Monochrome Palette Mode for Video Coding

Abstract

A method for decoding video data includes determining that a current block of video data is coded in palette mode; determining, between single-tree partitioning or dual-tree partitioning, that the current block is coded with single-tree partitioning enabled; determining that the current block is coded in monochrome format; determining that when the current block is coded with single-tree partitioning enabled and when the current block is coded in monochrome format, a number of color components used to decode the current block in palette mode is equal to 1; and palette-mode decoding the current block based on the determined number of color components used to decode the current block in palette mode being equal to 1.

Description

Claiming priority

[0001]

[0001] This application claims priority to U.S. Application No. 17 / 132,836, filed December 23, 2020, and U.S. Provisional Application No. 62 / 953,713, filed December 26, 2019, the entire contents of which are incorporated herein by reference. U.S. Application No. 17 / 132,836 claims the benefit of U.S. Provisional Application No. 62 / 953,713, filed December 26, 2019. [Technical field]

[0002]

[0002] This disclosure relates to video encoding and decoding. [Background technology]

[0003] Digital video capabilities may be incorporated into a wide range of devices, including digital televisions, digital direct broadcast systems, wireless broadcast systems, personal digital assistants (PDAs), laptop or desktop computers, tablet computers, e-book readers, digital cameras, digital recording devices, digital media players, video gaming devices, video game consoles, cellular or satellite radio telephones, so-called "smartphones," video teleconferencing devices, video streaming devices, and the like. Digital video devices implement video coding techniques, such as those described in standards defined by MPEG-2, MPEG-4, ITU-T H.263, ITU-T H.264 / MPEG-4, Part 10, Advanced Video Coding (AVC), ITU-T H.265 / High Efficiency Video Coding (HEVC), and extensions to such standards. By implementing such video coding techniques, video devices may more efficiently transmit, receive, encode, decode, and / or store digital video information.

[0004]

[0004] Video coding techniques include spatial (intra-picture) prediction and / or temporal (inter-picture) prediction to reduce or remove redundancy inherent in video sequences. In block-based video coding, a video slice (e.g., a video picture or a portion of a video picture) may be partitioned into video blocks, which may also be referred to as coding tree units (CTUs), coding units (CUs) and / or coding nodes. Video blocks in an intra-coded (I) slice of a picture are encoded using spatial prediction with respect to reference samples in neighboring blocks in the same picture. Video blocks in an inter-coded (P or B) slice of a picture may use spatial prediction with respect to reference samples in neighboring blocks in the same picture or temporal prediction with respect to reference samples in other reference pictures. A picture may be referred to as a frame, and a reference picture may be referred to as a reference frame. Summary of the Invention

[0005]

[0005] Generally, this disclosure describes techniques for enabling palette mode coding for monochrome content and / or for enabling palette mode coding when separate color plane coding is used. Example techniques may be applicable to video coding standards such as the Versatile Video Coding (VVC) standard, but may also be applicable to other video coding standards, and to video coding techniques in general, including standard and non-standard based video coding techniques.

[0006]

[0006] As will be described in more detail, in some examples, a picture may be partitioned according to dual tree partitioning or single tree partitioning. In dual tree partitioning, there may be different partitioning of the luma components of a picture and the chroma components of a picture. In single tree partitioning, the luma components of a picture and the chroma components of a picture are partitioned in the same manner.

[0007]

[0007] This disclosure describes an example of determining the number of color components to be used for palette mode coding using both the partition (e.g., single-tree partition or dual-tree partition) and the color format (e.g., monochrome or not) as a criterion. In this way, when the video decoder is performing an operation defined by a palette mode coding syntax structure, the video decoder can correctly determine the number of color components to be used for palette mode coding of the current block.

[0008]

[0008] In one example, the disclosure describes a method for decoding video data, the method comprising determining that a current block of the video data is coded in palette mode; determining that, between single-tree partitioning or dual-tree partitioning, the current block is coded with single-tree partitioning enabled; determining that the current block is coded in monochrome format; determining that when the current block is coded with single-tree partitioning enabled and when the current block is coded in monochrome format, a number of color components used to decode the current block in palette mode is equal to 1; and palette mode decoding the current block based on the determined number of color components used to decode the current block in palette mode being equal to 1.

[0009]

[0009] In one example, the disclosure describes a device for coding video data, the device comprising: a memory configured to store the video data; and a processing circuit coupled to the memory, the processing circuit configured to: determine that a current block of the video data is coded in palette mode; determine that, between single-tree partitioning or dual-tree partitioning, the current block is coded with single-tree partitioning enabled; determine that the current block is coded in monochrome format; determine that when the current block is coded with single-tree partitioning enabled and when the current block is coded in monochrome format, a number of color components used to decode the current block in palette mode is equal to 1; and palette mode decode the current block based on the determined number of color components used to decode the current block in palette mode being equal to 1.

[0010]

[0010] In one example, the disclosure describes a computer-readable storage medium having instructions stored thereon that, when executed, cause one or more processors to determine that a current block of video data is coded in palette mode; determine that, between single-tree partitioning or dual-tree partitioning, the current block is coded with single-tree partitioning enabled; determine that the current block is coded in monochrome format; determine that when the current block is coded with single-tree partitioning enabled and when the current block is coded in monochrome format, the number of color components used to decode the current block in palette mode is equal to 1; and palette mode decode the current block based on the determined number of color components used to decode the current block in palette mode being equal to 1.

[0011]

[0011] In one example, the disclosure describes a device for decoding video data, the device comprising: means for determining that a current block of the video data is coded in palette mode; means for determining, between single-tree partitioning or dual-tree partitioning, that the current block is coded with single-tree partitioning enabled; means for determining that the current block is coded in monochrome format; means for determining that when the current block is coded with single-tree partitioning enabled and when the current block is coded in monochrome format, a number of color components used to decode the current block in palette mode is equal to 1; and means for palette mode decoding the current block based on the determined number of color components used to decode the current block in palette mode being equal to 1.

[0012] The details of one or more examples are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will become apparent from the description, drawings, and claims. [Brief description of the drawings]

[0013] [Figure 1]

[0013] FIG. 1 is a block diagram illustrating an example video encoding and decoding system in which the techniques of this disclosure may be implemented. [Figure 2A]

[0014] 1 is a conceptual diagram illustrating an exemplary Quad Tree Binary Tree (QTBT) structure. [Figure 2B] A conceptual diagram showing a corresponding coding tree unit (CTU). [Diagram 3]

[0015] 1 is a block diagram illustrating an example video encoder that may implement the techniques of this disclosure. [Figure 4]

[0016] 1 is a block diagram illustrating an example video decoder that may implement the techniques of this disclosure. [Diagram 5]

[0017] 1 is a flowchart illustrating an example of coding video data. [Figure 6]

[0018] 1 is a flowchart illustrating an example technique described in this disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014]

[0019] In video coding, an exemplary coding mode is palette mode coding. In palette mode coding, a video encoder signals a palette mode table including sample values ​​referenced by an index into the palette mode table, and a video decoder builds the palette mode table based on the signaled sample values. For a sample in a current block, the video encoder signals an index into the palette mode table, and the video decoder determines a sample value for the sample in the current block based on the sample value in the palette mode table associated with the index into the palette mode table. Palette mode coding may be available regardless of color format. For example, palette mode coding may be available when there are both luma and chroma components, or when there is only a luma component (e.g., monochrome). For example, monochrome is a color format that is sometimes referred to as a 4:0:0 color format to indicate that there is only a luma component for the block and no chroma component for the block.

[0015]

[0020] Palette mode coding may be beneficial in screen content coding, as one non-limiting example. For example, if a string of samples in a current block has the same value, or the same value as a neighboring sample, the video encoder may signal a run length indicating the number of samples in the string, rather than signaling an index per sample. The video decoder may determine sample values ​​for samples in the string of samples based on the neighboring samples, rather than needing to process an index into the palette mode table for a sample in the string of samples. In some examples, sample values ​​for samples may not exist in the palette mode table (referred to as escape samples or escape pixels), and in such examples, the video encoder may signal actual sample values ​​for such escape samples.

[0016]

[0021] In video coding, there may also be partition tree types. The partition tree type indicates the manner in which a picture is partitioned into blocks. Examples of partition types include dual tree partitioning and single tree partitioning. In single tree partitioning, both the luma and chroma components of a picture are partitioned using the same tree structure, and thus the luma and chroma components are partitioned in the same manner. In dual tree partitioning, the luma and chroma components may be partitioned using different tree structures, and thus the luma and chroma components may not be partitioned in the same manner.

[0017]

[0022] This disclosure describes an example technique in which both the partition tree type and the color format (e.g., monochrome or not) are factors that affect the number of color components used to palette mode code (e.g., encode or decode) the current block. The number of color components used to palette mode code the current block may refer to the number of color components in the palette mode table. Thus, the number of color components used for palette mode coding may be considered as the number of color components used for palette mode coding. Examples of color components include luma components and chroma components.

[0018]

[0023] For example, when a first block is coded with single-tree partitioning enabled and when the first block is coded in a monochrome format, a video coder (e.g., a video encoder or a video decoder) may determine that the number of color components used for palette mode coding of the first block is equal to 1. For example, the video decoder may decode the first block based on a palette mode table for only the luma component (e.g., the palette mode table includes sample values ​​for only the luma component). However, when a second block is coded with single-tree partitioning enabled and when the second block is not coded in a monochrome format, the video coder may determine that the number of color components used for palette mode coding of the second block is equal to 3. For example, the video decoder may decode the second block based on a palette mode table that includes both luma and chroma components (e.g., the palette mode table includes sample values ​​for both luma and chroma components).

[0019]

[0024] As will be described in more detail, a video decoder may determine the number of color components used for palette mode coding as part of performing the operations defined in the palette mode coding syntax structure. By utilizing information indicating the partition tree type and information indicating the color format (e.g., monochrome or not), a video decoder may appropriately determine the number of color components used for palette mode coding as part of performing the operations defined in the palette mode coding syntax structure.

[0020]

[0025] For example, some other techniques determined whether single-tree partitioning or dual-tree partitioning was enabled, and determined that the number of color components used for palette mode coding was three if single-tree partitioning was enabled (e.g., the palette mode table included sample values ​​for both luma and chroma components). However, such other techniques failed to consider that if the color format was a monochrome format, the number of color components used for palette mode coding should be only one, not three, because monochrome formats only include a luma component. In the example techniques described in this disclosure, because both the partition tree type and the color format (e.g., monochrome or not) are factors in determining the number of color components used for palette mode coding, the video decoder may correctly determine the number of color components used for palette mode coding.

[0021]

[0026] 1 is a block diagram illustrating an example video encoding and decoding system 100 that may implement the techniques of this disclosure. The techniques of this disclosure are generally directed to coding (encoding and / or decoding) video data. In general, video data includes any data for processing video. Thus, video data may include raw uncoded video, coded video, decoded (e.g., reconstructed) video, and video metadata, such as signaling data.

[0022]

[0027] 1, system 100 includes a source device 102 that provides encoded video data to be decoded and displayed by a destination device 116, in this example. In particular, source device 102 provides the video data to destination device 116 via a computer-readable medium 110. Source device 102 and destination device 116 may comprise any of a wide range of devices, including desktop computers, notebook (i.e., laptop) computers, tablet computers, set-top boxes, telephone handsets such as smartphones, televisions, cameras, display devices, digital media players, video game consoles, video streaming devices, and the like. In some cases, source device 102 and destination device 116 may be equipped for wireless communication and therefore may be referred to as wireless communication devices.

[0023]

[0028] In the example of FIG. 1, source device 102 includes video source 104, memory 106, video encoder 200, and output interface 108. Destination device 116 includes input interface 122, video decoder 300, memory 120, and display device 118. According to this disclosure, video encoder 200 of source device 102 and video decoder 300 of destination device 116 may be configured to apply techniques for enabling palette mode for monochrome content and / or when separate color plane coding is used. Thus, source device 102 represents an example of a video encoding device, and destination device 116 represents an example of a video decoding device. In other examples, source and destination devices may include other components or arrangements. For example, source device 102 may receive video data from an external video source, such as an external camera. Similarly, destination device 116 may interface with an external display device rather than including an integrated display device.

[0024]

[0029] The system 100 shown in FIG. 1 is only an example. In general, any digital video encoding and / or decoding device may implement techniques for enabling palette mode for monochrome content and / or when separate color plane coding is used. The source device 102 and the destination device 116 are only examples of coding devices, such that the source device 102 generates coded video data for transmission to the destination device 116. This disclosure refers to a "coding" device as a device that performs coding (encoding and / or decoding) of data. Thus, the video encoder 200 and the video decoder 300 represent examples of coding devices, and in particular, video encoders and video decoders, respectively. In some examples, the source device 102 and the destination device 116 may operate substantially symmetrically, such that each of the source device 102 and the destination device 116 includes video encoding and video decoding components. Thus, the system 100 may support unidirectional or bidirectional video transmission between the source device 102 and the destination device 116, for example, video streaming, video playback, video broadcasting, or video telephony.

[0025]

[0030] Generally, video source 104 represents a source of video data (i.e., raw, unencoded video data) and provides a continuous series of pictures (also called “frames”) of the video data to video encoder 200, which encodes the data for the pictures. Video source 104 of source device 102 may include a video capture device, such as a video camera, a video archive containing previously captured raw video, and / or a video feed interface for receiving video from a video content provider. As a further alternative, video source 104 may generate computer graphics-based data as source video, or a combination of live, archived, and computer-generated video. In each case, video encoder 200 encodes the captured, pre-captured, or computer-generated video data. Video encoder 200 may reorder the pictures from a receiving order (sometimes called a “display order”) into a coding order for coding. Video encoder 200 may generate a bitstream including the encoded video data. The source device 102 may then output the encoded video data via the output interface 108 onto a computer-readable medium 110 for receipt and / or retrieval by, for example, an input interface 122 of the destination device 116 .

[0026]

[0031] The memory 106 of the source device 102 and the memory 120 of the destination device 116 represent general-purpose memories. In some examples, the memories 106, 120 may store raw video data, e.g., raw video from the video source 104 and raw decoded video data from the video decoder 300. Additionally or alternatively, the memories 106, 120 may store software instructions executable by, e.g., the video encoder 200 and the video decoder 300, respectively. Although the memories 106 and 120 are shown in this example as separate from the video encoder 200 and the video decoder 300, it should be understood that the video encoder 200 and the video decoder 300 may also include internal memories for functionally similar or equivalent purposes. Additionally, the memories 106, 120 may store encoded video data, e.g., the output from the video encoder 200 and the input to the video decoder 300. In some examples, portions of the memory 106, 120 may be allocated as one or more video buffers, for example, to store raw decoded and / or encoded video data.

[0027]

[0032] The computer-readable medium 110 may represent any type of medium or device capable of transporting encoded video data from the source device 102 to the destination device 116. In one example, the computer-readable medium 110 represents a communication medium for enabling the source device 102 to transmit the encoded video data directly to the destination device 116 in real time, for example, via a radio frequency network or a computer-based network. The output interface 108 may modulate a transmission signal including the encoded video data, and the input interface 122 may demodulate a received transmission signal according to a communication standard such as a wireless communication protocol. The communication medium may comprise any wireless or wired communication medium, such as a radio frequency (RF) spectrum or one or more physical transmission lines. The communication medium may form part of a packet-based network, such as a local area network, a wide area network, or a global network such as the Internet. The communication medium may include a router, a switch, a base station, or any other equipment that may be useful for facilitating communication from the source device 102 to the destination device 116.

[0028]

[0033] In some examples, source device 102 may output the encoded data from output interface 108 to storage device 112. Similarly, destination device 116 may access the encoded data from storage device 112 via input interface 122. Storage device 112 may include any of a variety of distributed or locally accessed data storage media, such as a hard drive, Blu-ray disc, DVD, CD-ROM, flash memory, volatile or non-volatile memory, or any other suitable digital storage medium for storing encoded video data.

[0029]

[0034] In some examples, source device 102 may output the encoded video data to a file server 114 or another intermediate storage device, which may store the encoded video data generated by source device 102. Destination device 116 may access the stored video data from file server 114 via streaming or download.

[0030]

[0035] The file server 114 may be any type of server device capable of storing encoded video data and transmitting the encoded video data to the destination device 116. The file server 114 may represent a web server (e.g., for a website), a server configured to provide a file transfer protocol service (such as File Transfer Protocol (FTP) or File Delivery over Unidirectional Transport (FLUTE) protocol), a content delivery network (CDN) device, a Hypertext Transfer Protocol (HTTP) server, a Multimedia Broadcast Multicast Service (MBMS) or enhanced MBMS (eMBMS) server, and / or a network attached storage (NAS) device. The file server 114 may additionally or alternatively implement one or more HTTP streaming protocols, such as Dynamic Adaptive Streaming over HTTP (DASH), HTTP Live Streaming (HLS), Real Time Streaming Protocol (RTSP), HTTP Dynamic Streaming, etc.

[0031]

[0036] The destination device 116 may access the encoded video data from the file server 114 through any standard data connection, including an Internet connection. This may include a wireless channel (e.g., a Wi-Fi connection), a wired connection (e.g., a Digital Subscriber Line (DSL), a cable modem, etc.), or a combination of both, that is suitable for accessing the encoded video data stored on the file server 114. The input interface 122 may be configured to operate according to any one or more of the various protocols described above for retrieving or receiving media data from the file server 114, or other such protocols for retrieving media data.

[0032]

[0037] The output interface 108 and the input interface 122 may represent a wireless transmitter / receiver, a modem, a wired networking component (e.g., an Ethernet card), a wireless communication component operating according to any of the various IEEE 802.11 standards, or other physical components. In examples in which the output interface 108 and the input interface 122 comprise wireless components, the output interface 108 and the input interface 122 may be configured to transfer data, such as encoded video data, according to a cellular communication standard, such as 4G, 4G-LTE (Long Term Evolution), LTE Advanced, 5G, etc. In some examples in which the output interface 108 comprises a wireless transmitter, the output interface 108 and the input interface 122 may be configured to transfer data, such as encoded video data, according to other wireless standards, such as the IEEE 802.11 specification, the IEEE 802.15 specification (e.g., ZigBee), the Bluetooth standard, etc. In some examples, the source device 102 and / or the destination device 116 may include respective system-on-chip (SoC) devices. For example, the source device 102 may include a SoC device for performing functions attributable to the video encoder 200 and / or the output interface 108, and the destination device 116 may include a SoC device for performing functions attributable to the video decoder 300 and / or the input interface 122.

[0033]

[0038] The techniques of this disclosure may be applied to video coding supporting any of a variety of multimedia applications, such as over-the-air television broadcast, cable television transmission, satellite television transmission, Internet streaming video transmission such as Dynamic Adaptive Streaming over HTTP (DASH), digital video encoded on a data storage medium, decoding of digital video stored on a data storage medium, or other applications.

[0034]

[0039] The input interface 122 of the destination device 116 receives the encoded video bitstream from the computer-readable medium 110 (e.g., a communication medium, a storage device 112, a file server 114, etc.). The encoded video bitstream may include signaling information defined by the video encoder 200 that is also used by the video decoder 300, such as syntax elements having values ​​that describe characteristics and / or processing of video blocks or other coded units (e.g., slices, pictures, groups of pictures, sequences, etc.). The display device 118 displays decoded pictures of the decoded video data to a user. The display device 118 may represent any of a variety of display devices, such as a cathode ray tube (CRT), a liquid crystal display (LCD), a plasma display, an organic light emitting diode (OLED) display, or another type of display device.

[0035]

[0040] 1, in some examples, the video encoder 200 and the video decoder 300 may each be integrated with an audio encoder and / or an audio decoder and may include an appropriate MUX-DEMUX unit, or other hardware and / or software, to handle multiplexed streams that include both audio and video in a common data stream. Where applicable, the MUX-DEMUX unit may conform to any of a variety of multiplexer protocols.

[0036]

[0041] The video encoder 200 and the video decoder 300 may each be implemented as any of a variety of suitable encoder and / or decoder circuits, or any combination thereof, such as one or more microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), discrete logic, software, hardware, firmware, etc. When the techniques are implemented partially in software, the device may store instructions for the software on a suitable non-transitory computer-readable medium and execute the instructions in hardware using one or more processors to implement the techniques of this disclosure. Each of the video encoder 200 and the video decoder 300 may be included in one or more encoders or decoders, any of which may be integrated as part of a combined encoder / decoder (codec) in the respective device. The device including the video encoder 200 and / or the video decoder 300 may comprise an integrated circuit, a microprocessor, and / or a wireless communication device such as a cellular phone.

[0037]

[0042] An example of a video coding standard is ITU-T H.265, also known as High Efficiency Video Coding (HEVC), or extensions thereof, such as multiview and / or scalable video coding extensions. Video encoder 200 and video decoder 300 may operate according to other proprietary or industry standards, such as ITU-T H.266, also known as Generic Video Coding (VVC). A recent draft of the VVC standard under development is described in Bross et al., "Versatile Video Coding (Draft 7)," Joint Video Experts Team (JVET) of ITU-T SG16 WP3 and ISO / IEC JTC1 / SC29 / WG11, 16th Meeting: Geneva, CH, 1-11 October 2019, JVET-P2001-vE, sometimes referred to as JVET-P2001-v14 (hereinafter "VVC Draft 7"). A more recent draft of the developing VVC standard is described in Bross et al., "Versatile Video Coding Editorial Refinements on Draft 10," Joint Video Experts Team (JVET) of ITU-T SG16 WP3 and ISO / IEC JTC1 / SC29, 20th Meeting, Teleconference, October 7-16, 2020, JVET-T2001-v11 (hereinafter, "VVC Draft 10"). However, the techniques of this disclosure are not limited to any particular coding standard.

[0038]

[0043] Generally, the video encoder 200 and the video decoder 300 may perform block-based coding of pictures. The term "block" generally refers to a structure that contains data to be processed (e.g., to be encoded, to be decoded, or to be used in other ways in the encoding and / or decoding process). For example, a block may contain a two-dimensional matrix of samples of luminance and / or chrominance data, also referred to as luma and chroma components. However, luminance and chrominance data may not be required in all instances. For example, in a monochrome format, there may be only luminance data (e.g., luma component) without chrominance data (e.g., no chroma component).

[0039]

[0044] In general, the video encoder 200 and the video decoder 300 may code video data represented in YUV (e.g., Y, Cb, Cr) format or Y only in the monochrome case. That is, rather than coding red, green, and blue (RGB) data for a sample of a picture, the video encoder 200 and the video decoder 300 may code a luminance component and a chrominance component, where the chrominance component may include both red and blue hues of chrominance components. In some examples, the video encoder 200 converts received RGB format data to a YUV representation prior to encoding, and the video decoder 300 converts the YUV representation to the RGB format. Alternatively, pre-processing and post-processing units (not shown) may perform these conversions.

[0040]

[0045] This disclosure may generally refer to coding (e.g., encoding and decoding) a picture to include processes of encoding or decoding data for a picture. Similarly, this disclosure may refer to coding a block of a picture to include processes of encoding or decoding data for the block, e.g., predictive and / or residual coding. A coded video bitstream generally includes a series of values ​​for syntax elements that represent coding decisions (e.g., coding modes) and partitioning of a picture into blocks. Thus, references to coding a picture or a block should be understood generally as coding values ​​for the syntax elements that form the picture or block.

[0041]

[0046] HEVC defines various blocks, including coding units (CUs), prediction units (PUs), and transform units (TUs). According to HEVC, a video coder (such as video encoder 200) partitions coding tree units (CTUs) into CUs according to a quadtree structure. That is, the video coder partitions CTUs and CUs into four equal non-overlapping squares, and each node of the quadtree has either zero or four child nodes. A node without children may be called a "leaf node", and a CU of such a leaf node may include one or more PUs and / or one or more TUs. The video coder may further partition PUs and TUs. For example, in HEVC, a residual quadtree (RQT) represents the partition of TUs. In HEVC, a PU represents inter-predicted data, and a TU represents residual data. An intra-predicted CU includes intra-prediction information, such as an intra-mode indication.

[0042]

[0047] As another example, the video encoder 200 and the video decoder 300 may be configured to operate according to VVC. According to VVC, a video coder (such as the video encoder 200) partitions a picture into multiple coding tree units (CTUs). The video encoder 200 may partition the CTUs according to a tree structure, such as a quad-tree binary tree (QTBT) structure or a multi-type tree (MTT) structure. The QTBT structure eliminates the concept of multiple partition types, such as the separation between CUs, PUs, and TUs in HEVC. The QTBT structure includes two levels, a first level partitioned according to a quad-tree partition and a second level partitioned according to a binary tree partition. The root node of the QTBT structure corresponds to a CTU. The leaf nodes of the binary tree correspond to coding units (CUs).

[0043]

[0048] In the MTT partitioning structure, blocks may be partitioned using quad tree (QT) partitioning, binary tree (BT) partitioning, and one or more types of triple tree (TT) (also called ternary tree (TT)) partitioning. A triple tree or ternary tree partitioning is a partitioning in which a block is split into three sub-blocks. In some examples, a triple tree or ternary tree partitioning splits a block into three sub-blocks without splitting the original block through the center. The partitioning types in MTT (e.g., QT, BT, and TT) may be symmetric or asymmetric.

[0044]

[0049] In some examples, the video encoder 200 and the video decoder 300 may use a single QTBT or MTT structure to represent each of the luminance and chrominance components, and in other examples, the video encoder 200 and the video decoder 300 may use two or more QTBT or MTT structures, such as one QTBT / MTT structure for the luminance component and another QTBT / MTT structure for both chrominance components (or two QTBT / MTT structures for each chrominance component). That is, in examples where the video encoder 200 and the video decoder 300 utilize a single QTBT or MTT structure, the video encoder 200 and the video decoder 300 may be considered to utilize single-tree partitioning. In examples where the video encoder 200 and the video decoder 300 utilize two or more QTBT or MTT structures, the video encoder 200 and the video decoder 300 may be considered to utilize dual-tree partitioning. Accordingly, video encoder 200 and video decoder 300 may be configured to determine, between single-tree or dual-tree partitioning, whether the current block is coded with single-tree partitioning enabled or with dual-tree partitioning enabled.

[0045]

[0050] Video encoder 200 and video decoder 300 may be configured to use quadtree partitioning, QTBT partitioning, MTT partitioning, or other partition structures in accordance with HEVC. For purposes of explanation, the description of the techniques of this disclosure is presented with respect to QTBT partitioning. However, it should be understood that the techniques of this disclosure may also be applied to video coders configured to use quadtree partitioning, or other types of partitioning as well.

[0046]

[0051] Blocks (e.g., CTUs or CUs) may be grouped in various ways in a picture. As an example, a brick may refer to a rectangular region of a CTU row in a particular tile in a picture. A tile may be a rectangular region of a CTU in a particular tile column and a particular tile row in a picture. A tile column refers to a rectangular region of a CTU having a height equal to the height of the picture and a width specified by a syntax element (e.g., in a picture parameter set). A tile row refers to a rectangular region of a CTU having a height specified by a syntax element (e.g., in a picture parameter set) and a width equal to the width of the picture.

[0047]

[0052] In some examples, a tile may be partitioned into multiple bricks, each of which may include one or more CTU rows within the tile. A tile that is not partitioned into multiple bricks may also be referred to as a brick. However, a brick that is a true subset of a tile may not be referred to as a tile.

[0048]

[0053] The bricks in a picture may also be arranged into slices. A slice may be an integer number of bricks of a picture that may be contained entirely in a single Network Abstraction Layer (NAL) unit. In some examples, a slice includes either several complete tiles or only a continuous sequence of complete bricks of one tile.

[0049]

[0054] This disclosure may use "NxN" and "N by N", e.g., 16x16 samples or 16 by 16 samples, interchangeably to refer to sample dimensions of a block (such as a CU or other video block) in terms of vertical and horizontal dimensions. Generally, a 16x16 CU has 16 samples in the vertical direction (y=16) and 16 samples in the horizontal direction (x=16). Similarly, an NxN CU generally has N samples in the vertical direction and N samples in the horizontal direction, where N represents a non-negative integer value. Samples in a CU may be arranged in rows and columns. Moreover, a CU does not necessarily have to have the same number of samples in the horizontal direction as in the vertical direction. For example, a CU may comprise NxM samples, where M is not necessarily equal to N.

[0050]

[0055] The video encoder 200 encodes video data for a CU that represents prediction and / or residual information, as well as other information. The prediction information indicates how the CU should be predicted to form a predictive block for the CU. The residual information generally represents sample-by-sample differences between samples of the CU prior to encoding and the predictive block.

[0051]

[0056] To predict a CU, the video encoder 200 may generally form a predictive block for the CU through inter-prediction or intra-prediction. Inter-prediction generally refers to predicting a CU from data of a previously coded picture, while intra-prediction generally refers to predicting a CU from previously coded data of the same picture. To perform inter-prediction, the video encoder 200 may generate a predictive block using one or more motion vectors. The video encoder 200 may generally perform a motion search to identify a reference block that closely matches the CU, for example, with respect to the difference between the CU and the reference block. The video encoder 200 may calculate a difference metric using a sum of absolute differences (SAD), sum of squared differences (SSD), mean absolute difference (MAD), mean squared difference (MSD), or other such difference calculation to determine whether the reference block closely matches the current CU. In some examples, the video encoder 200 may predict the current CU using unidirectional or bidirectional prediction.

[0052]

[0057] In some examples, VVC provides an affine motion compensation mode, which may be considered an inter-prediction mode. In an affine motion compensation mode, video encoder 200 may determine two or more motion vectors that represent non-translational motion, such as zooming in or out, rotation, perspective motion, or other irregular motion types.

[0053]

[0058] To perform intra prediction, the video encoder 200 may select an intra prediction mode to generate a predictive block. In some examples, VVC provides 67 intra prediction modes, including various directional modes, as well as planar and DC modes. In general, the video encoder 200 selects an intra prediction mode that describes neighboring samples relative to a current block (e.g., a block of a CU) from which samples of the current block should be predicted. Such samples may generally be above, to the left of, or to the left of the current block in the same picture as the current block, assuming that the video encoder 200 codes the CTUs and CUs in raster scan order (left to right, top to bottom).

[0054]

[0059] Video encoder 200 encodes data representing a prediction mode for the current block. For example, in an inter prediction mode, video encoder 200 may encode data representing which of various available inter prediction modes is used, as well as motion information for the corresponding mode. For example, in unidirectional or bidirectional inter prediction, video encoder 200 may encode motion vectors using advanced motion vector prediction (AMVP) or merge mode. Video encoder 200 may use similar modes to encode motion vectors for affine motion compensation modes.

[0055]

[0060] Following prediction, such as intra- or inter-prediction, of a block, the video encoder 200 may calculate residual data for the block. The residual data, such as a residual block, represents sample-by-sample differences between the block and a predictive block for the block formed using a corresponding prediction mode. The video encoder 200 may apply one or more transforms to the residual block to produce transformed data in a transform domain rather than the sample domain. For example, the video encoder 200 may apply a discrete cosine transform (DCT), an integer transform, a wavelet transform, or a conceptually similar transform to the residual video data. Additionally, the video encoder 200 may apply a secondary transform, such as a mode-dependent non-separable secondary transform (MDNSST), a signal-dependent transform, a Karhunen-Loeve transform (KLT), etc., following the first transform. The video encoder 200 produces transform coefficients following application of the one or more transforms.

[0056]

[0061] As mentioned above, following any transformation to produce transform coefficients, the video encoder 200 may perform quantization of the transform coefficients. Quantization generally refers to a process in which transform coefficients are quantized to possibly reduce the amount of data used to represent the transform coefficients, providing further compression. By performing a quantization process, the video encoder 200 may reduce the bit depth associated with some or all of the transform coefficients. For example, the video encoder 200 may round an n-bit value to an m-bit value during quantization, where n is greater than m. In some examples, to perform quantization, the video encoder 200 may perform a bitwise right shift of the value to be quantized.

[0057]

[0062] Following quantization, the video encoder 200 may scan the transform coefficients to produce a one-dimensional vector from a two-dimensional matrix including the quantized transform coefficients. The scan may be designed to place higher energy (and therefore lower frequency) transform coefficients at the front of the vector and lower energy (and therefore higher frequency) transform coefficients at the rear of the vector. In some examples, the video encoder 200 may utilize a predefined scan order to scan the quantized transform coefficients to produce a serialized vector, and then entropy code the quantized transform coefficients of the vector. In other examples, the video encoder 200 may perform an adaptive scan. After scanning the quantized transform coefficients to form the one-dimensional vector, the video encoder 200 may entropy code the one-dimensional vector, for example, according to context-adaptive binary arithmetic coding (CABAC). The video encoder 200 may also entropy code values ​​for syntax elements describing metadata associated with the encoded video data for use by the video decoder 300 in decoding the video data.

[0058]

[0063] To implement CABAC, the video encoder 200 may assign a context in a context model to a symbol to be transmitted. The context may relate, for example, to whether neighboring values ​​of the symbol are zero-valued or not. The probability determination may be based on the context assigned to the symbol.

[0059]

[0064] Video encoder 200 may further generate syntax data, such as block-based syntax data, picture-based syntax data, and sequence-based syntax data, for video decoder 300, e.g., in a picture header, block header, slice header, or other syntax data, such as a sequence parameter set (SPS), a picture parameter set (PPS), or a video parameter set (VPS). Video decoder 300 may similarly decode such syntax data to determine how to decode corresponding video data.

[0060]

[0065] In this manner, video encoder 200 may generate a bitstream including syntax elements that describe encoded video data, e.g., partitions of a picture into blocks (e.g., CUs) and predictive and / or residual information for the blocks. Finally, video decoder 300 may receive the bitstream and decode the encoded video data.

[0061]

[0066] In general, the video decoder 300 performs an inverse process to that performed by the video encoder 200 to decode the encoded video data of the bitstream. For example, the video decoder 300 may decode values ​​for syntax elements of the bitstream using CABAC in a manner that is inverse to, but substantially similar to, the CABAC encoding process of the video encoder 200. The syntax elements may define partition information of a picture into CTUs and partitioning of each CTU according to a corresponding partition structure, such as a QTBT structure, to define the CUs of the CTU. The syntax elements may further define prediction and residual information for blocks (e.g., CUs) of video data.

[0062]

[0067] The residual information may be represented, for example, by quantized transform coefficients. The video decoder 300 may dequantize and inverse transform the quantized transform coefficients of the block to reconstruct a residual block for the block. The video decoder 300 uses the signaled prediction mode (intra- or inter-prediction) and associated prediction information (e.g., motion information for inter-prediction) to form a predictive block for the block. The video decoder 300 may then combine (sample-by-sample) the predictive block and the residual block to reconstruct the original block. The video decoder 300 may perform additional processing, such as performing a deblocking process to reduce visual artifacts along block boundaries.

[0063]

[0068] The above describes example techniques for video coding, such as those using inter-prediction and intra-prediction. Another exemplary video coding technique is palette mode coding. In applications such as remote desktop, collaborative work, and wireless display, computer-generated screen content (e.g., text or computer graphics) may be the primary content to be compressed. This type of content tends to have discrete tones and feature sharp lines and high-contrast object boundaries. The assumptions of continuous tone and smoothness may no longer apply to screen content, and therefore traditional video coding techniques may not be an efficient way to compress video data including screen content.

[0064]

[0069] Generally, palette coding is designed to handle color clustering in screen content. Palette coding employs base colors and an index map to represent an input image block. The video encoder 200 may quantize samples to one of the base colors in the input block, and an index map may be generated to indicate the corresponding base color for each sample. Due to the low density histogram of the screen content, the coding cost is significantly reduced by the small number of colors in each block.

[0065]

[0070] The video encoder 200 and the video decoder 300 may code a table called a "palette" (e.g., called a palette mode table) for a CU to indicate the basic colors that may be visible in the CU. The palette mode table may include color entries (e.g., sample values), each of which is represented by an index. The palette mode table may include color entries in any color format, e.g., RGB, YCbCr, or another color format. The video encoder 200 and the video decoder 300 may code the palette using prediction techniques to save bits. The video encoder 200 and the video decoder 300 may then code the samples (e.g., the luma and chroma color components of a pixel) currently in the CU. The video encoder 200 may quantize the samples to one of the basic colors in the palette. The video encoder 200 may then code an index that corresponds to that basic color. To code the indexes for all of the samples more efficiently, the video encoder 200 may organize the indices as an index map and code the index map as a whole. Video encoder 200 and video decoder 300 may be configured to scan through the samples in the index map in a horizontally or vertically rotated way.

[0066]

[0071] In the case of a monochrome format, since there are no chroma components, the palette mode table may include sample values ​​for only the luma component. In the case of other color formats that include chroma components, the palette mode table may include sample values ​​for the luma component and the chroma component. For example, the video encoder 200 and the video decoder 300 may determine the number of color components used for palette mode coding of the current block. The number of color components used for palette mode coding of the current block may refer to the number of color components included in the palette mode table. In the case of a monochrome, the number of color components used for palette mode coding may be 1 (e.g., only luma), and in the case of other color formats that include luma and chroma components, the number of color components used for palette mode coding may be 3 (e.g., a luma component and two chroma components).

[0067]

[0072] The video encoder 200 may be configured to determine to apply the INDEX mode to signal an index for a particular sample. The video encoder 200 may also determine to use the COPY_ABOVE mode. In the COPY_ABOVE mode, an index for a sample is copied from the index of its above-neighboring sample. The video encoder 200 may signal a bit to indicate which mode is used for a particular sample. To further reduce bits, several consecutive samples may share the same mode. The video encoder 200 may code a run length to indicate how many consecutive samples share the same mode. If the current sample utilizes the INDEX mode, the number of consecutive samples indicated by the run length will share the same index with the current sample. If the current sample utilizes COPY_ABOVE, the number of consecutive samples indicated by the run length will share the COPY_ABOVE mode, i.e., the video decoder 300 will copy the index for these samples from their above-neighboring sample. Additionally, to handle outlier cases (eg, a sample value that is not in the palette mode table), the sample may also be directly coded in ESCAPE mode (ie, video encoder 200 may directly code the sample value).

[0068]

[0073] According to the techniques of this disclosure, palette mode may be enabled for monochrome content and / or when separate color plane coding is used. For example, video encoder 200 and video decoder 300 may determine that one or more blocks are for monochrome content (e.g., have a monochrome color format or are coded as monochrome content) and / or determine that one or more blocks are for separate color plane coding (e.g., there are multiple color planes and one or more blocks are for at least one of the color planes). Video encoder 200 or video decoder 300 may code (e.g., in the case of video encoder 200, encode, or in the case of video decoder 300, decode) one or more blocks using palette mode.

[0069]

[0074] For example, as described above, in one or more examples, the color format and the partition tree type may be factors in determining the number of color components used for palette mode coding. According to one or more examples, a video coder (e.g., video encoder 200 or video decoder 300) may determine that a current block of video data is coded in palette mode and determine that the current block is coded with single-tree partitioning enabled between single-tree partitioning or dual-tree partitioning. In such an example, the video coder may determine that the current block is coded in monochrome format. When the current block is coded with single-tree partitioning enabled and when the current block is coded in monochrome format, the video coder may determine that the number of color components used to palette mode code the current block is equal to one. The video coder may palette mode code (e.g., encode or decode) the current block based on the determined number of color components used to palette mode code the current block being equal to one.

[0070]

[0075] As an example, to palette mode code the current block, the video coder may palette mode code the current block based on a palette mode table only for the luma component. For example, video decoder 300 may receive an index into the palette mode table for the samples in the current block and assign luma values ​​to the samples in the current block based on the index into the palette mode table. Video encoder 200 may determine luma values ​​for the samples in the current block, determine an index into the palette mode table based on the determined luma values ​​for the samples, and signal information indicating the index into the palette mode table for the samples in the current block.

[0071]

[0076] This disclosure may generally refer to "signaling" certain information, such as syntax elements. The term "signaling" may generally refer to communication of values ​​for syntax elements and / or other data used to decode encoded video data. That is, video encoder 200 may signal values ​​for syntax elements in a bitstream. Generally, signaling refers to generating values ​​in a bitstream. As described above, source device 102 may transport the bitstream to destination device 116 in substantially real-time or may transport the bitstream to destination device 116 in non-real-time, such as may be done when storing syntax elements in storage device 112 for later retrieval by destination device 116.

[0072]

[0077] 2A and 2B are conceptual diagrams illustrating an exemplary quad-tree binary tree (QTBT) structure 130 and corresponding coding tree unit (CTU) 132. Solid lines represent quad-tree splitting, and dotted lines indicate binary tree splitting. At each split (i.e., non-leaf) node of the binary tree, one flag is signaled to indicate which splitting type (i.e., horizontal or vertical) is used, where in this example, 0 indicates horizontal splitting and 1 indicates vertical splitting. In quad-tree splitting, there is no need to indicate the splitting type, since the quad-tree node splits the block horizontally and vertically into four sub-blocks with equal size. Thus, video encoder 200 may encode, and video decoder 300 may decode, syntax elements (such as splitting information) for the region tree level of QTBT structure 130 (i.e., solid lines) and syntax elements (such as splitting information) for the prediction tree level of QTBT structure 130 (i.e., dashed lines). Video encoder 200 may encode, and video decoder 300 may decode, video data, such as prediction and transform data, for CUs represented by terminal leaf nodes of QTBT structure 130.

[0073]

[0078] 2B may be associated with parameters that define the sizes of blocks corresponding to nodes of the QTBT structure 130 at the first and second levels. These parameters may include a CTU size (representing the size of the CTU 132 in a sample), a minimum quad tree size (MinQTSize representing the minimum allowable quad tree leaf node size), a maximum binary tree size (MaxBTSize representing the maximum allowable binary tree root node size), a maximum binary tree depth (MaxBTDepth representing the maximum allowable binary tree depth), and a minimum binary tree size (MinBTSize representing the minimum allowable binary tree leaf node size).

[0074]

[0079] The root node of the QTBT structure corresponding to the CTU may have four child nodes at the first level of the QTBT structure, each of which may be partitioned according to a quadtree partition. That is, the nodes at the first level are either leaf nodes (without child nodes) or have four child nodes. The example QTBT structure 130 represents such a node including a parent node and a child node with solid lines for branching. If the nodes at the first level are not larger than the maximum allowed binary tree root node size (MaxBTSize), the nodes may be further partitioned by their respective binary trees. The binary tree splitting of one node may be repeated until the nodes resulting from the split reach the minimum allowed binary tree leaf node size (MinBTSize) or the maximum allowed binary tree depth (MaxBTDepth). The example QTBT structure 130 represents such a node with dashed lines for branching. The binary tree leaf nodes are called coding units (CUs), and the CUs are used for prediction (e.g., intra-picture or inter-picture prediction) and transformation without further partitioning. As explained above, a CU may also be referred to as a "video block" or a "block."

[0075]

[0080] In one example of a QTBT partitioning structure, the CTU size is set as 128x128 (luma samples and two corresponding 64x64 chroma samples), MinQTSize is set as 16x16, MaxBTSize is set as 64x64, MinBTSize is set as 4 (for both width and height), and MaxBTDepth is set as 4. Quad tree partitioning is first applied to the CTU to generate quad tree leaf nodes. The quad tree leaf nodes can have sizes from 16x16 (i.e., MinQTSize) to 128x128 (i.e., CTU size). If the leaf quad tree node is 128x128, the leaf quad tree node is not further split by the binary tree because the size exceeds MaxBTSize (i.e., 64x64 in this example). Otherwise, the leaf quad tree node is further partitioned by the binary tree. Therefore, the quad tree leaf node is also the root node of the binary tree and has the binary tree depth as 0. When the binary tree depth reaches MaxBTDepth (4 in this example), no further splitting is allowed. When a binary tree node has a width equal to MinBTSize (4 in this example), it implies that no further horizontal splitting is allowed. Similarly, a binary tree node having a height equal to MinBTSize implies that no further vertical splitting is allowed for that binary tree node. As mentioned above, the leaf node of the binary tree is called a CU and is further processed according to the prediction and transformation without further partitioning.

[0076]

[0081] VVC Draft 7 describes palette modes to be applied for 4:4:4 content (e.g., where the luma and chroma components are of the same size). VVC Draft 7 already supports luma-only mode when dual tree partitioning is enabled. For example, when dual tree partitioning is enabled, the luma and chroma components may be partitioned in different manners. Thus, in some examples, palette modes may be applied with dual tree partitioning such that palette mode coding is applied separately to each of the luma and chroma components since the partitioning of the luma and chroma components is different.

[0077]

[0082] As described above, dual tree partitioning may be where the luma and chroma components are partitioned differently. In single tree partitioning, the luma and chroma components are partitioned in a similar manner. However, VVC Draft 7 may not support palette mode, which does not apply for monochrome content and when separate color plane coding is used. Monochrome content may also be known as 4:0:0 chroma format or chroma sampling type.

[0078]

[0083] In some examples, palette mode, dual tree partitioning, and separate color plane coding control flags are signaled in the SPS (Sequence Parameter Set). Below are examples of signaling:

[0079] [Table 1]

[0080]

[0084] sps_palette_enabled_flag equal to 1 specifies that pred_mode_plt_flag may be present in the coding unit syntax. sps_palette_enabled_flag equal to 0 specifies that pred_mode_plt_flag is not present in the coding unit syntax. When sps_palette_enabled_flag is not present, it is inferred to be equal to 0.

[0081]

[0085] qtbtt_dual_tree_intra_flag equal to 1 specifies that for an I-slice, each CTU is split into coding units with 64x64 luma samples using an implicit quad-tree split, and these coding units are the root of two separate coding_tree syntax structures for luma and chroma. qtbtt_dual_tree_intra_flag equal to 0 specifies that no separate coding_tree syntax structures are used for I-slice. When qtbtt_dual_tree_intra_flag is not present, it is inferred to be equal to 0.

[0082]

[0086] separate_colour_plane_flag equal to 1 specifies that the three colour components of the 4:4:4 chroma format are coded separately. separate_colour_plane_flag equal to 0 specifies that the colour components are not coded separately. When separate_colour_plane_flag is not present, it is inferred to be equal to 0. When separate_colour_plane_flag is equal to 1, the coded picture consists of three separate components, each of which consists of coded samples of one colour plane (Y, Cb, or Cr), and uses the monochrome coding syntax. In this case, each colour plane is associated with a specific colour_plane_id value.

[0083]

[0087] In some examples, there is no dependency in the decoding process between color planes with different colour_plane_id values, for example, the decoding process of a monochrome picture with one value of colour_plane_id does not use any data from a monochrome picture with a different value of colour_plane_id for inter prediction.

[0084]

[0088] Depending on the value of separate_colour_plane_flag, the value of the variable ChromaArrayType is assigned as follows:

[0085] - if separate_colour_plane_flag is equal to 0, ChromaArrayType is set equal to chroma_format_idc.

[0086] - Otherwise (separate_colour_plane_flag is equal to 1), ChromaArrayType is set equal to 0.

[0087]

[0089] When separate_colour_plane_flag is set to 1, the three colour planes are processed separately as a monochrome sampled picture.

[0088]

[0090] There may be issues with palette mode coding in VVC Draft 7. Palette mode is not applied for monochrome content and separate color plane coding. Because palette mode is already supported for luma-only mode when dual tree partitioning is enabled in VVC Draft 7, it may be possible to enable palette mode for monochrome content and when separate color plane coding is used. For example, palette mode may not be applied for monochrome content and separate color plane coding. Because palette mode is already supported with separate luma-only mode when dual tree is enabled, there may be no disadvantage to enable palette mode operation for monochrome content and when separate color plane coding is used.

[0089]

[0091] According to examples described in this disclosure, palette mode is enabled for monochrome content and for separate color plane coding where each plane can be treated as a monochrome signal. In some examples, this disclosure describes examples of reusing the existing luma-only palette mode used for dual-tree partitioning, where luma and chroma components can be coded separately in an I-slice. In one or more examples, this luma-only mode of operation for palette mode is extended for single-tree coding when a monochrome context is input (in VVC, dual trees are disabled for monochrome and separate color plane coding).

[0090]

[0092] Video encoder 200 and video decoder 300 may identify monochrome content by assigning (e.g., by video encoder 200) or examining (e.g., by video decoder 300) a chroma_format_idc value (chroma_format_idc=0 indicates monochrome) or by assigning or examining a separate color plane flag (separate_colour_plane_flag=1 indicates that each color plane is coded as monochrome content).

[0091]

[0093] To enable a luma-only palette mode for monochrome content and separate color plane coding, in one example, video encoder 200 and video decoder 300 may define (e.g., determine) the number of color components involved in the palette mode based on the tree type and the chroma_format_idc condition check. For example, if it is a single-tree (separate tree or dual tree is disabled) type coding and chroma_format_idc is equal to 0, the number of color components in the palette is set to 1, otherwise it is set to 3.

[0092]

[0094] In other words, when the current block is coded with single-tree partitioning enabled and when the current block is coded in monochrome format, video encoder 200 and video decoder 300 may determine that the number of color components used for palette mode coding of the current block is equal to 1. When the current block is coded with single-tree partitioning enabled and when the current block is not coded in monochrome format, video encoder 200 and video decoder 300 may determine that the number of color components used for palette mode coding of the current block is equal to 3.

[0093]

[0095] In VVC Draft 7, in one example, the palette mode may be implemented as follows, where the addition <add> and< / add> The text is shown between numComps=(treeType==SINGLE_TREE)?( <add> ChromaArrayType==0?1< / add> :3): (treeType==DUAL_TREE_CHROMA)?2:1

[0096] In the above example, the derived number of color components may be used in palette mode syntax signaling.

[0094]

[0097] For example, in the following operation, numComps=(treeType==SINGLE_TREE)?(ChromaArrayType==0?1:3):(treeType==DUAL_TREE_CHROMA)?2:1, numComps is equal to the number of color components used for palette mode coding (e.g., the number of color components involved in the palette mode). The number of color components used for palette mode coding may refer to the number of color components included in the palette mode table.

[0095]

[0098] In the above operations for determining numComps, the value of numComps is based on the partition tree type (e.g., whether or not it is single-tree partition) and whether or not the block is of monochrome format (e.g., whether or not ChromaArrayType is 0). For example, the above operations for numComps may be parsed as follows: If the partition tree type is single-tree partition (e.g., treeType==SINGLE_TREE), then a determination is made whether the block is coded in monochrome format (e.g., ChromaArrayType==0). When the partition tree type is single-tree partition and when the block is coded in monochrome format, the number of color components currently used for palette mode coding of the block is equal to 1.

[0096]

[0099] For example, video encoder 200 and video decoder 300 may determine that a current block of video data is coded in palette mode and may determine that, between single-tree partitioning or dual-tree partitioning, the current block is coded with single-tree partitioning enabled (e.g., treeType==SINGLE_TREE). Video encoder 200 and video decoder 300 may determine that the current block is coded in monochrome format. As an example, in response to determining that the current block is coded with single-tree partitioning enabled, video encoder 200 and video decoder 300 may determine that the current block is coded in monochrome format (e.g., in response to treeType equal to SINGLE_TREE, video encoder 200 and video decoder 300 may determine that ChromaArrayType is equal to 0).

[0097]

[0100] When the current block is coded with single-tree partitioning enabled and when the current block is coded in a monochrome format, video encoder 200 and video decoder 300 may determine that the number of color components used for palette mode coding of the current block is equal to 1. For example, in response to determining that the current block is coded with single-tree partitioning enabled and in response to determining that the current block is coded in a monochrome format (e.g., in response to treeType being equal to SINGLE_TREE and ChromaArrayType being equal to 0), video encoder 200 and video decoder 300 may determine that the current block is coded in a monochrome format and determine that the number of color components used for palette mode coding is equal to 1 (e.g., numComps is equal to 1).

[0098]

[0101] In another example, the number of color components involved in palette mode processing may be modified for video encoder 200 or video decoder 300 if the number of color components is equal to 3 or is assumed to be equal to 3. In such an example, chroma_format_idc is further inspected, and if it is equal to 0, i.e., monochrome content, the number of color components in palette mode is set to 1.

[0099]

[0102] In one example, the above technique may be implemented as follows, where the changes to VVC Draft 7 are: <add> and< / add> This is indicated by additional wording inside: Depending on the value of treeType, the variables startComp and numComps are derived as follows: - If treeType is equal to SINGLE_TREE:

[0100]

number

[0101]

[0103] In this example, the derived number of color components may be used in the decoding process of the palette mode. Both of these examples of deriving the number of color components in the palette mode may be used together.

[0102]

[0104] In some instances, both of these modifications are implemented for palette modes in VVC Draft 7 to support monochrome and separate color plane coding. Changes to VVC Draft 7 include: <add> and< / add> The following additional wording is provided below:

[0103] [Table 2]

[0104] 8.4.5.3 Decoding Process for Palette Mode The inputs to this process are: - a location (xCbComp, yCbComp) that specifies the top-left sample of the current coding block relative to the top-left sample of the current picture, a variable treeType, which specifies whether a single or dual tree is used, and if a dual tree is used, whether the current tree corresponds to the luma or chroma component; - the variable cIdx that specifies the color components of the current block, - Two variables nCbW and nCbH which specify the width and height, respectively, of the current coding block. The output of this process is the array recSamples[x][y], where x=0..nCbW-1, y=0..nCbH-1 specify the reconstructed sample values ​​for the block. Depending on the value of treeType, the variables startComp and numComps are derived as follows: - If treeType is equal to SINGLE_TREE:

[0105]

number

[0106] - Else, treeType is equal to DUAL_TREE_LUMA:

[0107]

number

[0108] - Else, treeType is equal to DUAL_TREE_CHROMA:

[0109]

number

[0110]

[0105] As seen above, numComps = (treeType = = SINGLE_TREE)? (ChromaArrayType = = 0? 1:3): (treeType = = DUAL_TREE_CHROMA)? 2:1 is part of a palette mode coding syntax structure (e.g., 7.3.9.6. Palette Coding Syntax, referenced above). Thus, in one or more examples, video decoder 300 may be configured to perform operations defined in the palette mode coding syntax structure (e.g., operations of 7.3.9.6. Palette Coding Syntax, as one non-limiting example). In such an example, when a current block is coded with single tree partitioning enabled and when the current block is coded in monochrome, video encoder 200 and video decoder 300 may determine, as part of implementing operations defined in the palette mode coding syntax structure, that the number of color components (e.g., numComps) used for palette mode coding of the current block is equal to 1. For example, video encoder 200 and video decoder 300 may determine the numComps value as equal to 1 based on determining that numComps=(treeType==SINGLE_TREE)?(ChromaArrayType==0?1:3):(treeType==DUAL_TREE_CHROMA)?2:1 as part of performing the operations defined in the palette mode coding syntax structure.

[0111]

[0106] In the above example, the current block may be considered as the first block. For the second block, the video encoder 200 and the video decoder 300 may determine that the second block is coded in palette mode, and between single-tree partitioning or dual-tree partitioning, the second block is coded with single-tree partitioning enabled.

[0112]

[0107] However, in this example, video encoder 200 and video decoder 300 may determine that the second block is not coded in monochrome format (e.g., ChromaArrayType is not equal to 0). In this example, when the second block is coded with single tree partitioning enabled and when the second block is not coded in monochrome format, video encoder 200 and video decoder 300 may determine that the number of color components used for palette mode coding of the second block (e.g., numComps for the second block) is equal to 3. That is, numComps is equal to 3 because treeType is SINGLE_TREE and ChromaArrayType is not 0.

[0113]

[0108] Figure 3 is a block diagram illustrating an example video encoder 200 that may implement the techniques of this disclosure. Figure 3 is provided for illustrative purposes and should not be considered as limiting the techniques broadly illustrated and described in this disclosure. For illustrative purposes, this disclosure describes video encoder 200 in accordance with VVC (ITU-T H.266 under development) and HEVC (ITU-T H.265) techniques. However, the techniques of this disclosure may be implemented by video encoding devices configured for other video coding standards.

[0114] 3, the video encoder 200 includes a video data memory 230, a mode selection unit 202, a residual generation unit 204, a transform processing unit 206, a quantization unit 208, an inverse quantization unit 210, an inverse transform processing unit 212, a reconstruction unit 214, a filter unit 216, a decoded picture buffer (DPB) 218, and an entropy coding unit 220. Any or all of the video data memory 230, the mode selection unit 202, the residual generation unit 204, the transform processing unit 206, the quantization unit 208, the inverse quantization unit 210, the inverse transform processing unit 212, the reconstruction unit 214, the filter unit 216, the DPB 218, and the entropy coding unit 220 may be implemented in one or more processors or processing circuits. For example, the units of the video encoder 200 may be implemented as one or more circuits or logic elements, as part of a hardware circuit, or as part of a processor of an FPGA, an ASIC. Moreover, video encoder 200 may include additional or alternative processors or processing circuitry for performing these and other functions.

[0115]

[0110] The video data memory 230 may store video data to be encoded by components of the video encoder 200. The video encoder 200 may receive video data stored in the video data memory 230, for example, from the video source 104 (FIG. 1). The DPB 218 may act as a reference picture memory that stores reference video data for use in predicting subsequent video data by the video encoder 200. The video data memory 230 and the DPB 218 may be formed by any of a variety of memory devices, such as synchronous dynamic random access memory (DRAM), including DRAM (SDRAM), magnetoresistive RAM (MRAM), resistive RAM (RRAM), or other types of memory devices. The video data memory 230 and the DPB 218 may be provided by the same memory device or separate memory devices. In various examples, the video data memory 230 may be on-chip with other components of the video encoder 200, as shown, or off-chip relative to those components.

[0116] In this disclosure, references to video data memory 230 should not be construed as limited to memory internal to video encoder 200 unless specifically so described, or to memory external to video encoder 200 unless specifically so described. Instead, references to video data memory 230 should be understood as a reference memory that stores video data that video encoder 200 receives for encoding (e.g., video data for a current block to be encoded). Memory 106 of FIG. 1 may also provide temporary storage of outputs from various units of video encoder 200.

[0117]

[0112] The various units in FIG. 3 are shown to aid in understanding the operations performed by the video encoder 200. The units may be implemented as fixed-function circuits, programmable circuits, or a combination thereof. A fixed-function circuit refers to a circuit that provides a specific function and is preset with respect to the operations that may be performed. A programmable circuit refers to a circuit that may be programmed to perform various tasks and to provide flexible functionality in the operations that may be performed. For example, a programmable circuit may execute software or firmware that causes the programmable circuit to operate in a manner defined by the software or firmware instructions. A fixed-function circuit may execute software instructions (e.g., to receive parameters or output parameters), but the type of operations that the fixed-function circuit performs is generally unchanging. In some examples, one or more of the units may be separate circuit blocks (fixed function or programmable), and in some examples, one or more of the units may be an integrated circuit.

[0118]

[0113] The video encoder 200 may include an arithmetic logic unit (ALU), a basic functional unit (EFU), a programmable core formed of digital circuits, analog circuits, and / or programmable circuits. In examples in which the operations of the video encoder 200 are implemented using software executed by a programmable circuit, the memory 106 (FIG. 1) may store instructions (e.g., object code) of the software that the video encoder 200 receives and executes, or another memory (not shown) within the video encoder 200 may store such instructions.

[0119]

[0114] The video data memory 230 is configured to store the received video data. The video encoder 200 may retrieve pictures of the video data from the video data memory 230 and provide the video data to the residual generation unit 204 and the mode selection unit 202. The video data in the video data memory 230 may be raw video data to be encoded.

[0120]

[0115] The mode selection unit 202 includes a motion estimation unit 222, a motion compensation unit 224, and an intra prediction unit 226. The mode selection unit 202 may include additional functional units for performing video prediction according to other prediction modes. By way of example, the mode selection unit 202 may include a palette unit, an intra block copy unit (which may be part of the motion estimation unit 222 and / or the motion compensation unit 224), an affine unit, a linear model (LM) unit, etc.

[0121]

[0116] The mode selection unit 202 generally coordinates multiple encoding passes to test combinations of encoding parameters and the resulting rate-distortion values ​​for such combinations. The encoding parameters may include partitioning of the CTU into CUs, prediction modes for the CUs, transform types for the residual data of the CUs, quantization parameters for the residual data of the CUs, etc. The mode selection unit 202 may finally select a combination of encoding parameters that has a rate-distortion value that is better than other tested combinations.

[0122]

[0117] The video encoder 200 may partition a picture retrieved from the video data memory 230 into a series of CTUs and encapsulate one or more CTUs in a slice. The mode selection unit 202 may partition the CTUs of the picture according to a tree structure, such as the QTBT structure or quadtree structure of HEVC described above. As described above, the video encoder 200 may form one or more CUs from partitioning the CTUs according to the tree structure. Such a CU may also be generally referred to as a "video block" or "block."

[0123]

[0118] In general, the mode selection unit 202 also controls its components (e.g., the motion estimation unit 222, the motion compensation unit 224, and the intra prediction unit 226) to generate a prediction block for a current block (e.g., the current CU, or in HEVC, the overlapping portion of the PU and TU). In inter prediction of the current block, the motion estimation unit 222 may perform motion search to identify one or more closely matching reference blocks in one or more reference pictures (e.g., one or more previously coded pictures stored in the DPB 218). In particular, the motion estimation unit 222 may calculate a value representing how similar a potential reference block is to the current block according to, for example, a sum of absolute differences (SAD), a sum of squared differences (SSD), a mean absolute difference (MAD), a mean squared difference (MSD), etc. The motion estimation unit 222 may generally perform these calculations using a sample-by-sample difference between the current block and the reference block under consideration. Motion estimation unit 222 may identify the reference block having the lowest value resulting from these calculations, which indicates the reference block that most closely matches the current block.

[0124]

[0119] The motion estimation unit 222 may form one or more motion vectors (MVs) that define the position of a reference block in a reference picture relative to the position of a current block in a current picture. The motion estimation unit 222 may then provide the motion vectors to the motion compensation unit 224. For example, in unidirectional inter prediction, the motion estimation unit 222 may provide a single motion vector, while in bidirectional inter prediction, the motion estimation unit 222 may provide two motion vectors. The motion compensation unit 224 may then generate a predictive block using the motion vectors. For example, the motion compensation unit 224 may use the motion vectors to retrieve data of a reference block. As another example, if the motion vectors have sub-sample precision, the motion compensation unit 224 may interpolate values ​​for the predictive block according to one or more interpolation filters. Moreover, in bidirectional inter prediction, the motion compensation unit 224 may retrieve data for two reference blocks identified by the respective motion vectors and combine the retrieved data, for example, through sample-wise averaging or weighted averaging.

[0125]

[0120] As another example, in intra prediction, or intra predictive coding, the intra prediction unit 226 may generate a predictive block from samples neighboring a current block. For example, in a directional mode, the intra prediction unit 226 may generally mathematically combine values ​​of neighboring samples and populate these calculated values ​​in a defined direction across the current block to produce a predictive block. As another example, in a DC mode, the intra prediction unit 226 may calculate an average of the neighboring samples for the current block and generate a predictive block to include this resulting average for each sample of the predictive block.

[0126]

[0121] The mode selection unit 202 provides the prediction block to the residual generation unit 204. The residual generation unit 204 receives a raw uncoded version of the current block from the video data memory 230 and receives the prediction block from the mode selection unit 202. The residual generation unit 204 calculates sample-by-sample differences between the current block and the prediction block. The resulting sample-by-sample differences define a residual block for the current block. In some examples, the residual generation unit 204 may also determine differences between sample values ​​in the residual block to generate the residual block using residual differential pulse code modulation (RDPCM). In some examples, the residual generation unit 204 may be formed using one or more subtractor circuits that perform binary subtraction.

[0127]

[0122] In an example where the mode selection unit 202 partitions a CU into PUs, each PU may be associated with a luma prediction unit and a corresponding chroma prediction unit. The video encoder 200 and the video decoder 300 may support PUs having various sizes. As indicated above, the size of a CU may refer to the size of the luma coding block of the CU, and the size of a PU may refer to the size of the luma prediction unit of the PU. Assuming that the size of a particular CU is 2N×2N, the video encoder 200 may support a PU size of 2N×2N or N×N for intra prediction, and a symmetric PU size of 2N×2N, 2N×N, N×2N, N×N, or the like for inter prediction. The video encoder 200 and the video decoder 300 may also support asymmetric partitioning for PU sizes of 2N×nU, 2N×nD, nL×2N, and nR×2N for inter prediction.

[0128]

[0123] In examples where the mode selection unit 202 does not further partition the CUs into PUs, each CU may be associated with a luma coding block and a corresponding chroma coding block. As described above, the size of a CU may refer to the size of the luma coding block of the CU. The video encoder 200 and the video decoder 300 may support CU sizes of 2Nx2N, 2NxN, or Nx2N.

[0129]

[0124] In other video coding techniques, such as intra block copy mode coding, affine mode coding, and linear model (LM) mode coding, as some examples, the mode selection unit 202 generates a predictive block for the current block being coded via a respective unit associated with the coding technique. In some examples, such as palette mode coding, the mode selection unit 202 may not generate a predictive block, but instead generate syntax elements that indicate how the block should be reconstructed based on a selected palette. In such modes, the mode selection unit 202 may provide these syntax elements to be coded to the entropy coding unit 220.

[0130]

[0125] As described above, the residual generation unit 204 receives the video data for a current block and the corresponding predictive block. The residual generation unit 204 then generates a residual block for the current block. To generate the residual block, the residual generation unit 204 calculates sample-by-sample differences between the predictive block and the current block.

[0131]

[0126] Transform processing unit 206 applies one or more transforms to the residual block to generate a block of transform coefficients (referred to herein as a "transform coefficient block"). Transform processing unit 206 may apply various transforms to the residual block to form the transform coefficient block. For example, transform processing unit 206 may apply a discrete cosine transform (DCT), a directional transform, a Karhunen-Loeve transform (KLT), or a conceptually similar transform to the residual block. In some examples, transform processing unit 206 may perform multiple transforms on the residual block, e.g., a linear transform and a secondary transform, such as a rotation transform. In some examples, transform processing unit 206 does not apply a transform to the residual block.

[0132]

[0127] The quantization unit 208 may quantize the transform coefficients in the transform coefficient block to produce a quantized transform coefficient block. The quantization unit 208 may quantize the transform coefficients of the transform coefficient block according to a quantization parameter (QP) value associated with the current block. The video encoder 200 (e.g., via the mode selection unit 202) may adjust the degree of quantization applied to the transform coefficient block associated with the current block by adjusting the QP value associated with the CU. Quantization may result in loss of information, and thus the quantized transform coefficients may have less precision than the original transform coefficients produced by the transform processing unit 206.

[0133]

[0128] The inverse quantization unit 210 and the inverse transform processing unit 212 may apply inverse quantization and inverse transform to the quantized transform coefficient block, respectively, to reconstruct a residual block from the transform coefficient block. The reconstruction unit 214 may produce a reconstructed block that corresponds to the current block (potentially with some distortion) based on the reconstructed residual block and the predictive block generated by the mode selection unit 202. For example, the reconstruction unit 214 may add samples of the reconstructed residual block to corresponding samples from the predictive block generated by the mode selection unit 202 to produce a reconstructed block.

[0134]

[0129] Filter unit 216 may perform one or more filter operations on the reconstructed block. For example, filter unit 216 may perform a deblocking operation to reduce blockiness artifacts along the edges of a CU. In some examples, the operations of filter unit 216 may be skipped.

[0135]

[0130] The video encoder 200 stores the reconstructed blocks in the DPB 218. For example, in an example where the operation of the filter unit 216 is not required, the reconstruction unit 214 may store the reconstructed blocks in the DPB 218. In an example where the operation of the filter unit 216 is required, the filter unit 216 may store the filtered reconstructed blocks in the DPB 218. The motion estimation unit 222 and the motion compensation unit 224 may retrieve reference pictures formed from the reconstructed (and potentially filtered) blocks from the DPB 218 to inter predict blocks of a later-encoded picture. Furthermore, the intra prediction unit 226 may use the reconstructed blocks in the DPB 218 of the current picture to intra predict other blocks in the current picture.

[0136]

[0131] In general, the entropy encoding unit 220 may entropy encode syntax elements received from other functional components of the video encoder 200. For example, the entropy encoding unit 220 may entropy encode quantized transform coefficient blocks from the quantization unit 208. As another example, the entropy encoding unit 220 may entropy encode predictive syntax elements (e.g., motion information for inter prediction, or intra mode information for intra prediction) from the mode selection unit 202. The entropy encoding unit 220 may perform one or more entropy encoding operations on syntax elements, which are another example of video data, to generate entropy encoded data. For example, the entropy encoding unit 220 may perform a context-adaptive variable length coding (CAVLC) operation, a CABAC operation, a variable-to-variable (V2V) length coding operation, a syntax-based context-adaptive binary arithmetic coding (SBAC) operation, a probability interval partitioned entropy (PIPE) coding operation, an exponential-Golomb coding operation, or another type of entropy coding operation on the data. In some examples, the entropy encoding unit 220 may operate in a bypass mode in which syntax elements are not entropy coded.

[0137]

[0132] Video encoder 200 may output a bitstream that includes entropy-encoded syntax elements needed to reconstruct blocks of a slice or picture. In particular, entropy encoding unit 220 may output the bitstream.

[0138]

[0133] The operations described above are described with respect to blocks. Such descriptions should be understood as being operations for luma coding blocks and / or chroma coding blocks. As described above, in some examples, the luma coding blocks and chroma coding blocks are the luma and chroma components of a CU. In some examples, the luma coding blocks and chroma coding blocks are the luma and chroma components of a PU.

[0139]

[0134] In some examples, operations performed with respect to luma coding blocks do not need to be repeated for chroma coding blocks. As an example, operations for identifying motion vectors (MVs) and reference pictures for luma coding blocks do not need to be repeated to identify MVs and reference pictures for chroma blocks. Rather, MVs for luma coding blocks may be scaled to determine MVs for chroma blocks, and the reference pictures may be the same. As another example, the intra prediction process may be the same for luma coding blocks and chroma coding blocks.

[0140]

[0135] Video encoder 200 represents one example of a device configured to encode video data, including a memory configured to store video data and one or more processing units implemented in a circuit, where the one or more processing units are configured to determine that one or more blocks are for monochrome content (e.g., contain or include monochrome content) and encode the one or more blocks using a palette mode. In some examples, to determine that one or more blocks are for monochrome content, the processing unit may be configured to determine (e.g., assign) a chroma format value (e.g., chroma_format_idc), where the value indicates that the one or more blocks are for monochrome content. In some examples, to determine that one or more blocks are for monochrome content, the processing unit may determine (e.g., assign) a value of a separate color plane flag, where the value indicates that each color plane is coded as monochrome content, where at least one color plane includes one or more blocks. In some examples, the processing unit may be configured to determine that one or more blocks are for separate color plane coding and to encode the one or more blocks using a palette mode. In some examples, the processing unit may be configured to determine a number of color components for the palette mode based on at least one of a tree type or a chroma format.

[0141]

[0136] For example, Figure 3 illustrates a palette mode unit 227, which in combination with other components, such as the mode selection unit 202, may be configured to implement example techniques described in this disclosure, such as the palette mode coding described above. As an example, the mode selection unit 202 may determine that a current block of video data is to be coded in palette mode and, between single-tree partitioning or dual-tree partitioning, determine that the current block is to be coded with single-tree partitioning enabled. For example, the mode selection unit 202 may test through various encoding passes and, based on the encoding passes, determine that palette mode with single-tree partitioning results in the optimal rate-distortion.

[0142]

[0137] In some examples, mode selection unit 202 may determine that when the current block is coded with single-tree partitioning enabled and when the current block is coded in a monochrome format, the number of color components used to palette mode encode the current block is equal to 1. Palette mode unit 227 may palette mode decode the current block based on the determined number of color components used to palette mode decode the current block being equal to 1.

[0143]

[0138] Figure 4 is a block diagram illustrating an example video decoder 300 that may implement the techniques of this disclosure. Figure 4 is provided for illustrative purposes and is not intended to limit the techniques broadly illustrated and described in this disclosure. For illustrative purposes, this disclosure describes the video decoder 300 in accordance with VVC (ITU-T H.266 under development) and HEVC (ITU-T H.265) techniques. However, the techniques of this disclosure may be implemented by video coding devices configured for other video coding standards.

[0144] In the example of FIG. 4, the video decoder 300 includes a coded picture buffer (CPB) memory 320, an entropy decoding unit 302, a prediction processing unit 304, an inverse quantization unit 306, an inverse transform processing unit 308, a reconstruction unit 310, a filter unit 312, and a decoded picture buffer (DPB) 314. Any or all of the CPB memory 320, the entropy decoding unit 302, the prediction processing unit 304, the inverse quantization unit 306, the inverse transform processing unit 308, the reconstruction unit 310, the filter unit 312, and the DPB 314 may be implemented in one or more processors or processing circuits. For example, the units of the video decoder 300 may be implemented as one or more circuits or logic elements, as part of a hardware circuit, or as part of a processor of an FPGA, an ASIC. Moreover, the video decoder 300 may include additional or alternative processors or processing circuits for performing these and other functions.

[0145]

[0140] Prediction processing unit 304 includes a motion compensation unit 316 and an intra prediction unit 318. Prediction processing unit 304 may include additional units for performing prediction according to other prediction modes. By way of example, prediction processing unit 304 may include a palette unit, an intra block copy unit (which may form part of motion compensation unit 316), an affine unit, a linear model (LM) unit, etc. In other examples, video decoder 300 may include more, fewer, or different functional components.

[0146]

[0141] The CPB memory 320 may store video data, such as an encoded video bitstream, to be decoded by components of the video decoder 300. The video data stored in the CPB memory 320 may be obtained, for example, from the computer-readable medium 110 (FIG. 1). The CPB memory 320 may include a CPB that stores encoded video data (e.g., syntax elements) from the encoded video bitstream. The CPB memory 320 may also store video data other than syntax elements of a coded picture, such as temporary data representing output from various units of the video decoder 300. The DPB 314 generally stores decoded pictures that the video decoder 300 may output and / or use as reference video data when decoding subsequent data or pictures of the encoded video bitstream. The CPB memory 320 and the DPB 314 may be formed by any of a variety of memory devices, such as DRAM, including SDRAM, MRAM, RRAM, or other types of memory devices. The CPB memory 320 and the DPB 314 may be provided by the same memory device or separate memory devices. In various examples, the CPB memory 320 may be on-chip with other components of the video decoder 300 or off-chip relative to those components.

[0147] Additionally or alternatively, in some examples, the video decoder 300 may retrieve the coded video data from memory 120 (FIG. 1). That is, memory 120 may store data as described above along with CPB memory 320. Similarly, memory 120 may store instructions to be executed by the video decoder 300 when some or all of the functionality of the video decoder 300 is implemented in software to be executed by processing circuitry of the video decoder 300.

[0148]

[0143] The various units shown in FIG. 4 are shown to aid in understanding the operations performed by the video decoder 300. The units may be implemented as fixed-function circuits, programmable circuits, or a combination thereof. As in FIG. 3, a fixed-function circuit refers to a circuit that provides a specific function and is preset with respect to the operations that may be performed. A programmable circuit refers to a circuit that may be programmed to perform various tasks and to provide flexible functionality in the operations that may be performed. For example, a programmable circuit may execute software or firmware that causes the programmable circuit to operate in a manner defined by the software or firmware instructions. Although a fixed-function circuit may execute software instructions (e.g., to receive parameters or output parameters), the type of operations that the fixed-function circuit performs is generally invariant. In some examples, one or more of the units may be separate circuit blocks (fixed function or programmable), and in some examples, one or more of the units may be an integrated circuit.

[0149]

[0144] The video decoder 300 may include a programmable core formed from ALUs, EFUs, digital circuits, analog circuits, and / or programmable circuits. In examples in which the operations of the video decoder 300 are performed by software executing on programmable circuits, on-chip or off-chip memory may store instructions (e.g., object code) of the software that the video decoder 300 receives and executes.

[0150]

[0145] The entropy decoding unit 302 may receive the encoded video data from the CPB and entropy decode the video data to recover the syntax elements. The prediction processing unit 304, the inverse quantization unit 306, the inverse transform processing unit 308, the reconstruction unit 310, and the filter unit 312 may generate decoded video data based on the syntax elements extracted from the bitstream.

[0151]

[0146] Generally, the video decoder 300 reconstructs a picture on a block-by-block basis. The video decoder 300 may perform a reconstruction operation on each block individually (wherein the block currently being reconstructed, i.e., decoded, may be referred to as the "current block").

[0152]

[0147] The entropy decoding unit 302 may entropy decode syntax elements defining the quantized transform coefficients of a quantized transform coefficient block, as well as transform information, such as a quantization parameter (QP) and / or a transform mode indication(s). The inverse quantization unit 306 may use the QP associated with the quantized transform coefficient block to determine the degree of quantization, and likewise the degree of inverse quantization that the inverse quantization unit 306 should apply. The inverse quantization unit 306 may perform, for example, a bitwise left shift operation to inverse quantize the quantized transform coefficients. The inverse quantization unit 306 may thereby form a transform coefficient block including the transform coefficients.

[0153]

[0148] After the inverse quantization unit 306 forms the transform coefficient block, the inverse transform processing unit 308 may apply one or more inverse transforms to the transform coefficient block to generate a residual block associated with the current block. For example, the inverse transform processing unit 308 may apply an inverse DCT, an inverse integer transform, an inverse Karhunen-Loeve transform (KLT), an inverse rotational transform, an inverse transform, or another inverse transform to the transform coefficient block.

[0154]

[0149] Furthermore, prediction processing unit 304 generates a prediction block according to the prediction information syntax element entropy decoded by entropy decoding unit 302. For example, if the prediction information syntax element indicates that the current block is inter predicted, motion compensation unit 316 may generate a prediction block. In this case, the prediction information syntax element may indicate a reference picture in DPB 314 from which to retrieve a reference block, as well as a motion vector that identifies the location of the reference block in the reference picture relative to the location of the current block in the current picture. Motion compensation unit 316 may generally perform an inter prediction process in a manner substantially similar to that described with respect to motion compensation unit 224 (FIG. 3).

[0155]

[0150] As another example, if the prediction information syntax element indicates that the current block is intra predicted, the intra prediction unit 318 may generate a prediction block according to the intra prediction mode indicated by the prediction information syntax element. Again, the intra prediction unit 318 may generally perform an intra prediction process in a manner substantially similar to that described with respect to the intra prediction unit 226 (FIG. 3). The intra prediction unit 318 may retrieve data of neighboring samples for the current block from the DPB 314.

[0156]

[0151] The reconstruction unit 310 may reconstruct the current block using the predictive block and the residual block. For example, the reconstruction unit 310 may add samples of the residual block to corresponding samples of the predictive block to reconstruct the current block.

[0157]

[0152] Filter unit 312 may perform one or more filter operations on the reconstructed block. For example, filter unit 312 may perform a deblocking operation to reduce blockiness artifacts along edges of the reconstructed block. The operations of filter unit 312 are not necessarily performed in all instances.

[0158]

[0153] The video decoder 300 may store the reconstructed block in the DPB 314. For example, in an example where the operation of the filter unit 312 is not performed, the reconstruction unit 310 may store the reconstructed block in the DPB 314. In an example where the operation of the filter unit 312 is performed, the filter unit 312 may store the filtered reconstructed block in the DPB 314. As described above, the DPB 314 may provide reference information to the prediction processing unit 304, such as samples of the current picture for intra prediction and previously decoded pictures for subsequent motion compensation. Moreover, the video decoder 300 may output the decoded picture (e.g., decoded video) from the DPB 314 for subsequent presentation on a display device, such as the display device 118 of FIG. 1.

[0159]

[0154] The above describes example techniques for inter-prediction and intra-prediction. In one or more examples, the video decoder 300 may be configured to perform palette mode coding, as described above. For example, as shown, the video decoder 300 may include a palette mode unit 319. In one or more examples, the palette mode unit 319 may be configured to determine the number of color components used for palette mode decoding of the current block (e.g., the palette mode unit 319 may determine a value for numComps based on numComps = (treeType == SINGLE_TREE)? (ChromaArrayType == 0? 1:3): (treeType == DUAL_TREE_CHROMA)? 2:1).

[0160]

[0155] For example, prediction processing unit 304 may determine that a current block of video data is coded in palette mode based on a syntax element signaled by video encoder 200 and received from entropy decoding unit 302. Prediction processing unit 304 may determine whether the current block is coded with single-tree partitioning or dual-tree partitioning, between single-tree partitioning or dual-tree partitioning. For example, prediction processing unit 304 may receive a syntax element signaled by video encoder 200 indicating whether single-tree partitioning or dual-tree partitioning is enabled. In some examples, prediction processing unit 304 may determine that the current block is coded with single-tree partitioning enabled (e.g., determine that treeType is equal to SINGLE_TREE), between single-tree partitioning or dual-tree partitioning.

[0161]

[0156] Prediction processing unit 304 may determine (e.g., based on the value of ChromaArrayType) that the current block is coded in monochrome format. As an example, in response to determining that the current block is coded with single-tree partitioning enabled, prediction processing unit 304 may determine whether the current block is coded in monochrome format. For example, in response to treeType being equal to SINGLE_TREE, prediction processing unit 304 may determine whether ChromaArrayType is equal to 0. When the current block is coded with single-tree partitioning enabled and when the current block is coded in monochrome format, prediction processing unit 304 may determine that the number of color components used to decode the current block in palette mode is equal to 1 (e.g., numComps is equal to 1).

[0162]

[0157] That is, in response to determining that the current block is to be coded with single-tree partitioning enabled, prediction processing unit 304 may determine that the current block is to be coded in monochrome format. Also, in response to determining that the current block is to be coded with single-tree partitioning enabled and in response to determining that the current block is to be coded in monochrome format, prediction processing unit 304 may determine that the number of color components used for palette mode coding is equal to 1.

[0163]

[0158] In one or more examples, the prediction processing unit 304 may be configured to perform operations defined in a palette mode coding syntax structure. One non-limiting example of a palette mode coding syntax structure is the 7.3.9.6 palette coding syntax structure described above. When the current block is coded with single-tree partitioning enabled and when the current block is coded in monochrome format, the prediction processing unit 304 may be configured to determine, as part of performing the operations defined in the palette mode coding syntax structure, that the number of color components used to palette mode decode the current block is equal to 1.

[0164]

[0159] The palette mode unit 319 may be configured to palette mode decode the current block based on the determined number of color components used to palette mode decode the current block being equal to one. For example, the palette mode unit 319 may decode the current block based on a palette mode table for only the luma component. In some examples, the video encoder 200 may signal information about the palette mode table, such as sample values ​​of the palette mode table, and the palette mode unit 319 may build the palette mode table with the sample values. In this example, only luma sample values ​​may be in the palette mode table because the current block is coded in monochrome format. In one or more examples, the palette mode unit 319 may receive an index into the palette mode table for the samples in the current block and assign luma values ​​to the samples in the current block based on the index into the palette mode table.

[0165] In the above examples, the current block may be considered as the first block. In some examples, the prediction processing unit 304 may determine that the second block is coded in palette mode, and between single-tree partitioning or dual-tree partitioning, the second block is coded with single-tree partitioning enabled.

[0166]

[0161] In this example, assume that prediction processing unit 304 determines that the second block is not coded in monochrome format (e.g., ChromaArrayType is not equal to 0). When the second block is coded with single tree partitioning enabled and when the second block is not coded in monochrome format, prediction processing unit 304 may determine that the number of color components used to palette mode code the second block is equal to 3 (e.g., numComps = (treeType == SINGLE_TREE)? ( <add> ChromaArrayType==0?1< / add>:3):(treeType==DUAL_TREE_CHROMA)?2:In 1, treeType is SINGLE_TREE and ChromaArrayType is not 0, so numComps is equal to 3).

[0167]

[0162] Palette mode unit 319 may then palette mode decode the second block based on the determined number of color components used to palette mode code the second block being equal to 3. For example, in this example, because there are three color components, the palette mode table may include sample values ​​for luma and chroma components.

[0168]

[0163] Thus, the video decoder 300 represents one example of a video decoding device including a memory configured to store video data and one or more processing units implemented in a circuit, the one or more processing units configured to determine that one or more blocks are for monochrome content and decode the one or more blocks using a palette mode. In some examples, to determine that one or more blocks are for monochrome content (e.g., include or contain monochrome content), the processing unit may be configured to determine (e.g., receive) a chroma format value (e.g., chroma_format_idc), where the value indicates that the one or more blocks are for monochrome content. In some examples, to determine that one or more blocks are for monochrome content, the processing unit may determine values ​​of separate color plane flags, where the value indicates that each color plane is coded as monochrome content, where at least one color plane includes one or more blocks. In some examples, the processing unit may be configured to determine that one or more blocks are for (e.g., include or have included) separate color plane coding and to decode the one or more blocks using a palette mode. In some examples, the processing unit may be configured to determine a number of color components for the palette mode based on at least one of a tree type or a chroma format.

[0169]

[0164] Figure 5 is a flow chart illustrating an example method for encoding a current block. The current block may comprise a current CU. The example of Figure 5 is described with a memory, the example of which includes memory 120, CPB memory 320, DPB 314, or some other memory, and a processing circuit, the example of which includes a video decoder 300, and components of the video decoder 300. For example, the example of Figure 5 describes a device for decoding video data, where the device includes a memory configured to store the video data and a processing circuit coupled to the memory and configured to perform one or more example techniques.

[0170]

[0165] For example, the processing circuit may determine (e.g., based on signaled information) that a current block of video data is to be coded in palette mode (500). The processing circuit may also determine (e.g., based on signaled information) that the current block is to be coded between single-tree partitioning or dual-tree partitioning with single-tree partitioning enabled (502).

[0171]

[0166] The processing circuit may determine that the current block is coded in monochrome format (504). As an example, in response to determining that the current block is coded with single tree partitioning enabled, the processing circuit may determine that the current block is coded in monochrome format. For example, in response to determining that treeType is equal to SINGLE_TREE, the processing circuit may determine whether ChromaArrayType is equal to 0, and in this example, the processing circuit may determine that the current block is coded in monochrome format (e.g., ChromaArrayType is equal to 0).

[0172]

[0167] When the current block is coded with single-tree partitioning enabled, and when the current block is coded in monochrome format, the processing circuit may determine that the number of color components used for palette mode decoding of the current block is equal to 1 (506). For example, in response to determining that the current block is coded with single-tree partitioning enabled, and in response to determining that the current block is coded in monochrome format, the processing circuit may determine that the number of color components used for palette mode decoding is equal to 1.

[0173]

[0168] As an example, the processing circuit may be configured to perform operations defined in a palette mode coding syntax structure. In such an example, to determine that the number of color components used to palette mode decode the current block is equal to 1, the processing circuit may be configured to perform, as part of performing the operations defined in the palette mode coding syntax structure, determining that the number of color components used to palette mode decode the current block is equal to 1. For example, the operations defined by the palette mode coding syntax structure may include determining numComps, which is numComps = (treeType = = SINGLE_TREE)? (ChromaArrayType = = 0? 1:3): (treeType = = DUAL_TREE_CHROMA)? 2:1. In the formula for numComps, if treeType is SINGLE_TREE (e.g., single tree partitioning is enabled) and if ChromaArrayType is 0 (e.g., monochrome format), then numComps is equal to 1.

[0174]

[0169] The processing circuit may be configured to palette mode decode the current block based on the determined number of color components used to palette mode decode the current block being equal to one (508). For example, the processing circuit may palette mode decode the current block based on a palette mode table for only the luma component. As an example, the processing circuit may receive an index into a palette mode table for samples in the current block and assign luminance values ​​to the samples in the current block based on the index into the palette mode table.

[0175]

[0170] In the above examples, treeType was SINGLE_TREE (e.g., single tree partitioning is enabled) and ChromaArrayType was 0 (e.g., monochrome format), in which case numComps was equal to 1. However, in some examples, for a second block coded in palette mode and with single tree partitioning mode enabled, the processing circuit may determine that the second block is not coded in monochrome format (e.g., ChromaArrayType is not equal to 0).

[0176]

[0171] In this case, when the second block is coded with single tree partitioning enabled and when the second block is not coded in monochrome format, the processing circuit may determine that the number of color components used to palette mode decode the second block is equal to 3. For example, numComps = (treeType == SINGLE_TREE)? (ChromaArrayType == 0? 1:3): (treeType == DUAL_TREE_CHROMA)? 2:1. Thus, if treeType is SINGLE_TREE but ChromaArrayType is not equal to 0, then numComps is equal to 3.

[0177]

[0172] The processing circuit may palette mode decode the second block based on the determined number of color components used to palette mode decode the second block being equal to 3. For example, the palette mode table may include sample values ​​for luma and chroma components, rather than only the luma component as may be the case for a monochrome format.

[0178]

[0173] Figure 6 is a flow chart illustrating an example technique described in this disclosure. Figure 6 is described with respect to a processing circuit, examples of which include the video encoder 200 or the video decoder 300. Figure 6 illustrates how the processing circuit may determine the number of color components used for palette mode coding according to numComps = (treeType = = SINGLE_TREE)? (ChromaArrayType = = 0? 1:3): (treeType = = DUAL_TREE_CHROMA)? 2:1.

[0179]

[0174] The processing circuit may start (600) and determine whether single-tree partitioning is enabled for the current block between dual-tree partitioning and single-tree partitioning (e.g., determine whether treeType == SINGLE_TREE) (602). In response to determining that single-tree partitioning is enabled for the current block (yes in 602), the processing circuit may determine whether the current block is coded in monochrome format (e.g., whether ChromaArrayType is equal to 0) (604).

[0180]

[0175] In response to determining that the current block is coded in monochrome format (yes at 604), the processing circuit may determine that numComps = 1, which may mean that when the current block is coded with single-tree partitioning enabled and when the current block is coded in monochrome format, the processing circuit may determine that the number of color components used for palette mode coding of the current block is equal to 1. In response to determining that the current block is not coded in monochrome format (no at 604), the processing circuit may determine that numComps = 3, which may mean that when the current block is coded with single-tree partitioning enabled and when the current block is not coded in monochrome format, the processing circuit may determine that the number of color components used for palette mode coding of the current block is equal to 3.

[0181]

[0176] In response to determining that the current block is not coded using single-tree partitioning (e.g., dual-tree partitioning is enabled) (no in 602), the processing circuit may determine whether a chroma component or a luma component is being processed (610). In response to determining that a chroma component is being processed (yes in 610), the processing circuit may determine that numComps=2 (612). In this example, there are two color components (e.g., Cb and Cr), so numComps is equal to 2. In response to determining that a chroma component is not being processed (no in 610), which means that the luma component is being processed, the processing circuit may determine that numComps=1. In this example, there is only a luma component being processed, so numComps is equal to 1 (614).

[0182]

[0177] The following techniques, described as clauses, may be implemented together or in any combination. The example techniques should not be construed as limited to the following clauses.

[0183]

[0178] Clause 1. A method for coding video data, the method comprising determining that one or more blocks of the video data are for monochrome content, and coding the one or more blocks using a palette mode.

[0184]

[0179] Clause 2. The method of clause 1, wherein determining that one or more blocks are for monochrome content comprises determining a value of a chroma format, wherein the value indicates that the one or more blocks are for monochrome content.

[0185]

[0180] Clause 3. The method of clause 1, wherein determining that one or more blocks are for monochrome content comprises determining a value of a separate color plane flag, where the value indicates that each color plane of a plurality of color planes is coded as monochrome content, and where at least one of the color planes includes one or more blocks.

[0186]

[0181] Clause 4. A method of coding video data, the method comprising determining that one or more blocks of the video data are for separate color plane coding, and coding the one or more blocks using a palette mode.

[0187]

[0182] Clause 5. The method of any of clauses 1 to 4, further comprising determining a number of color components for a palette mode based on at least one of a tree type or a chroma format.

[0188]

[0183] Clause 6. A method comprising any one or combination of clauses 1 to 5.

[0189]

[0184] Clause 7. The method of any of clauses 1 to 6, wherein the coding comprises decoding.

[0190]

[0185] Clause 8. The method of any of clauses 1-6, wherein coding comprises encoding.

[0191]

[0186] Clause 9. A device for coding video data, the device comprising: a memory configured to store the video data; and a processing circuit coupled to the memory and configured to perform a method according to any one or any combination of clauses 1 to 8.

[0192]

[0187] Clause 10. The device of clause 9, further comprising a display configured to display the decoded video data.

[0193]

[0188] Clause 11. A device according to any of clauses 9 and 10, wherein the device comprises one or more of a camera, a computer, a mobile device, a broadcast receiver device, or a set-top box.

[0194]

[0189] Clause 12. A device according to any one of clauses 9 to 11, wherein the device comprises a video decoder.

[0195]

[0190] Clause 13. A device according to any one of clauses 9 to 11, wherein the device comprises a video encoder.

[0196]

[0191] Clause 14. A computer-readable storage medium storing instructions that, when executed, cause one or more processors to perform the method described in any one of clauses 1 to 8.

[0197]

[0192] Clause 15. A device for coding video data, the device comprising means for performing the method according to any one or any combination of clauses 1 to 8.

[0198]

[0193] In accordance with the above examples, it should be recognized that some acts or events of any of the techniques described herein may be performed in a different sequence, added, merged, or omitted entirely (e.g., not all described acts or events are necessary to the practice of the techniques). Moreover, in some examples, acts or events may be performed simultaneously rather than sequentially, for example, through multi-threaded processing, interrupt processing, or multiple processors.

[0199]

[0194] In one or more examples, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or transmitted via a computer-readable medium as one or more instructions or code and executed by a hardware-based processing unit. A computer-readable medium may include a computer-readable storage medium corresponding to a tangible medium, such as a data storage medium, or a communication medium including any medium that enables the transfer of a computer program from one place to another, for example according to a communication protocol. In this manner, a computer-readable medium may generally correspond to (1) a tangible computer-readable storage medium that is non-transitory, or (2) a communication medium such as a signal or carrier wave. A data storage medium may be any available medium that may be accessed by one or more computers or one or more processors to retrieve instructions, code and / or data structures for implementation of the techniques described in this disclosure. A computer program product may include a computer-readable medium.

[0200]

[0195] By way of example and not limitation, such computer-readable storage media may comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, flash memory, or any other medium that may be used to store desired program code in the form of instructions or data structures and that may be accessed by a computer. Also, any connection is properly referred to as a computer-readable medium. For example, if the instructions are transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of the medium. However, it should be understood that computer-readable storage media and data storage media do not include connections, carrier waves, signals, or other transitory media, but instead cover non-transitory tangible storage media. As used herein, disk and disc include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc, where disks typically reproduce data magnetically and discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer readable media.

[0201]

[0196] The instructions may be executed by one or more processors, such as one or more digital signal processors (DSPs), general-purpose microprocessors, application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or other equivalent integrated or discrete logic circuits. Thus, the terms "processor" and "processing circuitry" as used herein may refer to any of the above structures, or any other structures suitable for implementing the techniques described herein. Furthermore, in some aspects, the functions described herein may be provided in dedicated hardware and / or software modules configured for encoding and decoding, or incorporated into a composite codec. Also, the techniques may be fully implemented in one or more circuits or logic elements.

[0202]

[0197] The techniques of the present disclosure may be implemented in a wide variety of devices or apparatuses, including wireless handsets, integrated circuits (ICs) or sets of ICs (e.g., chipsets). In this disclosure, various components, modules, or units have been described to highlight functional aspects of devices configured to implement the disclosed techniques, but those components, modules, or units do not necessarily require realization by different hardware units. Rather, as described above, the various units may be combined in a codec hardware unit or provided by a collection of interoperable hardware units, including one or more processors described above, along with suitable software and / or firmware.

[0203]

[0198] Various examples have been described. These and other examples are within the scope of the following claims. The invention as described in the claims of the original application is set forth below. [C1] A method for decoding video data, the method comprising: determining that a current block of video data is coded in palette mode; determining that the current block is coded with single-tree partitioning enabled between single-tree partitioning and dual-tree partitioning; determining that the current block is coded in a monochrome format; determining that a number of color components used to decode the current block in a palette mode is equal to 1 when the current block is coded with single-tree partitioning enabled and when the current block is coded in a monochrome format; and palette mode decoding the current block based on the determined number of color components used to palette mode decode the current block being equal to one. [C2] determining that the current block is coded in a monochrome format includes: The method of claim 1, comprising: in response to determining that the current block is coded with single-tree partitioning enabled, determining that the current block is coded in a monochrome format. [C3] determining that the number of color components used for palette mode decoding is equal to 1, The method of claim 1, comprising: in response to determining that the current block is coded with single-tree partitioning enabled and in response to determining that the current block is coded in a monochrome format, determining that the number of color components used for palette mode decoding is equal to 1. [C4] performing operations defined in a palette mode coding syntax structure; determining that the number of color components used to palette mode decode the current block is equal to one comprises, as part of performing the operations defined in the palette mode coding syntax structure, determining that the number of color components used to palette mode decode the current block is equal to one. The method according to C1. [C5] the current block comprises a first block, and the method further comprises: determining that the second block is coded in palette mode; determining that, between a single-tree partition or a dual-tree partition, the second block is coded with the single-tree partition enabled; determining that the second block is not coded in a monochrome format; determining that a number of color components used to decode the second block in a palette mode is equal to three when the second block is coded with single-tree partitioning enabled and when the second block is not coded in a monochrome format; palette mode decoding the second block based on the determined number of color components used to palette mode decode the second block being equal to three; and The method of claim C1, further comprising: [C6] The method of C1, wherein palette mode decoding of the current block comprises palette mode decoding of the current block based on a palette mode table only for a luma component. [C7] Palette mode decoding the current block based on the palette mode table, receiving an index into the palette mode table for a sample in the current block; assigning luminance values ​​to the samples in the current block based on the index into the palette mode table; The method of C6, comprising: [C8] A device for coding video data, said device comprising: a memory configured to store the video data; a processing circuit coupled to the memory, the processing circuit comprising: determining that a current block of video data is coded in palette mode; determining that the current block is coded with single-tree partitioning enabled between single-tree partitioning and dual-tree partitioning; determining that the current block is coded in a monochrome format; determining that a number of color components used to decode the current block in a palette mode is equal to 1 when the current block is coded with single-tree partitioning enabled and when the current block is coded in a monochrome format; and palette mode decoding the current block based on the determined number of color components used to palette mode decode the current block being equal to one. [C9] To determine that the current block is coded in a monochrome format, the processing circuitry in response to determining that the current block is to be coded with single-tree partitioning enabled, determining that the current block is to be coded in a monochrome format; 9. The device of claim 8, configured to: [C10] To determine that the number of color components used for palette mode decoding is equal to one, the processing circuitry determining, in response to determining that the current block is coded with single-tree partitioning enabled and in response to determining that the current block is coded in a monochrome format, that the number of color components used for palette mode decoding is equal to one; 9. The device of claim 8, configured to: [C11] The processing circuitry comprises: performing operations defined in a palette mode coding syntax structure; configured to: To determine that the number of color components used to decode the current block in palette mode is equal to one, the processing circuit is configured to determine, as part of performing the operations defined in the palette mode coding syntax structure, that the number of color components used to decode the current block in palette mode is equal to one. The device described in C8. [C12] The current block comprises a first block, and the processing circuitry determining that the second block is coded in palette mode; determining that, between a single-tree partition or a dual-tree partition, the second block is coded with the single-tree partition enabled; determining that the second block is not coded in a monochrome format; determining that a number of color components used to decode the second block in a palette mode is equal to three when the second block is coded with single-tree partitioning enabled and when the second block is not coded in a monochrome format; palette mode decoding the second block based on the determined number of color components used to palette mode decode the second block being equal to three; and 9. The device of claim 8, configured to: [C13] The device of C8, wherein the processing circuitry is configured to palette mode decode the current block based on a palette mode table for only a luma component. [C14] To palette mode decode the current block based on the palette mode table, the processing circuitry receiving an index into the palette mode table for a sample in the current block; assigning luminance values ​​to the samples in the current block based on the index into the palette mode table; The device of C13, configured to: [C15] The device of C8, further comprising a display configured to display the decoded video data. [C16] The device of C8, wherein the device comprises one or more of a camera, a computer, a mobile device, a broadcast receiver device, or a set-top box. [C17] A computer-readable storage medium having stored thereon instructions that, when executed, cause one or more processors to: determining that a current block of video data is coded in palette mode; determining that the current block is coded with single-tree partitioning enabled between single-tree partitioning and dual-tree partitioning; determining that the current block is coded in a monochrome format; determining that a number of color components used to decode the current block in a palette mode is equal to 1 when the current block is coded with single-tree partitioning enabled and when the current block is coded in a monochrome format; and palette mode decoding the current block based on the determined number of color components used to palette mode decode the current block being equal to one. [C18] A device for decoding video data, said device comprising: means for determining that the current block of video data is coded in palette mode; means for determining, between single-tree partitioning or dual-tree partitioning, that the current block is coded with single-tree partitioning enabled; means for determining that the current block is coded in a monochrome format; means for determining that a number of color components used for palette mode decoding of the current block is equal to one when the current block is coded with single-tree partitioning enabled and when the current block is coded in a monochrome format; means for palette mode decoding the current block based on the determined number of color components used to palette mode decode the current block being equal to one; A device comprising: [C19] The means for determining that the current block is coded in a monochrome format comprises: means for determining, in response to determining that the current block is to be coded with single-tree partitioning enabled, that the current block is to be coded in a monochrome format. The device described in C18. [C20] The means for determining that the number of color components used for palette mode decoding is equal to one, means for determining, in response to determining that the current block is coded with single-tree partitioning enabled and in response to determining that the current block is coded in a monochrome format, that the number of color components used for palette mode decoding is equal to one. The device described in C18. [C21] further comprising means for performing operations defined in a palette mode coding syntax structure, the means for determining that the number of color components used for palette mode decoding of the current block is equal to one comprises means for determining that the number of color components used for palette mode decoding of the current block is equal to one as part of performing the operations defined in the palette mode coding syntax structure. The device described in C18. [C22] The current block comprises a first block, and the device: means for determining that the second block is coded in palette mode; means for determining that the second block is coded with single tree partitioning enabled between single tree partitioning or dual tree partitioning; means for determining that the second block is not coded in a monochrome format; means for determining that a number of color components used to decode the second block in a palette mode is equal to three when the second block is coded with single-tree partitioning enabled and when the second block is not coded in a monochrome format; means for palette mode decoding the second block based on the determined number of color components used to palette mode decode the second block being equal to three; and The device of C18, further comprising: [C23] The device of C18, wherein the means for palette mode decoding the current block comprises means for palette mode decoding the current block based on a palette mode table only for a luma component. [C24] The means for palette mode decoding the current block based on the palette mode table further comprises: means for receiving an index into the palette mode table for a sample in the current block; means for assigning luminance values ​​to the samples in the current block based on the index into the palette mode table; The device of C23, comprising:

Claims

1. 1. A method for decoding video data, the method comprising: determining that a current block of video data is coded in palette mode; determining that the current block is coded with single-tree partitioning enabled between single-tree partitioning and dual-tree partitioning; determining that the current block is coded in a monochrome format; determining that when the current block is coded with single-tree partitioning enabled and the current block is coded in a monochrome format, a number of color components used to decode the current block in a palette mode is equal to one; palette mode decoding the current block based on the determined number of color components used to palette mode decode the current block being equal to one; A method comprising:

2. Determining that the current block is coded in a monochrome format includes:

2. The method of claim 1, comprising: in response to determining that the current block is to be coded with single-tree partitioning enabled, determining that the current block is to be coded in a monochrome format.

3. determining that the number of color components used for palette mode decoding is equal to one, 2. The method of claim 1, comprising: in response to determining that the current block is coded with single-tree partitioning enabled and determining that the current block is coded in a monochrome format, determining that the number of color components used for palette mode decoding is equal to one.

4. performing operations defined in a palette mode coding syntax structure; determining that the number of color components used to palette mode decode the current block is equal to one comprises, as part of performing the operations defined in the palette mode coding syntax structure, determining that the number of color components used to palette mode decode the current block is equal to one. The method of claim 1.

5. The current block comprises a first block, and the method further comprises: determining that the second block is coded in palette mode; determining that, between a single-tree partition or a dual-tree partition, the second block is coded with single-tree partition enabled; determining that the second block is not coded in a monochrome format; determining that when the second block is coded with single-tree partitioning enabled and the second block is not coded in a monochrome format, a number of color components used to decode the second block in a palette mode is equal to three; palette mode decoding the second block based on the determined number of color components used to palette mode decode the second block being equal to three; and The method of claim 1 further comprising:

6. 1. A device for coding video data, said device comprising: a memory configured to store the video data; a processing circuit coupled to the memory, the processing circuit comprising: determining that a current block of video data is coded in palette mode; determining that the current block is coded with single-tree partitioning enabled between single-tree partitioning and dual-tree partitioning; determining that the current block is coded in a monochrome format; determining that when the current block is coded with single-tree partitioning enabled and the current block is coded in a monochrome format, a number of color components used to decode the current block in a palette mode is equal to one; palette mode decoding the current block based on the determined number of color components used to palette mode decode the current block being equal to one; A device configured to:

7. To determine that the current block is coded in a monochrome format, the processing circuitry in response to determining that the current block is to be coded with single-tree partitioning enabled, determining that the current block is to be coded in a monochrome format; The device of claim 6 configured to:

8. To determine that the number of color components used for palette mode decoding is equal to one, the processing circuitry determining that the current block is coded with single-tree partitioning enabled and in response to determining that the current block is coded in a monochrome format, determining that the number of color components used for palette mode decoding is equal to one; The device of claim 6 configured to:

9. The processing circuitry includes: performing operations defined in a palette mode coding syntax structure; configured to: To determine that the number of color components used to decode the current block in palette mode is equal to one, the processing circuit is configured to determine, as part of performing the operations defined in the palette mode coding syntax structure, that the number of color components used to decode the current block in palette mode is equal to one. The device of claim 6.

10. the current block comprises a first block, the processing circuitry comprising: determining that the second block is coded in palette mode; determining that, between a single-tree partition or a dual-tree partition, the second block is coded with single-tree partition enabled; determining that the second block is not coded in a monochrome format; determining that when the second block is coded with single-tree partitioning enabled and the second block is not coded in a monochrome format, a number of color components used to decode the second block in a palette mode is equal to three; palette mode decoding the second block based on the determined number of color components used to palette mode decode the second block being equal to three; and The device of claim 6 configured to:

11. The device of claim 6 , wherein the processing circuitry is configured to palette mode decode the current block based on a palette mode table for only a luma component, to palette mode decode the current block.

12. To palette mode decode the current block based on the palette mode table, the processing circuitry receiving an index into the palette mode table for a sample in the current block; assigning luminance values ​​to the samples in the current block based on the index into the palette mode table; The device of claim 11 configured to:

13. The device of claim 6 , further comprising a display configured to display the decoded video data.

14. The device of claim 6 , wherein the device comprises one or more of a camera, a computer, a mobile device, a broadcast receiver device, or a set-top box.

15. A computer-readable storage medium having stored thereon instructions that, when executed, cause one or more processors to: determining that a current block of video data is coded in palette mode; determining that the current block is coded with single-tree partitioning enabled between single-tree partitioning and dual-tree partitioning; determining that the current block is coded in a monochrome format; determining that when the current block is coded with single-tree partitioning enabled and the current block is coded in a monochrome format, a number of color components used to decode the current block in a palette mode is equal to one; palette mode decoding the current block based on the determined number of color components used to palette mode decode the current block being equal to one; A computer-readable storage medium for causing a computer to perform the above steps.

Images