0169] The process of Fig. 3B is executed by the processing module 40 implementing the post-processing module 32.

[0170] In a step 321, the processing module 40 obtains a decoded version of the SDR video, of the SL-HDR1 metadata and of the energy-aware information from the decoding module 31 and reconstructs the HDR video from the SL-HDR1 metadata and the SDR video.

[0171] In a step 322, the processing module 40 determines a set of display Energy reduction rate hdrDisplayEnergyReduction rate, maximal luminance value hdrDisplayEnergyReduction MaxLuminancepval, quality metric value hdrDisplayEnergyReduction VideoQualityMetric and quality reduction value hdrDisplayEnergyReduction VideoQualityReduction

[0172] If the flag sl hdr reduction supervised mode Jlag= , the energy-aware information specifies a single set of display Energy reduction rate hdrDisplayEnergyReduction_rate, maximal luminance value hdrDisplayEnergyReduction MaxLuminance val, quality metric value hdrDisplayEnergyReduction VideoQualityMetric and quality reduction value hdrDisplayEnergyReduction VideoQualityReduction. In that case, called supervised mode, the processing module 40 determines a target peak luminance value Lpdispequal to the single value of maximal luminance value hdrDisplayEnergyReduction MaxLuminance val.

[0173] If sl hdr reduction supervised mode Jlag=Q, a list of sets is provided by the energy-aware information. In that case, called unsupervised mode, the processing module 40 applies its own energy reduction strategy to determine the best set in the list. The processing module 40 then determines a target peak luminance value Lpdispequal to the value of maximal luminance value hdrDisplayEnergyReduction MaxLuminance val of the best set.

[0174] In step 323, the processing module 40 modifies the reconstructed HDR into a HDR video compliant with the determined target peak luminance value Lpdisp. For instance, the processing module 40 applies the display adaptation process described in annex E of ETSI TS 103 433. During step 323, the processing module 40 determines a TM function (for example, in the form of a LUT) allowing transforming the reconstructed HDR video in a HDR video compliant with the determined target peak luminance value Lpdisptaking account current energy constraints of the receiver system 3, an energy budget of the receiver system 3 and a QoE expected by a user. Then, the processing module 40 applies the display adaptation process on the HDR video reconstructed in step 321 using the TM function.

[0175] In a step 324, the processing module 40 sends the display adapted HDR video to the HDR display 33.

[0176] Until now in this document, steps 322 and 323 are implemented by the postprocessing module 32. In a variant, only step 321 is implemented by the post-processing module 32. Steps 322 and 323 are implemented by an independent module dedicated to the display adaptation. In some cases, the set (or the list of sets) of display Energy reduction rate hdrDisplayEnergyReduction rate, maximal luminance value hdrDisplayEnergyReduction MaxLuminancepval, quality metric value hdrDisplayEnergyReduction VideoQualityMetric and quality reduction value hdrDisplayEnergyReduction VideoQualityReduction may be incompatible with energy constraints of the receiver system 3. For example, the reduction of energy allowed by the set (or by any set of the list) provided by the energy- aware information is too low to allow the receiver system 3 displaying the HDR video. In that case, in an embodiment, the receiver system transmits a message to the sender system 1 to request a transmission of other energy-aware information.

[0177] We described above a number of embodiments. Features of these embodiments can be provided alone or in any combination. Further, embodiments can include one or more of the following features, devices, or aspects, alone or in any combination, across various claim categories and types:

[0178] • A TV, set-top box, cell phone, tablet, personal computer or other electronic device that performs at least one of the embodiments described, and that displays (e.g., using a monitor, screen, or other type of display) a resulting picture.

[0179] • A TV, set-top box, cell phone, tablet, personal computer or other electronic device that tunes (e.g., using a tuner) a channel to receive a signal including an encoded SDR video and metadata, and performs at least one of the embodiments described.

[0180] • A TV, set-top box, cell phone, tablet, or other electronic device that receives (e.g., using an antenna) a signal over the air that includes an encoded SDR video and metadata, and performs at least one of the embodiments described.

[0181] • A server, camera, cell phone, tablet, personal computer or other electronic device that tunes (e.g., using a tuner) a channel to transmit a signal including a SDR video and metadata, and performs at least one of the embodiments described. A server, camera, cell phone, tablet, personal computer or other electronic device that transmits (e.g., using an antenna) a signal over the air that includes a SDR video and metadata, and performs at least one of the embodiments described.

Claims

Claims1. A method comprising: generating (111) a standard dynamic range video from a first high dynamic range video; generating (112) energy-aware information by analyzing a distribution of tones of the first high dynamic range video; generating (113) first metadata allowing transforming the standard dynamic range video into a second high dynamic range video and second metadata representing the energy-aware information, the energy aware information allowing controlling an energy consumed for displaying a third high dynamic range video obtained from a reconstructed version of the second high dynamic range video, the second metadata comprising at least one set comprising an energy reduction rate and a peak luminance value; and encoding the standard dynamic range video and the first and second metadata in video data.

2. The method of claim 1 wherein the second metadata further comprise a first information in each set indicating a quality metric considered to indicate a reduction of a video quality responsive to a peak luminance of the third high dynamic range video is decreased with respect to the first high dynamic range video.

3. The method of claim 2 wherein the second metadata further comprise a second information in each set indicating a percentage of reduction of the quality metric responsive to a maximal peak luminance of the second high dynamic range video is decreased with respect to the first high dynamic range video.

4. The method of claim 1, 2 or 3 wherein the second metadata further comprise a flag indicating with a first value that the second metadata comprise a single set and with a second value that the second metadata comprise a list of sets.

5. The method of claim 4 wherein the flag further indicates with the first value that a display adaptation process to be applied to the reconstructed version of thesecond high dynamic range video uses the single set to determine a target peak luminance value and with the second value that the display adaptation process to be applied to a reconstructed version of the second high dynamic range video uses one set selected in the list to determine the peak luminance value.

6. The method of claim 4 or 5 wherein the second metadata further comprise and information indicating a number of sets in the list.

7. The method of any previous claim wherein the second metadata are encoded in a supplemental enhancement information message.

8. A method comprising: obtaining (321) a decoded version of a standard dynamic range video, first metadata allowing transforming the standard dynamic range video into a first high dynamic range video and second metadata representing energy-aware information and reconstructing the first high dynamic range video from the first metadata and the standard dynamic range video, the energy aware information allowing controlling an energy consumed for displaying a second high dynamic range video obtained from the first high dynamic range video, the second metadata comprising at least one set comprising an energy reduction rate and a peak luminance value; determining (322) a target peak luminance value from the second metadata; and applying (323) a display adaptation process to the first high dynamic range video based on the determined target peak luminance value to obtain the second high dynamic range video.

9. The method of claim 8 wherein the second metadata further comprise in each set a first information indicating a quality metric considered to indicate a reduction of a video quality responsive to a peak luminance of the second high dynamic range video is decreased with respect to the first high dynamic range video.

10. The method of claim 9 wherein the second metadata further comprise for each set a second information indicating a percentage of reduction of the quality metric responsive to a maximal peak luminance of the second high dynamic range video is decreased with respect to the first high dynamic range video.

11. The method of claim 8, 9 or 10 wherein the second metadata further comprise a flag indicating with a first value that the second metadata comprises a single set and with a second value that the second metadata comprise a list of sets.

12. The method of claim 11 wherein the flag further indicates with the first value that a display adaptation process to be applied to obtain the second high dynamic range video uses the single set to determine the target peak luminance value and with the second value that the display adaptation process to be applied to obtain the second high dynamic range video uses one set selected in the list to determine the target peak luminance value.

13. The method of claim 11 or 12 wherein the second metadata further comprise and information indicating a number of sets.

14. The method of any previous claim from claim 8 to 13 wherein the second metadata are decoded in a supplemental enhancement information message.

15. A device comprising electronic circuitry configured for: generating (111) a standard dynamic range video from a first high dynamic range video; generating (112) energy-aware information by analyzing a distribution of tones of the first high dynamic range video; generating (113) first metadata allowing transforming the standard dynamic range video into a second high dynamic range video and second metadata representing the energy-aware information, the energy aware information allowing controlling an energy consumed for displaying a third high dynamic range video obtained from a reconstructed version of the second high dynamic range video, the second metadata comprising at least one set comprising an energy reduction rate and a peak luminance value; and encoding the standard dynamic range video and the first and second metadata in video data.

16. The device of claim 15 wherein the second metadata further comprise a first information in each set indicating a quality metric considered to indicate areduction of a video quality responsive to a peak luminance of the third high dynamic range video is decreased with respect to the first high dynamic range video.

17. The device of claim 16 wherein the second metadata further comprise a second information in each set indicating a percentage of reduction of the quality metric responsive to a maximal peak luminance of the second high dynamic range video is decreased with respect to the first high dynamic range video.

18. The device of claim 15, 16 or 17 wherein the second metadata further comprise a flag indicating with a first value that the second metadata comprise a single set and with a second value that the second metadata comprise a list of sets.

19. The device of claim 18 wherein the flag further indicates with the first value that a display adaptation process to be applied to the reconstructed version of the second high dynamic range video uses the single set to determine a target peak luminance value and with the second value that the display adaptation process to be applied to a reconstructed version of the second high dynamic range video uses one set selected in the list to determine the peak luminance value.

20. The device of claim 18 or 19 wherein the second metadata further comprise and information indicating a number of sets in the list.

21. The device of any previous claim from claim 15 to 20 wherein the second metadata are encoded in a supplemental enhancement information message.

22. A device comprising electronic circuitry configured for: obtaining (321) a decoded version of a standard dynamic range video, first metadata allowing transforming the standard dynamic range video into a first high dynamic range video and second metadata representing energy-aware information and reconstructing the first high dynamic range video from the first metadata and the standard dynamic range video, the energy aware information allowing controlling an energy consumed for displaying a second high dynamic range videoobtained from the first high dynamic range video, the second metadata comprising at least one set comprising an energy reduction rate and a peak luminance value; determining (322) a target peak luminance value from the second metadata; and applying (323) a display adaptation process to the first high dynamic range video based on the determined target peak luminance value to obtain the second high dynamic range video.

23. The device of claim 22 wherein the second metadata further comprise in each set a first information indicating a quality metric considered to indicate a reduction of a video quality responsive to a peak luminance of the second high dynamic range video is decreased with respect to the first high dynamic range video.

24. The device of claim 23 wherein the second metadata further comprise for each set a second information indicating a percentage of reduction of the quality metric responsive to a maximal peak luminance of the second high dynamic range video is decreased with respect to the first high dynamic range video.

25. The device of claim 22, 23 or 24 wherein the second metadata further comprise a flag indicating with a first value that the second metadata comprises a single set and with a second value that the second metadata comprise a list of sets.

26. The device of claim 25 wherein the flag further indicates with the first value that a display adaptation process to be applied to obtain the second high dynamic range video uses the single set to determine the target peak luminance value and with the second value that the display adaptation process to be applied to obtain the second high dynamic range video uses one set selected in the list to determine the target peak luminance value.

27. The device of claim 25 or 26 wherein the second metadata further comprise and information indicating a number of sets.

28. The device of any previous claim from claim 22 to 27 wherein the second metadata are decoded in a supplemental enhancement information message.

29. A signal representing energy aware information comprising at least one set comprising an energy reduction rate and a peak luminance value generated by the method of claims 1 to 7 or by the device of claims 15 to 21.

30. Non-transitory information storage medium storing program code instructions for implementing the method according to any previous claim from claim 1 to 14.

31. A computer program comprising program code instructions for implementing the method according to any previous claim from claim 1 to 14.

Images