Source color volume information messaging

Abstract

To provide methods of communicating source color volume information in a coded bitstream using supplemental enhancement information (SEI) messaging.SOLUTION: The method includes: detecting whether a first SEI messaging variable (source_colour_volume_id) indicating an identification number (ID) of source color volume information is present; checking whether its value is within an allowable range; reading a further flag concerning persistence of the first variable across a bitstream; checking, via a second SEI messaging variable, whether metadata explicitly specifies a color volume actually occupied by source data content; and extracting a minimum luminance value, a maximum luminance value, and an average luminance value.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Patent Application No. 62 / 427,677, filed November 29, 2016, and U.S. Provisional Patent Application No. 62 / 404,302, filed October 5, 2016, the disclosures of which are incorporated herein by reference in their entireties. technology

[0002] The present invention relates generally to images, and more particularly to conveying and processing source color volume information. [Background technology]

[0003] background ITU-T Recommendation H.265 [1] for "Coding of Moving Images" (also known as HEVC) describes in Annex D, "Supplemental enhancement information" (SEI), and Annex E, "Video usability information" (VUI), a syntax for providing supplemental SEI and VUI information in the coded bitstream to allow a decoder to better map the decoded samples to a display.

[0004] Along with the MPEG / ITU standardization process, the Society of Motion Picture and Television Engineers (SMPTE) has also specified many recommendations for conveying metadata about color volume information for both source video and target displays. For example, the SMPTE ST 2094 suite of documents (e.g., [5] and [6]) specifies metadata for use in color volume transformation of video content. These metadata may vary from scene to scene or frame to frame. For example, such metadata may help decoders present high dynamic range (HDR) and wide color gamut (WCG) data on displays with a smaller color volume than the color volume of the mastering display used to master the source image.

[0005] As used herein, the term "metadata" refers to any auxiliary information that is transmitted as part of an encoded bitstream and that assists a decoder in rendering a decoded image. Such metadata may include, but is not limited to, color space or gamut information, prediction parameters, reference display parameters, and auxiliary signal parameters, as described herein.

[0006] While H.265 Annexes D and E address much color volume-related metadata, they do not address all of the metadata required for the most efficient display management of HDR content. At the Joint Working Group on Video Coding (JCT-VC) meeting in Geneva in June 2016, three proposals [2-4] were presented on how to describe content color volume information using SEI or VUI messaging. Some of these proposals were influenced by SMPTE ST.2094 [5], but their scope is very different.

[0007] In [2], the Content-SEI message, which describes the actual color distribution of the video content, is proposed to signal the content gamut in 2D. In the VUI, the variable c In [1], the color_primaries message is used. In [3], multiple primary expressions and spatial regions are proposed to be associated with specified source characteristics. In [4], the Content Color Volume SEI message is proposed to indicate the color volume occupied by the content. It uses an (x,y,Y) description of color coordinates and has slices of luminance Y, with each slice having an associated polygon. These proposals have many drawbacks: they provide information that is of little use to most display manufacturers, can add significant overhead, and require computational overhead that may be too large to produce. To improve existing encoding and decoding methods, the inventors have concluded that improved techniques for generating and conveying source color volume information are needed.

[0008] The approaches described in this section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued. Thus, unless otherwise indicated, it should not be assumed that any of the approaches described in this section qualify as prior art merely by virtue of their description in this section. Similarly, unless otherwise indicated, it should not be assumed, based on this section, that problems identified with one or more approaches have been recognized in any prior art. [Brief explanation of the drawings]

[0009] BRIEF DESCRIPTION OF THE DRAWINGS Certain embodiments of the present invention are illustrated, without limitation, in the figures of the accompanying drawings, in which like reference numerals refer to like parts, and in which: FIG.

[0010] [Figure 1] FIG. 1 illustrates an example process for a video delivery pipeline, according to one embodiment of the present invention. [Figure 2] FIG. 2 shows an example of a "maximum" possible color volume plot for a video container format. [Figure 3A] FIG. 3A shows an example of a source content color gamut within a container color volume. [Figure 3B] FIG. 3B shows an example of a 2D slice of the container color volume and the source color volume at a particular luminance (Y) value. [Figure 3C] FIG. 3C shows an example of a 2D slice of the container color volume and the source color volume at a particular luminance (Y) value. [Figure 4] FIG. 4 illustrates an example process for extracting source color volume information from SEI messaging, according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] Description of Example Embodiments Techniques for conveying source color volume information using SEI messaging are described herein. In the following description, for convenience, numerous details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, that the present invention may be practiced without these details. In other instances, detailed details of well-known structures and devices are not set forth in order to avoid unnecessarily cluttering, obscuring, or obfuscating the description of the present invention.

[0012] overview Example embodiments described herein relate to techniques for conveying source color volumetric information using SEI messaging. In a decoder, a processor for extracting SEI messaging detects the presence of source color volumetric information in the input bitstream. The processor receives a source color volume identification messaging variable identifying the presence of a color volume in the input bitstream. The processor receives a first messaging variable as part of the source color volume information. If the first messaging variable matches a first predetermined value, then for one or more primary colors, the processor generates x and y chromaticity coordinates for the one or more primary colors based on the source color volume information in the input bitstream. The processor generates a minimum luminance value, a maximum luminance value, and an average luminance value based on the source color volume information in the input bitstream. The processor receives a second messaging variable as part of the source color volume information, and if the second messaging variable matches a second predetermined value, then for one or more primary colors, the processor generates x and y chromaticity coordinates for the one or more primary colors based on the source color volume information that correspond to the minimum luminance value, the maximum luminance value, and the average luminance value.

[0013] Source Color Volume Messaging Example 1 illustrates an example process for a video delivery pipeline (100), showing various stages from video capture to display of video content. An image generation block (105) is used to capture or generate a sequence of video frames (102). The video frames (102) are captured digitally (e.g., by a digital camera) or generated by a computer (e.g., using computer animation) to provide video data (107). Alternatively, the video frames (102) may be captured on film by a film camera. After appropriate editing (not shown), the film is converted to a digital format to provide video data (107).

[0014] The video data (107) is then provided to a processor in block (110) for post-production editing. Post-production editing (110) involves adjusting or changing the color or brightness in specific areas of the image to enhance the image or achieve a particular look according to the videographer's creative intent. This is sometimes referred to as "color timing" or "color grading." Other editing (e.g., scene selection and sequencing, image cropping, addition of computer-generated visual special effects, etc.) may occur in block (110) to produce a final version (112) of the production for distribution. During post-production editing (110), the video image is viewed on a reference display (125) (also called a "target display" because it is for which the studio optimizes the video).

[0015] In some embodiments, prior to video encoding (120), the video content may be analyzed to extract source color volume metadata (119), e.g., as specified in SMPTE ST 2094-1 [5] or as defined later in this specification. Such metadata may also specify the characteristics of a target display (e.g., a reference display (125)) and color remapping information so that a downstream receiver can render the decoded data in the best possible way.

[0016] After post-production (110) and source color volume analysis (115), the final generated video data (117) and associated metadata (119) may be delivered in an appropriate color format (e.g., 10-bit YCbCr in 4:2:0, ICtCp, etc.) to an encoding block (120) for downstream delivery to decoding and playback devices such as television sets, set-top boxes, movie theaters, etc. In some embodiments, the encoding block (120) may include audio and video encoders (such as audio and video encoders specified by ATSC, DVB, DVD, Blu-Ray, and other distribution formats) to generate an encoded bitstream (122). The encoded bitstream (122) may be a single-layer video encoding bitstream. The signal (122) may be represented by a single bitstream or by a multi-layer bitstream. For example, in a multi-layer bitstream, the signal (122) may include a base layer (e.g., an SDR layer or a 10-bit HDR (HDR10) layer) and an enhancement layer. The enhancement layer, when combined with the base layer, produces an HDR bitstream (e.g., a 12-bit HDR signal) with a higher dynamic range than the base layer alone. The signal (122), which is the output bitstream from the encoder (120), may also include additional encoding-related metadata, such as the metadata (119), prediction parameters, and other data to help a decoder better reconstruct the HDR signal.

[0017] At the receiver, the encoded bitstream (122) is decoded by a decoding unit (130) to generate a decoded signal (132) and associated metadata (119). The receiver (or target) display (150) may have characteristics that are quite different from those of the reference (or target) display (125). For example, without limitation, the reference display (125) may be a 1,000-nit display and the receiver display may be a 500-nit display. In this case, a display management module (140) may be used to map the dynamic range of the decoded signal (132) to the characteristics of the receiver display (150) by generating a display mapping signal (142). As used herein, the term "display management" refers to the processing (e.g., tone mapping and color gamut mapping) required to map an input video signal of a first dynamic range (e.g., 1,000 nits) to a display of a second dynamic range (e.g., 500 nits). The display management unit 140 may take into account the metadata 119 to improve the quality of the output video on the display 150. For example, as shown in [7], information about the luminance range of the target (or reference) display (e.g., 125) and source data may be used at the receiver to better map the dynamic range of the video content to the receiver display (e.g., 150).

[0018] Color Volume Information 2 shows an example of the "maximum" possible color volume for a given container format (e.g., BT.2020) (also referred to as the "container color volume"). Such a volume may be constructed by two-dimensional (2D) color gamut primaries, a white point chromaticity (e.g., D65), a maximum luminance value (e.g., Lmax=4,000 nits), and a minimum luminance value (e.g., 0.005 nits). Such a plot shows the maximum possible color volume boundary for all colors in the source video content.

[0019] In practice, as indicated by the darker "cloud" (305) in FIG. 3A or the darker regions (305) in FIGS. 3B and 3C, the source color volume of the source content (e.g., 112) for a particular frame, or even within an entire scene, can be significantly smaller than the maximum possible color volume (310). Because actual color volumes (305) have highly irregular shapes, transmitting such source color volume information for each frame or for an entire scene requires a lot of information. For example, in one embodiment, color gamut information may be signaled for multiple luminance values ​​(e.g., at 0.1, 1, 10, etc.). The question then becomes, how many luminance values ​​are most significant, and which are they? One must also consider not only the overhead on the encoded bitstream that such information requires, but also the complexity of generating such content at an encoder and / or reconstructing the color volume information at a decoder.

[0020] It is important to convey the minimum and maximum luminance values ​​in the source content, As the inventors understand, conveying the average luminance (or midpoint luminance) is also useful for the receiver. These three values, together, can help generate a reasonable tone curve for display mapping. In this disclosure, we propose signaling the following metadata to describe the source color volume: a) the maximum 2D color gamut occupied by the source (e.g., source color volume), b) the source's maximum, minimum, and average luminance, and c) optionally, the sliced ​​(2D) color gamut for these three luminance values ​​(see, e.g., Figures 3B and 3C). Since the white points of the container primaries and the source content primaries are expected to be the same, there is no reason to retransmit such information. This information can be updated as needed, for example, on a frame-by-frame or scene-by-scene basis. Figures 3B and 3C show example 2D slices of the source color volume (305) and the container color volume (310) at specific luminance (Y) values. In Figure 3B, the 2D slice is at Y=84 nits, and in Figure 3C, the 2D slice is at Y=246 nits. The chromaticity (rgb) triangle that encloses the source color volume (305) and is within the container RGB space is given for illustrative purposes only. The encoder may choose to define and transmit smaller or larger such regions to the receiver.

[0021] Table 1 shows an example of source color volume SEI messaging according to an embodiment that follows the terminology and syntax of the H.265 specification. The color primary description follows the CIE 1931 (x,y) chromaticity coordinate convention for color primaries specified in ISO 11664-1 (see also ISO 11664-3 and CIE 15), using red, green, and blue primaries. Other types of color primaries, such as 4-polygon, 5-polygon, or 6-polygon, or other polygon-based color primary representations, may also be used. For the largest actual color gamut in the source content, in an embodiment, without limitation, the syntax is similar to the color_primaries parameter (or variable) convention specified in Section E.3.1 for Table E.3 of the H.265 specification. Current source content can reach the P3 color space, but it is believed that it will be some time before it reaches BT.2020 / 2010 color ("DCI-P3" is specified in SMPTE EG 432-1 and SMPTE RP 431-2). Therefore, if the source color gamut is equal to or less than P3 or equal to the BT.2020 / 2010 primaries, Table E.3 may be used. However, for sources whose color gamut is greater than P3 but less than BT.2020 / 2010, explicit signaling of the color gamut may be required. Luminance values ​​are expressed in nits (cd / m 2 ) units. Alternatively, to save bits, the luminance values ​​may also be coded using a non-linear representation (e.g., as values ​​coded according to the inverse EOTF of SMPTE ST 2084). The color gamut information corresponding to the maximum, minimum, and mean (mean) luminance values ​​is kept optional, allowing applications to reduce metadata overhead as desired.

[0022] Note that in a preferred embodiment, 1) the source color volume metadata should describe the color volume of the source in its original form, before any luma or chroma pre-processing has been performed. For example, the source color volume metadata should describe the source color volume before any chroma subsampling (e.g., from 4:4:4 to 4:2:0) or bit-depth conversion (e.g., from 12b to 10b) has been performed. This is because chroma subsampling or bit-depth conversion changes the color volume information. 2) The source color gamut is typically different from the container primaries. This is shown in Appendix E (e.g., Table E.3). 3) The source color volume is typically different from the mastering display color volume (which may be indicated by the Mastering Display Color Volume SEI message).

[0023] In an example embodiment, the parameters (or variables) and encoding semantics in Table 1 can be explained as follows:

[0024] source_colour_volume_id contains an identification number that can be used to identify the purpose of the source colour volume. The value of source_colour_volume_id must be between 0 and 2 32 -2 or less. Values ​​of source_colour_volume_id can be in the range 0-255 and 512-2, as determined by the application. 31 -1 may be used. 31 2 more 32 -2 and below are reserved for future use by ITU-T / ISO / IEC. Decoders should use the range 256 to 511, inclusive, or 2 31 2 more 32 All Color Remapping Information SEI messages containing source_colour_volume_id values ​​in the range less than or equal to -2 shall be ignored, and the bitstream shall never contain such values.

[0025] source_colour_volume_cancel_flag, when equal to 1, indicates that the source color volume SEI message cancels the persistence of any previous source color volume SEI message in the output order that applies to the current layer. When source_colour_volume_cancel_flag is equal to 0, it indicates that the source color volume will continue.

[0026] source_colour_volume_persistence_flag specifies the persistence of the source color volume SEI message for the current layer. When source_colour_volume_persistence_flag is equal to 0, it specifies that the source color volume information applies to the current picture only.

[0027] Let picA be the current picture. source_colour_volume_persistence_flag, when equal to 1, specifies that the source colour volume will persist in output order for the current layer until one of the following conditions is true: - A new coded layer video sequence (CLVS) for the current layer begins -Bitstream ends - Picture picB in the current layer in an access unit containing a Source Color Volume SEI message applicable to the current layer with the same value of source_colour_volume_id is output, where PicOrderCnt(picB) and PicOrderCnt(picA) are the PicOrderCnt values ​​of picB and picA, respectively, immediately after performing the decoding process for the picture order count on picB.

[0028] source_colour_primaries has the same semantics as specified in section E.3.1 for the colour_primaries syntax element, except that colour_primaries in section E.3.1 signals the container source primaries, and source_colour_primaries signals the primaries that the source content actually occupies. If the value of source_colour_primaries is equal to 2, then source_colour_primaries are explicitly specified by the syntax source_primaries_x[c] and source_primaries_y[c].

[0029] source_primaries_x[c] and source_primaries_y[c] are the values ​​specified in ISO 11664-1 (also ISO 11664-3 and CIE Specifies the normalized x and y chromaticity coordinates of the primary color component c of the source content, according to the CIE 1931 convention for x and y as specified in [reference 15], in increments of 0.00002, respectively. When describing source content that uses red, green, and blue primaries, it is suggested that an index value c equal to 0 should correspond to the green primary, c equal to 1 should correspond to the blue primary, and c equal to 2 should correspond to the red primary (see also Appendix E and Table E.3). The values ​​of source_primaries_x[c] and source_primaries_y[c] are in the range 0 to 50,000, inclusive.

[0030] max_source_luminance, min_source_luminance and avg_source_luminance are 0.0001 candela / m 2Specifies the nominal maximum luminance, nominal minimum luminance, and nominal average luminance of the source in (nits), respectively. min_source_luminance is less than avg_source_luminance, and avg_source_luminance is less than max_source_luminance.

[0031] luminance_colour_primaries_info_present_flag, when equal to 1, specifies that the syntax elements luminance_primaries_x and luminance_primaries_y are present, and when luminance_colour_primaries_info_present_flag is equal to 0, specifies that the syntax elements luminance_primaries_x and luminance_primaries_y are not present.

[0032] luminance_primaries_x[i][c] and luminance_primaries_y[i][c] are the CIE luminance values ​​of x and y as specified in ISO 11664-1 (see also ISO 11664-3 and CIE 15). Specifies the normalized x and y chromaticity coordinates of a primary color component c of source content at some nominal luminance, according to the 1931 standard, each in increments of 0.00002. When describing source content luminance, index values ​​0, 1, and 2 correspond to max_source_luminance, min_source_luminance, and avg_source_luminance, respectively. When describing source content that uses red, green, and blue primaries, it is suggested that an index value c equal to 0 should correspond to the green primary, c equal to 1 should correspond to the blue primary, and c equal to 2 should correspond to the red primary (also see Appendix E and Table E.3). The values ​​of source_primaries_x[c] and source_primaries_y[c] are in the range 0 to 50,000, inclusive.

[0033] Table 1 shows what is considered the minimum information for a useful representation of a source color volume. Alternative embodiments may specify further details, such as multiple primary [3] or primary color descriptions for more than three slices of luminance (Y), each with an associated polygon.

[0034] Table 1: Source Color Volume SEI Messaging Syntax Examples [Table 1]

[0035] 4 shows an example process for extracting color volume information for a video source using SEI messaging, according to one embodiment. First (405), the decoder detects whether a first SEI messaging variable (e.g., source_colour_volume_id) indicating an identification number (ID) of the source color volume information is present. If such a variable is present, the decoder may then check whether its value is within an allowed range (step 407). If the value is not allowed, the process ends (step 409). If the value is allowed, in step (410), the decoder may also read an additional flag regarding the first variable being persisted across the bitstream, as shown in Table 1 (e.g., see the syntax elements for source_colour_volume_cancel_flag and source_colour_volume_persistence_flag). In step (412), via a second SEI messaging parameter (e.g., source_colour_primaries), the decoder may check whether the metadata explicitly specifies the color volume actually occupied by the source data content. If it is true (e.g., source_colour_primaries=2), then in step (420) the (x,y) chromaticity coordinates are read for each primary color (e.g., red, green, and blue); if not true, in step (425), the decoder extracts the minimum, maximum, and average luminance values. Optionally, the SEI messaging may also specify the (x,y) chromaticity coordinates corresponding to the minimum, midpoint, and maximum luminance primaries specified above. In some embodiments, this may be indicated by a third parameter (e.g., luminance_colour_primaries_info_present_flag=1). If no such information is present (step 430), then , the process ends (409), and if present (step 435), the decoder extracts the (x,y) chromaticity coordinates for the primary colors for each of the minimum, midpoint, and maximum luminance values.

[0036] After extracting the source color volume information, the decoder may use the source color volume data in its display management process (e.g., 140). In one example, the display management may include two steps: tone mapping and gamut mapping. The minimum, midpoint, and maximum luminance values ​​may be used to generate a tone mapping curve, as described in [6-7]. The maximum RGB gamut and sliced ​​RGB gamut may be used to perform gamut mapping.

[0037] Active Area Consideration In some embodiments, specifying the active region as part of the metadata for the source color volume may be advantageous. For example, if video is encoded in letterbox format, encoders and decoders should not include black letterbox areas when calculating the luma and chroma characteristics (e.g., minimum luminance, maximum luminance, and average luminance) of each video frame. Experimental results have shown that taking into account the "framing" or "matting" of frames in a video sequence (e.g., pillarboxing, windowboxing, and letterboxing) can significantly improve overall output picture quality. While letterbox detection may be implemented by the decoder, thereby reducing the notification overhead of specifying the active picture region, in some embodiments, such notification may be explicitly signaled to support low-computational-complexity decoders. Table 2 shows an example of source color volume SEI messaging with active region notification, according to one embodiment.

[0038] Table 2: Example of source color volume SEI message syntax with active region notification [Table 2]

[0039] Table 2 is a superset of Table 1 and allows for two different semantics for defining active regions. Semantics 1. In one embodiment, the active region is specified for the decoded picture before conformance window cropping and output. The active region parameters may then be interpreted as follows:

[0040] active_region_flag, when equal to 1, indicates that active region offset parameters follow in the source color volume information SEI message. When active_region_flag is equal to 0, it indicates that no active region offset parameters are present.

[0041] active_region_left_offset, active_region_right_offset, active_region_top_offset, and active_region_bottom_offset specify the active rectangular region. If active_region_flag is equal to 0, then active_region_left_offset, active_region_right_offset, active_region_top_offset, and active_region_bottom_offset specify the active rectangular region. The values ​​of region_left_offset, active_region_right_offset, active_region_top_offset and active_region_bottom_offset are inferred to be equal to 0.

[0042] The active region is defined using the horizontal picture coordinate from SubWidthC*active_region_left_offset to pic_width_in_luma_samples-SubWidthC*active_region_right_offset+1) and the vertical picture coordinate from SubHeightC*active_region_top_offset to pic_height_in_luma_samples-(SubHeightC*active_region_bottom_offset+1). The value of SubWidthC*(active_region_left_offset+active_region_right_offset) is less than pic_width_in_luma_samples, and the value of SubHeightC*(active_region_top_offset+active_region_bottom_offset) is less than pic_height_in_luma_samples. Semantics 2. In one embodiment, the active region offset value is specified relative to the final output picture for display. Therefore, the conformance window parameters need to be taken into account. The active region parameters can then be interpreted as follows:

[0043] active_region_flag, when equal to 1, indicates that active region offset parameters follow in the Source Color Volume Information SEI message. When active_region_flag is equal to 0, it indicates that no active region offset parameters are present.

[0044] active_region_left_offset, active_region_right_offset, active_region_top_offset, and active_region_bottom_offset specify the active rectangular region. If active_region_flag is equal to 0, the values ​​of active_region_left_offset, active_region_right_offset, active_region_top_offset, and active_region_bottom_offset are inferred to be equal to 0.

[0045] The active region is defined using the horizontal picture coordinate from active_region_left_offset+SubWidthC*conf_win_left_offset to CtbSizeY*PicWidthInCtbsY-SubWidthC*conf_win_right_offset-active_region_right_offset-1 and the vertical picture coordinate from active_region_top_offset+SubHeightC*conf_win_top_offset to CtbSizeY*PicHeightInCtbsY-SubHeightC*conf_win_bottom_offset-active_region_bottom_offset-1, inclusive.

[0046] The value of (active_region_left_offset+active_region_right_offset) is less than CtbSizeY*PicWidthInCtbsY-SubWidthC*(conf_win_right_offset+conf_win_left_offset), and the value of (active_region_top_offset+active_region_bottom_offset) is less than CtbSizeY*PicHeightInCtbsY-SubHeightC * Less than (conf_win_bottom_offset+conf_win_top_offset).

[0047] Each of the documents listed below is incorporated herein by reference in its entirety. References [1]Rec.ITU-T H.265, “Series H:Audiovisual and Multimedia systems,Infrastructure of audiovisual services - Coding of moving video, High efficiency video coding,”ITU,Oct.2014. [2]HM Oh et al., “Content color gamut SEI message”, JCTVC-X0040, May 2016, Geneva, CH. [3]AM Tourapis, “Improvements to the Effective Color Volume SEI”, JCTVC-X0052, May 2016, Geneva, CH. [4] AK Ramasubramonian, “Content color volume SEI message”, JCTVC-X0052, May 2016, Geneva, CH. [5]SMPTE ST 2094-1:2016:“Dynamic Metadata for Color Volume Transform - Core Components,” SMPTE, May 18, 2016. [6]SMPTE ST 2094-10:2016:“Dynamic Metadata for Color Volume Transform - Application #1,”SMPTE,May 18,2016. [7] R. Atkins et al.,USPatent Publication US2016 / 0005349,“Display management for high dynamic range video.”

[0048] Computer system implementation example Embodiments of the present invention may be implemented using computer systems, systems comprised of electronic circuits and components, integrated circuit (IC) devices such as microcontrollers, field programmable gate arrays (FPGAs) or other configurable or programmable logic devices (PLDs), discrete-time or digital signal processors (DSPs), application-specific integrated circuits (ASICs), and / or apparatuses including one or more such systems, devices, or components. The computers and / or ICs may perform, control, or execute instructions related to conveying source color volume information using SEI messaging as described herein. The computers and / or ICs may compute any of various parameters or values ​​related to the processes described herein. Image and video embodiments may be implemented in hardware, software, firmware, and various combinations thereof.

[0049] Certain embodiments of the present invention include computer processors that execute software instructions to cause the processor to perform the methods of the present invention. For example, one or more processors in a display, encoder, set-top box, transcoder, etc., may implement the methods relating to conveying source color volume information using SEI messaging as described above by executing software instructions in a program memory accessible to the processor. The present invention may also be provided in the form of a program product. The program product may include any non-transitory medium that stores a set of computer-readable signals that, when executed by a data processor, cause the data processor to perform the methods of the present invention. Program products according to the present invention may take various forms. For example, the program product may include physical media such as magnetic data storage media including floppy disks and hard disk drives, optical data storage media including CD-ROMs and DVDs, electronic data storage media including ROMs, flash RAM, etc. The computer-readable signals on the program product may optionally be compressed or encrypted.

[0050] When a component (e.g., software module, processor, assembly, device, circuit, etc.) is mentioned above, the reference to that component (" Unless expressly stated otherwise, any reference to a "means" (including references to "means") should be construed to include any component that performs the function of (e.g., is functionally equivalent to) the component in question, as an equivalent of the component (including components that are not structurally equivalent to the disclosed structures that perform the function(s) appearing in the above-described example embodiments of the invention).

[0051] Equivalents, Extensions, Substitutes, etc. Exemplary embodiments relating to conveying source color volume information using SEI messaging have been described above. Embodiments of the invention have been described herein with reference to numerous specific details that may vary from implementation to implementation. Accordingly, the sole and exclusive indication of what the invention is and what Applicant intends the invention to be is the set of claims issuing from this application, in the specific form in which those claims arise, including any subsequent amendments. Any definitions expressly set forth in this specification for terms contained in the claims shall determine the meaning of those terms as used in the claims. Accordingly, no limitations, elements, properties, features, advantages, or attributes not expressly recited in the claims shall limit the scope of the claims in any way. Accordingly, the specification and drawings are to be regarded as illustrative and not restrictive.

Claims

1. 1. A processor-implemented method for extracting source color volume information for an input bitstream from associated metadata, comprising: receiving, by the processor, an input video bitstream and metadata including source color volume information for the input video bitstream; decoding one or more pictures in the input video bitstream to generate decoded pictures; if the persistent metadata flag is set to 0, applying the source color volume information to the currently decoded picture only; If the metadata flag indicating the presence of source primaries metadata is set, extracting, for one or more primary colors, x and y chromaticity coordinates from the metadata that define, for each of the one or more primary colors, a two-dimensional color gamut of the input video bitstream; extracting from the metadata luminance value parameters including an average luminance value, where for one or more coded pictures in the input video bitstream that are coded in letterbox format, the average luminance value is for an active region of the one or more coded video pictures in the input video bitstream that are coded in letterbox format; A method comprising:

2. The method of claim 1 , further comprising generating an output video signal based on the metadata about the decoded picture and the source color volume information.

Images