Methods, apparatuses and storage media related to processing of source color volume information

Abstract

Methods, apparatuses and storage media related to processing of source color volume information are described. Such data includes at least minimum luminance value, maximum luminance value and average luminance value from source data plus optional data which can include color volume x and y chromaticity coordinates for input primaries (e.g., red, green and blue) of the source data and color x and y chromaticity coordinates for the primaries corresponding to the minimum luminance value, average luminance value and maximum luminance value from the source data. Messaging data can also be included to signal active areas in each picture.

Description

[0001] Case Separation Statement

[0002] This application is a divisional application of the invention patent application with PCT international application number PCT / US2017 / 054920, international application date of October 3, 2017, application number 201780069607.7 which entered the Chinese national phase, and invention title "Source Color Volume Information Message Transmission".

[0003] Cross-reference to related applications

[0004] 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, both of which are incorporated herein by reference in their entirety. Technical Field

[0005] This invention generally relates to images. More specifically, embodiments of the invention relate to conveying and processing source color volume information. Background Technology

[0006] Recommendation ITU-T H.265[1] (also known as HEVC) for “Mobile Video Coding”, “Supplemental Enhancement Information” (SEI) in Annex D and “Video Availability Information” (VUI) in Annex E describes the syntax for providing supplemental SEI and VUI information in the encoded bitstream so that the decoder can better map the decoded samples to the display.

[0007] In parallel with the MPEG / ITU standardization process, the Society of Motion Picture and Television Engineers (SMPTE) has also defined several recommendations relating to metadata related to conveying color volume information for both source video and targeted display. For example, the SMPTE ST 2094 document suite (e.g., [5] and [6]) defines metadata for use in color volume transformations of video content. This metadata can vary scene-by-scene or frame-by-frame. For example, such metadata can help decoders render high dynamic range (HDR) and wide color gamut (WCG) data on displays with a color volume smaller than that of the master display used for the master source image.

[0008] As used herein, the term "metadata" refers to any auxiliary information that is transmitted as part of the encoded bitstream and assists the decoder in rendering the 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.

[0009] While H.265 Annexes D and E support a lot of color volume-related metadata, they do not carry all the metadata needed for the most efficient display management of HDR content. In July 2016, at the Joint Collaborative Video Coding Team (JCT-VC) meeting in Geneva, three proposals were submitted regarding how to use SEI or VUI messaging to describe content color volume information [2-4]. Some of these proposals were influenced by SMPTE ST.2094 [5], but their scopes differed considerably.

[0010] In [2], a content-SEI message was proposed for the signal content color gamut in 2D, which describes the actual color distribution of the video content. In VUI, the variable colour_primaries is used to indicate the container color gamut rather than the true source color gamut [1]. In [3], it was proposed to associate multiple primary color expressions and spatial regions with the identified source characteristics. In [4], a content color volume SEI message was proposed to indicate the color volume occupied by the content. It is described using (x, y, Y) for color coordinates and has multiple slices of luminance Y, each slice having an associated polygon. These proposals have many drawbacks, such as: providing information that is rarely used to most display manufacturers may increase overhead significantly and may require too much computational overhead. As the inventors understand here, in order to improve existing encoding and decoding schemes, there is a need for improved techniques for generating and conveying source color volume information.

[0011] The methods described in this section are permissible but not necessarily methods that have been previously conceived or adopted. Therefore, unless otherwise specified, no method described in this section should be considered prior art simply by virtue of its inclusion in this section. Similarly, unless otherwise specified, problems identified by one or more methods should not be considered to have been recognized in any prior art based on this section. Summary of the Invention

[0012] According to some embodiments of this disclosure, a method is provided for extracting source color volume information of an input bitstream from associated metadata, the method being executed on a processor, the method comprising: receiving an input video bitstream and metadata via the processor, the metadata including source color volume information of the input video bitstream; if a metadata marker indicates the presence of source primary color metadata, extracting x and y chromaticity coordinates from the metadata for one or more primary colors, the x and y chromaticity coordinates defining a 2D color gamut of the input video bitstream for each of the one or more primary colors; and extracting a luminance value parameter including an average luminance value from the metadata, wherein the average luminance value is used for one or more decoded images or a valid region of one or more decoded images in the input video bitstream.

[0013] According to some embodiments of this disclosure, a method for generating an encoded bitstream is provided, the method comprising: receiving a sequence of video images; encoding one or more of the video images to generate a compressed video image; generating a metadata message indicating source color volume information of the compressed video image; and generating an output video bitstream including the compressed video image and the metadata message, wherein the metadata message includes: normalized x and y chromaticity coordinates of one or more primary color components in the encoded bitstream; and a luminance value parameter including an average luminance value, wherein the average luminance value is used for valid regions of one or more encoded images in the encoded bitstream. Attached Figure Description

[0014] Embodiments of the invention are shown in the accompanying drawings by way of example rather than limitation, and the same reference numerals refer to the same elements, and in the drawings:

[0015] Figure 1 An example process of a video delivery pipeline according to an embodiment of the present invention is described;

[0016] Figure 2 An example depicting the "maximum" possible color volumetric map for a video container format;

[0017] Figure 3A An example depicting the source content color gamut within the container's color volume;

[0018] Figure 3B and Figure 3C An example of 2D slicing of the container and source color volume at a specific brightness (Y) value is depicted; and

[0019] Figure 4 An example process for extracting source color volume information from SEI message transmission according to an embodiment of the present invention is described. Detailed Implementation

[0020] This document describes a technique for conveying source color volume information using SEI message transmission. In the following description, numerous specific details are set forth for purposes of explanation in order to provide a thorough understanding of the invention. However, it will be apparent that the invention may be practiced without these specific details. In other instances, well-known structures and apparatuses have not been described in detail to avoid unnecessarily obscuring, obscuring, or confusing the invention.

[0021] Overview

[0022] The example embodiments described herein relate to techniques for conveying source color volume information using SEI messaging. In a decoder, a processor for extracting SEI messaging receives a source color volume identifier messaging variable that identifies the presence of source color volume information 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-chromaticity coordinates and y-chromaticity coordinates for 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-chromaticity coordinates and y-chromaticity coordinates for one or more primary colors corresponding to the minimum luminance value, maximum luminance value, and average luminance value based on the source color volume information.

[0023] Example of source color volume message transmission

[0024] Figure 1 An example process of a video delivery pipeline (100) is depicted, illustrating the various stages from video capture to video content display. An image generation block (105) is used to capture or generate a sequence of video frames (102). The video frames (102) can be 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) can be captured on film by a film camera. The film is then converted to a digital format after appropriate editing (not shown) to provide video data (107).

[0025] The video data (107) is then provided to the processor at block (110) for post-production editing. Post-production editing (110) may include adjusting or modifying the color or brightness in specific areas of the image to enhance image quality or achieve a specific look for the image according to the creative intent of the video creator. This is sometimes referred to as “color timing” or “color grading”. Other edits (e.g., scene selection and sorting, image cropping, adding computer-generated visual effects, etc.) may be performed at block (110) to produce a final version (112) of the work for release. During post-production editing (110), the video image is viewed on a reference monitor (125) (also referred to as a “targeted monitor” because the production studio has optimized the video for it).

[0026] In some embodiments, prior to video encoding (120), the video content may be analyzed to extract source color volume metadata (119), such as that defined in SMPTE ST 2094-1 [5] or as will be defined later in this invention. This metadata may also define characteristics and color remapping information for a specific display (e.g., a reference display (125)) so that downstream receivers can present the decoded data in the most feasible manner.

[0027] Following post-production (110) and source color volumetric analysis (115), the video data and associated metadata (119) of the final product (117) can be delivered to the encoding block (120) in an appropriate color format (e.g., 10-bit YCbCr, ICtCp, etc., in 4:2:0) for downstream delivery to decoding and playback devices such as televisions, set-top boxes, and cinemas. In some embodiments, the encoding block (120) may include audio encoders and video encoders such as those defined by ATSC, DVB, DVD, Blu-ray, and other delivery formats to generate an encoded bitstream (122). The encoded bitstream (122) may be represented by a single-layer video encoded 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, which, 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) (i.e., the output bitstream from the encoder (120)) may also include metadata (119) and additional encoding-related metadata, such as prediction parameters and other data, to assist the decoder in better reconstructing the HDR signal.

[0028] In the receiver, the encoded bitstream (122) is decoded by the decoding unit (130) to generate a decoded signal (132) and associated metadata (119). The receiver (or target) display (150) may have characteristics completely different from those of the reference (or targeted) display (125). For example, but not limited to, the reference display (125) may be a 1,000-nit display, while the receiver display may be a 500-nit display. In this case, the 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., hue and gamut mapping) required to map an input video signal with a first dynamic range (e.g., 1,000 nits) to a display with a second dynamic range (e.g., 500 nits). The display management unit (140) may take the metadata (119) into account to improve the quality of the output video on the display (150). For example, as shown in [7], information about the brightness range of the targeted (or reference) display (e.g., 125) and the source data can be used on the receiver to better map the dynamic range of the video content onto the receiver display (e.g., 150).

[0029] Color volume information

[0030] Figure 2 This describes an example of the "maximum" possible color volume (also known as the "container color volume") of a predefined container format (e.g., BT.2020). This volume can be composed of two-dimensional (2D) color gamut primary colors, white point chromaticity (e.g., D65), and maximum lightness value (e.g., L). 最大 =4,000 nits), and a minimum luminance value (e.g., 0.005 nits). This graph indicates the maximum possible color volume boundaries for all colors in the source video content.

[0031] In practice, such as by Figure 3A The deeper "cloud" (305) or Figure 3B and Figure 3CThe source color volume depicted in the deeper regions (305) of the image, used for source content (e.g., 112) within a specific frame or even the entire scene, can be significantly smaller than the maximum possible color volume (310). Because the actual color volume (305) has a highly irregular shape, transmitting this source color volume information for each frame or the entire scene requires a large amount of information. For example, in an embodiment, gamut information can be represented by signals for multiple luminance values ​​(e.g., 0.1, 1, 10, etc.). The question then becomes: how many luminance values ​​are there, and which are the most important? It is also necessary to consider not only the overhead required for this information on the encoded bitstream, but also the complexity of generating this content on the encoder and / or reconstructing the color volume information on the decoder.

[0032] While conveying the minimum and maximum luminance values ​​of the source content is important, as the inventors understand, conveying the average luminance (or midpoint luminance) is also valuable to the receiver. These three values ​​together can help generate a reasonable tone curve for display mapping. In this disclosure, it is proposed to represent the following metadata using signals 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 (2D) color gamut used for segmentation of these three luminance values ​​(e.g., see [link to relevant documentation]). Figure 3B and Figure 3C Assuming the container's primary color and the source content's primary color should have the same white point, there's no reason to retransmit this information. This information can be updated as needed, for example, frame-by-frame or scene-by-scene. Figure 3B and Figure 3C An example of a 2D slice depicting the source color volume (305) and container color volume (310) at a specific brightness (Y) value is shown. Figure 3B In the 2D slice, Y = 84 nits, and... Figure 3C In this context, the 2D slice is Y = 246 nits. For illustrative purposes only, a chromaticity (rgb) triangle is provided around the source color volume (305) and within the container RGB space. The encoder can optionally define smaller or larger such regions and transmit them to the receiver.

[0033] Table 1 illustrates an example of source color volume SEI message transmission following the naming and syntax of the H.265 specification according to an embodiment. The description of the primary colors follows the definition of the CIE 1931 (x, y) color chromaticity coordinates of the primary colors as defined in ISO 11664-1 (see also ISO 11664-3 and CIE 15), using red, green, and blue primary colors. Other types of primary colors may also be used, such as four, five, or six, or other polygon-based primary color representations. For the maximum actual color gamut in the source content, in the embodiment, but not limited to, the syntax is similar to the definition of the colour_primaries parameter (or variable) as defined in Section E.3.1 (Table E.3) of the H.265 specification. It is believed that the current source content can reach the P3 color space, but reaching BT.2020 / 2010 colors (defined as "DCI-P3" in SMPTE EG 432-1 and SMPTE RP 431-2) will take some time. Therefore, Table E.3 can be used for sources with a color gamut less than or equal to P3, or equal to the BT.2020 / 2010 primary colors; however, for sources with a color gamut greater than P3 but less than BT.2020 / 2010, explicit signal representation of the color gamut may be necessary. Luminance values ​​are expressed in nits (cd / m²). 2 The luminance value is specified as the absolute value in units of luminance. Alternatively, to save bits, the luminance value can be encoded using a non-linear representation, for example, as an inverse EOTF encoded according to SMPTE ST 2084. Making gamut information corresponding to the maximum, minimum, and average (intermediate) luminance values ​​optional allows applications to reduce metadata overhead as needed.

[0034] Note: In a preferred embodiment, 1) the source color volume metadata should describe the source color volume in its original form prior to any luma or chroma preprocessing. For example, it should describe the source color volume prior to any chroma subsampling process (e.g., from 4:4:4 to 4:2:0) or bit depth conversion process (e.g., from 12b to 10b), as chroma subsampling or bit depth conversion will modify the color volume information. 2) The source color gamut is typically different from the container primary color, which is indicated in Appendix E of H.265 (e.g., Table E.3). 3) The source color volume is typically different from the master display color volume, which may be indicated by the master display color volume SEI message.

[0035] In the example embodiment, the parameters (or variables) and encoding semantics in Table 1 can be described as follows:

[0036] `source_colour_volume_id` contains an identifier that can be used to identify the volume of the source color. The value of `source_colour_volume_id` should be between 0 and 2. 32 The range is -2, including the endpoints. As determined by the application, ranges from 0 to 255 and from 512 to 2... 31 -1 is the value of source_colour_volume_id. Reserve values ​​from 256 to 511 (inclusive) and from 2... 31 to 2 32 -2 (including endpoints) of the source_colour_volume_id value for future use by ITU-T|ISO / IEC. The decoder should ignore values ​​in the range of 256 to 511 (including endpoints) or 2... 31 to 2 32 All color remapping information SEI messages containing source_colour_volume_id values ​​in the range of -2 (inclusive of endpoints), and the bitstream should not contain such values.

[0037] `source_colour_volume_cancel_flag` equal to 1 indicates that source color volume SEI messages are cancelled in the output order, cancelling any previous source color volume SEI messages applied to the current layer. `source_colour_volume_cancel_flag` equal to 0 indicates that source color volumes follow suit.

[0038] `source_colour_volume_persistence_flag(source_color_volume_persistence_flag)` specifies the persistence of the source color volume SEI message for the current layer. A `source_colour_volume_persistence_flag` value of 0 indicates that the source color volume information applies only to the current image.

[0039] Make picA the current image. `source_colour_volume_persistence_flag` equal to 1 specifies that the source color volume persists in the current layer in output order until either of the following conditions is true:

[0040] - Start of a new coding layer video sequence (CLVS) for the current layer

[0041] -End of bitstream

[0042] - Output the image picB in the current layer of the access unit. Image picB contains source color volume SEI messages with the same source_colour_volume_id value and applicable to the current layer. For image picB, PicOrderCnt(picB) is greater than PicOrderCnt(picA), where PicOrderCnt(picB) and PicOrderCnt(picA) are the respective PicOrderCntVal values ​​of picB and picA immediately after the decoding process for image order counting of picB is called.

[0043] The source_colour_primaries(source_color_primary_color) syntax element has the same semantics as the clause E.3.1 of the colour_primaries syntax element. The difference is that colour_primaries in clause E.3.1 uses a signal to represent the container source primary color, while source_colour_primaries uses a signal to represent the primary color actually occupied by the source content.

[0044] When the value of source_colour_primaries is equal to 2, source_colour_primaries is explicitly specified by the syntax source_primaries_x[c] and source_primaries_y[c].

[0045] `source_primaries_x[c]` and `source_primaries_y[c]` specify the normalized x-chromatic and y-chromatic coordinates of the primary color components `c` of the source content, respectively, according to the CIE 1931 definitions of x and y as specified in ISO 11664-1 (see also ISO 11664-3 and CIE 15), in increments of 0.00002. To describe source content using red, green, and blue primary colors, it is recommended that an index value of `c` equal to 0 correspond to the green primary color, `c` equal to 1 correspond to the blue primary color, and `c` equal to 2 correspond to the red primary color (see also Appendix E and Table E.3). The values ​​of `source_primaries_x[c]` and `source_primaries_y[c]` should be in the range of 0 to 50,000 (inclusive).

[0046] `max_source_luminance` (maximum source luminance), `min_source_luminance` (minimum source luminance), and `avg_source_luminance` (average source luminance) specify the nominal maximum, minimum, and average luminance of the source, respectively, in units of 0.0001 candela per square meter (nits). `min_source_luminance` should be less than `avg_source_luminance`, and `avg_source_luminance` should be less than `max_source_luminance`.

[0047] The luminance_colour_primaries_info_present_flag(luminance_color_primary_color_information_existence_flag) value of 1 indicates that the syntax elements luminance_primaries_x and luminance_primaries_y exist, while the luminance_colour_primaries_info_present_flag value of 0 indicates that the syntax elements luminance_primaries_x and luminance_primaries_y do not exist.

[0048] `luminance_primaries_x[i][c]` and `luminance_primaries_y[i][c]` specify the normalized x-chromaticity coordinates and y-chromaticity coordinates of the primary color components `c` of the source content at a nominal luminance, according to the CIE 1931 definitions of x and y as specified in ISO 11664-1 (see also ISO 11664-3 and CIE 15), in increments of 0.00002. To describe the luminance of the source content, index values ​​0, 1, and 2 should correspond to `max_source_luminance`, `min_source_luminance`, and `avg_source_luminance`, respectively. To describe source content using red, green, and blue primary colors, it is recommended that an index value of `c` equal to 0 correspond to the green primary color, `c` equal to 1 correspond to the blue primary color, and `c` equal to 2 correspond to the red primary color (see also Appendix E and Table E.3). The values ​​of source_primaries_x[c] and source_primaries_y[c] should be in the range of 0 to 50,000 (inclusive).

[0049] Table 1 provides the minimum information that is considered a useful representation of the source color volume. In another embodiment, additional details may be defined, such as multiple primary color expressions [3] or descriptions of the primary colors for more than three luminance (Y) slices, each with an associated polygon.

[0050] Table 1: Examples of Source Color Volume SEI Message Transmission Syntax

[0051]

[0052]

[0053] Figure 4 An example process for extracting color volume information of a video source using SEI messaging, according to an embodiment, is described. First (405), the decoder can detect the presence of a first SEI messaging variable indicating an identifier (ID) of the source color volume information (e.g., source_colour_volume_id). Then, considering the presence of such a variable, the decoder can check (step 407) whether the value of the variable is within an allowable range. If it is an illegal value, the process terminates (step 409). If it is a legal value, then in step (410), as also shown in Table 1, the decoder can read additional flags related to the retention of the first variable on the bitstream (e.g., see the syntax elements of 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 can check whether the metadata explicitly defines the color volume actually occupied by the source data content. If true (e.g., source_colour_primaries = 2), then in step (420), the (x, y) chromaticity coordinates of each primary color (e.g., red, green, and blue) are read; otherwise, in step (425), the decoder extracts the minimum luminance value, maximum luminance value, and average luminance value. Optionally, the SEI message transmission may also define (x, y) chromaticity coordinates corresponding to the previously defined primary colors having minimum, intermediate, and maximum luminance values. In an embodiment, this may be indicated by a third parameter (e.g., luminance_colour_primaries_info_present_flag = 1). If such information does not exist (step 430), the process terminates (409); otherwise, (in step 435), the decoder extracts the (x, y) chromaticity coordinates of the primary color for each of the minimum, intermediate, and maximum luminance values.

[0054] After extracting the source color volume information, the decoder can use the source color volume data during its display management process (e.g., 140). In this example, display management can include two steps: tone mapping and gamut mapping. Minimum luminance values, intermediate luminance values, and maximum luminance values ​​can be used to generate tone mapping curves as described in [6-7]. The maximum RGB gamut and sliced ​​RGB gamut can be used to perform gamut mapping.

[0055] Consideration of the active region

[0056] In some embodiments, defining the effective region as part of the metadata related to the source color volume may be beneficial. For example, when encoding video in a letterbox format, the encoder and decoder should not include black areas with horizontal black borders when calculating the luminance and chrominance characteristics (e.g., minimum luminance, maximum luminance, and average luminance) for each video frame. Experimental results show that considering “framing” or “matting” of frames in a video sequence (e.g., adding vertical black borders, adding windowboxing, and adding horizontal black borders) can significantly improve the overall output image quality. While horizontal black border detection can be implemented by the decoder, thereby reducing the signaling overhead used to define the effective image region, in embodiments, this signaling can be explicitly represented by signals to support decoders with low computational complexity. Table 2 depicts examples of source color volume SEI message transmission with effective region signaling according to embodiments.

[0057] Table 2: Examples of Source Color Volume SEI Message Syntax with Valid Region Signaling

[0058]

[0059]

[0060] Table 2 is a superset of Table 1 and considers two different semantics for defining the effective region.

[0061] Semantic 1. In this embodiment, the valid region is specified relative to the decoded image before cropping and outputting the consistency window. The valid region parameter can then be interpreted as follows:

[0062] An active_region_flag value of 1 indicates a valid region offset parameter, which is subsequently included in the source color volume information (SEI) message. An active_region_flag value of 0 indicates that no valid region offset parameter exists.

[0063] `active_region_left_offset` (effective region left offset), `active_region_right_offset` (effective region right offset), `active_region_top_offset` (effective region top offset), and `active_region_bottom_offset` (effective region bottom offset) specify the effective rectangular region. When `active_region_flag` equals 0, it is inferred that the values ​​of `active_region_left_offset`, `active_region_right_offset`, `active_region_top_offset`, and `active_region_bottom_offset` are equal to 0.

[0064] The effective region is defined using the horizontal image coordinates from SubWidthC*active_region_left_offset to pic_width_in_luma_samples-(SubWidthC*active_region_right_offset+1) and the vertical image coordinates from SubHeightC*active_region_top_offset to pic_height_in_luma_samples-(SubHeightC*active_region_bottom_offset+1), including the endpoints. The value of SubWidthC*(active_region_left_offset+active_region_right_offset) should be less than pic_width_in_luma_samples, and the value of SubHeightC*(active_region_top_offset+active_region_bottom_offset) should be less than pic_height_in_luma_samples.

[0065] Semantic 2. In this embodiment, the effective region offset value is defined relative to the final output image to be displayed, therefore the consistency window parameter needs to be considered. The effective region parameter can then be interpreted as follows:

[0066] An active_region_flag value of 1 indicates that the valid region offset parameter is subsequently included in the source color volume information (SEI) message. An active_region_flag value of 0 indicates that no valid region offset parameter exists.

[0067] `active_region_left_offset`, `active_region_right_offset`, `active_region_top_offset`, and `active_region_bottom_offset` specify the valid rectangular region. When `active_region_flag` equals 0, it is inferred that the values ​​of `active_region_left_offset`, `active_region_right_offset`, `active_region_top_offset`, and `active_region_bottom_offset` are equal to 0.

[0068] The effective region is defined using the horizontal image coordinates 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 image coordinates from active_region_top_offset+SubHeightC*conf_win_top_offset to CtbSizeY*PicHeightInCtbsY-SubHeightC*conf_win_bottom_offset-active_region_bottom_offset-1, including the endpoints.

[0069] The value of (active_region_left_offset+active_region_right_offset) should be 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) should be less than CtbSizeY*PicHeightInCtbsY-SubHeightC*(conf_win_bottom_offset+conf_win_top_offset).

[0070] Each of the references listed below is incorporated herein by reference in its entirety.

[0071] References

[0072] [1] Recommendation ITU-T H.265, “Series H: Audiovisual and Multimedia systems, Infrastructure of audiovisual services – Coding of moving video, High efficiency video coding”, ITU, October 2014.

[0073] [2] HMOh et al., “Content color gamut SEI message”, JCTVC-X0040, May 2016, Geneva, CH.

[0074] [3]AMTourapis, “Improvements to the Effective Colour Volume SEI”, JCTVC-X0052, May 2016, Geneva, CH.

[0075] [4]AKRamasubramonian, “Content colour volume SEI message”, JCTVC-X0069, May 2016, Geneva, CH.

[0076] [5] SMPTE ST 2094-1:2016: "Dynamic Metadata for Color Volume Transform – Core Components", SMPTE, May 18, 2016.

[0077] [6] SMPTE ST 2094-10:2016: "Dynamic Metadata for Color VolumeTransform – Application #1", SMPTE, May 18, 2016.

[0078] [7] R. Atkins et al., U.S. Patent Publication US2016 / 0005349, “Display Management for High Dynamic Range Video”.

[0079] Example computer system implementation

[0080] Embodiments of the present invention may be implemented using computer systems, systems configured with 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 devices comprising one or more such systems, devices, or components. The computer and / or IC may execute, control, or implement instructions relating to the use of SEI messaging to convey source color volume information, such as those described herein. The computer and / or IC may calculate any of the various parameters or values ​​relating to the processes described herein. Image and video embodiments may be implemented in hardware, software, firmware, and various combinations thereof.

[0081] Some embodiments of the present invention include a computer processor that executes software instructions that cause the processor to perform the methods of the present invention. For example, one or more processors, such as those in a display, encoder, set-top box, transcoder, etc., can implement the methods relating to conveying source color volume information using SEI message transmission as described above by executing software instructions in a program memory accessible to the processor. The present invention can also be provided in the form of a program product. The program product may include any non-transitory medium carrying a set of computer-readable signals, including instructions that, when executed by a data processor, cause the data processor to perform the methods of the present invention. The program product according to the present invention can take any of a variety of forms. The program product may include, for example, 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 and flash RAMs, etc. The computer-readable signals on the program product may optionally be compressed or encrypted.

[0082] In the case of the components mentioned above (e.g., software modules, processors, components, devices, circuits, etc.), unless otherwise stated, references to such components (including references to “devices”) should be interpreted as including equivalents (e.g., functionally equivalents) of any component that performs the function of the described component, including components that are structurally different from those performing the functions in the exemplary embodiments described in this invention.

[0083] Equivalence, Extension, Substitution and Miscellaneous

[0084] This description presents an example embodiment involving the use of SEI message transmission to convey source color volume information. In the foregoing specification, embodiments of the invention have been described with reference to numerous specific details, which may vary depending on the implementation. Therefore, the claims that are the sole and unique indications of the invention, and intended by the applicant to be the only ones published in this application in this set of claims, including any subsequent modifications, are the specific claims. Any definitions of terms expressly set forth herein that are included in such claims shall govern the meaning of such terms as used in the claims. Therefore, any limitations, elements, characteristics, features, advantages, or attributes not expressly referenced in the claims shall not in any way limit the scope of such claims. Consequently, the specification and drawings should be considered illustrative rather than restrictive.

Claims

1. A method for extracting source color volume information of an input bitstream from associated metadata, the method being executed on a processor, the method comprising: The processor receives an input video bitstream and metadata, the metadata including source color volume information of the input video bitstream; If the metadata tag included in the metadata indicates the presence of source primary color metadata, then For one or more primary colors, x and y chromaticity coordinates are extracted from the metadata, and the x and y chromaticity coordinates define the 2D color gamut of the input video bitstream for each of the one or more primary colors; as well as Extract a luminance value parameter, including an average luminance value, from the metadata, wherein the average luminance value is used for one or more decoded images or a valid region of one or more decoded images in the input video bitstream; The metadata further includes a source color volume retention flag used to specify the retention of the source color volume supplementation enhancement information (SEI) message for the current layer, wherein: The source color volume retention flag being equal to 0 indicates that the source color volume information applies only to the current image; and The source color volume retention flag being equal to 1 indicates that the source color volume information persists in the current layer in the output order until a set condition occurs.

2. The method of claim 1, further comprising: The output video signal is generated based on the metadata of the input video bitstream and the source color volume information.

3. The method of claim 1, wherein, The x and y chromaticity coordinates are specified in increments of 0.00002 according to the CIE 1931 definition of x and y as specified in ISO 11664-1.

4. The method of claim 1, wherein, The metadata tag indicating the existence of source primary color metadata includes the source color primary color tag.

5. The method of claim 1, wherein, The metadata further includes the source color volume unmarking, wherein: The source color volume cancellation flag being equal to 1 indicates that the source color volume SEI message cancels any previous source color volume SEI messages applied to the current layer in the output order; and The source color volume de-marking value being equal to 0 indicates that the source color volume should follow.

6. A method for generating an encoded bitstream, the method comprising: Receive a sequence of video images; Encode one or more of the video images to generate a compressed video image; Generate a metadata message indicating the source color volume information of the compressed video image; as well as Generate an output video bitstream including the compressed video images and the metadata message, wherein the metadata message includes: Normalization indicating the presence of one or more primary color components in the encoded bitstream. x and y Metadata tags for chromaticity coordinates; and A brightness value parameter including an average brightness value, wherein the average brightness value is used for a valid region of one or more encoded images in the encoded bitstream; The metadata message further includes a retained source color volume retention flag for specifying the source color volume supplementation enhancement information (SEI) message of the current layer, wherein: The source color volume retention flag being equal to 0 indicates that the source color volume information applies only to the current image; and The source color volume retention flag being equal to 1 indicates that the source color volume information persists in the current layer in the output order until a set condition occurs.

7. The method of claim 6, wherein, The normalized x and y chromaticity coordinates are specified in increments of 0.00002 according to the CIE 1931 definition of x and y as specified in ISO 11664-1.

8. The method of claim 6, wherein, The metadata messages include SEI messages.

9. The method of claim 6, wherein, The metadata message further includes the source color volume unmarking, wherein: The source color volume cancellation flag being equal to 1 indicates that the source color volume SEI message cancels any previous source color volume SEI messages applied to the current layer in the output order; and The source color volume de-marking value being equal to 0 indicates that the source color volume should follow.

10. The method of claim 6, wherein, The metadata tag indicating the presence of one or more primary color components in the encoded bitstream includes the source color primary color tag.

11. An apparatus for extracting source color volume information of an input bitstream from associated metadata, the apparatus comprising: processor; as well as A memory that stores instructions, which, when executed by the processor, cause the processor to perform the method as described in any one of claims 1 to 5.

12. An apparatus for generating an encoded bitstream, the apparatus comprising: processor; as well as A memory that stores instructions, which, when executed by the processor, cause the processor to perform the method as described in any one of claims 6 to 10.

13. A computer-readable storage medium having computer-executable instructions stored thereon for performing the method according to any one of claims 1 to 10 using one or more processors.

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