Scaling list signaling for video coding

Abstract

The video decoder can be configured to determine that a new scaling list of the scaling list set is to be predicted from a reference scaling list, wherein the new scaling list corresponds to a new scaling matrix, receive a syntax element that identifies an ID number corresponding to a scaling list of the scaling list set that is to be used as the reference scaling list, determine that the scaling list set does not include a scaling list having the ID number, and in response to determining that the scaling list set does not include a scaling list having the ID number, determine the new scaling matrix based on a default set of values.

Description

[0001] This application claims the benefit of priority to:

[0002] U.S. Provisional Application No. 62 / 985,815, filed March 5, 2020;

[0003] U.S. Provisional Application No. 62 / 988,329, filed March 11, 2020;

[0004] U.S. Provisional Application No. 63 / 004,903, filed April 3, 2020, and

[0005] U.S. Application No. 17 / 191,413, filed March 3, 2021,

[0006] the entire contents of which are hereby incorporated by reference.

[0007] U.S. Application No. 17 / 191,413, filed March 3, 2021, claims the benefit of priority to:

[0008] U.S. Provisional Application No. 62 / 985,815, filed March 5, 2020;

[0009] U.S. Provisional Application No. 62 / 988,329, filed March 11, 2020; and

[0010] U.S. Provisional Application No. 63 / 004,903, filed April 3, 2020. TECHNICAL FIELD

[0011] This disclosure relates to video encoding and video decoding. BACKGROUND

[0012] Digital video capabilities can 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 “smart phones,” video teleconferencing devices, video streaming devices, and the like. Digital video devices implement video coding techniques, such as those described in the 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 of such standards. The video devices can thereby

[0013] Video coding techniques include spatial (intra-picture) prediction and / or temporal (inter-picture) prediction to reduce or remove redundancy of the video sequence. For block-based video coding, a video slice (e.g., a video picture or a portion of a video picture) can be partitioned into video blocks, which can also be referred to as coding tree units (CTUs), coding units (CUs), and / or coding nodes. Video blocks in the intra coded (I) slices of a picture are coded using spatial prediction with respect to reference samples in neighboring blocks within the same picture. Video blocks in the inter coded (P or B) slices of a picture can be coded by using either spatial prediction with respect to reference samples in neighboring blocks within the same picture or temporal prediction with respect to reference samples in other reference pictures. Pictures can be referred to as frames, and reference pictures can be referred to as reference frames. SUMMARY

[0014] This disclosure describes techniques for signaling scaling lists in video encoding and decoding. Scaling lists can be used to signal scaling matrices for blocks of video data. A scaling matrix can be defined for each transform block size and prediction type of a block of video data, and the matrix can be derived from a scaling list. For video bitstreams that do not include chroma components, scaling lists are not typically signaled for chroma components.

[0015] To reduce the bit overhead associated with signaling scaling lists, for some new scaling lists, a video decoder can copy a decoded scaling list or use a decoded scaling list as a predictor for the new scaling list. However, in some coding scenarios, a video encoder can include signaling that causes the video decoder to predict a new scaling list from a decoded scaling list that does not actually exist. For example, the video data can be monochrome video data or video data coded in separate color planes that does not include scaling lists for chroma components, but the video encoder can signal to the video decoder that a scaling list associated with a chroma component is to be used as a scaling list predictor. To prevent decoder crashes, or to prevent otherwise incorrectly decoding the video data in such scenarios, techniques of this disclosure include determining a new scaling matrix based on a default set of values in response to determining that a new scaling list of a set of scaling lists is to be predicted from a reference scaling list that has not been previously decoded. Such techniques can prevent decoder crashes, or can prevent otherwise incorrectly decoding the video in such scenarios.

[0016] According to one example, a method of decoding video data includes determining a set of scaling lists for video data, wherein each scaling list in the set of scaling lists is used to determine an associated scaling matrix in a set of scaling matrices, and wherein each scaling list and each associated scaling matrix has an associated identification (ID) number; determining that a new scaling list of the set of scaling lists is to be predicted from a reference scaling list, wherein the new scaling list corresponds to a new scaling matrix; receiving a syntax element; determining the ID number based on the syntax element; determining that the set of scaling lists does not include a scaling list having the ID number; in response to determining that the set of scaling lists does not include a scaling list having the ID number, determining the new scaling matrix based on a set of default values; decoding the video data based on the new scaling matrix; and outputting the decoded video data.

[0017] According to another example, an apparatus for decoding video data includes a memory configured to store video data; and one or more processors implemented in circuitry and configured to: determine a set of scaling lists for video data, wherein each scaling list in the set of scaling lists is used to determine an associated scaling matrix in a set of scaling matrices, and wherein each scaling list and each associated scaling matrix determined has an associated identification (ID) number; determine that a new scaling list of the set of scaling lists is to be predicted from a reference scaling list, wherein the new scaling list corresponds to a new scaling matrix; receive a syntax element; determine the ID number based on the syntax element; determine that the set of scaling lists does not include a scaling list having the ID number; in response to determining that the set of scaling lists does not include a scaling list having the ID number, determine the new scaling matrix based on a set of default values; decode the video data based on the new scaling matrix; and output the decoded video data.

[0018] According to another example, a computer-readable storage medium stores instructions that, when executed by one or more processors, cause the one or more processors to: determine a set of scaling lists for video data, wherein each scaling list in the set of scaling lists is used to determine an associated scaling matrix in a set of scaling matrices, and wherein each scaling list and each associated scaling matrix determined has an associated identification (ID) number; determine that a new scaling list of the set of scaling lists is to be predicted from a reference scaling list, wherein the new scaling list corresponds to a new scaling matrix; receive a syntax element; determine the ID number based on the syntax element; determine that the set of scaling lists does not include a scaling list having the ID number; in response to determining that the set of scaling lists does not include a scaling list having the ID number, determine the new scaling matrix based on a set of default values; decode the video data based on the new scaling matrix; and output the decoded video data.

[0019] According to another example, an apparatus comprises means for determining a set of scaling lists for video data, wherein each scaling list in the set of scaling lists is used to determine an associated scaling matrix in a set of scaling matrices, and wherein each scaling list and each associated scaling matrix that is determined has an associated identification (ID) number; means for determining that a new scaling list of the set of scaling lists is to be predicted from a reference scaling list, wherein the new scaling list corresponds to a new scaling matrix; means for receiving a syntax element; means for determining the ID number based on the syntax element; means for determining that the set of scaling lists does not include a scaling list having the ID number; means for determining the new scaling matrix based on a set of default values in response to determining that the set of scaling lists does not include a scaling list having the ID number; means for decoding the video data based on the new scaling matrix; and means for outputting the decoded video data.

[0020] 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 the claims. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 FIG. 1 is a block diagram illustrating an example video encoding and decoding system that can perform the techniques of this disclosure.

[0022] Figure 2A and Figure 2B FIG. 2 is a conceptual diagram illustrating an example quad-tree binary tree (QTBT) structure and corresponding coding tree units (CTUs).

[0023] Figure 3 FIG. 3 is a block diagram illustrating an example video encoder that can perform the techniques of this disclosure.

[0024] Figure 4 FIG. 4 is a block diagram illustrating an example video decoder that can perform the techniques of this disclosure.

[0025] Figure 5 FIG. 5 is a flowchart illustrating an example process for encoding video data.

[0026] Figure 6 FIG. 6 is a flowchart illustrating an example process for decoding video data.

[0027] Figure 7 FIG. 7 is a flowchart illustrating an example process for decoding video data. DETAILED DESCRIPTION

[0028] Video coding (e.g., video encode and / or video decode) often involves predicting a block of video data from a block of already coded video data in the same picture (e.g., intra prediction) or a block of already coded video data in a different picture (e.g., inter prediction). In some cases, a video encoder also computes residual data by comparing a predicted block to an original block. Thus, the residual data represents the difference between the predicted block and the original block. To reduce the number of bits needed to signal the residual data, the video encoder transforms and quantizes the residual data and signals the transformed and quantized residual data in an encoded bitstream. The video encoder can uniformly quantize the transformed residual data based on a value of a quantization parameter (QP). The video encoder can additionally or alternatively perform frequency-based quantization of the transformed residual data using a quantization matrix (also referred to as a scaling list), which causes different coefficients (associated with different frequencies) to be quantized differently. As will be explained in greater detail below, a scaling list is used to signal values of the scaling matrix. The compression achieved by the transform and quantization process can be lossy, meaning that the transform and quantization process can introduce distortion into decoded video data.

[0029] A video decoder decodes the residual data and adds it to the predicted block to produce a reconstructed video block that more closely matches the original video block than the predicted block alone. Due to the loss introduced by the transform and quantization of the residual data, the first reconstructed block can have distortion or artifacts. One common type of artifact or distortion is referred to as blocking artifacts, where visible discontinuities across boundaries of coded blocks are often observed due primarily to different coding methods of neighboring coded blocks.

[0030] To further improve the quality of decoded video, a video decoder can perform one or more filtering operations on the reconstructed video block. Examples of these filtering operations include deblocking filtering, sample adaptive offset (SAO) filtering, and adaptive loop filtering (ALF). Parameters of these filtering operations can be determined by the video encoder and explicitly signaled in the encoded video bitstream, or can be implicitly determined by the video decoder without needing these parameters to be explicitly signaled in the encoded video bitstream.

[0031] As will be explained in greater detail below, video data can include one luma component and two chroma components. In some video bitstreams, the chroma components can be subsampled relative to the luma component, but in other cases, the chroma components can not be subsampled. Moreover, in some video bitstreams, the decoding of the chroma components can depend on the luma component. That is, information associated with the luma component can be needed to decode the chroma components. However, other types of video bitstreams, such as monochrome video bitstreams or video bitstreams encoded using separate color plane coding, use only a decoding process according to the luma component and not a decoding process for the chroma components.

[0032] This disclosure describes techniques for signaling scaling lists in video encoding and decoding. Scaling lists can be used to signal scaling matrices. A scaling matrix can be defined for each transform block size and prediction type of a block, and the matrix can be derived from a scaling list. For video bitstreams that do not include chroma components, scaling lists are typically not signaled for chroma components.

[0033] To reduce the bit overhead associated with signaling scaling lists, for some new scaling lists, a video decoder can copy a scaling list that has already been decoded or use a scaling list that has already been decoded as a predictor for the new scaling list. However, in some coding scenarios, a video encoder can include signaling that causes a video decoder to predict a new scaling list from a scaling list that has not actually been decoded. For example, the video data can be monochrome video data or video data encoded using separate color plane coding that does not include scaling lists for chroma components, but the video encoder can signal to the video decoder that a scaling list associated with a chroma component is to be used as a scaling list predictor. To prevent decoder crashes, or to prevent otherwise incorrectly decoding the video data in such scenarios, the techniques of this disclosure include determining a new scaling matrix based on a default set of values in response to determining that a new scaling list of a set of scaling lists is to be predicted from a reference scaling list that has not been previously decoded. Such techniques can prevent decoder crashes, or can prevent otherwise incorrectly decoding the video in such scenarios.

[0034] Figure 1 FIG. 1 is a block diagram illustrating an example video encoding and decoding system 100 that can perform the techniques of this disclosure. The techniques of this disclosure are generally directed toward coding (encoding and / or decoding) video data. In general, video data includes any data for processing video. Thus, video data can include raw, uncoded video, coded video, decoded (e.g., reconstructed) video, and video metadata, such as signaling data.

[0035] As Figure 1As shown, in this example, system 100 includes a source device 102 that provides encoded video data to be decoded and displayed by a destination device 116. Specifically, 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 include any of a wide variety of devices, including desktop computers, notebook (i.e., laptop) computers, mobile devices, tablet computers, set-top boxes, telephone handsets (such as smartphones), televisions, cameras, display devices, digital media players, video game consoles, video streaming devices, broadcast receiver devices, etc. 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.

[0036] exist Figure 1 In the example of , 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 the present disclosure, the video encoder 200 of source device 102 and the video decoder 300 of destination device 116 can be configured to apply the technology for scaling list signaling notification described herein. Therefore, source device 102 represents an example of a video encoding device, while destination device 116 represents an example of a video decoding device. In other examples, the source device and destination device may include other components or arrangements. For example, source device 102 can receive video data from an external video source (such as an external camera). Similarly, destination device 116 can be connected to an external display device instead of including an integrated display device.

[0037] like Figure 1 The system 100 shown is merely an example. In general, any digital video encoding and / or decoding device can perform the techniques described herein for scaling list signaling notifications. The source device 102 and the destination device 116 are merely examples of such codec devices in which the source device 102 generates encoded video data for transmission to the destination device 116. This disclosure refers to a "codec" device as a device that performs encoding and decoding (encoding and / or decoding) of data. Thus, the video encoder 200 and the video decoder 300 represent examples of codec devices, and more specifically, examples of a video encoder and a video decoder, respectively. In some examples, the source device 102 and the destination device 116 can operate in a substantially symmetrical manner, such that each of the source device 102 and the destination device 116 includes video encoding and decoding components. Thus, the system 100 can support one-way or two-way video transmission between the source device 102 and the destination device 116, for example, for video streaming, video playback, video broadcasting, or video telephony.

[0038] In general, video source 104 represents a source of video data (i.e., raw, uncoded video data) and provides a sequence of pictures (also referred to as “frames”) of the video data to video encoder 200, which encodes data for the pictures. Video source 104 of source device 102 can include a video capture device, such as a video camera, a video archive containing previously captured raw video, and / or a video feed interface to receive video from a video content provider. As yet another alternative, video source 104 can generate computer graphics-based data as the source video, or a combination of live video, archived video, and computer-generated video. In each case, video encoder 200 encodes the captured, pre-captured, or computer-generated video data. Video encoder 200 can rearrange the pictures from the received order (sometimes referred to as “display order”) into an encoding order for coding. Video encoder 200 can generate a bitstream including encoded video data. Source device 102 can then output the encoded video data via output interface 108 onto computer-readable medium 110 for reception and / or retrieval by, e.g., input interface 122 of destination device 116.

[0039] Memory 106 of source device 102 and memory 120 of destination device 116 represent general purpose memories. In some examples, memories 106, 120 can store raw video data, e.g., raw video from video source 104 and raw decoded video data from video decoder 300. Additionally or alternatively, memories 106, 120 can store software instructions executable by, e.g., video encoder 200 and video decoder 300, respectively. Although memory 106 and memory 120 are shown as separate from video encoder 200 and video decoder 300 in this example, it should be understood that video encoder 200 and video decoder 300 can also include internal memories for similar or equivalent purposes. Furthermore, memories 106, 120 can store encoded video data, e.g., output from video encoder 200 and input to video decoder 300. In some examples, portions of memories 106, 120 can be allocated as one or more video buffers, e.g., to store raw decoded and / or encoded video data.

[0040] Computer-readable medium 110 can represent any type of medium or device capable of storing encoded video data from source device 102 and communicating that encoded video data to destination device 116. In one example, computer-readable medium 110 represents a communication medium to enable source device 102 to transmit encoded video data directly to destination device 116 in real-time, e.g., via a radio frequency network or computer-based network. Output interface 108 can modulate a transmission signal including the encoded video data, and input interface 122 can demodulate the received transmission signal, according to a communication standard, such as a wireless communication protocol. The communication medium can comprise any wireless or wired communication medium, such as a radio frequency (RF) spectrum or one or more physical transmission lines. The communication medium can 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 can include routers, switches, base stations, or any other equipment that can be useful to facilitate communication from source device 102 to destination device 116.

[0041] In some examples, source device 102 can output encoded data from output interface 108 to storage device 112. Similarly, destination device 116 can access encoded data from storage device 112 via input interface 122. Storage device 112 can include any of a variety of distributed or locally accessed data storage media such as a hard drive, Blu-ray discs, DVDs, CD-ROMs, flash memory, volatile or non-volatile memory, or any other suitable digital storage media for storing encoded video data.

[0042] In some examples, source device 102 can output encoded video data to a file server 114 or another intermediate storage device that can store the encoded video data generated by source device 102. Destination device 116 can access stored video data from file server 114 via streaming or download.

[0043] The file server 114 can be any type of server device capable of storing encoded video data and transmitting that encoded video data to the destination device 116. The file server 114 can represent a web server (e.g., for a website), a server configured to provide file delivery protocol services (such as the File Delivery Protocol (FTP) or the 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 can 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, and the like.

[0044] The destination device 116 can access encoded video data from the file server 114 through any standard data connection, including an Internet connection. This can include a wireless channel (e.g., a Wi-Fi connection), a wired connection (e.g., a digital subscriber line (DSL), a cable modem, or the like), or a combination of both that is suitable for accessing encoded video data stored on the file server 114. The input interface 122 can be configured to operate according to any one or more of various protocols

[0045] The output interface 108 and the input interface 122 can represent wireless transmitters / receivers, modems, wired networking components (e.g., Ethernet cards), wireless communication components operating according to any of a variety of IEEE 802.11 standards, or other physical components. In examples where the output interface 108 and the input interface 122 include wireless components, the output interface 108 and the input interface 122 can 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, or the like. In some examples where the output interface 108 includes a wireless transmitter, the output interface 108 and the input interface 122 can be configured to transfer data according to other wireless standards, such as an IEEE 802.11 specification, an IEEE 802.15 specification (e.g., ZigBee), a Bluetooth TM TM ​Standards, etc.) to transfer data (such as encoded video data). In some examples, source device 102 and / or destination device 116 may include corresponding system-on-chip (SoC) devices. For example, source device 102 may include a SoC device to perform the functions attributed to video encoder 200 and / or output interface 108, and destination device 116 may include a SoC device to perform the functions attributed to video decoder 300 and / or input interface 122.

[0046] The technology disclosed herein can be applied to video encoding and decoding that supports any of a variety of multimedia applications, such as over-the-air television broadcasting, cable television transmission, satellite television transmission, Internet streaming video transmission (such as Dynamic Adaptive Streaming over HTTP (DASH)), digital video encoded onto a data storage medium, decoding of digital video stored on a data storage medium, or other applications.

[0047] The input interface 122 of the destination device 116 receives an 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 and also used by the video decoder 300, such as syntax elements with values ​​describing 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 liquid crystal display (LCD), a plasma display, an organic light emitting diode (OLED) display, or other types of display devices.

[0048] although Figure 1 2. Although not shown, in some examples, the video encoder 200 and the video decoder 300 can each be integrated with an audio encoder and / or an audio decoder and can include appropriate MUX-DEMUX units or other hardware and / or software to process a multiplexed stream including both audio and video in a common data stream. If applicable, the MUX-DEMUX units can conform to the ITU H.223 multiplexer protocol, or other protocols such as the User Datagram Protocol (UDP).

[0049] Video encoder 200 and video decoder 300 each can be implemented as any of a variety of suitable encoder and / or decoder circuitry, 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 or any combinations thereof. When the techniques are implemented partially in software, a device can store instructions for the software in any suitable non-transitory computer-readable medium and execute the instructions in hardware using one or more processors to perform the techniques of this disclosure. Each of video encoder 200 and video decoder 300 can be included in one or more encoders or decoders, any of which alone can be a component of a combined encoder / decoder (CODEC) in a respective device. A device including video encoder 200 and / or video decoder 300 can comprise an integrated circuit, a microprocessor, and / or a wireless communication device, such as a cellular telephone.

[0050] Video encoder 200 and video decoder 300 can operate according to a video coding standard, such as ITU-T H.265, also referred to as High Efficiency Video Coding (HEVC) or extensions such as multi-view and / or scalable video coding extensions. Alternatively, video encoder 200 and video decoder 300 can operate according to other proprietary or industry standards, such as ITU-T H.266, also referred to as Versatile Video Coding (VVC). A recent draft of the VVC standard is described in Bross, et al.“Versatile Video Coding (Draft 8),” Joint Video Team (JVT) of ITU-T SG 16 WP 3 and ISO / IEC JTC 1 / SC 29 / WG 11, 17thMeeting, Brussels, BE, 7-17 January 2020, JVET-Q2001-vl4 (hereinafter“VVC Draft 8”). The techniques of this disclosure, however, are not limited to any particular coding standard.

[0051] In general, video encoder 200 and video decoder 300 can perform block-based coding of pictures. The term “block” generally refers to a structure comprising data to be processed (for example, encoded, decoded, or otherwise used in the encoding and / or decoding process). For example, a block can comprise a two-dimensional matrix of samples of luma and / or chroma data. In general, video encoder 200 and video decoder 300 can code video data represented in a YUV (for example, Y, Cb, Cr) format. That is, video encoder 200 and video decoder 300 can code luma and chroma components as opposed to coding red, green, and blue (RGB) data of picture samples. In some examples, video encoder 200 converts received RGB format data into a YUV representation prior to encoding and video decoder 300 converts the YUV representation into the RGB format. Alternatively, pre- and post-processing units (not shown) can perform these conversions.

[0052] This disclosure can generally relate to coding (for example, encoding and decoding) of pictures, including processes of encoding or decoding data of pictures. Similarly, this disclosure can relate to coding of blocks of pictures, including processes of encoding or decoding data of blocks, for example, prediction and / or residual coding. An encoded video bitstream generally includes a series of syntax elements representing coding decisions (for example, coding modes) and partitioning of pictures into blocks. Accordingly, references to coding of pictures or blocks should generally be understood to refer to coding of values of syntax elements forming the pictures or blocks.

[0053] 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 a coding tree unit (CTU) 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. Nodes with zero child nodes can be referred to as “leaf nodes,” and CUs of such leaf nodes can include one or more PUs and / or one or more TUs. Video coder can further partition PUs and TUs. For example, in HEVC, a residual quadtree (RQT) represents partitioning of TUs. In HEVC, PUs represent inter-predicted data, while TUs represent residual data. Intra-predicted CUs include intra-prediction information, such as an intra-mode indication.

[0054] As another example, video encoder 200 and video decoder 300 can be configured to operate according to VVC. According to VVC, a video coder (such as video encoder 200) partitions a picture into a plurality of coding tree units (CTUs). Video encoder 200 can partition a CTU according to a tree structure such as a quad-tree binary tree (QTBT) structure or a multi-type tree (MTT) structure. The QTBT structure removes the multiple separation type concepts, such as the distinction between CUs, PUs, and TUs of HEVC. The QTBT structure includes two layers: a first layer partitioned according to quad-tree partitioning, and a second layer partitioned according to binary tree partitioning. A root node of the QTBT structure corresponds to a CTU. Leaf nodes of the binary trees correspond to coding units (CUs).

[0055] In the MTT partitioning structure, quad-tree (QT) partitioning, binary tree (BT) partitioning, and one or more types of triple tree (TT) (also referred to as temary tree (TT)) partitioning can be used to partition a block. Triple tree or temary tree partitioning is a partitioning that splits one block into three sub-blocks. In some examples, triple tree or temary tree partitioning splits one block into three sub-blocks without splitting the original block through a center split. The partitioning types (e.g., QT, BT, and TT) in the MTT can be symmetric or asymmetric.

[0056] In some examples, video encoder 200 and video decoder 300 can use a single QTBT or MTT structure to represent each of luma and chroma components, while in other examples, video encoder 200 and video decoder 300 can use two or more QTBT or MTT structures, such as one QTBT / MTT structure for luma components and another QTBT / MTT structure for two chroma components, or two QTBT / MTT structures for respective chroma components.

[0057] Video encoder 200 and video decoder 300 can be configured to use quad-tree partitioning according to HEVC, QTBT partitioning, MTT partitioning, or other partition structures. For purposes of explanation, the description of the techniques of this disclosure is presented relative to QTBT partitioning. However, it should be understood that the techniques of this disclosure can also be applied to video coders configured to use quad-tree partitioning or other types of partitioning.

[0058] In some examples, a CTU includes a coding tree block (CTB) of luma samples, two corresponding CTBs of chroma samples of a picture having three arrays of samples, or a CTB of samples of a monochrome picture or a picture coded using three separate color planes and syntax structures used to code the samples. A CTB can be a block of NxN samples for a certain value of N, such that partitioning a component into CTBs is a type of partitioning. A component is an array or a single sample in one of three arrays (one luma and two chroma) that make up a picture in 4:2:0, 4:2:2, or 4:4:4 color format or an array or a single sample of a picture in monochrome format. In some examples, a coding block is a block of MxN samples for certain values of M and N, such that partitioning a CTB into coding blocks is a type of partitioning.

[0059] A block (e.g., a CTU or CU) can be grouped in various ways in a picture. As one example, a brick can refer to a rectangular region of CTU rows within a particular tile in a picture. A tile can be a rectangular region of CTUs within a particular tile column and a particular tile row in a picture. A tile column refers to a rectangular region of CTUs whose height is equal to a picture height and whose width is specified by a syntax element (e.g., such as in a picture parameter set). A tile row refers to a rectangular region of CTUs whose height is specified by a syntax element (e.g., such as in a picture parameter set) and whose width is equal to a picture width.

[0060] In some examples, a tile can be partitioned into multiple bricks, each of which can include one or more CTU rows within the tile. A tile that is not partitioned into multiple bricks can also be referred to as a brick. However, a brick that is a true subset of a tile can not be referred to as a tile.

[0061] Bricks in a picture can also be arranged in slices. A slice can be an integer number of bricks of a picture, which can be exclusively contained in a single network abstraction layer (NAL) unit. In some examples, a slice includes multiple complete tiles or only a complete sequence of bricks of a single tile.

[0062] The present disclosure can interchangeably use“NxN” and“N by N” to refer to the sample dimensions of a block (such as a CU or other video block) in terms of vertical and horizontal dimensions, e.g., 16x16 samples or 16 by 16 samples. In general, a 16x16 CU has 16 samples in the vertical direction (y = 16) and 16 samples in the horizontal direction (x = 16). Likewise, an NxN CU typically has N samples in the vertical direction and N samples in the horizontal direction, where N represents a non negative integer value. The samples in a CU can be arranged in rows and columns. Moreover, a CU need not have the same number of samples in the horizontal direction as in the vertical direction. For example, a CU can include NxM samples, where M is not necessarily equal to N.

[0063] Video encoder 200 encodes video data of CUs that represent prediction and / or residual information, among other information. Prediction information indicates how to predict a CU in order to form a prediction block for the CU. Residual information generally represents sample-by-sample differences between the CU prior to encoding and the prediction block.

[0064] To predict a CU, video encoder 200 can generally form a prediction block for the CU through inter prediction or intra prediction. Inter prediction generally refers to predicting the CU from data of a previously coded picture, while intra prediction generally refers to predicting the CU from previously coded data of the same picture. To perform inter prediction, video encoder 200 can use one or more motion vectors to generate the prediction block. Video encoder 200 can generally perform a motion search to identify a reference block that closely matches the CU (e.g., in terms of differences between the CU and the reference block). Video encoder 200 can calculate a difference metric using a sum of absolute difference (SAD), sum of squared differences (SSD), mean absolute difference (MAD), mean squared differences (MSD), or other such difference calculations to determine whether a reference block closely matches a current CU. In some examples, video encoder 200 can use uni -prediction or bi-prediction to predict a current CU.

[0065] Some examples of VVC also provide an affine motion compensation mode, which can be considered a type of inter prediction mode. In the affine motion compensation mode, video encoder 200 can determine two or more motion vectors that represent non-translational motion, such as scaling or zooming, rotation, perspective motion, or other types of irregular motion.

[0066] To perform intra prediction, video encoder 200 can select an intra prediction mode to generate the prediction block. Some examples of VVC provide 67 intra prediction modes, including various directional modes as well as a planar mode and a DC mode. In general, video encoder 200 selects an intra prediction mode that describes neighboring samples of the current block (e.g., a block of a CU) from which to predict samples of the current block according to the intra prediction mode. Assuming that video encoder 200 encodes CTUs and CUs in a raster scan order (left to right, top to bottom), such samples can generally be above, above and to the left, or to the left of the current block in the same picture as the current block.

[0067] Video encoder 200 encodes data that represents the prediction mode for the current block. For example, for inter prediction modes, video encoder 200 can encode data that indicates which of various available inter prediction modes to use, as well as motion information for the corresponding mode. For example, for uni- or bi-prediction, video encoder 200 can use advanced motion vector prediction (AMVP) or merge mode to encode motion vectors. Video encoder 200 can use similar modes to encode motion vectors for affine motion compensation modes.

[0068] After prediction, such as intra prediction or inter prediction for a block, video encoder 200 can calculate residual data for the block. The residual data, such as a residual block, represents sample-by-sample differences between the block and a prediction block formed using the corresponding prediction mode. Video encoder 200 can apply one or more transforms to the residual block to produce transformed data in a transform domain instead of the sample domain. For example, video encoder 200 can apply a discrete cosine transform (DCT), an integer transform, a wavelet transform, or a conceptually similar transform. Moreover, video encoder 200 can apply a secondary transform after the first transform, such as a mode-dependent non-separable secondary transform (MDNSST), a signal-dependent transform, a Karhunen-Loeve transform (KLT), and the like. Video encoder 200 produces transform coefficients after applying the one or more transforms.

[0069] As described above, after any transforms to produce transform coefficients, video encoder 200 can 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 the quantization process, video encoder 200 can reduce the bit depth of some or all of the transform coefficients. For example, video encoder 200 can round an n-bit value down to an m-bit value during quantization, where n is greater than m. In some examples, to perform quantization, video encoder 200 can perform a bitwise right-shift of the value to be quantized.

[0070] After quantization, video encoder 200 can scan the transform coefficients, producing a one-dimensional vector from the two-dimensional matrix including the quantized transform coefficients. The scan can 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 back of the vector. In some examples, video encoder 200 can utilize a pre-defined scan order to scan the quantized transform coefficients to produce a serialized vector, and then entropy encode the quantized transform coefficients of the vector. In other examples, video encoder 200 can perform an adaptive scan. After scanning the quantized transform coefficients to form a one-dimensional vector, video encoder 200 can entropy encode the one-dimensional vector (e.g., according to context adaptive binary arithmetic coding (CABAC)). Video encoder 200 can also entropy encode values for syntax elements describing metadata associated with the encoded video data for use by video decoder 300 when decoding the video data.

[0071] To perform CABAC, video encoder 200 can assign a context within a context model to a symbol to be transmitted. The context can relate to, for example, whether neighboring values of the symbol are zero-valued or not. The probability determination can be based on the context assigned to the symbol.

[0072] Video encoder 200 can 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 picture headers, block headers, slice headers, or other syntax data, such as sequence parameter sets (SPS), picture parameter sets (PPS), or video parameter sets (VPS). Video decoder 300 can likewise decode such syntax data to determine how to decode corresponding video data.

[0073] In this way, video encoder 200 can generate a bitstream including encoded video data, e.g., syntax elements describing partitioning of a picture into blocks (e.g., CUs) and prediction and / or residual information for the blocks. Ultimately, video decoder 300 can receive the bitstream and decode the encoded video data.

[0074] In general, video decoder 300 performs a reciprocal process to that performed by video encoder 200 to decode encoded video data of the bitstream. For example, video decoder 300 can decode values for syntax elements of the bitstream using CABAC in a manner substantially similar, albeit reciprocal, to the CABAC encoding process of video encoder 200. The syntax elements can define partitioning information for partitioning a picture into CTUs and partitioning each CTU according to a corresponding partition structure, such as a QTBT structure, to define CUs of the CTU. The syntax elements can further define prediction and residual information for blocks (e.g., CUs) of video data.

[0075] The residual information can be represented by, for example, quantized transform coefficients. Video decoder 300 can inverse quantize and inverse transform the quantized transform coefficients of a block to reproduce a residual block for the block. Video decoder 300 uses the signaled prediction mode (intra- or inter-prediction) and related prediction information (e.g., motion information for inter-prediction) to form a prediction block for the block. Video decoder 300 can then combine (on a sample-by-sample basis) the prediction block and the residual block to reproduce the original block. Video decoder 300 can perform additional processing, such as performing a deblocking process to reduce visual artifacts along block boundaries.

[0076] This disclosure can generally refer to “signaling” certain information, such as syntax elements. The term “signaling” can generally refer to a communication of values for syntax elements and / or other data used to decode encoded video data. That is, video encoder 200 can signal values for the syntax elements in the bitstream. In general, signaling refers to generating the values in the bitstream. As described above, source device 102 can communicate the bitstream to destination device 116 in substantially real-time or non-real time, such as can occur when the syntax elements are stored to storage device 112 for later retrieval by destination device 116.

[0077] Figure 2A and Figure 2Bis a conceptual diagram illustrating an example quad-tree binary tree (QTBT) structure 130 and a corresponding coding tree unit (CTU) 132. Solid lines represent quad-tree splitting, and dashed lines indicate binary-tree splitting. In each split (i.e., non-leaf) node of the binary tree, a flag is signaled to indicate which splitting type (i.e., horizontal or vertical) is used, where 0 indicates horizontal splitting and 1 indicates vertical splitting in this example. For quad-tree splitting, the splitting type does not need to be indicated because a quad-tree node splits a block horizontally and vertically into 4 equally-sized sub-blocks. Accordingly, video encoder 200 can encode and video decoder 300 can decode syntax elements (such as splitting information) for a region tree layer (i.e., solid lines) of QTBT structure 130 and syntax elements (such as splitting information) for a prediction tree layer (i.e., dashed lines) of QTBT structure 130. Video encoder 200 can encode and video decoder 300 can decode video data, such as prediction and transform data, for CUs represented by terminal leaf nodes of QTBT structure 130.

[0078] In general, Figure 2B CTU 132 of FIG. 13A can be associated with parameters defining block sizes corresponding to nodes of QTBT structure 130 at the first and second layers. These parameters can include a CTU size (representing the size of CTU 132 in samples), a minimum quadtree size (MinQTSize representing a minimum allowed quadtree leaf node size), a maximum binary tree size (MaxBTSize representing a maximum allowed binary tree root node size), a maximum binary tree depth (MaxBTDepth representing a maximum allowed binary tree depth), and a minimum binary tree size (MinBTSize representing a minimum allowed binary tree leaf node size).

[0079] The root node of the QTBT structure corresponding to a CTU can have four child nodes at the first level of the QTBT structure, each of which can be partitioned according to quadtree partitioning. That is, a node at the first level is either a leaf node (having no child nodes) or has four child nodes. The example of QTBT structure 130 represents such nodes as including a parent node and child nodes with solid branches. If a node at the first level is not larger than a maximum allowed binary tree root node size (MaxBTSize), then the node can be further partitioned by a corresponding binary tree. Binary tree partitioning of a node can be iterated until nodes resulting from the partitioning reach a minimum allowed binary tree leaf node size (MinBTSize) or a maximum allowed binary tree depth (MaxBTDepth). The example of QTBT structure 130 represents such nodes as having dashed branches. Binary tree leaf nodes are referred to as coding units (CUs), which are used for prediction (e.g., intra- or inter-prediction) and transform without any further partitioning. As discussed above, a CU can also be referred to as a “video block” or “block.”

[0080] In one example of a QTBT partitioning structure, the CTU size is set to 128x128 (luma samples and two corresponding 64x64 chroma samples), MinQTSize is set to 16x16, MaxBTSize is set to 64x64, MinBTSize (for both width and height) is set to 4, and MaxBTDepth is set to 4. Quadtree partitioning is first applied to the CTU to generate quadtree leaf nodes. The quadtree leaf nodes can be from 16x16 (i.e., MinQTSize) to 128x128 (i.e., the CTU size) in size. If a quadtree leaf node is 128x128, then the leaf quadtree node will not be further divided by a binary tree because the size exceeds MaxBTSize (i.e., 64x64 in this example). Otherwise, the quadtree leaf node will be further partitioned by a binary tree. Thus, the quadtree leaf node is also a root node of a binary tree, and its binary tree depth is 0. When the binary tree depth reaches MaxBTDepth (4 in this example), no further partitioning is allowed. A binary tree node with a width equal to MinBTSize (4 in this example) means that no further vertical partitioning (i.e., partitioning of the width) is allowed for that binary tree node. Similarly, a binary tree node with a height equal to MinBTSize means that no further horizontal partitioning (i.e., partitioning of the height) is allowed for that binary tree node. As noted above, leaf nodes of a binary tree are referred to as CUs and are further processed for prediction and transform without further partitioning.

[0081] Video encoder 200 and video decoder 300 can be configured to process quantization parameters. QP values are used to determine the step size for quantizing / dequantizing coefficients. QP values are specified in the range of -QpBdOffset to 63, inclusive, where 63 is the maximum QP value. QpBdOffset is specified as a fixed value for a particular bit depth, which is derived as 6*(bitDepth - 8). The QP prime value, which is calculated by adding QpBdOffset to the specified QP value, is used to derive the actual step size. For ease of description, QP and QP prime value can be used interchangeably in the remaining description, with the understanding that QP values can be used only in most QP derivation processes, and QP prime values can be used only in the last stage before determining the step size. A QP value change of 1 roughly indicates a step size change of 12%, and a QP value change of 6 corresponds to a step size change of a factor of 2. Higher quantization parameter values imply larger quantization step sizes and coarser representation of quantized coefficients.

[0082] Video encoder 200 and video decoder 300 can be configured to process quantization and scaling matrices. In video coding, a residual obtained after a prediction operation is transformed using a DCT2 or other transform operation. The transform coefficients are then quantized, and the quantized coefficients are entropy coded.

[0083] The quantization process is controlled by two factors: the quantization parameter and the scaling matrix. The description of the quantization parameter is described above. At the decoder (e.g., video decoder 300), a scaling factor corresponding to the quantization parameter is determined. The scaling factor is applied as follows:

[0084] levelScale [ ][ qP % 6 ] ) « ( qP / 6 )

[0085] where qP is the quantization parameter, and levelScale [ ][ ] is an array defined as follows

[0086] The list levelScale [ ][ ] is specified as levelScale [ j ][ k ] = { { 40, 45, 51, 57, 64, 72}, { 57, 64, 72, 80, 90, 102}}, where j = 0..1, k = 0..5.

[0087] A QP difference of 6 causes a shift of 1, so the scaling associated with QP is applied by shifting by qP / 6 and using qp%6 for the scaling calculation.

[0088] In addition, a scaling parameter is applied to each coefficient. The scaling parameter can be different for different coefficients. The scaling factor associated with the scaling matrix is derived as follows:

[0089] – The intermediate scaling factor m[ x ][ y ] is derived as follows:

[0090] – If one or more of the following conditions is true, m[ x ][ y ] is set equal to 16:

[0091] – sps_scaling_list_enabled_flag is equal to 0.

[0092] – transform_skip_flag[ xTbY ][ yTbY ] is equal to 1.

[0093] – Otherwise, the following applies:

[0094] m[ x ][ y ] = ScalingFactor[ Log2( nTbW ) ][ Log2( nTbH ) ]

[0095] [ matrixId ][ x ][ y ], where matrixId is as specified in Table 7-5 (8-958)

[0096] The final scaling factor used in inverse quantization is obtained by multiplying the two scaling terms (from QP and scaling matrix) as follows:

[0097] – If dep_quant_enabled_flag is equal to 1, the following applies:

[0098] ls[ x ][ y ] = ( m[ x ][ y ] * levelScale[ rectNonTsFlag ][ ( qP + 1 ) % 6 ] ) « ( ( qP + 1 ) / 6 ) (8-959)

[0099] – Otherwise ( dep_quant_enabled_flag is equal to 0 ), the following applies:

[0100] ls[ x ][ y ] = ( m[ x ][ y ] * levelScale[ rectNonTsFlag ][ qP % 6 ] ) « ( qP / 6 ) (8-960)

[0101] The scaled transform coefficients are derived as follows, and the results are then sent to the inverse quantization step.

[0102] – The dnc[ x ][ y ] values are derived as follows:

[0103] dnc[ x ][ y ] = ( dz[ x ][ y ] * ls[ x ][ y ] + bdOffset ) » bdShift

[0104] (8-963)

[0105] - The scaled transform coefficients d[x][y] are derived as follows:

[0106] d[x][y] = Clip3(CoeffMin, CoeffMax, dnc[x][y]) (8-964)

[0107] A description of signaling and defining scaling matrices is next described. Video encoder 200 and video decoder 300 can be configured to process scaling matrices. A scaling matrix is a set of coefficients used to scale transform coefficients. Two uses of scaling matrices are rate control and perceptual quality control. Rate control of a video is often performed by adjusting the QP value of a block. However, QP differences result in uniform scaling factors applied to the entire block. Scaling matrices can be used for relative control between various coefficients within a transform block. For example, a scaling matrix can be defined such that low frequency coefficients are quantized less than high frequency coefficients, which can be beneficial for content with less high frequency content. For perceptual quality control, scaling matrices can also be used to control the relative accuracy of coefficients within a transform block such that the perceptual quality of a video is maintained at a lower bitrate. Human visual system (HVS) based quantization using scaling matrices can provide better quality video for certain types of content.

[0108] The scaling matrix is signaled using a scaling list signaled in an adaptation parameter set (APS). The scaling list can be enabled or disabled in the SPS. If the SPS indicates that the scaling list is enabled, additional signaling in the slice header can be used to toggle the scaling matrix on and off.

[0109] The scaling matrix is defined for each transform block size and for the prediction type of the block. The matrix is derived from the scaling list. The syntax of the scaling list signaled in the PPS / SPS is as follows:

[0110]

[0111]

[0112] The semantics of the scaling matrix are provided in Section 7.4.3.21 of JVET-Q2001 (e.g., VVC Draft 8), and reproduced here for reference.

[0113] The scaling list data semantics are described as follows.

[0114] scaling_matrix_for_lfnst_disabled_flag equal to 1 specifies that the scaling matrix is not applied to blocks coded with LFNST. scaling_matrix_for_lfnst_disabled_flag equal to 0 specifies that the scaling matrix can be applied to blocks coded with LFNST.

[0115] scaling_list_chroma_present_flag equal to 1 specifies that chroma scaling lists are present in scaling_list_data(). scaling_list_chroma_present_flag equal to 0 specifies that chroma scaling lists are not present in scaling_list_data(). The requirement for bitstream conformance is that scaling_list_chroma_present_flag (when present) shall be equal to 0 when ChromaArrayType is equal to 0 and shall be equal to 1 when ChromaArrayType is not equal to 0.

[0116] scaling_list_copy_mode_flag[ id ] equal to 1 specifies that the value of the scaling list is the same as the value of the reference scaling list. The reference scaling list is specified by scaling_list_pred_id_delta[ id ]. scaling_list_copy_mode_flag[ id ] equal to 0 specifies that scaling_list_pred_mode_flag is present.

[0117] scaling_list_pred_mode_flag[ id ] equal to 1 specifies that the value of the scaling list can be predicted from the reference scaling list. The reference scaling list is specified by scaling_list_pred_id_delta[ id ]. scaling_list_pred_mode_flag[ id ] equal to 0 specifies that the value of the scaling list can be signaled explicitly. When not present, the value of scaling_list_pred_mode_flag[ id ] is inferred to be equal to 0.

[0118] scaling_list_pred_id_delta[ id ] specifies the reference scaling list used to derive the predicted scaling matrix ScalingMatrixPred[ id ]. When not present, the value of scaling_list_pred_id_delta[ id ] is inferred to be equal to 0. The value of scaling_list_pred_id_delta[ id ] shall be in the range of 0 to maxIdDelta, where maxIdDelta is derived as follows depending on id:

[0119] maxIdDelta = ( id < 2 )? id : ( ( id < 8 )? ( id - 2 ) : ( id - 8 ) ) (106)

[0120] The variables refId and matrixSize are derived as follows:

[0121] refId = id - scaling_list_pred_id_delta[ id ] (107)

[0122] matrixSize = ( id < 2 )? 2 : ( ( id < 8 )? 4 : 8 ) (108)

[0123] The ( matrixSize ) x ( matrixSize ) array ScalingMatrixPred[ x ][ y ], with x = 0..matrixSize - 1, y = 0..matrixSize - 1, and the variable ScalingMatrixDCPred can be derived as follows:

[0124] - When both scaling_list_copy_mode_flag[ id ] and scaling_list_pred_mode_flag[ id ] are equal to 0, all elements of ScalingMatrixPred are set equal to 8, and the value of ScalingMatrixDCPred is set equal to 8.

[0125] - Otherwise, when scaling_list_pred_id_delta[ id ] is equal to 0, all elements of ScalingMatrixPred are set equal to 16, and ScalingMatrixDCPred is set equal to 16.

[0126] - Otherwise (scaling_list_copy_mode_flag[ id ] or scaling_list_pred_mode_flag[ id ] is equal to 1 and scaling_list_pred_id_delta[ id ] is greater than 0), ScalingMatrixPred is set equal to ScalingMatrixRec[ refId ] and the following applies for ScalingMatrixDCPred:

[0127] - If refId is greater than 13, ScalingMatrixDCPred is set equal to ScalingMatrixDCRec[ refId - 14 ].

[0128] - Otherwise (refId is less than or equal to 13), ScalingMatrixDCPred is set equal to ScalingMatrixPred[ 0 ][ 0 ].

[0129] scaling_list_dc_coef[ id - 14 ] is used to derive the value of the variable ScalingMatrixDC[ id - 14 ] when id is greater than 13 as follows:

[0130] ScalingMatrixDCRec[ id - 14 ] = ( ScalingMatrixDCPred + scaling_list_dc_coef[ id - 14 ] ) & 255 (109)

[0131] When not present, the value of scaling_list_dc_coef[ id - 14 ] is inferred to be equal to 0. The value of scaling_list_dc_coef[ id - 14 ] shall be in the range of -128 to 127, inclusive. The value of ScalingMatrixDCRec[ id - 14 ] shall be greater than 0.

[0132] scaling_list_delta_coef[ id ][ i ] specifies the difference between the current matrix coefficient ScalingList[ id ][ i ] and the previous matrix coefficient ScalingList[ id ][ i - 1 ] when scaling_list_copy_mode_flag[ id ] is equal to 0. The value of scaling_list_delta_coef[ id ][ i ] shall be in the range of -128 to 127, inclusive. When scaling_list_copy_mode_flag[ id ] is equal to 1, all elements of ScalingList[ id ] are set to be equal to 0.

[0133] The ( matrixSize ) x ( matrixSize ) array ScalingMatrixRec[ id ] is derived as follows:

[0134] ScalingMatrixRec[ id ][ x ][ y ] = ( ScalingMatrixPred[ x ][ y ] + ScalingList[ id ][ k ] ) & 255 ( 110 )

[0135] where k = 0.. ( matrixSize * matrixSize - 1 ),

[0136] x = DiagScanOrder[ Log2( matrixSize ) ][ Log2( matrixSize ) ][ k ][ 0 ], and

[0137] y = DiagScanOrder[ Log2( matrixSize ) ][ Log2( matrixSize ) ][ k ][ 1 ]

[0138] The value of ScalingMatrixRec[ id ][ x ][ y ] shall be greater than 0.

[0139] The scaling matrix represented by the variable ScalingFactor[ wId ][ hId ][ matrixId ][ x ][ y ] is derived from the scaling list data. wId and hId refer to the sizeID variable representing the transform block size. sizeId and matrixId are given by the following table:

[0140] Table 7-5 - Association of scaling list ID to prediction mode and component

[0141]

[0142] Some notable features of the scaling matrix and its derivation are provided as follows:

[0143] • The scaling matrices are specified separately for each of the three color components and two prediction types: Inter prediction and IBC are considered as one type together and Intra prediction is considered as another type.

[0144] • The scaling list (and thus the derived matrix) is specified for square transform blocks. For rectangular TBs, the scaling matrix is derived from the scaling matrix of the corresponding square TB.

[0145] • For 16x16, 32x32 and 64x64 scaling matrices, only 64 coefficients are specified as an 8x8 grid and the matrix coefficients for the larger block are obtained by upsampling the coefficients to the desired size. In this case, the DC coefficient is also signaled.

[0146] • The scaling lists are categorized into three categories based on the size of the signaled scaling list:

[0147] o Category 1: Scaling lists with IDs 0 and 1; these lists have a size of 4 (2x2) coefficients

[0148] o Category 2: Scaling lists with IDs 2 to 7 (including 2 and 7); these lists have a size of 16 (4x4) coefficients

[0149] o Category 3: Scaling lists with IDs 8 to 27 (including 8 and 7); these lists have a size of 64 (8x8) coefficients

[0150] A total of 28 scaling lists can be specified in the scaling list APS. Within each of the 3 categories, a scaling list can be predicted or copied from other scaling lists with smaller IDs. For example, a scaling list with ID 5 (Category 2) can be predicted from any of the scaling lists with IDs 2 to 4 (including 2 and 4) (also Category 2), but not from Category 1 and 3 or from scaling lists with IDs 6 and 7. The prediction can be a copy (the values of the reference scaling list are used without change) or a delta prediction (a delta value is signaled to the values of the reference scaling matrix). When the DC coefficient is also signaled for a particular sizeID, the DC coefficient can also be copied or predicted from the DC coefficient of the reference scaling list or explicitly signaled.

[0151] Video encoder 200 and video decoder 300 can be configured to perform chroma format and separate color plane coding. A common video format includes three components - e.g., one luma component and two chroma components (Cb and Cr). However, some content can be coded as monochrome - i.e., only one component. This is also referred to as indicating a 4:0:0 chroma format with no chroma components. In some examples, when there are three components and no sub-sampling of chroma components, the chroma format is referred to as 4:4:4. Although 4:4:4 content is typically coded by considering the luma and chroma components together, some applications code the three components of 4:4:4 content independently - i.e., treat each component in the 4:4:4 format as monochrome. This separate coding is controlled by the syntax element separate colour plane flag. In this case, there is no correlation between the decoding of any of the three components.

[0152] The variable ChromaArrayType is referred to as follows:

[0153] The value of the variable ChromaArrayType is assigned as follows, depending on the value of separate colour plane flag:

[0154] - If separate colour plane flag is equal to 0, ChromaArrayType is set equal to chroma format idc.

[0155] - Otherwise (separate colour plane flag is equal to 1), ChromaArrayType is set equal to 0.

[0156]

[0157]

[0158] Note - when separate colour plane flag is equal to 1 and chroma format idc is equal to 3, the variable ChromaArrayType is derived to be equal to 0. In the decoding process, the value of this variable is evaluated, resulting in the same operation as for monochrome pictures (when chroma format idc is equal to 0).

[0159] The prior art can suffer from some potential problems. When ChromaArrayType is 0 (i.e., monochrome or 444 separate color plane coding), the scaling lists corresponding to the chroma components are not signaled. In this case, scaling_list_chroma_present_flag is set equal to 0. When ChromaArrayType = 0, fewer scaling lists are effectively signaled because only scaling lists with IDs 2, 5, 8, 11, 14, 17, 20, 23, 26, and 27 are signaled. These scaling lists can be specified to be copied / predicted based on the syntax elements scaling_list_copy_mode_flag, scaling_list_pred_mode_flag, and scaling_list_pred_id_delta[]. However, the allowed values of scaling_list_pred_id_delta[] can result in a reference scaling list ID that is not valid / signaled. For example, for a scaling list with ID 8, a predID delta value of 1 results in a reference scaling list ID of 7 - this corresponds to a missing chroma scaling list. This incorrect reference can potentially cause a decoder to crash because there is no behavior defined in the specification for this scenario.

[0160] The present disclosure describes techniques for improving the signaling of scaling lists in video coding, and potentially addresses some of the problems introduced above. It should be appreciated that one or more of these techniques can be used independently, or in combination with other techniques.

[0161] The following description provides an example of how to implement one or more of the techniques described in the present disclosure.

[0162] In one example, the value range of scaling_list_pred_id_delta[] and the derivation of the reference scaling list ID are modified so that the reference scaling list always points to a valid scaling list.

[0163] scaling_list_pred_id_delta[ id ] specifies the reference scaling list used to derive the predicted scaling matrix ScalingMatrixPred[ id ]. When not present, the value of scaling_list_pred_id_delta[ id ] is inferred to be equal to 0. The value of scaling_list_pred_id_delta[ id ] shall be in the range of 0 to maxIdDelta, where maxIdDelta is derived depending on id as follows:

[0164] if (scaling_list_chroma_present_flag)

[0165] maxIdDelta = (id < 2)? id : ((id < 8)? (id - 2) : (id - 8)) (106)

[0166] else

[0167] maxIdDelta = (((id < 8)? (id - 2) : (id - 8)) + 2) / 3

[0168] (or equivalently in the else branch, maxIdDelta = ((id < 8)? id : (id - 6)) / 3)

[0169] (or equivalently in the else branch, maxIdDelta = ((id < 8)? id : (id - 6)) / 3)

[0170] The variables refId and matrixSize can be derived as follows:

[0171] if (scaling_list_chroma_present_flag)

[0172] refId = id - scaling_list_pred_id_delta[id] (107)

[0173] else

[0174] refId = (id == 27 && scaling_list_pred_id_delta > 0)? 2 : 0 +

[0175] id - scaling_list_pred_id_delta[id] * 3

[0176] matrixSize = (id < 2)? 2 : ((id < 8)? 4 : 8) (108)

[0177] In some examples, the value of refId can be derived as follows:

[0178] if (scaling_list_chroma_present_flag)

[0179] refId = id - scaling_list_pred_id_delta[id] (107)

[0180] else

[0181] refld = Clip3(2, 27, (id == 27? 2 : 0) + id - scaling_list_pred_id_delta[id] * 3)

[0182] matrixSize = (id < 2)? 2 : ((id < 8)? 4 : 8) (108)

[0183] In some examples, the value of refld can be derived as follows:

[0184] if (scaling_list_chroma_present_flag)

[0185] refld = id - scaling_list_pred_id_delta[id] (107)

[0186] else

[0187] refld = scaling_list_pred_id_delta[id]? ((id / 3) * 3 - scaling_list_pred_id_delta[id] + 2 : id

[0188] matrixSize = (id < 2)? 2 : ((id < 8)? 4 : 8) (108)

[0189] In another example, the derivation of refld and maxldDelta can be updated as follows:

[0190] scaling_list_pred_id_delta[id] specifies the reference scaling list used to derive the predicted scaling matrix ScalingMatrixPred[id]. When not present, the value of scaling_list_pred_id_delta[id] is inferred to be equal to 0. The value of scaling_list_pred_id_delta[id] shall be in the range of 0 to maxldDelta, where maxldDelta is derived depending on id as follows:

[0191] maxldDelta = (id < 2)? id : ((id < 8)? (id - 2) : (id - 8)) (105)

[0192] if (!scaling_list_chroma_present_flag)

[0193] maxIdDelta = (maxIdDelta + 2) / 3

[0194] The variables refld and matrixSize are derived as follows:

[0195] if (scaling_list_chroma_present_flag)

[0196] refld = id - scaling_list_pred_id_delta[id] (106)

[0197] else

[0198] refld = id - scaling_list_pred_id_delta[id] * 3 + (id == 27? 2 : 0)

[0199] matrixSize = (id < 2)? 2 : ((id < 8)? 4 : 8) (107)

[0200] In some examples, two or more chroma matrices can be added corresponding to max(nTbW, nTbH) = 64 in Table 7.5. In this case, the matrices with indices 27, 28, 30 and 31 can be assigned to chroma, and the list ID 29 can be assigned to luma. In this case, the derivation of refld and maxIdDelta can be further simplified as follows:

[0201] scaling_list_pred_id_delta[id] specifies the reference scaling list used to derive the predicted scaling matrix ScalingMatrixPred[id]. When not present, the value of scaling_list_pred_id_delta[id] is inferred to be equal to 0. The value of scaling_list_pred_id_delta[id] shall be in the range of 0 to maxIdDelta, where maxIdDelta is derived depending on id as follows:

[0202] maxIdDelta = (id < 2)? id : ((id < 8)? (id - 2) : (id - 8)) (105)

[0203] if (!scaling_list_chroma_present_flag)

[0204] maxIdDelta = maxIdDelta / 3

[0205] The variables refld and matrixSize are derived as follows:

[0206] if (scaling_list_chroma_present_flag)

[0207] refld = id - scaling_list_pred_id_delta[ id ] (106)

[0208] else

[0209] refld = id - scaling_list_pred_id_delta[ id ] * 3

[0210] matrixSize = ( id < 2 )? 2 : ( ( id < 8 )? 4 : 8 ) (107)

[0211] In another example, the array lumaIndices can be set to { 2, 5, 8, 11, 14, 17, 20, 23, 26, 27}. The value of refld can be derived as follows:

[0212] if (scaling_list_chroma_present_flag)

[0213] refld = id - scaling_list_pred_id_delta[ id ] (107)

[0214] else

[0215] refld = lumaIndices[ id / 3 - scaling_list_pred_id_delta[ id ] ]

[0216] The above definition of lumaIndices is only an example, and other definitions of lumaIndices can also be specified.

[0217] In another example, the inferred scaling list for prediction is such that when the scaling list points to an invalid scaling list, a default behavior is specified for the scaling list.

[0218] The following steps can be added in the derivation of ScalingMatrixPred and ScalingMatrixDCPred:

[0219] - When scaling_list_chroma_present_flag is equal to 0 and refld % 3 is not equal to 2, all elements of ScalingMatrixPred are set equal to N, and the value of ScalingMatrixDCPred is set equal to N.

[0220] The value of N can be fixed, or set as a function of refld and Id, or as a function of scaling_list_pred_id_delta, or as a function of scaling_list_copy_flag and scaling_list_pred_flag, or a combination thereof. For example, N can be fixed equal to 4. In another example, when scaling_list_copy_mode_flag is equal to 1, N can be set equal to 8 * (scaling_list_pred_id_delta + 1), and when scaling_list_pred_mode_flag is equal to 1, the value of N can be set equal to 16 * (scaling_list_pred_id_delta + 1).

[0221] In another example, the range of scaling_list_pred_id_delta[ ] is not modified. Instead, when refld points to an unavailable matrix / chroma matrix, video encoder 200 and video decoder 300 can be configured to remap refld to the corresponding luma scaling matrix.

[0222] For example, video encoder 200 and video decoder 300 can be configured to derive or update the value of refld as follows:

[0223] refld = id - scaling_list_pred_id_delta[ id ] (107)

[0224] if(!scaling_list_chroma_present_flag )

[0225] refld = ( refld = = 27? 0 : 2 ) + ( refld / 3 ) * 3

[0226] In another example, video encoder 200 and video decoder 300 can be configured to equivalently derive or update the value of refld as follows:

[0227] refld = id - scaling_list_pred_id_delta[ id ] (107)

[0228] if (!scaling_list_chroma_present_flag)

[0229] refld = Clip3(2, 27, (refld / 3) * 3 + 2) / / lower bound clipping operation can also be set to 0

[0230] In another example, the video encoder 200 and the video decoder 300 can be configured to derive or update the value of refld as follows:

[0231] refld = id-scaling_list_pred_id_delta[id] (107)

[0232] if (!scaling_list_chroma_present_flag)

[0233] refld = (refld == 27? 0 : -1) + ((refld + 1) / 3) * 3

[0234] In another example of the disclosure, when the chroma format is 444 and the content is not coded with separate color planes, the chroma scaling lists corresponding to IDs 0 and 1 are not signaled. The syntax table can be modified as follows:

[0235]

[0236] scaling_list_chroma_2x2_absent_flag equal to 1 specifies that the scaling lists corresponding to IDs 0 and 1 are not signaled in the scaling list APS. scaling_list_chroma_2x2_absent_flag equal to 0 specifies that the scaling lists corresponding to IDs 0 and 1 can be signaled in the scaling list APS.

[0237] When scaling_list_chroma_2x2_absent_flag is equal to 1, the semantics of the syntax elements can be modified so that default lists can be derived for scaling list IDs 0 and 1.

[0238] In one example, chroma_format_idc can be signaled instead of scaling_list_chroma_2x2_absent_flag, and the condition for not signaling the scaling lists with IDs 0 and 1 is when chroma_format_idc corresponds to 444 coding.

[0239] In one example, a constraint can be added that the syntax element scaling_list_chroma_2x2_absent_flag is equal to 1 when chroma format idc corresponds to 444 coding, and is equal to 0 otherwise.

[0240] According to the above techniques, video decoder 300 can be configured to determine a set of scaling lists for video data, where each scaling list in the set of scaling lists is used to determine an associated scaling matrix in a set of scaling matrices. Each scaling list and each associated scaling matrix determined can have an identification (ID) number, such as 0-27 shown in Table 7-5 above. Video decoder 300 can be configured to determine, based on a value of scaling_list_pred_mode_flag, for example, that a new scaling list of the set of scaling lists is to be predicted from a reference scaling list, and determine a new scaling matrix based on the new scaling list. Video decoder 300 can be configured to receive a syntax element, such as scaling_list_pred_id_delta[id], that identifies an ID number corresponding to a scaling list in the set of scaling lists to be used as the reference scaling list. Video decoder 300 can determine that the set of scaling lists does not include a scaling list having the ID number, and determine the new scaling matrix based on a set of default values, such as 16 or more generally N, in response to determining that the set of scaling lists does not include a scaling list having the ID number.

[0241] To determine the new scaling matrix based on the set of default values, video decoder 300 can be configured to determine a predicted scaling matrix (e.g., ScalingMatrixDCPred above) based on the set of default values, receive a delta value (e.g., scaling_list_dc_coef above) that represents a difference between the predicted scaling matrix and the new scaling matrix, and determine the new scaling matrix based on the predicted scaling matrix and the delta value using, for example, Equation 109 above.

[0242] To determine that the set of scaling lists does not include a scaling list having the ID number, video decoder 300 can be configured to determine that the video data is coded without chroma components, and determine that the ID number corresponds to a scaling list for a chroma component. To determine that the video data is coded without chroma components, video decoder 300 can receive a syntax element indicating that no scaling list is included for chroma components. To determine that the set of scaling lists does not include a scaling list having the ID number, video decoder 300 can determine that the ID number divided by 3 has a remainder of 0 or 1.

[0243] Figure 3 FIG. 1 is a block diagram illustrating an example video encoder 200 that can perform the techniques of this disclosure. Figure 3are provided for purposes of explanation and should not be considered to be limitations thereof. In the interest of clarity, not all features of the techniques are described. For purposes of explanation, the present disclosure describes video encoder 200 in accordance with the techniques of VVC (ITU-T H.266, in development) and HEVC (ITU-T H.265). However, the techniques of the present disclosure can be performed by video encoding devices configured to other video coding standards.

[0244] In Figure 3 In the example of FIG. 2, video encoder 200 includes video data memory 230, mode select unit 202, residual generation unit 204, transform processing unit 206, quantization unit 208, inverse quantization unit 210, inverse transform processing unit 212, reconstruction unit 214, filter unit 216, decoded picture buffer (DPB) 218, and entropy encoding unit 220. Any or all of video data memory 230, mode select unit 202, residual generation unit 204, transform processing unit 206, quantization unit 208, inverse quantization unit 210, inverse transform processing unit 212, reconstruction unit 214, filter unit 216, DPB 218, and entropy encoding unit 220 can be implemented in one or more processors or in processing circuitry. For instance, the units of video encoder 200 can be implemented as one or more circuits or logic elements as part of hardware circuitry or as part of a processor of a FPGA, ASIC. Also, video encoder 200 can include additional or alternative processors or processing circuitry to perform these and other functions.

[0245] Video data memory 230 can store video data to be encoded by the components of video encoder 200. Video encoder 200 can receive the video data stored in video data memory 230 from, for example, video source 104 Figure 1 DPB 218 can act as a reference picture memory that stores reference video data for use in prediction of subsequent video data by video encoder 200. Video data memory 230 and DPB 218 can be formed by any of a variety of memory devices, such as dynamic random access memory (DRAM) (including synchronous DRAM (SDRAM)), magnetoresistive RAM (MRAM), resistive RAM (RRAM), or other types of memory devices. Video data memory 230 and DPB 218 can be provided by the same memory device or separate memory devices. In various examples, video data memory 230 can be on-chip with other components of video encoder 200, as illustrated, or off-chip relative to those components.

[0246] In this disclosure, references to the video data memory 230 should not be construed as limited to memory internal to the video encoder 200 (unless specifically described as such), or to memory external to the video encoder 200 (unless specifically described as such). Specifically, references to the video data memory 230 should be understood as references to memory that stores video data received by the video encoder 200 for encoding (e.g., video data of a current block to be encoded). Figure 1 The memory 106 may also provide temporary storage for outputs from the various units of the video encoder 200 .

[0247] Shown Figure 3 The various units of the video encoder 200 are described to help understand the operations performed by the video encoder 200. These units can be implemented as fixed-function circuits, programmable circuits, or a combination thereof. Fixed-function circuits refer to circuits that provide a specific function and have preset operations that can be performed. Programmable circuits refer to circuits that can be programmed to perform various tasks and provide flexible functions in the operations that can be performed. For example, a programmable circuit can execute software or firmware that causes the programmable circuit to operate in a manner defined by the instructions of the software or firmware. Fixed-function circuits can execute software instructions (for example, to receive parameters or output parameters), but the type of operation performed by the fixed-function circuit is generally immutable. In some examples, one or more units can be different circuit blocks (fixed-function or programmable), and in some examples, one or more units can be integrated circuits.

[0248] The video encoder 200 may include a programmable core, an arithmetic logic unit (ALU), an elementary function unit (EFU), a digital circuit, and / or an analog circuit formed of a programmable circuit. In an example where the operation of the video encoder 200 is performed using software executed by the programmable circuit, the memory 106 ( Figure 1 ) may store instructions (eg, object code) for software that the video encoder 200 receives and executes, or another memory (not shown) within the video encoder 200 may store such instructions.

[0249] The video data memory 230 is configured to store received video data. The video encoder 200 can retrieve pictures of 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 can be the original video data to be encoded.

[0250] 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 can include additional functional units to perform video prediction according to other prediction modes. As examples, the mode selection unit 202 can include a palette unit, an intra-block copy unit (which can be part of the motion estimation unit 222 and / or the motion compensation unit 224), an affine unit, a linear model (LM) unit, etc.

[0251] The mode selection unit 202 generally coordinates multiple encoding passes to test combinations of encoding parameters and resulting rate-distortion values for those combinations. The encoding parameters can include partitioning of CTUs into CUs, prediction modes for the CUs, transform types for residual data of the CUs, quantization parameters for residual data of the CUs, etc. The mode selection unit 202 can ultimately select the combination of encoding parameters that has a better rate-distortion value than other tested combinations.

[0252] The video encoder 200 can partition a picture retrieved from the video data memory 230 into a series of CTUs, and encapsulate one or more CTUs within a slice. The mode selection unit 202 can partition the CTUs of the picture according to a tree structure such as the QTBT structure described above or the quad-tree structure of HEVC. As described above, the video encoder 200 can form one or more CUs from partitioning a CTU according to the tree structure. Such CUs can also be generally referred to as “video blocks” or “blocks.”

[0253] 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., a current CU, or an overlapping portion of a PU and a TU in HEVC). For inter-prediction of a current block, the motion estimation unit 222 can perform a 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). Specifically, the motion estimation unit 222 can compute a value that represents how similar a potential reference block is to the current block (e.g., according to a sum of absolute difference (SAD), a sum of squared difference (SSD), a mean absolute difference (MAD), a mean squared difference (MSD), etc.). The motion estimation unit 222 can generally perform these computations using point-wise differences between the current block and the reference block being considered. The motion estimation unit 222 can identify the reference block with the lowest value resulting from these computations, thereby indicating the reference block that most closely matches the current block.

[0254] Motion estimation unit 222 can form one or more motion vectors (MVs) that define a position of a reference block in a reference picture relative to a position of a current block in a current picture. Motion estimation unit 222 can then provide the motion vector(s) to motion compensation unit 224. For example, for uni-directional inter-prediction, motion estimation unit 222 can provide a single motion vector, while for bi-directional inter-prediction, motion estimation unit 222 can provide two motion vectors. Motion compensation unit 224 can then generate a prediction block using the motion vector(s). For example, motion compensation unit 224 can use the motion vector(s) to retrieve data for the reference block. As another example, if the motion vector(s) have fractional-sample precision, motion compensation unit 224 can interpolate values for the prediction block according to one or more interpolation filters. Further, for bi-directional inter-prediction, motion compensation unit 224 can retrieve data for two reference blocks identified by the respective motion vectors and combine the retrieved data (e.g., by averaging or weighted-averaging sample-by-sample).

[0255] As another example, for intra-prediction or intra-prediction coding, intra-prediction unit 226 can generate a prediction block from samples neighboring the current block. For example, for directional modes, intra-prediction unit 226 can mathematically combine values of the neighboring samples and fill these computed values in a defined direction on the current block to produce the prediction block. As another example, for a DC mode, intra-prediction unit 226 can compute an average of the neighboring samples of the current block and generate the prediction block to include this resulting average for each sample of the prediction block.

[0256] Mode selection unit 202 provides the prediction block to residual generation unit 204. Residual generation unit 204 receives the original, unencoded version of the current block from video data memory 230 and the prediction block from mode selection unit 202. Residual generation unit 204 computes the sample-by-sample difference between the current block and the prediction block. The resulting sample-by-sample difference defines a residual block for the current block. In some examples, residual generation unit 204 can also determine the difference between sample values in the residual block to generate the residual block using residual differential pulse code modulation (RDPCM). In some examples, residual generation unit 204 can form using one or more subtractor circuits that perform binary subtraction.

[0257] In examples where the mode selection unit 202 partitions the CU into PUs, each PU can be associated with a luma prediction unit and corresponding chroma prediction units. The video encoder 200 and the video decoder 300 can support PUs having various sizes. As described above, the size of the CU can refer to the size of the luma coding block of the CU, and the size of the PU can refer to the size of the luma prediction unit of the PU. Assuming that a particular CU has a size of 2Nx2N, the video encoder 200 can support PU sizes of 2Nx2N or NxN for intra prediction and 2Nx2N, 2NxN, Nx2N, NxN, or similar symmetric PU sizes for inter prediction. The video encoder 200 and the video decoder 300 can also support asymmetric partitioning for PU sizes of 2NxnU, 2NxnD, nLx2N, and nRx2N for inter prediction.

[0258] In examples where the mode selection unit 202 does not further partition the CU into PUs, each CU can be associated with a luma coding block and corresponding chroma coding blocks. As described above, the size of the CU can refer to the size of the luma coding block of the CU. The video encoder 200 and the video decoder 300 can support CU sizes of 2Nx2N, 2NxN, or Nx2N.

[0259] For other video coding techniques, such as intra block copy mode coding, affine mode coding, and linear model (LM) mode coding, as a few examples, the mode selection unit 202 generates, via a respective unit associated with the coding technique, a prediction block for the current block being coded. In some examples, such as palette mode coding, the mode selection unit 202 can not generate a prediction block, but rather generate syntax elements that indicate a way to reconstruct the block based on a selected palette. In such modes, the mode selection unit 202 can provide the syntax elements to the entropy encoding unit 220 for encoding.

[0260] As described above, the residual generation unit 204 receives the video data of the current block and the corresponding prediction 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 the point-wise difference between the prediction block and the current block.

[0261] Transform processing unit 206 applies one or more transforms to the residual block to produce a block of raw transform coefficients (referred to herein as a "transform coefficient block"). Transform processing unit 206 can apply various transforms to the residual block to form the transform coefficient block. For example, transform processing unit 206 can apply a discrete cosine transform (DCT), a directional transform, a Karhunen-Loeve transform (KLT), or a conceptually similar transform. In some examples, transform processing unit 206 can perform multiple transforms, such as a primary transform and a secondary transform (such as a rotation transform), on the residual block. In some examples, transform processing unit 206 does not apply a transform to the residual block.

[0262] Quantization unit 208 can quantize the transform coefficients in a transform coefficient block, to produce a quantized transform coefficient block. Quantization unit 208 can quantize transform coefficients of a transform coefficient block according to a QP value associated with the current block and using a scaling matrix as described above. Video encoder 200 (e.g., via mode select unit 202) can adjust the degree of quantization applied to transform coefficient blocks associated with the current block by adjusting the QP value associated with the CU. Quantization can introduce loss of information, and thus, quantized transform coefficients can have lower precision than the original transform coefficients produced by transform processing unit 206.

[0263] Inverse quantization unit 210 and inverse transform processing unit 212 can apply inverse quantization and inverse transforms, respectively, to a quantized transform coefficient block to reconstruct a residual block from the transform coefficient block. Reconstruction unit 214 can generate a reconstructed block corresponding to the current block (albeit with some degree of distortion) based on the reconstructed residual block and the prediction block generated by mode select unit 202. For example, reconstruction unit 214 can add samples of the reconstructed residual block to corresponding samples from the prediction block generated by mode select unit 202 to produce the reconstructed block.

[0264] Filter unit 216 can perform one or more filtering operations on the reconstructed block. For example, filter unit 216 can perform a deblocking operation to reduce blocking artifacts along the edges of the CU. In some examples, the operations of filter unit 216 can be skipped.

[0265] Video encoder 200 stores reconstructed blocks in DPB 218. For instance, in examples where no operation of filter unit 216 is needed, reconstructed unit 214 can store reconstructed blocks to DPB 218. In examples where operation of filter unit 216 is needed, filter unit 216 can store filtered reconstructed blocks to DPB 218. Motion estimation unit 222 and motion compensation unit 224 can retrieve reference pictures formed from reconstructed (and possibly filtered) blocks from DPB 218 to inter-predict blocks of subsequent encoded pictures. In addition, intra-prediction unit 226 can use reconstructed blocks in DPB 218 of the current picture to intra-predict other blocks in the current picture.

[0266] In general, entropy encoding unit 220 can entropy encode syntax elements received from other functional components of video encoder 200. For example, entropy encoding unit 220 can entropy encode quantized transform coefficient blocks from quantization unit 208. As another example, entropy encoding unit 220 can entropy encode prediction syntax elements (e.g., motion information for inter-prediction or intra-mode information for intra-prediction) from mode select unit 202. Entropy encoding unit 220 can perform one or more entropy encoding operations on syntax elements, as another example of video data, to generate entropy encoded data. For example, entropy encoding unit 220 can 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 partitioning entropy (PIPE) coding operation, an exponential-Golomb coding operation, or another type of entropy coding operation on the data. In some examples, entropy encoding unit 220 can operate in a bypass mode that does not entropy encode the syntax elements.

[0267] Video encoder 200 can output a bitstream that includes the entropy encoded syntax elements needed to reconstruct blocks of a slice or picture. In particular, entropy encoding unit 220 can output the bitstream.

[0268] The operations described above are described with respect to blocks. Such description should be understood to be operations on luma coding blocks and / or chroma coding blocks. As described above, in some examples, luma coding blocks and chroma coding blocks are luma components and chroma components of CUs. In some examples, luma coding blocks and chroma coding blocks are luma components and chroma components of PUs.

[0269] In some examples, for chroma coding blocks, operations performed with respect to luma coding blocks need not be repeated. As one example, for identifying a motion vector (MV) and a reference picture for a chroma block, operations used to identify an MV and a reference picture for a luma coding block need not be repeated. In particular, the MV for the luma coding block can be scaled to determine the MV for the chroma block, and the reference picture can be the same. As another example, for luma and chroma coding blocks, the intra prediction process can be the same.

[0270] Video encoder 200 represents an 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 circuitry and configured to perform techniques for signaling scaling lists as described herein.

[0271] Figure 4 is a block diagram illustrating an example video decoder 300 that can perform the techniques of this disclosure. Figure 4 is provided for explanatory purposes and does not limit the techniques broadly set forth in this disclosure. For explanatory purposes, this disclosure describes a video decoder 300 in accordance with the techniques of VVC (ITU-T H.266, in development) and HEVC (ITU-T H.265). However, the techniques of this disclosure can be performed by video coding devices configured to other video coding standards.

[0272] In Figure 4 In the example of FIG. 3, video decoder 300 includes coded picture buffer (CPB) memory 320, entropy decoding unit 302, prediction processing unit 304, inverse quantization unit 306, inverse transform processing unit 308, reconstruction unit 310, filter unit 312, and decoded picture buffer (DPB) 314. Any or all of CPB memory 320, entropy decoding unit 302, prediction processing unit 304, inverse quantization unit 306, inverse transform processing unit 308, reconstruction unit 310, filter unit 312, and DPB 314 can be implemented in one or more processors or in processing circuitry. For instance, the units of video decoder 300 can be implemented as one or more circuits or logic elements as part of hardware circuitry or as part of a processor of an FPGA, ASIC. Moreover, video decoder 300 can include additional or alternative processors or processing circuitry to perform these and other functions.

[0273] The prediction processing unit 304 includes a motion compensation unit 316 and an intra prediction unit 318. The prediction processing unit 304 may include additional units to perform prediction according to other prediction modes. As an example, the prediction processing unit 304 may include a palette unit, an intra block copy unit (which may form part of the motion compensation unit 316), an affine unit, a linear model (LM) unit, etc. In other examples, the video decoder 300 may include more, fewer, or different functional components.

[0274] 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, for example, received from the computer readable medium 110 ( Figure 1 ). The CPB memory 320 may include a CPB that stores coded video data (e.g., syntax elements) from a coded video bitstream. In addition, the CPB memory 320 may store video data other than syntax elements of coded and decoded pictures, such as temporary data representing outputs from various units of the video decoder 300. The DPB 314 typically stores decoded pictures, which the video decoder 300 may output and / or use as reference video data when decoding subsequent data or pictures of the coded 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 by separate memory devices. In various examples, the CPB memory 320 may be located on-chip with other components of the video decoder 300, or off-chip relative to those components.

[0275] Additionally or alternatively, in some examples, video decoder 300 may retrieve the video from memory 120 ( Figure 1 ) retrieves the encoded and decoded video data. That is, memory 120 may use CPB memory 320 to store data as discussed above. Similarly, when some or all of the functions of video decoder 300 are implemented in software executed by the processing circuitry of video decoder 300, memory 120 may store instructions to be executed by video decoder 300.

[0276] Shown Figure 4 The various units shown in FIG. 1 and FIG. 2 are provided to assist in understanding the operations performed by the video decoder 300. These units may be implemented as fixed function circuits, programmable circuits, or a combination thereof. Figure 3Fixed function circuitry refers to circuitry that provides specific functionality and has operations that can be performed preprogrammed. Programmable circuitry refers to circuitry that can be programmed to perform various tasks and provide flexible functionality among the operations that can be performed. For example, programmable circuitry can execute software or firmware that causes the programmable circuitry to operate in the manner defined by instructions of the software or firmware. Fixed function circuitry can execute software instructions (e.g., to receive parameters or output parameters), but the types of operations that the fixed function circuitry performs are generally immutable. In some examples, one or more units can be different circuit blocks (fixed function or programmable), and in some examples, one or more units can be an integrated circuit.

[0277] Video decoder 300 can include programmable cores, ALUs, EFUs, digital circuits, and / or analog circuits formed from programmable circuitry. In examples where the operations of video decoder 300 are performed by software executing on the programmable circuitry, on-chip or off-chip memory can store instructions (e.g., object code) of the software that video decoder 300 receives and executes.

[0278] Entropy decoding unit 302 can receive encoded video data from a CPB and entropy decode the video data to reproduce syntax elements. Prediction processing unit 304, inverse quantization unit 306, inverse transform processing unit 308, reconstruction unit 310, and filter unit 312 can generate decoded video data based on the syntax elements extracted from the bitstream.

[0279] In general, video decoder 300 reconstructs pictures on a block-by-block basis. Video decoder 300 can perform reconstruction operations separately for each block, where the block that is currently being reconstructed (i.e., decoded) can be referred to as the “current block.”

[0280] Entropy decoding unit 302 can entropy decode syntax elements defining quantized transform coefficients of a quantized transform coefficient block, as well as transform information such as a QP and / or transform mode indication(s). Inverse quantization unit 306 can use the QP and a scaling matrix associated with the quantized transform coefficient block to determine a degree of quantization, and, likewise, a degree of inverse quantization for inverse quantization unit 306 to apply. Inverse quantization unit 306 may, for example, perform a bitwise left shift operation to inverse quantize the quantized transform coefficients. Inverse quantization unit 306 can thereby form a transform coefficient block comprising transform coefficients.

[0281] After inverse quantization unit 306 forms a transform coefficient block, inverse transform processing unit 308 can apply one or more inverse transforms to the transform coefficient block to generate a residual block associated with the current block. For example, inverse transform processing unit 308 can apply an inverse DCT, an inverse integer transform, an inverse Karhunen-Loeve transform (KLT), an inverse rotational transform, an inverse directional transform, or another inverse transform to the transform coefficient block.

[0282] Furthermore, prediction processing unit 304 generates a prediction block from the prediction information syntax elements entropy decoded by entropy decoding unit 302. For example, if the prediction information syntax elements indicate that the current block is inter-predicted, motion compensation unit 316 can generate the prediction block. In that case, the prediction information syntax elements can indicate a reference picture in DPB 314 from which to retrieve a reference block and a motion vector that identifies a position of the reference block in the reference picture relative to a position of the current block in the current picture. Motion compensation unit 316 can generally perform the inter-prediction process in a manner substantially similar to that described with respect to motion compensation unit 224 Figure 3 ) except that the reference blocks are retrieved from DPB 314 instead of picture buffer 234.

[0283] As another example, if the prediction information syntax elements indicate that the current block is intra-predicted, intra-prediction unit 318 can generate the prediction block according to an intra-prediction mode indicated by the prediction information syntax elements. Again, intra-prediction unit 318 can generally perform the intra-prediction process in a manner substantially similar to that described with respect to intra-prediction unit 226 Figure 3 ) except that the reference blocks are retrieved from DPB 314 instead of picture buffer 234.

[0284] Reconstruction unit 310 can use the prediction block and the residual block to reconstruct the current block. For example, reconstruction unit 310 can add the samples of the residual block to corresponding samples of the prediction block to reconstruct the current block.

[0285] Filtering unit 312 can perform one or more filtering operations on the reconstructed block. For example, filtering unit 312 can perform a deblocking operation to reduce blocking artifact pseudo-ghosts along edges of the reconstructed block. The operations of filtering unit 312 are not necessarily performed in all examples.

[0286] Video decoder 300 can store the reconstructed blocks in DPB 314. For instance, in examples where operations of filter unit 312 are not performed, reconstructed unit 310 can store the reconstructed blocks to DPB 314. In examples where operations of filter unit 312 are performed, filter unit 312 can store the filtered reconstructed blocks to DPB 314. As discussed above, DPB 314 can provide reference information, such as samples of current pictures for intra prediction and previously decoded pictures for subsequent motion compensation, to prediction processing unit 304. Moreover, video decoder 300 can output decoded pictures (e.g., decoded video) from DPB 314 for subsequent presentation on a display device, such as display device 118 of FIG. 1. Figure 1

[0287] In this way, video decoder 300 represents an example of a video decoding device including a memory configured to store video data and one or more processing units implemented in circuitry and configured to perform techniques for signaling scaling lists as described herein.

[0288] Figure 5 is a flowchart illustrating an example method for encoding a current block. The current block can include a current CU. Although described with respect to video encoder 200 Figure 1 and Figure 3 ), it should be understood that other devices can also be configured to perform a method similar to Figure 5 .

[0289] In this example, video encoder 200 initially predicts the current block (350). For instance, video encoder 200 can form a prediction block for the current block. Video encoder 200 can then calculate a residual block for the current block (352). To calculate the residual block, video encoder 200 can calculate a difference between the original, unencoded block and the prediction block for the current block. Video encoder 200 can then transform the residual block and quantize transform coefficients of the residual block (354). Next, video encoder 200 can scan the quantized transform coefficients of the residual block (356). During or after the scan, video encoder 200 can entropy encode the transform coefficients (358). For instance, video encoder 200 can encode the transform coefficients using CAVLC or CABAC. Video encoder 200 can then output the entropy encoded data for the block (360).

[0290] Figure 6 is a flowchart illustrating an example method for decoding a current block of video data. The current block can include a current CU. Although described with respect to video decoder 300 Figure 1 and Figure 4 ​) is described, but it should be understood that other devices may be configured to perform similar Figure 6 method.

[0291] The video decoder 300 may receive entropy-encoded data for a current block, such as entropy-encoded data of transform coefficients of a residual block corresponding to the current block and entropy-encoded prediction information (370). The video decoder 300 may entropy decode the entropy-encoded data to determine prediction information for the current block and reproduce transform coefficients of the residual block (372). The video decoder 300 may predict the current block (374), for example, by calculating a prediction block for the current block using an intra-frame or inter-frame prediction mode as indicated by the prediction information for the current block. The video decoder 300 may then inverse scan the reproduced transform coefficients (376) to produce a block of quantized transform coefficients. The video decoder 300 may then inverse quantize the transform coefficients and apply an inverse transform to the transform coefficients to produce a residual block (378). The video decoder 300 may ultimately decode the current block (380) by combining the prediction block and the residual block.

[0292] Figure 7 is a flowchart illustrating an example method for decoding a current block of video data. The current block may include a current CU. Although with respect to the video decoder 300 ( Figure 1 and Figure 4 ) is described, but it should be understood that other devices may be configured to perform similar Figure 7 method.

[0293] The video decoder 300 determines a set of scaling lists for video data (402), wherein each scaling list in the set of scaling lists is used to determine an associated scaling matrix in a set of scaling matrices, and wherein each scaling list and each associated scaling matrix determined has an associated ID number. The video decoder 300 determines a new scaling list of the determined set of scaling lists to be predicted based on a reference scaling list, wherein the new scaling list corresponds to a new scaling matrix (404). The video decoder 300 receives a syntax element (406). The video decoder 300 determines an ID number based on the syntax element (408). In response to determining that the set of scaling lists does not include a scaling list with the ID number, the video decoder 300 determines a new scaling matrix based on a set of default values ​​(410). The video decoder 300 decodes the video data based on the new scaling matrix (412). The video decoder 300 outputs decoded video data (414).

[0294] The following items represent examples of the techniques and devices described above.

[0295] Clause 1: A method of coding video data, the method comprising: determining whether a chroma scaling list is present in a data structure; and determining a reference scaling list based on whether the chroma scaling list is present in the data structure.

[0296] Clause 2: The method of clause 1, wherein determining the reference scaling list based on whether the chroma scaling list is present in the data structure comprises determining a range of identification values of the reference scaling list.

[0297] Clause 3: The method of clause 2, further comprising: determining whether the reference scaling list is within the range.

[0298] Clause 4: The method of clause 1, wherein determining the reference scaling list based on whether the chroma scaling list is present in the data structure comprises determining a maximum value of a range of identification values of the reference scaling list.

[0299] Clause 5: The method of clause 4, further comprising: determining whether the reference scaling list is less than the maximum value.

[0300] Clause 6: The method of any of clauses 1-5, further comprising: based on the determined reference scaling list, determining a predicted scaling matrix.

[0301] Clause 7: The method of any of clauses 1-6, wherein the data structure comprises one or both of a picture parameter set or a sequence parameter set.

[0302] Clause 8: The method of any of clauses 1-7, wherein coding comprises decoding, and wherein determining whether the chroma scaling list is present in the data structure comprises receiving a flag indicating whether the chroma scaling list is present in the data structure.

[0303] Clause 9: The method of any of clauses 1-5, wherein coding comprises encoding.

[0304] Clause 10: The method of any of clauses 1-9, wherein the scaling list is used for signaling a scaling matrix.

[0305] Clause 11: The method of clause 10, wherein the scaling matrix is used for scaling transform coefficients used for encoding or decoding.

[0306] Clause 12: The method of clause 11, wherein the transform coefficients represent residual values between a current block and a prediction block transformed from a sample domain to a transform domain.

[0307] Clause 13: The method of clause 1, further comprising: determining that a reference id (refld) points to a scaling matrix that is not available in the chroma scaling list; and mapping a value of the reference id (refld) to a luma scaling matrix.

[0308] Clause 14: A device for coding video data, the device comprising one or more means for performing the method of any of clauses 1-13.

[0309] Clause 15: The device of clause 14, wherein the one or more means comprise one or more processors implemented in circuitry.

[0310] Clause 16: The device of any of clauses 14 and 15, further comprising a memory for storing video data.

[0311] Clause 17: The device of any of clauses 14-16, further comprising a display configured to display decoded video data.

[0312] Clause 18: The device of any of clauses 14-17, wherein the device comprises one or more of a camera, a computer, a mobile device, a broadcast receiver device, or a set-top box.

[0313] Clause 19: The device of any of clauses 14-18, wherein the device comprises a video decoder.

[0314] Clause 20: The device of any of clauses 14-18, wherein the device comprises a video encoder.

[0315] Clause 21: A computer-readable storage medium having stored thereon instructions that, when executed, cause one or more processors to perform the method of any of clauses 1-13.

[0316] Clause 22: A method of decoding video data, the method comprising: determining a set of scaling lists for video data, wherein each scaling list in the set of scaling lists is used to determine an associated scaling matrix in a set of scaling matrices, and wherein each scaling list and each associated scaling matrix has an associated identification (ID) number; determining that a new scaling list of the set of scaling lists is to be predicted from a reference scaling list, wherein the new scaling list corresponds to a new scaling matrix; receiving a syntax element; determining the ID number based on the syntax element; determining that the set of scaling lists does not include a scaling list having the ID number; in response to determining that the set of scaling lists does not include a scaling list having the ID number, determining the new scaling matrix based on a set of default values; decoding the video data based on the new scaling matrix; and outputting the decoded video data.

[0317] Clause 23: The method of clause 22, wherein determining the new scaling matrix based on the set of default values comprises: determining a predicted scaling matrix based on the set of default values; receiving a bias value representing a difference between the predicted scaling matrix and the new scaling matrix; and determining the new scaling matrix based on the predicted scaling matrix and the bias value.

[0318] Clause 24: The method of clause 22 or 23, wherein decoding the video data based on the new scaling list comprises: determining a prediction mode and a block size of a block of the video data; selecting a scaling matrix for the block from the set of scaling matrices based on the prediction mode and the block size; dequantizing first transform coefficients of the block using first scaling values from the selected scaling matrix; dequantizing second transform coefficients of the block using second scaling values from the selected scaling matrix, wherein the second scaling values are different from the first scaling values; and decoding the video data based on the dequantized first and second transform coefficients.

[0319] Clause 25: The method of any of clause 24, wherein decoding the video data based on the new scaling list comprises: determining a quantization parameter (QP) value for the block; dequantizing the first transform coefficients of the block based on the QP value and the first scaling values; and dequantizing the second transform coefficients of the block based on the QP value and the second scaling values.

[0320] Clause 26: The method of any of clauses 22-25, wherein determining that the set of scaling lists does not include the scaling list having the ID number comprises: determining that the video data is coded without chroma components; and determining that the ID number corresponds to a scaling list for a chroma component.

[0321] Clause 27: The method of clause 26, wherein determining that the video data is coded without chroma components comprises receiving a syntax element indicating that a scaling list is not included for a chroma component.

[0322] Clause 28: The method of any of clauses 22-27, wherein determining that the set of scaling lists does not include the scaling list having the ID number comprises: determining that a remainder of the ID number divided by 3 is 0 or 1.

[0323] Clause 29: The method of any of clauses 22-28, wherein determining that the set of scaling lists does not include the scaling list having the ID number comprises: receiving a syntax element indicating that a scaling list is not included for a chroma component; and determining that a remainder of the ID number divided by 3 is 0 or 1.

[0324] Clause 30: The method of any of clauses 22-29, wherein the video data comprises monochrome video data.

[0325] Clause 31 : The method of any of clauses 22-30, wherein the video data comprises video data encoded in a separate color plane coding mode.

[0326] Clause 32: A device for decoding video data, the device comprising: a memory configured to store the video data; one or more processors implemented in circuitry and configured to: determine a set of scaling lists for the video data, wherein each scaling list in the set of scaling lists is used to determine an associated scaling matrix in a set of scaling matrices, and wherein each scaling list and each associated scaling matrix that is determined has an associated identification (ID) number; determine that a new scaling list of the set of scaling lists is to be predicted from a reference scaling list, wherein the new scaling list corresponds to a new scaling matrix; receive a syntax element; determine the ID number based on the syntax element; determine that the set of scaling lists does not include a scaling list having the ID number; in response to determining that the set of scaling lists does not include a scaling list having the ID number, determine the new scaling matrix based on a set of default values; decode the video data based on the new scaling matrix; and output the decoded video data.

[0327] Clause 33: The device of clause 32, wherein to determine the new scaling matrix based on the set of default values, the one or more processors are further configured to: determine a predicted scaling matrix based on the set of default values; receive a bias value representing a difference between the predicted scaling matrix and the new scaling matrix; and determine the new scaling matrix based on the predicted scaling matrix and the bias value.

[0328] Clause 34: The device of clause 32 or 33, wherein to decode the video data based on the new scaling list, the one or more processors are further configured to: determine a prediction mode and a block size for a block of the video data; select a scaling matrix for the block from the set of scaling matrices based on the prediction mode and the block size; dequantize first transform coefficients of the block using first scaling values from the selected scaling matrix; dequantize second transform coefficients of the block using second scaling values from the selected scaling matrix, wherein the second scaling values are different from the first scaling values; and decode the video data based on the dequantized first transform coefficients and the second transform coefficients.

[0329] Clause 35: The device of clause 34, wherein to decode the video data based on the new scaling list, the one or more processors are further configured to: determine a quantization parameter (QP) value for the block; dequantize the first transform coefficients of the block based on the QP value and the first scaling values; and dequantize the second transform coefficients of the block based on the QP value and the second scaling values.

[0330] Clause 36: The device of any of clauses 32-35, wherein to determine that the set of scaling lists does not include a scaling list having the ID number, the one or more processors are further configured to: determine that the video data is coded without a chroma component; and determine that the ID number corresponds to a scaling list for the chroma component.

[0331] Clause 37: The device of clause 36, wherein to determine that the video data is coded without a chroma component, the one or more processors are further configured to receive a syntax element indicating that a scaling list is not included for a chroma component.

[0332] Clause 38: The device of any of clauses 32-37, wherein to determine that the set of scaling lists does not include a scaling list having the ID number, the one or more processors are further configured to determine that a remainder of the ID number divided by 3 is 0 or 1.

[0333] Clause 39: The device of any of clauses 32-38, wherein to determine that the set of scaling lists does not include a scaling list having the ID number, the one or more processors are further configured to: receive a syntax element indicating that a scaling list is not included for a chroma component; and determine that a remainder of the ID number divided by 3 is 0 or 1.

[0334] Clause 40: The device of any of clauses 32-39, wherein the video data comprises monochrome video data.

[0335] Clause 41: The device of any of clauses 32-40, wherein the video data comprises video data encoded in a separate color plane coding mode.

[0336] Clause 42: The device of any of clauses 32-41, wherein the device comprises a wireless communication device, further comprising a receiver configured to receive the encoded video data.

[0337] Clause 43: The device of clause 42, wherein the wireless communication device comprises a telephone handset, and wherein the receiver is configured to demodulate a signal comprising the encoded video data according to a wireless communication standard.

[0338] Clause 44: The device of any of clauses 32-43, further comprising: a display configured to display the decoded video data.

[0339] Clause 45: The device of any of clauses 32-44, wherein the device comprises one or more of a camera, a computer, a mobile device, a broadcast receiver device, or a set-top box.

[0340] Clause 46: A computer-readable storage medium storing instructions that, when executed by one or more processors, cause the one or more processors to: determine a set of scaling lists for video data, wherein each scaling list in the set of scaling lists is used to determine an associated scaling matrix in a set of scaling matrices, and wherein each scaling list and each associated scaling matrix that is determined has an associated identification (ID) number; determine that a new scaling list of the set of scaling lists is to be predicted from a reference scaling list, wherein the new scaling list corresponds to a new scaling matrix; receive a syntax element; determine the ID number based on the syntax element; determine that the set of scaling lists does not include a scaling list having the ID number; in response to determining that the set of scaling lists does not include a scaling list having the ID number, determine the new scaling matrix based on a set of default values; decode the video data based on the new scaling matrix; and output the decoded video data.

[0341] Clause 47: The computer-readable storage medium of clause 46, wherein to determine the new scaling matrix based on the set of default values, the instructions cause the one or more processors to: determine a predicted scaling matrix based on the set of default values; receive a bias value representing a difference between the predicted scaling matrix and the new scaling matrix; and determine the new scaling matrix based on the predicted scaling matrix and the bias value.

[0342] Clause 48: The computer-readable storage medium of clause 46 or 47, wherein to decode the video data based on the new scaling list, the instructions cause the one or more processors to: determine a prediction mode and a block size of a block of the video data; select a scaling matrix for the block from the set of scaling matrices based on the prediction mode and the block size; dequantize first transform coefficients of the block using first scaling values from the selected scaling matrix; dequantize second transform coefficients of the block using second scaling values from the selected scaling matrix, wherein the second scaling values are different from the first scaling values; and decode the video data based on the dequantized first transform coefficients and the second transform coefficients.

[0343] Clause 49: The computer-readable storage medium of clause 48, wherein to decode the video data based on the new scaling list, the instructions cause the one or more processors to: determine a quantization parameter (QP) value for the block; dequantize the first transform coefficients of the block based on the QP value and the first scaling values; and dequantize the second transform coefficients of the block based on the QP value and the second scaling values.

[0344] Clause 50: The computer-readable storage medium of any of clauses 46-49, wherein to determine that the set of scaling lists does not include a scaling list having the ID number, the instructions cause the one or more processors to: determine that the video data is coded without chroma components; and determine that the ID number corresponds to a scaling list for a chroma component.

[0345] Clause 51 : The computer-readable storage medium of clause 50, wherein to determine that the video data is coded without chroma components, the instructions cause the one or more processors to receive a syntax element indicating that scaling lists are not included for chroma components.

[0346] Clause 52: The computer-readable storage medium of any of clauses 46-51, wherein to determine that the scaling list set does not include a scaling list having the ID number, the instructions cause the one or more processors to determine that the ID number divided by 3 has a remainder of 0 or 1.

[0347] Clause 53: The computer-readable storage medium of any of clauses 46-52, wherein to determine that the scaling list set does not include a scaling list having the ID number, the instructions cause the one or more processors to: receive a syntax element indicating that scaling lists are not included for chroma components; and determine that the ID number divided by 3 has a remainder of 0 or 1.

[0348] Clause 54: The computer-readable storage medium of any of clauses 46-53, wherein the video data comprises monochrome video data.

[0349] Clause 55: The computer-readable storage medium of any of clauses 46-54, wherein the video data comprises video data encoded in a separate color plane coding mode.

[0350] Clause 56: An apparatus comprising: means for determining a scaling list set for video data, wherein each scaling list in the scaling list set is used to determine an associated scaling matrix in a set of scaling matrices, and wherein each scaling list and each associated scaling matrix that is determined has an associated identification (ID) number; means for determining that a new scaling list of the scaling list set is to be predicted from a reference scaling list, wherein the new scaling list corresponds to a new scaling matrix; means for receiving a syntax element; means for determining the ID number based on the syntax element; means for determining that the scaling list set does not include a scaling list having the ID number; means for determining the new scaling matrix based on a set of default values in response to determining that the scaling list set does not include a scaling list having the ID number; means for decoding the video data based on the new scaling matrix; and means for outputting the decoded video data.

[0351] It is recognized that, depending on the example, certain acts or events of any of the techniques described herein can be performed in a different sequence, can be added, modified or omitted (e.g., not all described acts or events are necessary for practice of the techniques), and / or can be performed concurrently in some embodiments, rather than sequentially. Also, certain acts or events can be performed at the same time as one another, e.g., through multi-threaded processing, interrupt processing, or multiple processors, rather than sequentially.

[0352] In one or more examples, the functions described can be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions can be stored on or transmitted on a computer-readable medium as one or more instructions or codes and executed by a hardware-based processing unit. Computer-readable media can include computer-readable storage media, which corresponds to tangible media (such as data storage media) or communication media (including, for example, any media that facilitates the transfer of a computer program from one place to another according to a communication protocol). In this manner, computer-readable media can generally correspond to (1) tangible, non-transitory computer-readable storage media or (2) communication media (such as signals or carrier waves). Data storage media can be any available media that can be accessed by one or more computers or one or more processors to retrieve instructions, codes, and / or data structures for implementing the techniques described in this disclosure. A computer program product can include computer-readable media.

[0353] As an example and not limitation, such computer-readable storage media may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, disk storage or other magnetic storage devices, flash memory, or any other medium that can be used to store the required program code in the form of instructions or data structures and can be accessed by a computer. In addition, any connection is properly referred to as a computer-readable medium. For example, if a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL) or wireless technology (such as infrared, radio and microwave) is used to transmit instructions from a website, server or other remote source, then the coaxial cable, fiber optic cable, twisted pair, DSL or wireless technology (such as infrared, radio and microwave) is 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 temporary media, but rather point to non-temporary tangible storage media. Disks and optical disks used herein include compact discs (CDs), laser discs, optical discs, digital versatile discs (DVDs), floppy disks and blue-ray discs, wherein disks usually reproduce data magnetically, while optical discs reproduce data optically with lasers. The above combination should also be included in the scope of computer-readable media.

[0354] Instructions can 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 circuitry. Accordingly, as used herein the terms "processor" and "processing circuitry" can refer to any of the foregoing structures or any other structure suitable for implementation of the techniques described herein. In addition, in some aspects, the functionality described herein can be provided within dedicated hardware and / or software modules configured for encoding and decoding, or incorporated in a combined codec. Also, the techniques could be fully implemented in one or more circuits or logic elements.

[0355] The techniques of this disclosure can be implemented in a wide variety of devices or apparatuses, including a wireless handset, an integrated circuit (IC) or a set of ICs (e.g., a chip set). Various components, modules, or units are described herein to emphasize functionality that can be implemented, for example, in an integrated circuit or set of integrated circuits. The various components, modules, or units can be implemented by hardware, software, firmware, or any combination thereof.

[0356] Various examples have been described. These and other examples are within the scope of the following claims.

Claims

1. A method for decoding video data, the method comprising: determining a set of scaling lists for the video data, wherein each scaling list in the set of scaling lists is used to determine an associated scaling matrix in a set of scaling matrices, and wherein each scaling list and each associated scaling matrix has an associated identification ID number; determining a new scaling list of the set of scaling lists to be predicted based on the reference scaling list, wherein the new scaling list corresponds to a new scaling matrix; Receive grammatical elements; Determining an ID number based on the syntax element; Determining that the zoom list set does not include the zoom list with the ID number, wherein determining that the zoom list set does not include the zoom list with the ID number includes determining that a remainder when the ID number is divided by 3 is 0 or 1; In response to determining that the set of zoom lists does not include the zoom list with the ID number, determining the new zoom matrix based on a set of default values; decoding the video data based on the new scaling matrix; as well as Outputs the decoded video data.

2. The method of claim 1 , wherein determining the new scaling matrix based on a default value set comprises: determining a predicted scaling matrix based on the set of default values; receiving a bias value representing a difference between the predicted scaling matrix and the new scaling matrix; as well as The new scaling matrix is ​​determined based on the predicted scaling matrix and the bias value.

3. The method of claim 1 , wherein decoding the video data based on the new scaling list comprises: determining a prediction mode and a block size for a block of the video data; selecting a scaling matrix for the block from the set of scaling matrices based on the prediction mode and the block size; dequantizing a first transform coefficient of the block using a first scaling value from the selected scaling matrix; dequantizing second transform coefficients of the block using a second scaling value from the selected scaling matrix, wherein the second scaling value is different from the first scaling value; as well as The video data is decoded based on the dequantized first and second transform coefficients.

4. The method of claim 3 , wherein decoding the video data based on the new scaling list comprises: Determining a quantization parameter (QP) value for the block; dequantizing a first transform coefficient of the block based on the QP value and the first scaling value; as well as Second transform coefficients of the block are dequantized based on the QP value and the second scaling value.

5. The method of claim 1 , wherein determining that the set of zoom lists does not include the zoom list having the ID number comprises: A syntax element is received that indicates that a scaling list is not included for a chroma component. The method of claim 1 , wherein the video data comprises monochrome video data.

7. The method of claim 1, wherein the video data comprises video data encoded in a separate color plane codec mode.

8. A method for decoding video data, the method comprising: determining a set of scaling lists for the video data, wherein each scaling list in the set of scaling lists is used to determine an associated scaling matrix in a set of scaling matrices, and wherein each scaling list and each associated scaling matrix has an associated identification ID number; determining a new scaling list of the set of scaling lists to be predicted based on the reference scaling list, wherein the new scaling list corresponds to a new scaling matrix; Receive grammatical elements; Determining an ID number based on the syntax element; determining that the set of scaling lists does not include the scaling list having the ID number, wherein determining that the set of scaling lists does not include the scaling list having the ID number comprises determining that the video data is encoded and decoded without a chroma component, and determining that the ID number corresponds to a scaling list having a chroma component; In response to determining that the set of zoom lists does not include the zoom list with the ID number, determining the new zoom matrix based on a set of default values; decoding the video data based on the new scaling matrix; as well as Outputs the decoded video data. 9 . The method of claim 8 , wherein determining that the video data is encoded without chroma components comprises receiving a syntax element indicating that scaling lists are not included for chroma components.

10. A device for decoding video data, the device comprising: at least one memory including instructions and configured to store video data; one or more processors implemented in circuitry and configured to execute the instructions to cause the apparatus to: Determining a set of scaling lists for the video data, wherein each scaling list in the set of scaling lists is used to determine an associated scaling matrix in a set of scaling matrices, and wherein each scaling list and each associated scaling matrix determined have an associated identification ID number; determining a new scaling list of the set of scaling lists to be predicted based on the reference scaling list, wherein the new scaling list corresponds to a new scaling matrix; Receive grammatical elements; Determining an ID number based on the syntax element; Determining that the zoom list set does not include the zoom list with the ID number, wherein determining that the zoom list set does not include the zoom list with the ID number includes determining that a remainder when the ID number is divided by 3 is 0 or 1; In response to determining that the set of zoom lists does not include the zoom list with the ID number, determining the new zoom matrix based on a set of default values; decoding the video data based on the new scaling matrix; as well as Outputs the decoded video data.

11. The device of claim 10, wherein to determine the new scaling matrix based on a default value set, the one or more processors are further configured to cause the device to: determining a predicted scaling matrix based on the set of default values; receiving a bias value representing a difference between the predicted scaling matrix and the new scaling matrix; and The new scaling matrix is ​​determined based on the predicted scaling matrix and the bias value.

12. The device of claim 10, wherein to decode the video data based on the new scaling list, the one or more processors are further configured to cause the device to: determining a prediction mode and a block size for a block of the video data; selecting a scaling matrix for the block from the set of scaling matrices based on the prediction mode and the block size; dequantizing a first transform coefficient of the block using a first scaling value from the selected scaling matrix; dequantizing second transform coefficients of the block using a second scaling value from the selected scaling matrix, wherein the second scaling value is different from the first scaling value; as well as The video data is decoded based on the dequantized first and second transform coefficients.

13. The device of claim 12, wherein to decode the video data based on the new scaling list, the one or more processors are further configured to cause the device to: Determining a quantization parameter (QP) value for the block; dequantizing a first transform coefficient of the block based on the QP value and the first scaling value; as well as Second transform coefficients of the block are dequantized based on the QP value and the second scaling value.

14. The device of claim 10, wherein to determine that the set of zoom lists does not include the zoom list having the ID number, the one or more processors are further configured to cause the device to: A syntax element is received that indicates that a scaling list is not included for a chroma component.

15. The apparatus of claim 10, wherein the video data comprises monochrome video data.

16. The apparatus of claim 10, wherein the video data comprises video data encoded in a separate color plane codec mode.

17. The device of claim 10, wherein the device comprises a wireless communication device, further comprising a receiver configured to receive the encoded video data.

18. The device of claim 17, wherein the wireless communication device comprises a telephone handset, and wherein the receiver is configured to demodulate a signal comprising the encoded video data in accordance with a wireless communication standard.

19. The apparatus of claim 10, further comprising: A display is configured to display the decoded video data.

20. The device of claim 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.

21. A device for decoding video data, the device comprising: at least one memory including instructions and configured to store video data; one or more processors implemented in circuitry and configured to execute the instructions to cause the apparatus to: determining a set of scaling lists for the video data, wherein each scaling list in the set of scaling lists is used to determine an associated scaling matrix in a set of scaling matrices, and wherein each scaling list and each associated scaling matrix has an associated identification ID number; determining a new scaling list of the set of scaling lists to be predicted based on the reference scaling list, wherein the new scaling list corresponds to a new scaling matrix; Receive grammatical elements; Determining an ID number based on the syntax element; determining that the set of scaling lists does not include the scaling list having the ID number, wherein upon determining that the set of scaling lists does not include the scaling list having the ID number, the one or more processors are further configured to determine that the video data is encoded and decoded without a chroma component, and to determine that the ID number corresponds to a scaling list having a chroma component; In response to determining that the set of zoom lists does not include the zoom list with the ID number, determining the new zoom matrix based on a set of default values; decoding the video data based on the new scaling matrix; as well as Outputs the decoded video data.

22. The device of claim 21, wherein it is determined that the video data is encoded without a chroma component, and the one or more processors are further configured to cause the device to receive a syntax element indicating that a scaling list is not included for the chroma component.

23. A computer-readable storage medium storing instructions that, when executed by one or more processors, cause the one or more processors to: Determining a set of scaling lists for video data, wherein each scaling list in the set of scaling lists is used to determine an associated scaling matrix in the set of scaling matrices, and wherein each scaling list and each associated scaling matrix determined has an associated identification ID number; determining a new scaling list of the set of scaling lists to be predicted based on the reference scaling list, wherein the new scaling list corresponds to a new scaling matrix; Receive grammatical elements; Determining an ID number based on the syntax element; Determining that the zoom list set does not include the zoom list with the ID number, wherein determining that the zoom list set does not include the zoom list with the ID number includes determining that a remainder when the ID number is divided by 3 is 0 or 1; In response to determining that the set of zoom lists does not include the zoom list with the ID number, determining the new zoom matrix based on a set of default values; decoding the video data based on the new scaling matrix; as well as Outputs the decoded video data.

24. The computer-readable storage medium of claim 23, wherein to determine the new scaling matrix based on a set of default values, the instructions cause the one or more processors to: determining a predicted scaling matrix based on the set of default values; receiving a bias value representing a difference between the predicted scaling matrix and the new scaling matrix; and The new scaling matrix is ​​determined based on the predicted scaling matrix and the bias value.

25. The computer-readable storage medium of claim 23, wherein to decode the video data based on the new scaling list, the instructions cause the one or more processors to: determining a prediction mode and a block size for a block of the video data; selecting a scaling matrix for the block from the set of scaling matrices based on the prediction mode and the block size; dequantizing a first transform coefficient of the block using a first scaling value from the selected scaling matrix; dequantizing second transform coefficients of the block using a second scaling value from the selected scaling matrix, wherein the second scaling value is different from the first scaling value; as well as The video data is decoded based on the dequantized first and second transform coefficients.

26. The computer-readable storage medium of claim 25, wherein to decode the video data based on the new scaling list, the instructions cause the one or more processors to: Determining a quantization parameter (QP) value for the block; dequantizing a first transform coefficient of the block based on the QP value and the first scaling value; as well as Second transform coefficients of the block are dequantized based on the QP value and the second scaling value.

27. The computer-readable storage medium of claim 23, wherein to determine that the set of zoom lists does not include the zoom list having the ID number, the instructions cause the one or more processors to: A syntax element is received that indicates that a scaling list is not included for a chroma component.

28. The computer-readable storage medium of claim 23, wherein the video data comprises monochrome video data.

29. The computer-readable storage medium of claim 23, wherein the video data comprises video data encoded in a separate color plane codec mode.

30. A computer-readable storage medium storing instructions that, when executed by one or more processors, cause the one or more processors to: Determining a set of scaling lists for video data, wherein each scaling list in the set of scaling lists is used to determine an associated scaling matrix in the set of scaling matrices, and wherein each scaling list and each associated scaling matrix determined has an associated identification ID number; determining a new scaling list of the set of scaling lists to be predicted based on the reference scaling list, wherein the new scaling list corresponds to a new scaling matrix; Receive grammatical elements; Determining an ID number based on the syntax element; determining that the set of scaling lists does not include the scaling list having the ID number, wherein determining that the set of scaling lists does not include the scaling list having the ID number comprises the one or more processors being further configured to determine that the video data is encoded and decoded without a chroma component, and determining that the ID number corresponds to a scaling list for a chroma component; In response to determining that the set of zoom lists does not include the zoom list with the ID number, determining the new zoom matrix based on a set of default values; decoding the video data based on the new scaling matrix; as well as Outputs the decoded video data.

31. The computer-readable storage medium of claim 30, wherein to determine that the video data is encoded without chroma components, the instructions cause the one or more memories to receive a syntax element indicating that scaling lists are not included for chroma components.

32. An apparatus for decoding video data, comprising: means for determining a set of scaling lists for the video data, wherein each scaling list in the set of scaling lists is used to determine an associated scaling matrix in the set of scaling matrices, and wherein each scaling list and each associated scaling matrix determined has an associated identification ID number; means for determining a new scaling list of the set of scaling lists to be predicted from the reference scaling list, wherein the new scaling list corresponds to a new scaling matrix; A component for receiving a grammatical element; means for determining an ID number based on the grammatical element; means for determining that the set of zoom lists does not include the zoom list with the ID number, wherein the means for determining that the set of zoom lists does not include the zoom list with the ID number comprises means for determining that a remainder when the ID number is divided by 3 is 0 or 1; means for determining the new zoom matrix based on a set of default values ​​in response to determining that the set of zoom lists does not include a zoom list having the ID number; means for decoding the video data based on the new scaling matrix; as well as Means for outputting decoded video data.

33. A computer program product comprising computer-readable instructions, which, when executed by a processor, cause the processor to perform the method for decoding video data according to any one of claims 1 to 7.

34. A computer program product comprising computer-readable instructions, which, when executed by a processor, cause the processor to perform the method for decoding video data according to any one of claims 8 to 9.

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