Binarization in Transform-Skip Residual Decoding

Abstract

A video decoder may be configured to: determine whether a block of video data is encoded without transforming residual data for the block; determine a quantization parameter for the block of video data; determine a range of levels of quantized residual values ​​of the block based on the determined quantization parameter; divide the range into k intervals, where k is an integer value; determine the levels of the quantized residual values ​​of the block based on the k intervals by: receiving information indicating that the level of the quantized residual value is within a specific interval among the k intervals; receiving information indicating a difference value, the difference value representing a difference between a reference level value in the specific interval and the level of the quantized residual value of the block; and determine the level of the quantized residual value based on the reference level value and the difference value.

Description

[0001] This application claims priority from the following applications:

[0002] U.S. Patent Application No. 16 / 909,892, filed on June 23, 2020, which claims the benefits of:

[0003] U.S. Provisional Patent Application No. 62 / 865,883, filed on June 24, 2019, and

[0004] U.S. Provisional Patent Application No. 62 / 894,449, filed on August 30, 2019, the entire contents of each of which are hereby incorporated by reference. Technical Field

[0005] This disclosure relates to video encoding and video decoding. Background Art

[0006] Digital video capabilities can be incorporated into a wide variety of devices, including digital televisions, digital live 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 game devices, video game consoles, cellular or satellite radio telephones, so-called "smartphones," video teleconferencing devices, video streaming devices, and the like. Digital video devices implement video coding techniques, such as those described in 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. Video devices can more efficiently transmit, receive, encode, decode, and / or store digital video information by implementing such video coding techniques.

[0007] Video coding techniques include spatial (intra-picture) prediction and / or temporal (inter-picture) prediction to reduce or remove redundancy inherent in video sequences. For block-based video coding, a video slice (e.g., a video picture or a portion of a video picture) may be partitioned into video blocks, which may also be referred to as coding tree units (CTUs), coding units (CUs), and / or coding nodes. Video blocks in an intra-coded (I) slice of a picture are encoded using spatial prediction relative to reference samples in neighboring blocks in the same picture. Video blocks in an inter-coded (P or B) slice of a picture may use spatial prediction relative to reference samples in neighboring blocks in the same picture or temporal prediction relative to reference samples in other reference pictures. Pictures may be referred to as frames, and reference pictures may be referred to as reference frames. Summary of the Invention

[0008] This disclosure describes techniques related to binarization performed in transform-skip residual coding. More specifically, this disclosure describes techniques related to the entropy decoding process that converts a binary representation into a series of non-binary values ​​of quantized coefficients. The corresponding entropy encoding process, which is the inverse of entropy decoding, is also described.

[0009] According to the techniques of the present disclosure, a binarization process for decoding transform skip coefficients is described. For an input quantization parameter (QP), a video decoder can derive a corresponding dynamic range [0, maxTsLevel] for the level of the transform skip coefficient, where "maxTsLevel" represents the maximum possible level of the transform skip coefficient allowed for a particular QP value, i.e., the maximum possible level of the quantized residual value. The maximum possible level of the transform skip coefficient for a block can be a function of the QP value for the block, but can also depend on the bit depth for the block. The video decoder can then receive an index or other indication of an interval that includes the levels for the values ​​of the transform skip coefficient. The video decoder can also receive a remainder value that represents the difference between an initial value for the interval that includes the levels for the values ​​of the transform skip coefficient and the actual level value for the transform skip coefficient.

[0010] According to an example of the present disclosure, a method for decoding video data includes: determining that a block of video data is encoded without transforming residual data for the block; determining a quantization parameter for the block of video data; determining a range of levels of quantized residual values ​​of the block of video data based on the determined quantization parameter; dividing the range into k intervals, where k is an integer value; determining the levels of the quantized residual values ​​of the block based on the k intervals, where determining the levels of the quantized residual values ​​of the block based on the k intervals includes: receiving information indicating that the levels of the quantized residual values ​​are within a specific interval among the k intervals; receiving information indicating a difference value, where the difference value represents a difference between a reference level value in the specific interval and the level of the quantized residual value of the block; and determining the levels of the quantized residual values ​​based on the reference level value and the difference value; and outputting decoded video data based on the levels of the quantized residual values.

[0011] According to another example of the present disclosure, a device for decoding video data includes: a memory configured to store video data; and one or more processors configured to: determine whether a block of video data is encoded without transforming residual data for the block; determine a quantization parameter for the block of video data; determine a range of levels of quantized residual values ​​of the block of video data based on the determined quantization parameter; divide the range into k intervals, where k is an integer value; determine the level of the quantized residual value of the block based on the k intervals, wherein, in order to determine the level of the quantized residual value of the block based on the k intervals, the one or more processors are further configured to: receive information indicating that the level of the quantized residual value is within a specific interval of the k intervals; receive information indicating a difference value, wherein the difference value represents a difference between a reference level value in the specific interval and the level of the quantized residual value of the block; and determine the level of the quantized residual value based on the reference level value and the difference value; and output decoded video data based on the level of the quantized residual value.

[0012] According to another example of the present disclosure, a computer-readable storage medium storing instructions, the instructions, when executed by one or more processors, causes the one or more processors to perform the following operations: determine whether a block of video data is encoded without transforming residual data for the block; determine a quantization parameter for the block of video data; determine a range of levels of quantized residual values ​​of the block of video data based on the determined quantization parameter; divide the range into k intervals, where k is an integer value; determine the level of the quantized residual value of the block based on the k intervals, wherein, in order to determine the level of the quantized residual value of the block based on the k intervals, the instructions cause the one or more processors to perform the following operations: receive information indicating that the level of the quantized residual value is within a specific interval of the k intervals; receive information indicating a difference value, where the difference value represents a difference between a reference level value in the specific interval and the level of the quantized residual value of the block; and determine the level of the quantized residual value based on the reference level value and the difference value; and output decoded video data based on the level of the quantized residual value.

[0013] According to another example, a device for decoding video data includes: a unit for determining whether a block of video data is encoded without transforming residual data for the block; a unit for determining a quantization parameter for the block of video data; a unit for determining a range of levels of quantized residual values ​​of the block of video data based on the determined quantization parameter; a unit for dividing the range into k intervals, wherein k is an integer value; a unit for determining the levels of the quantized residual values ​​of the block based on the k intervals, wherein the unit for determining the levels of the quantized residual values ​​of the block based on the k intervals includes: a unit for receiving information indicating that the levels of the quantized residual values ​​are within a specific interval of the k intervals; a unit for receiving information indicating a difference value, wherein the difference value represents a difference between a reference level value in the specific interval and the level of the quantized residual value of the block; and a unit for determining the levels of the quantized residual values ​​based on the reference level value and the difference value; and a unit for outputting decoded video data based on the levels of the quantized residual values.

[0014] According to another example of the present disclosure, a method for generating a bitstream of encoded video data includes: determining that a block of video data is encoded without transforming residual data for the block; determining a level of a quantized residual value of the block; determining a quantization parameter for the block of video data; determining a range of the level of the quantized residual value of the block of video data based on the determined quantization parameter; dividing the range into k intervals, where k is an integer value; determining a specific interval of the k intervals that includes the level of the quantized residual value; determining a difference value, where the difference value represents a difference between a reference level value in the specific interval and the level of the quantized residual value of the block; signaling the level of the quantized residual value of the block based on the k intervals, where signaling the level of the quantized residual value of the block based on the k intervals includes: generating one or more syntax elements indicating the specific interval for inclusion in the bitstream of the encoded video data; generating a syntax element indicating the difference value for inclusion in the bitstream of the encoded video data; and outputting the bitstream of the encoded video data.

[0015] According to another example of the present disclosure, a device for encoding video data includes: a memory configured to store video data; and one or more processors configured to: determine whether a block of video data is encoded without transforming residual data for the block; determine a level of a quantized residual value of the block; determine a quantization parameter for the block of video data; determine a range of levels of quantized residual values ​​of the block of video data based on the determined quantization parameter; divide the range into k intervals, where k is an integer value; determine a specific interval of the k intervals that includes the level of the quantized residual value; determine a difference value , wherein the difference value represents a difference between a reference level value in the specific interval and the level of the quantized residual value of the block; the level of the quantized residual value of the block is signaled based on the k intervals, wherein, in order to signal the level of the quantized residual value of the block based on the k intervals, the one or more processors are further configured to: generate one or more syntax elements indicating the specific interval for inclusion in the bitstream of the encoded video data; generate a syntax element indicating the difference value for inclusion in the bitstream of the encoded video data; and output the bitstream of the encoded video data.

[0016] According to another example of the present disclosure, a computer-readable storage medium storing instructions, the instructions, when executed by one or more processors, causes the one or more processors to perform the following operations: determining whether a block of video data is encoded without transforming residual data for the block; determining a level of a quantized residual value of the block; determining a quantization parameter for the block of video data; determining a range of levels of quantized residual values ​​of the block of video data based on the determined quantization parameter; dividing the range into k intervals, where k is an integer value; determining a specific interval of the k intervals that includes the level of the quantized residual value; determining a difference value, wherein the difference value represents a difference between a reference level value at the specific interval and the level of the quantized residual value of the block; the level of the quantized residual value of the block is sent as a signal based on the k intervals, wherein, in order to send the level of the quantized residual value of the block as a signal based on the k intervals, the one or more processors are further configured to: generate one or more syntax elements indicating the specific interval for inclusion in the bitstream of the encoded video data; generate a syntax element indicating the difference value for inclusion in the bitstream of the encoded video data; and output the bitstream of the encoded video data.

[0017] According to another example of the present disclosure, an apparatus for generating a bitstream of encoded video data includes: a unit for determining whether a block of video data is encoded without transforming residual data for the block; a unit for determining a level of a quantized residual value of the block; a unit for determining a quantization parameter for the block of video data; a unit for determining a range of levels of quantized residual values ​​of the block of video data based on the determined quantization parameter; a unit for dividing the range into k intervals, where k is an integer value; a unit for determining a specific interval of the k intervals that includes the level of the quantized residual value; and a unit for determining a difference value. wherein the difference value represents a difference between a reference level value in the specific interval and the level of the quantized residual value of the block; a unit for signaling the level of the quantized residual value of the block based on the k intervals, wherein the unit for signaling the level of the quantized residual value of the block based on the k intervals comprises: a unit for generating one or more syntax elements indicating the specific interval for inclusion in the bitstream of the encoded video data; a unit for generating a syntax element indicating the difference value for inclusion in the bitstream of the encoded video data; and a unit for outputting the bitstream of the encoded video data.

[0018] The details of one or more examples are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a block diagram illustrating an example video encoding and decoding system that may perform the techniques of this disclosure.

[0020] Figure 2A and Figure 2B is a conceptual diagram illustrating an example quadtree binary tree (QTBT) structure and a corresponding coding tree unit (CTU).

[0021] Figure 3 is a block diagram illustrating an example video encoder that may perform the techniques of this disclosure.

[0022] Figure 4 is a block diagram illustrating an example video decoder that may perform the techniques of this disclosure.

[0023] Figure 5 is a flow chart illustrating an example video encoding process.

[0024] Figure 6 is a flow chart illustrating an example video decoding process.

[0025] Figure 7 is a flow chart illustrating an example video encoding process.

[0026] Figure 8 is a flow chart illustrating an example video decoding process. DETAILED DESCRIPTION

[0027] Video coding (e.g., video encoding and / or video decoding) typically involves predicting a block of video data from already coded blocks of video data in the same picture (e.g., intra-frame prediction) or predicting a block of video data from already coded blocks of video data in different pictures (e.g., inter-frame prediction). In some cases, the video encoder also calculates residual data by comparing the predicted block with the original block. Thus, the residual data represents the difference between the predicted block and the original block. To reduce the number of bits required to signal the residual data, the video encoder can transform and quantize the residual data and signal the transformed and quantized residual data in the coded bitstream.

[0028] The video decoder decodes the residual data and adds the residual data to the prediction block to produce a reconstructed video block that more closely matches the original video block than the prediction block alone. The compression achieved by the transform and quantization processes can be lossy, meaning that the transform and quantization processes can introduce distortion into the decoded video data. Due to the losses 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 known as blocking, where the boundaries of the blocks used to decode the video data become visible.

[0029] To further improve the quality of the decoded video, the video decoder may perform one or more filtering operations on the reconstructed video blocks. Examples of these filtering operations include deblocking filtering, sample adaptive offset (SAO) filtering, and adaptive loop filtering (ALF). The parameters for these filtering operations may be determined by the video encoder and explicitly signaled in the coded video bitstream, or may be implicitly determined by the video decoder without explicitly signaling the parameters in the coded video bitstream.

[0030] In some decoding scenarios, a video encoder may encode a block of video data in a transform skip mode, in which the transform process described above is not performed (i.e., the transform process is skipped). Thus, for blocks encoded in transform skip mode, the residual data is not transformed, but may still be quantized. Thus, transform skip coefficients generally correspond to quantized representations of residual values, while transform coefficients generally correspond to residual values ​​of a block that have been quantized and transformed to generate transform coefficients. As used in this disclosure, the term coefficient may refer to either a transform coefficient or a transform skip coefficient, and may be quantized or unquantized.

[0031] This disclosure describes techniques related to binarization performed in transform skip residual decoding. More specifically, this disclosure describes techniques related to an entropy decoding process that converts a binary representation into a series of non-binary values ​​of quantized coefficients. A corresponding entropy encoding process, which is the inverse of entropy decoding, is also described herein. In the following disclosure, when a video decoder is described as receiving or parsing a syntax element, it can be assumed that the video encoder is configured to signal (e.g., generate) the same syntax element for inclusion in the bitstream of the encoded video data. Similarly, when a video encoder is described as signaling a syntax element, it can be assumed that the video decoder is configured to receive and parse the same syntax element.

[0032] According to the techniques of this disclosure, a binarization process for decoding transform skip coefficients is described. For an input quantization parameter (QP), a video decoder can derive a corresponding dynamic range [0, maxTsLevel] for the level of the transform skip coefficients, where "maxTsLevel" represents the maximum level of the transform skip coefficients, i.e., the maximum level of the quantized residual value. In this context, "level" refers to the magnitude or absolute value of the quantized residual value.

[0033] According to one example technique of the present disclosure, once the dynamic range of the levels of the transform skip coefficients is calculated, the range can be divided into k (inclusive) intervals as follows:

[0034] [X,t0],[t0+1,t1],[t1+1,t2],…[t k-3 +1,t k-2 ],[t k-2 +1,maxTsLevel].

[0035] In the above example, X represents the minimum value of interval 0. As discussed later in this disclosure, in different implementations, X can be equal to 0, 1, 2, or some other value. The k intervals can have indices from 0 to k-1. Referring again to the above example, index 0 corresponds to the interval [X, t0], index 1 corresponds to the interval [t0+1, t1], and so on, up to index k-1, which corresponds to the interval [t k-2 +1,maxTsLevel]. In the above example, t n Indicates the upper threshold of the nth interval, where n ranges from 0 to k-1.

[0036] The video decoder may then receive an index or other indication of an interval including the level of the transform skip coefficient value. The video decoder may also receive a remainder value representing the difference between the initial value of the interval including the level of the transform skip coefficient value and the actual level value of the transform skip coefficient. As an example, if Y represents the actual level of the transform skip coefficient value and Y is within interval 2, then the remainder value is equal to Y-(t1+1).

[0037] In some examples, the video decoder may receive a significant-coefficient flag indicating whether the transform skip coefficient is equal to zero or not equal to zero before receiving the indication of the interval. In such an example, the value of X in the first interval may be equal to 1. In some examples, the video decoder may also receive a flag greater than one indicating whether the level of the transform skip coefficient is equal to 1 or greater than 1 before receiving the indication of the interval. In such an example, the value of X in the first interval may be equal to 2. The video decoder may additionally receive a flag indicating whether the actual value of the transform skip coefficient is negative or positive.

[0038] The distribution of transform coefficient values ​​in a transformed block tends to be quite different from the distribution of transform-skipped coefficient values ​​in untransformed blocks. For example, almost all transform coefficients in the lower right half of a transformed block may be equal to zero. Only a few transform coefficients near the upper left corner of the block may have large values, such as greater than 2, while some transform coefficients between the upper left corner and the lower left half of the block may have small values, such as 1 or 2. Existing techniques for decoding coefficients are typically designed to exploit the large number of zeros and the prevalence of 1s and 2s found in transformed blocks, which can present potential problems when decoding blocks in transform-skipped mode.

[0039] Compared to transform blocks, transform skip blocks have relatively few zero values, and to the extent that transform skip values ​​do have zero values, these zero values ​​tend not to be clustered into specific areas of the transform skip block. Consequently, coefficient decoding techniques designed for decoding transform skip blocks tend to be less efficient when decoding transform skip blocks. By dividing the range of transform skip coefficient levels into k intervals, receiving one or more syntax values ​​indicating which of the k intervals the quantized residual value level is within, and receiving a syntax element indicating the difference between a reference level value for the interval in which the quantized residual value level is within and the actual level of the quantized residual value for the block, a video decoder configured according to the techniques of this disclosure can achieve the advantage of achieving better decoding efficiency when decoding transform skip blocks compared to existing coefficient decoding techniques. The reference level can, for example, be the lowest value included in the interval, but other reference values ​​(such as the highest value in the interval or any other value in the interval) can also be used as the reference level.

[0040] The techniques of this disclosure may be applied to any existing video codec, such as High Efficiency Video Coding (HEVC), or to promising coding tools proposed as part of currently developing standards, such as Versatile Video Coding (VVC), and other future video coding standards.

[0041] Figure 1 1 is a block diagram illustrating an example video encoding and decoding system 100 that can perform the techniques of the present disclosure. The techniques of the present disclosure are generally directed to decoding (encoding and / or decoding) video data. Generally, video data includes any data used to process video. Thus, video data can include original, unencoded video, encoded video, decoded (e.g., reconstructed) video, and video metadata (e.g., signaling data).

[0042] like 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 computers (i.e., laptop computers), tablet computers, set-top boxes, telephone handsets such as smartphones, televisions, cameras, display devices, digital media players, video game consoles, video streaming devices, etc. In some cases, source device 102 and destination device 116 may be equipped for wireless communication according to a wireless communication standard and, therefore, may be referred to as wireless communication devices.

[0043] exist Figure 1 In the example of FIG, 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, video encoder 200 of source device 102 and video decoder 300 of destination device 116 may be configured to apply techniques for signaling residual data of transform skip blocks.

[0044] Thus, 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 and destination devices may include other components or arrangements. For example, source device 102 may receive video data from an external video source, such as an external camera. Similarly, destination device 116 may interface with an external display device, rather than including an integrated display device.

[0045] like Figure 1The illustrated system 100 is merely an example. Generally, any digital video encoding and / or decoding device can implement the techniques for signaling residual data for transform skip blocks. Source device 102 and destination device 116 are merely examples of such decoding devices, where source device 102 generates decoded video data for transmission to destination device 116. This disclosure refers to a "decoding" device as a device that performs decoding (e.g., encoding and / or decoding) of data. Thus, video encoder 200 and video decoder 300 represent examples of decoding devices (specifically, a video encoder and a video decoder, respectively). In some examples, devices 102 and 116 can operate in a substantially symmetrical manner, such that each device 102 and 116 includes both video encoding and decoding components. Thus, system 100 can support one-way or two-way video transmission between video devices 102 and 116, for example, for video streaming, video playback, video broadcasting, or video telephony.

[0046] Typically, video source 104 represents a source of video data (i.e., raw, unencoded video data) and provides a series of consecutive pictures (also referred to as "frames") of video data to video encoder 200, which encodes the data for the pictures. Video source 104 of source device 102 may include a video capture device (such as a camera), a video archive containing previously captured raw video, and / or a video feed interface for receiving video from a video content provider. As another alternative, video source 104 may generate computer graphics-based data as source video or a combination of real-time video, archived video, and computer-generated video. In each case, video encoder 200 may encode captured, pre-captured, or computer-generated video data. Video encoder 200 may rearrange the pictures from the order in which they were received (sometimes referred to as "display order") into a decoding order for decoding. Video encoder 200 may generate a bitstream comprising the encoded video data. Source device 102 may then output the encoded video data onto computer-readable medium 110 via output interface 108 to be received and / or retrieved by, for example, input interface 122 of destination device 116 .

[0047] Memory 106 of source device 102 and memory 120 of destination device 116 represent general purpose memory. In some examples, memories 106 and 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 and 120 can store software instructions executable by, for example, video encoder 200 and video decoder 300, respectively. Although shown separately from video encoder 200 and video decoder 300 in this example, it should be understood that video encoder 200 and video decoder 300 may also include internal memory for functionally similar or equivalent purposes. Furthermore, memories 106 and 120 can store, for example, encoded video data output from video encoder 200 and input to video decoder 300. In some examples, portions of memories 106 and 120 can be allocated, for example, as one or more video buffers for storing raw, decoded, and / or encoded video data.

[0048] The computer-readable medium 110 can represent any type of medium or device capable of transmitting encoded video data from the source device 102 to the destination device 116. In one example, the computer-readable medium 110 represents a communication medium that enables the source device 102 to send the encoded video data directly to the destination device 116 in real time, for example, via a radio frequency network or a computer-based network. According to a communication standard (such as a wireless communication protocol), the output interface 108 can modulate the transmission signal including the encoded video data, and the input interface 122 can demodulate the received transmission signal. The communication medium can include any wireless communication medium 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 may be useful for facilitating communication from the source device 102 to the destination device 116.

[0049] In some examples, source device 102 may output the encoded data from output interface 108 to storage device 112. Similarly, destination device 116 may access the encoded data from storage device 112 via input interface 122. Storage device 112 may include any of a variety of distributed or locally accessed data storage media, such as a hard drive, Blu-ray disc, DVD, CD-ROM, flash memory, volatile or non-volatile memory, or any other suitable digital storage medium for storing encoded video data.

[0050] In some examples, source device 102 may output the encoded video data to a file server 114 or another intermediate storage device that may store the encoded video generated by source device 102. Destination device 116 may access the stored video data from file server 114 via streaming or downloading. File server 114 may be any type of server device capable of storing encoded video data and transmitting the encoded video data to destination device 116. File server 114 may represent a web server (e.g., for a website), a file transfer protocol (FTP) server, a content delivery network device, or a network attached storage (NAS) device. Destination device 116 may access the encoded video data from file server 114 via any standard data connection, including an internet connection. This may include a wireless channel (e.g., a Wi-Fi connection), a wired connection (e.g., a digital subscriber line (DSL), a cable modem, etc.), or a combination of both suitable for accessing the encoded video data stored on file server 114. File server 114 and input interface 122 may be configured to operate according to a streaming protocol, a download transfer protocol, or a combination thereof.

[0051] Output interface 108 and input interface 122 may represent wireless transmitters / receivers, modems, wired networking components (e.g., Ethernet cards), wireless communication components that operate according to any of the various IEEE 802.11 standards, or other physical components. In examples where output interface 108 and input interface 122 include wireless components, output interface 108 and input interface 122 may be configured to transmit data (e.g., encoded video data) according to a cellular communication standard (e.g., 4G, 4G-LTE (Long Term Evolution), LTE Advanced, 5G, etc.). In some examples where output interface 108 includes a wireless transmitter, output interface 108 and input interface 122 may be configured to transmit data (e.g., encoded video data) according to other wireless standards (e.g., IEEE 802.11 specifications, IEEE 802.15 specifications (e.g., ZigBee TM ), Bluetooth TM Standards, etc.) to transmit data (such as encoded video data). In some examples, source device 102 and / or destination device 116 may include respective system-on-chip (SoC) devices. For example, source device 102 may include a SoC device for performing functionality attributed to video encoder 200 and / or output interface 108, and destination device 116 may include a SoC device for performing functionality attributed to video decoder 300 and / or input interface 122.

[0052] The techniques of the present disclosure may be applied to video decoding to support 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.

[0053] The input interface 122 of the destination device 116 receives an encoded video bitstream from the computer-readable medium 110 (e.g., the storage device 112, the file server 114, etc.). The encoded video bitstream may include signaling information defined by the video encoder 200 (which is also used by the video decoder 300), such as syntax elements having 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 the decoded pictures of the decoded video data to a user. The display device 118 may represent any of a variety of display devices, such as a cathode ray tube (CRT), a liquid crystal display (LCD), a plasma display, an organic light emitting diode (OLED) display, or another type of display device.

[0054] Despite 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 multiplexing-demultiplexing units or other hardware and / or software to process the multiplexed streams of both audio and video included in the common data stream. If applicable, the multiplexing-demultiplexing units can follow the ITU H.223 multiplexer protocol or other protocols such as the User Datagram Protocol (UDP).

[0055] The video encoder 200 and the video decoder 300 can each be implemented as any of a variety of suitable encoder and / or decoder circuits, 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 combination thereof. When the technology is partially implemented in software, the device can store instructions for the software in a suitable non-transitory computer-readable medium and use one or more processors to execute the instructions in hardware to perform the technology of the present disclosure. Each of the video encoder 200 and the video decoder 300 can be included in one or more encoders or decoders, and any of the encoders or decoders can be integrated as part of a combined encoder / decoder (CODEC) in the respective device. The device including the video encoder 200 and / or the video decoder 300 may include an integrated circuit, a microprocessor, and / or a wireless communication device (such as a cellular phone).

[0056] The video encoder 200 and the video decoder 300 may operate in accordance with a video coding standard, such as the ITU-T H.265 (also known as the High Efficiency Video Coding standard) or an extension thereof, such as the multi-view and / or scalable video coding extension. Alternatively, the video encoder 200 and the video decoder 300 may operate in accordance with other proprietary or industry standards, such as the Joint Exploratory Test Model (JEM) or the ITU-T H.266 standard, also known as Versatile Video Coding (VVC). The latest draft of the VVC standard is described in the following document: Bross et al., “Versatile Video Coding (Draft 5)”, Joint Video Experts Group (JVET) of ITU-T SG16WP 3 and ISO / IEC JTC 1 / SC 29 / WG 11, 14th Meeting: Geneva, Switzerland, March 19-27, 2019, JVET-N1001-v8 (hereinafter referred to as “VVC Draft 5”). However, the techniques of the present disclosure are not limited to any particular coding standard.

[0057] Typically, the video encoder 200 and the video decoder 300 can perform block-based decoding of a picture. The term "block" generally refers to a structure that includes data to be processed (e.g., encoded, decoded, or otherwise used in an encoding and / or decoding process). For example, a block can include a two-dimensional matrix of samples of luma and / or chroma data. Typically, the video encoder 200 and the video decoder 300 can decode video data represented in a YUV (e.g., Y, Cb, Cr) format. That is, rather than decoding red, green, and blue (RGB) data for samples of a picture, the video encoder 200 and the video decoder 300 can decode luma and chroma components, where the chroma components can include both a red-hue chroma component and a blue-hue chroma component. In some examples, the video encoder 200 converts the received RGB-formatted data to a YUV representation before encoding, and the video decoder 300 converts the YUV representation to an RGB format. Alternatively, a pre-processing unit and a post-processing unit (not shown) can perform these conversions.

[0058] The present disclosure may generally refer to the decoding of a picture (e.g., encoding and decoding) to include the process of encoding or decoding the data of the picture. Similarly, the present disclosure may refer to the decoding of a block of a picture to include the process of encoding or decoding the data for the block (e.g., prediction and / or residual decoding). A coded video bitstream generally includes a series of values ​​for syntax elements that represent decoding decisions (e.g., decoding mode) and the partitioning of the picture into blocks. Therefore, references to decoding a picture or block should generally be understood to refer to decoding the values ​​of the syntax elements that form the picture or block.

[0059] HEVC defines various blocks, including coding units (CUs), prediction units (PUs), and transform units (TUs). According to HEVC, a video decoder (such as the video encoder 200) partitions a coding tree unit (CTU) into CUs based on a quadtree structure. That is, the video decoder partitions the CTU and CU into four equal, non-overlapping squares, and each node of the quadtree has zero or four child nodes. A node without child nodes may be referred to as a "leaf node," and the CU of such a leaf node may include one or more PUs and / or one or more TUs. The video decoder may further partition the PU and TU. For example, in HEVC, the residual quadtree (RQT) represents the partitioning of the TU. In HEVC, PU represents inter-frame prediction data, and TU represents residual data. The intra-predicted CU includes intra-frame prediction information, such as an intra-frame mode indication.

[0060] As another example, the video encoder 200 and the video decoder 300 can be configured to operate according to JEM or VVC. According to JEM or VVC, a video decoder (such as the video encoder 200) partitions a picture into multiple coding tree units (CTUs). The video encoder 200 can partition the CTU according to a tree structure (such as a quadtree-binary tree (QTBT) structure or a multi-type tree (MTT) structure). The QTBT structure removes the concept of multiple partition types, such as the separation between CU, PU, ​​and TU in HEVC. The QTBT structure includes two levels: a first level partitioned according to quadtree partitioning, and a second level partitioned according to binary tree partitioning. The root node of the QTBT structure corresponds to the CTU. The leaf nodes of the binary tree correspond to the coding units (CUs).

[0061] In the MTT partitioning structure, blocks can be partitioned using quadtree (QT) partitioning, binary tree (BT) partitioning, and one or more types of ternary tree (TT) partitioning. Ternary tree partitioning is a partitioning in which a block is split into three sub-blocks. In some examples, ternary tree partitioning divides a block into three sub-blocks without dividing the original block through the center. The partitioning types in MTT (e.g., QT, BT, and TT) can be symmetric or asymmetric.

[0062] In some examples, the video encoder 200 and the video decoder 300 may use a single QTBT or MTT structure to represent each of the luma component and the chroma components, while in other examples, the video encoder 200 and the video decoder 300 may use two or more QTBT or MTT structures, such as one QTBT / MTT structure for the luma component and another QTBT / MTT structure for the two chroma components (or two QTBT / MTT structures for respective chroma components).

[0063] The video encoder 200 and the video decoder 300 can be configured to use per-HEVC quadtree segmentation, QTBT segmentation, MTT segmentation, or other segmentation structures. For purposes of explanation, the technology of the present disclosure is described with respect to QTBT segmentation. However, it should be understood that the technology of the present disclosure can also be applied to video decoders configured to use quadtree segmentation or other types of segmentation.

[0064] Blocks (e.g., CTUs or CUs) may be grouped in a picture in various ways. As an example, a brick may refer to a rectangular area of ​​a CTU row within a particular tile in a picture. A tile may be a rectangular area of ​​a CTU within a particular tile column and a particular tile row in a picture. A tile column refers to a rectangular area of ​​a CTU having a height equal to the height of the picture and a width specified by a syntax element (e.g., such as in a picture parameter set). A tile row refers to a rectangular area of ​​a CTU having a height specified by a syntax element (e.g., such as in a picture parameter set) and a width equal to the width of the picture.

[0065] In some examples, a slice may be partitioned into multiple bricks, each of which may include one or more CTU rows within the slice. A slice that is not partitioned into multiple bricks may also be referred to as a brick. However, a brick that is a true subset of a slice may not be referred to as a slice.

[0066] Bricks in a picture can also be arranged in slices. A slice can be an integer number of bricks in a picture, which can be exclusively contained in a single Network Abstraction Layer (NAL) unit. In some examples, a slice includes multiple complete slices or a series of consecutive complete bricks of just one slice.

[0067] This disclosure may use "NxN" and "N by N" interchangeably to refer to the sample dimensions of a block (such as a CU or other video block) in terms of vertical and horizontal dimensions, for example, 16x16 samples or 16 by 16 samples. Typically, a 16x16 CU will have 16 samples in the vertical direction (y=16) and will have 16 samples in the horizontal direction (x=16). Likewise, an NxNCU 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 may be arranged in rows and columns. Furthermore, a CU does not necessarily have the same number of samples in the horizontal direction as in the vertical direction. For example, a CU may include NxM samples, where M is not necessarily equal to N.

[0068] The video encoder 200 encodes video data representing prediction and / or residual information and other information for a CU. The prediction information indicates how the CU will be predicted in order to form a prediction block for the CU. The residual information typically represents the sample-by-sample difference between the samples of the CU before encoding and the prediction block.

[0069] To predict a CU, the video encoder 200 may typically form a prediction block for the CU through inter-frame prediction or intra-frame prediction. Inter-frame prediction typically refers to predicting a CU from data of a previously decoded picture, while intra-frame prediction typically refers to predicting a CU from previously decoded data of the same picture. To perform inter-frame prediction, the video encoder 200 may use one or more motion vectors to generate a prediction block. The video encoder 200 may typically perform a motion search to identify a reference block that closely matches the CU, for example, in terms of the difference between the CU and the reference block. The video encoder 200 may calculate a difference metric using the sum of absolute differences (SAD), the sum of squared differences (SSD), the mean absolute difference (MAD), the mean squared difference (MSD), or other such difference calculations to determine whether the reference block closely matches the current CU. In some examples, the video encoder 200 may use unidirectional prediction or bidirectional prediction to predict the current CU.

[0070] Some examples of JEM and VVC also provide an affine motion compensation mode that can be considered an inter-frame prediction mode. In the affine motion compensation mode, the video encoder 200 can determine two or more motion vectors representing non-translational motion (such as zooming in or out, rotation, perspective motion, or other irregular motion types).

[0071] To perform intra prediction, the video encoder 200 can select an intra prediction mode to generate a prediction block. Some examples of JEM and VVC provide sixty-seven intra prediction modes, including various directional modes, as well as planar mode and DC mode. Typically, the video encoder 200 selects an intra prediction mode that describes neighboring samples of the current block from which the current block (e.g., a block of a CU) is predicted. Assuming that the video encoder 200 decodes CTUs and CUs in raster scan order (from left to right, from top to bottom), such samples may typically be above, above left, or to the left of the current block in the same picture as the current block.

[0072] The video encoder 200 encodes data indicating a prediction mode for the current block. For example, for inter-frame prediction mode, the video encoder 200 may encode data indicating which of various available inter-frame prediction modes to use, as well as motion information for the corresponding mode. For unidirectional inter-frame prediction or bidirectional inter-frame prediction, for example, the video encoder 200 may encode motion vectors using Advanced Motion Vector Prediction (AMVP) or Merge Mode. The video encoder 200 may use a similar mode to encode motion vectors for affine motion compensation mode.

[0073] After a prediction, such as intra-prediction or inter-prediction of a block, the video encoder 200 may calculate residual data for the block. The residual data (e.g., a residual block) represents the sample-by-sample difference between the block and a prediction block for the block, which was formed using a corresponding prediction mode. The video encoder 200 may apply one or more transforms to the residual block to produce transformed data in a transform domain rather than a sample domain. For example, the video encoder 200 may apply a discrete cosine transform (DCT), an integer transform, a wavelet transform, or a conceptually similar transform to the residual video data. In addition, the video encoder 200 may apply a secondary transform, such as a mode-dependent non-separable secondary transform (MDNSST), a signal-dependent transform, a Karhunen-Loeve transform (KLT), etc., after the first transform. The video encoder 200 generates transform coefficients after applying the one or more transforms.

[0074] Although examples of performing a transform are described above, in some examples, the transform can be skipped. For example, the video encoder 200 can implement a transform skip mode in which the transform operation is skipped. In the example of skipping the transform, the video encoder 200 can output coefficients corresponding to residual values ​​instead of transform coefficients. The coefficients corresponding to the residual values ​​can, for example, correspond to quantized residual values. In the following description, the term "coefficient" should be interpreted to include coefficients corresponding to residual values ​​or transform coefficients generated from the results of the transform.

[0075] As described above, the video encoder 200 may perform quantization on the transform coefficients or residual values. Quantization generally refers to a process in which a value is quantized to potentially reduce the amount of data used to represent the value, thereby providing further compression. By performing the quantization process, the video encoder 200 may reduce the bit depth associated with some or all of the coefficients. For example, the video encoder 200 may round down an n-bit value to an m-bit value during quantization, where n is greater than m. In some examples, to perform quantization, the video encoder 200 may perform a bit-by-bit right shift of the value to be quantized.

[0076] After quantization, the video encoder 200 can scan the coefficients to produce a one-dimensional vector from the two-dimensional matrix including the quantized coefficients. For transform coefficients, the scan can be designed to place higher energy (and therefore lower frequency) coefficients at the front of the vector and lower energy (and therefore higher frequency) transform coefficients at the back of the vector. For transform skip coefficients, the same or different scans can be used. In some examples, the video encoder 200 can scan the quantized coefficients using a predefined scan order to produce a serialized vector and then entropy encode the quantized coefficients of the vector. In other examples, the video encoder 200 can perform adaptive scanning. After scanning the quantized coefficients to form a one-dimensional vector, the video encoder 200 can entropy encode the one-dimensional vector, for example, according to context-adaptive binary arithmetic coding (CABAC). The video encoder 200 can also entropy encode the values ​​of syntax elements used to describe metadata associated with the encoded video data for use by the video decoder 300 when decoding the video data.

[0077] To perform CABAC, the video encoder 200 may assign context within a context model to a symbol to be transmitted. The context may relate to, for example, whether the neighboring values ​​of the symbol are zero values. The probability determination may be based on the context assigned to the symbol.

[0078] The video encoder 200 may further generate syntax data (such as block-based syntax data, picture-based syntax data, and sequence-based syntax data) in, for example, a picture header, a block header, or a slice header, or other syntax data (such as a sequence parameter set (SPS), a picture parameter set (PPS), or a video parameter set (VPS)) to be sent to the video decoder 300. The video decoder 300 may similarly decode such syntax data to determine how to decode the corresponding video data.

[0079] In this way, the video encoder 200 can generate a bitstream that includes coded video data, such as syntax elements describing the partitioning of a picture into blocks (e.g., CUs) and prediction and / or residual information for the blocks. Ultimately, the video decoder 300 can receive the bitstream and decode the coded video data.

[0080] In general, the video decoder 300 performs a process that is reciprocal to the process performed by the video encoder 200 to decode the encoded video data of the bitstream. For example, the video decoder 300 can use CABAC to decode the values ​​of syntax elements for the bitstream in a manner substantially similar (albeit reciprocal) to the CABAC encoding process of the video encoder 200. The syntax elements can define partitioning information for partitioning a picture into CTUs and partitioning each CTU according to a corresponding partitioning structure (such as a QTBT structure) to define CUs of the CTU. The syntax elements can further define prediction and residual information for a block (e.g., a CU) of video data.

[0081] The residual information may be represented, for example, by quantized transform coefficients or quantized transform skip coefficients. The video decoder 300 may inverse quantize the quantized coefficients of the block and, if coded in transform mode, inverse transform the quantized coefficients of the block to regenerate a residual block for the block. The video decoder 300 uses the signaled prediction mode (intra-frame prediction or inter-frame prediction) and associated prediction information (e.g., motion information for inter-frame prediction) to form a prediction block for the block. The video decoder 300 may then combine the prediction block and the residual block (on a sample-by-sample basis) to regenerate the original block. The video decoder 300 may perform additional processing, such as performing a deblocking process to reduce visual artifacts along block boundaries.

[0082] According to the techniques of the present disclosure, a video encoder 200 may be configured to determine whether a block of video data is encoded in a transform skip mode, determine a level of a quantized residual value for the block, and determine a quantization parameter for the block of video data. The video encoder 200 may be configured to determine a range of the level of the quantized residual value for the block of video data based on the determined quantization parameter, and divide the range into k intervals, where k represents an integer value. The video encoder 200 may determine which of the k intervals the level of the quantized residual value falls within, and then determine a difference value representing the difference between a reference level value for the interval in which the level of the quantized residual value falls and the level of the quantized residual value for the block. The video encoder 200 may be configured to signal the level of the quantized residual value for the block based on the k intervals by generating one or more syntax elements indicating the interval in which the level of the quantized residual value falls and a syntax element indicating the difference value for inclusion in the bitstream of the encoded video data.

[0083] According to the technology of the present disclosure, the video decoder 300 can be configured to determine whether a block of video data is encoded in a transform skip mode and determine a quantization parameter for the block of video data. The video decoder 300 can determine a range of levels of quantized residual values ​​of the block of video data based on the determined quantization parameter and divide the range into k intervals, where k represents an integer value. The video decoder 300 can determine the level of the quantized residual value of the block based on the k intervals by the following operations: receiving one or more syntax elements indicating which interval of the k intervals the level of the quantized residual value is within; receiving a syntax element indicating a difference value, wherein the difference value represents a difference between a reference level value of the interval in which the level of the quantized residual value is located and the level of the quantized residual value of the block; and determining the level of the quantized residual value based on the reference level value and the difference value.

[0084] By signaling the level of the quantized residual value based on which of the k intervals the level of the quantized residual value falls within and a difference value representing the difference between the reference level value of the interval in which the level of the quantized residual value falls and the level of the quantized residual value of the block, the video encoder 200 and the video decoder 300 can use fewer bits to entropy decode the quantized residual value of the block decoded in the transform skip mode when compared to the existing technology for decoding the quantized residual value. By using fewer bits to entropy decode the quantized residual value of the block decoded in the transform skip mode, the video encoder 200 and the video decoder 300 can achieve better compression without adding any additional distortion, thereby improving the rate-distortion tradeoff of the decoded video data.

[0085] In general, the present disclosure may involve "signaling" certain information (such as syntax elements). The term "signaling" may generally refer to the transmission of values ​​for syntax elements and / or other data used to decode encoded video data. That is, video encoder 200 may signal values ​​for syntax elements in a bitstream. Generally, signaling refers to generating values ​​in a bitstream. As described above, source device 102 may transmit the bitstream to destination device 116 in substantially real time or in non-real time (such as may occur when storing syntax elements to storage device 112 for later retrieval by destination device 116).

[0086] Figure 2A and Figure 2Bis a conceptual diagram showing an example quadtree binary tree (QTBT) structure 130 and a corresponding coding tree unit (CTU) 132. The solid lines represent quadtree splits, and the dashed lines indicate binary tree splits. In each split (i.e., non-leaf) node of the binary tree, a flag is signaled to indicate which split type (i.e., horizontal or vertical) is used, where, in this example, 0 indicates horizontal splitting and 1 indicates vertical splitting. For quadtree splitting, since the quadtree node splits the block horizontally and vertically into 4 sub-blocks of equal size, there is no need to indicate the split type. Therefore, the video encoder 200 can encode the following, and the video decoder 300 can decode the following: syntax elements (such as split information) for the region tree level (i.e., solid line) of the QTBT structure 130, and syntax elements (such as split information) for the prediction tree level (i.e., dashed line) of the QTBT structure 130. The video encoder 200 may encode video data (such as prediction and transform data) for the CU represented by the terminal leaf node of the QTBT structure 130 , and the video decoder 300 may decode the video data.

[0087] generally, Figure 2B The CTU 132 may be associated with parameters defining the size of blocks corresponding to nodes at the first and second levels of the QTBT structure 130. These parameters may include a CTU size (indicating the size of the CTU 132 in samples), a minimum quadtree size (MinQTSize, indicating the minimum allowed quadtree leaf node size), a maximum binary tree size (MaxBTSize, indicating the maximum allowed binary tree root node size), a maximum binary tree depth (MaxBTDepth, indicating the maximum allowed binary tree depth), and a minimum binary tree size (MinBTSize, indicating the minimum allowed binary tree leaf node size).

[0088] The root node of the QTBT structure corresponding to the CTU can have four child nodes at the first level of the QTBT structure, each of which can be split according to quadtree partitioning. That is, the nodes at the first level are leaf nodes (no child nodes) or have four child nodes. The example of the QTBT structure 130 represents such nodes as including parent nodes and child nodes with solid branches. If the nodes at the first level are not larger than the maximum allowed binary tree root node size (MaxBTSize), these nodes can be further partitioned by their respective binary trees. The binary tree splitting of a node can be iterated until the node resulting from the split reaches the minimum allowed binary tree leaf node size (MinBTSize) or the maximum allowed binary tree depth (MaxBTDepth). The example of the QTBT structure 130 represents such nodes as having dotted branches. The binary tree leaf nodes are called decoding units (CUs), which are used for prediction (e.g., intra-picture or inter-picture prediction) and transformation without any further partitioning. As discussed above, CUs can also be referred to as "video blocks" or "blocks."

[0089] In one example of a QTBT partitioning structure, the CTU size is set to 128x128 (luminance sample 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. Quadtree leaf nodes can have sizes from 16x16 (i.e., MinQTSize) to 128x128 (i.e., CTU size). If the leaf quadtree node is 128x128, then since the size exceeds MaxBTSize (i.e., 64x64 in this example), the leaf quadtree node will not be further split by the binary tree. Otherwise, the leaf quadtree node will be further split by the binary tree. Therefore, the quadtree leaf node is also the root node for the binary tree and has a binary tree depth of 0. When the binary tree depth reaches MaxBTDepth (4 in this example), no further splitting is allowed. When a binary tree node has a width equal to MinBTSize (4 in this example), it means that no further horizontal splitting is allowed. Similarly, a binary tree node with a height equal to MinBTSize means that no further vertical splitting is allowed for the binary tree node. As described above, the leaf nodes of the binary tree are called CUs and are further processed according to prediction and transformation without further segmentation.

[0090] This disclosure describes techniques related to binarization performed in transform-skip residual coding (also known as transform-skip mode). More specifically, this disclosure describes techniques related to the entropy decoding process that converts a binary representation into a series of non-binary values ​​of quantized coefficients. The corresponding entropy encoding process, which is the inverse of entropy decoding, is also described herein.

[0091] The following document describes techniques related to transform skip residual decoding: B. Bross, T. Nguyen, P. Keydel, H. Schwarz, D. Marpe, T. Wiegand, “Non-CE8: Unified Transform Type Signalling and Residual Coding for Transform Skip”, JVET document JVET-M0464, Marrakech, MD, January 2019 (hereafter referred to as JVET-M0464).

[0092] If transform skip residual coding as described in JVET-M0464 is implemented, the video decoder 300 uses the syntax elements sig_coeff_flag and abs_level_gtX_flags (where X=1, 2, ... 5), par_level_flag, abs_remainder, and coeff_sign_flag to decode the coefficient level (CoeffLevel). The syntax element sig_coeff_flag indicates whether the coefficient is non-zero. The syntax element coeff_sign_flag indicates whether the coefficient is negative, and the syntax element par_level_flag indicates whether the coefficient is odd or even. The syntax element abs_level_gtX_flags (X=1, 2, ... 5) indicates whether the absolute coefficient level is greater than 1<<(X-1), where << represents a left shift operation. Specifically, if the coefficient is non-zero (i.e., sig_coeff_flag=0), the video decoder 300 receives and parses the flag abs_level_gt1_flags, which indicates whether the absolute coefficient value is greater than 1. If the absolute coefficient value is greater than 1, the video decoder 300 receives the syntax element abs_level_gt2_flags, which indicates whether the absolute coefficient value is greater than 2. Similarly, if the absolute coefficient value is greater than 1<<(a-1), the video decoder 300 receives the syntax element abs_level_gtX_flags, where a+1 indicates whether the absolute coefficient value is greater than 1<<a. If the absolute coefficient level is greater than 10, the video decoder 300 receives and parses the syntax element abs_remainder, which indicates the difference, e.g., abs(CoeffLevel)−10.

[0093] The video decoder 300 may then derive the reconstructed transform coefficients for the a non-zero coefficients as follows:

[0094] CoeffLevel=(1–2*coeff_sign_flag)*(1+abs_level_gt1_flag+par_level_flag+2*(abs_level_gt2_flag+abs_level_gt3_flag+…+abs_level_gt5_flag)+2*abs_remainder).

[0095] However, the binarization technique in JVET-M0464 fails to reflect the dynamic range of absolute coefficient levels for different quantization parameters. For low QP ranges, the absolute quantized transform skip coefficients can have large values, such as values ​​greater than 20. In such cases, the video encoder 200 must signal all abs_level_gtX_flags for decoding in the normal bins, but must also utilize the bypass bins to signal the large residual value (CoeffLevel) -10. Bypass decoding generally refers to non-context adaptive entropy decoding.

[0096] According to the technology of the present disclosure, a new binarization process for transform skip residual decoding is proposed. For the input quantization parameter of QP, the video encoder 200 and the video decoder 300 can be configured to derive the corresponding dynamic range [0, maxTsLevel] of the transform skip coefficient as follows:

[0097] const int iQBits=QUANT_SHIFT+qpPer;

[0098] int maxTsLevel=((quantisationCoefficient*((1< <channelBitDepth)-1)+(1<<(iQBits-1)))> >iQBits);

[0099] Where QUANT_SHIFT is the quantization shift parameter (currently set to 14 in VTM5.0), qpPer is equal to QP / 6, and quantisationCoefficient is the quantizationScaler currently derived based on the lookup table quantisationLookUp in VTM5.0:

[0100] quantificationLookUp=[26214,23302,20560,18396,16384,14564].

[0101] quantizationScaler quantisationCoefficient is equal to quantisationLookUp[qpRem], where qpRem is the remainder of QP divided by 6. The value in quantisationLookUp[] is derived as follows:

[0102]

[0103] For the purpose of explanation, the raw residual can be denoted as R and the quantized residual can be denoted as Rq. The formula for quantization is

[0104] Rq=R / qStep

[0105] Where qStep is a function of QP: qStep = 2 QP-4 / 6 .

[0106] Large values ​​of QP correspond to large values ​​of qStep and therefore to smaller Rq, which means coarser quantization.

[0107] The following pseudocode shows an example implementation of the above formula in software using integer implementation:

[0108] Rq=(quantisationLookUp[QP%6]*R+(1<<(iQBits–1)))>>iQbits

[0109] QP%6 indicates the remainder after QP is divided by 6.

[0110] The value in quantisationLookUp[] can be derived as follows:

[0111]

[0112] iQBits = 14 + qpPer, where qpPer is the quotient of QP / 6

[0113] For a given QP value, the maximum residual value has the maximum quantization level maxTsLevel, which is (1 < <channelBitDepth)–1。

[0114] In one example, after the video encoder 200 and the video decoder 300 calculate the dynamic range of the quantized coefficients, the video encoder 200 and the video decoder 300 may divide the range into k intervals:

[0115] [2,t1],[t1+1,t2],[t2+1,t3],……[t k-2 +1,tk-1 ],[t k-1 +1,maxTsLevel].

[0116] After signaling the syntax elements sig_coeff_flag, coeff_sign_flag, and abs_level_gt1_flag (as in the current transform skip residual coefficients described in JVET-M0464), the video encoder 200 may signal the syntax element abs_level_gtTX_flag, which indicates the level of the absolute coefficient. Specifically, if the absolute coefficient level is greater than 1, the video encoder 200 signals the syntax element abs_level_gtT1_flag, which indicates whether the absolute level is greater than t1. Similarly, for other level syntaxes, if the absolute coefficient level is greater than t X-1 , the video encoder 200 signals a syntax element abs_level_gtTX_flag, which indicates whether the absolute coefficient level is greater than t X . The syntax element abs_level_gtTX_flag can be decoded in the following ways: bit-plane mode, where the syntax abs_level_gtTX_flag of all coefficients in the current block will be decoded before decoding the syntax element abs_level_gtT(X+1)_flag; or interleaved mode, where all abs_level_gtTX_flag elements of a coefficient are decoded before decoding the next coefficient. Similar to the abs_level_gtX_flag decoding in the current transform skip residual decoding in VTM5.0, if the number of bins limit for regular decoding (currently set to 2*blockwidth*blockheight) is not reached, the syntax element abs_level_gtTX_flag can be decoded using regular bins. If the limit is reached, the rest of the syntax element is bypassed for decoding.

[0117] After encoding sig_coeff_flag, coeff_sign_flag, abs_level_gt1_flag, and abs_level_gtTX_flag, in the last pass, the video encoder 200 may signal, in bypass mode, for example, using truncated unary coding or Rice codes, a syntax element abs_remainder indicating the remainder within the interval that the absolute coefficient level falls within. For example, if the absolute coefficient level absCoeffLevel falls within the interval [t c-1 +1,t c], the syntax abs_level_gtT1_flag, abs_level_gtT1_flag, ... abs_level_gtTc_flag shall be signaled. In the last pass, the remainder absCoeffLevel–(t c-1 +1).

[0118] The video decoder 300 may receive the above syntax elements and derive the reconstructed transform coefficients for the non-zero coefficients as follows:

[0119] CoeffLevel=(1–2*coeff_sign_flag)*(1+abs_level_gt1_flag+abs_level_gtT1_flag*(t1–1)+abs_level_gtT2_flag*(t2–t1)+abs_level_gtT3_flag*(t3–t2)…+abs_level_gt(k-1)_flag*(t k-1 –t k-2 )+abs_remainder).

[0120] Since the proposed binarization process for transform skip residual decoding can better model the large dynamic range of coefficient levels, the technology of this disclosure can also be used in conjunction with a quantization parameter offset (qp_offset), where if the proposed binarization for transform skip residual decoding is applied, the QP set for the current decoding unit is modified to QP-qp_offset. qp_offset is a positive integer.

[0121] The binarization technique described herein for transform skip residual decoding can also be applied to coefficients decoded after applying quantized residual DPCM (RDPCM). However, due to the residual subtraction, the maximum coefficient size is 2*maxTsLevel, rather than maxTsLevel. When the value coefficient -maxTsLevel is used to predict the value coefficient maxTsLevel, the maximum amplitude occurs, resulting in a coefficient residual value of 2*maxTsLevel. Therefore, the video encoder 200 and the video decoder 300 can be configured to calculate the dynamic range of the block decoded in RDPCM as [0, 2*maxTsLevel].

[0122] According to one example technique of the present disclosure, the video encoder 200 and the video decoder 300 may be configured to calculate the dynamic range of a coefficient and divide the range into k (inclusive) intervals as follows:

[0123] For coefficients in transform skip mode:

[0124] [2,t1],[t1+1,t2],[t2+1,t3],…[t k-2 +1,t k-1 ],[t k-1 +1,maxTsLevel].

[0125] For coefficients in RDPCM mode:

[0126] [2,t1],[t1+1,t2],[t2+1,t3],…[t k-2 +1,t k-1 ],[t k-1 +1,2*maxTsLevel].

[0127] After signaling the syntax elements sig_coeff_flag, coeff_sign_flag, and abs_level_gt1_flag in the current transform skipped residual coefficients as described in JVET-M0464, the video encoder 200 can signal the index of the bin that the coefficient falls in and the remainder within the bin. The following are several examples of signaling the bin index.

[0128] In a first example, if the absolute coefficient level is greater than 1, ie, abs_level_gt1_flag=1, the video encoder 200 signals a syntax element abs_level_gtT1_flag indicating whether the absolute level is greater than t1. Similarly, for other level syntaxes, if the absolute coefficient level is greater than t X-1 , the video encoder 200 signals a syntax element abs_level_gtTX_flag, which indicates whether the absolute coefficient level is greater than t X The syntax element abs_level_gtTX_flag can be decoded in the following ways: bit-plane mode, where the syntax abs_level_gtTX_flag of all coefficients in the current block will be decoded before decoding the syntax element abs_level_gtT(X+1)_flag; or interleaved mode, where all abs_level_gtTX_flag elements of a coefficient are decoded before decoding the next coefficient. Similar to the decoding of abs_level_gtX_flag in current transform skip residual decoding in VTM, the syntax element abs_level_gtTX_flag can be decoded with regular bins if the number of bins limit for regular decoding (currently set to 2*blockwidth*blockheight) is not reached. If the limit is reached, the rest of the syntax element is bypassed for decoding.

[0129] In another example, if the absolute coefficient level is greater than 1, ie, abs_level_gt1_flag=1, then if the coefficient falls within the interval [t k-1 +1,t k ], the video encoder 200 signals the value k. The video encoder 200 can, for example, encode the value in bypass mode, such as using Rice-Golomb decoding or truncated binary decoding. In some examples, the video encoder 200 can encode the value using context-coded bins after binarization (e.g., using unary decoding), where each bin in the unary code is decoded as a context-coded bin. If the bin limit for conventional decoding is reached, such as set at 2*block width*block height, the video encoder 200 can bypass decoding the rest of the bins.

[0130] After signaling the interval index, video encoder 200 may signal a syntax element abs_remainder indicating the remainder within the interval that the absolute coefficient level falls within. For example, if the absolute coefficient level absCoeffLevel falls within the interval [t c-1 +1,t c ], the video encoder 200 signals the remainder absCoeffLevel–(t c-1 +1). The video encoder 200 may signal the remainder in bypass mode, for example, using truncated unary coding or Rice codes. The video decoder 300 may receive the syntax elements described herein and determine the value of absCoeffLevel based on the received syntax elements in the manner described above.

[0131] According to another example of the present disclosure, the video encoder 200 and the video decoder 300 may be configured to calculate the dynamic range of coefficient values ​​and divide the range into k (inclusive) intervals as follows:

[0132] For coefficients in transform skip mode:

[0133] [1,t1],[t1+1,t2],[t2+1,t3],…[t k-2 +1,t k-1 ],[t k-1 +1,maxTsLevel].

[0134] For coefficients in RDPCM mode:

[0135] [1,t1],[t1+1,t2],[t2+1,t3],…[t k-2 +1,t k-1 ],[t k-1 +1,2*maxTsLevel].

[0136] After signaling the syntax elements sig_coeff_flag and coeff_sign_flag (in current transform skip residual coding as described in JVET-M0464), video encoder 200 may signal the index of the bin in which the coefficient falls and the remainder within the bin, as described above.

[0137] Figure 3 is a block diagram illustrating an example video encoder 200 that may perform the techniques of this disclosure. Figure 3 This is provided for purposes of explanation and should not be considered limiting of the techniques broadly illustrated and described in this disclosure. For purposes of explanation, this disclosure describes video encoder 200 in the context of video coding standards such as the HEVC video coding standard and the developing H.266 video coding standard. However, the techniques of this disclosure are not limited to these video coding standards and are generally applicable to video encoding and decoding.

[0138] exist Figure 3 In the example of FIG, the video encoder 200 includes a video data memory 230, a mode selection unit 202, a residual generation unit 204, a transform processing unit 206, a quantization unit 208, an inverse quantization unit 210, an inverse transform processing unit 212, a reconstruction unit 214, a filter unit 216, a decoded picture buffer (DPB) 218, and an entropy coding unit 220. The entropy coding unit 220 includes a transform skip syntax processing unit 221. Any one or all of the video data memory 230, the mode selection unit 202, the residual generation unit 204, the transform processing unit 206, the quantization unit 208, the inverse quantization unit 210, the inverse transform processing unit 212, the reconstruction unit 214, the filter unit 216, the DPB 218, and the entropy coding unit 220 may be implemented in one or more processors or processing circuits. Furthermore, the video encoder 200 may include additional or alternative processors or processing circuits to perform these functions and other functions.

[0139] The video data memory 230 may store video data to be encoded by the components of the video encoder 200. The video encoder 200 may receive video data from, for example, the video source 104 ( Figure 1) receives video data stored in the video data memory 230. The DPB 218 can act as a reference picture memory that stores reference video data for use when the video encoder 200 predicts subsequent video data. The video data memory 230 and the 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. The video data memory 230 and the DPB 218 can be provided by the same memory device or by separate memory devices. In various examples, the video data memory 230 can be on-chip with other components of the video encoder 200 (as shown), or off-chip relative to those components.

[0140] In this disclosure, references to 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). Rather, references to video data memory 230 should be understood as reference memory that stores video data received by the video encoder 200 for encoding (e.g., video data for 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 .

[0141] Shown Figure 4 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 specific functions and are pre-set with respect to the operations that can be performed. Programmable circuits refer to circuits that can be programmed to perform various tasks and provide flexible functionality with respect to 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 (e.g., to receive parameters or output parameters), but the types of operations performed by fixed-function circuits are generally immutable. In some examples, one or more of these units can be different circuit blocks (fixed-function or programmable), and in some examples, one or more units can be integrated circuits.

[0142] The video encoder 200 may include an arithmetic logic unit (ALU), an elementary function unit (EFU), a digital circuit, an analog circuit, and / or a programmable core formed by a programmable circuit. In an example where the operation of the video encoder 200 is performed using software executed by a programmable circuit, the memory 106 ( Figure 1 ) may store object code for software that video encoder 200 receives and executes, or another memory (not shown) within video encoder 200 may store such instructions.

[0143] The video data memory 230 is configured to store the received video data. The video encoder 200 can retrieve the picture of the video data from the video data memory 230 and provide the video data to the residual generation unit 204 and the mode selection unit 202. The video data in the video data memory 230 can be the original video data to be encoded.

[0144] The mode selection unit 202 includes a motion estimation unit 222, a motion compensation unit 224, and an intra prediction unit 226. The mode selection unit 202 may include additional functional units to perform video prediction according to other prediction modes. For example, the mode selection unit 202 may include a palette unit, an intra-block copy unit (which may be part of the motion estimation unit 222 and / or the motion compensation unit 224), an affine unit, a linear model (LM) unit, etc.

[0145] The mode selection unit 202 typically coordinates multiple encoding passes to test combinations of encoding parameters and the resulting rate-distortion values ​​for such combinations. The encoding parameters may include the partitioning of a CTU into CUs, the prediction mode used for a CU, the transform type used for the residual data of a CU, the quantization parameter used for the residual data of a CU, etc. The mode selection unit 202 may ultimately select a combination of encoding parameters that has a better rate-distortion value than other tested combinations.

[0146] The video encoder 200 may partition a picture retrieved from the video data memory 230 into a series of CTUs and encapsulate one or more CTUs into a slice. The mode selection unit 202 may partition the CTUs of the picture according to a tree structure (such as the QTBT structure or quadtree structure of HEVC described above). As described above, the video encoder 200 may partition the CTUs according to the tree structure to form one or more CUs. Such CUs may also be generally referred to as "video blocks" or "blocks."

[0147] Typically, mode select unit 202 also controls its components (e.g., motion estimation unit 222, motion compensation unit 224, and intra prediction unit 226) to generate a prediction block for the current block (e.g., the current CU, or, in HEVC, the overlapping portions of a PU and TU). To inter-predict the current block, motion estimation unit 222 may 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 decoded pictures stored in DPB 218). Specifically, motion estimation unit 222 may calculate values ​​representing how similar potential reference blocks are to the current block, such as based on sum of absolute differences (SAD), sum of squared differences (SSD), mean absolute difference (MAD), mean squared difference (MSD), and the like. Motion estimation unit 222 may typically perform these calculations using the sample-by-sample difference between the current block and the reference block under consideration. Motion estimation unit 222 may identify the reference block with the lowest value resulting from these calculations, indicating the reference block that most closely matches the current block.

[0148] Motion estimation unit 222 may form one or more motion vectors (MVs) that define the position of a reference block in a reference picture relative to the position of a current block in the current picture. Motion estimation unit 222 may then provide the motion vectors to motion compensation unit 224. For example, for unidirectional inter prediction, motion estimation unit 222 may provide a single motion vector, while for bidirectional inter prediction, motion estimation unit 222 may provide two motion vectors. Motion compensation unit 224 may then use the motion vectors to generate a prediction block. For example, motion compensation unit 224 may use the motion vectors to retrieve data for the reference block. As another example, if the motion vectors have fractional sample precision, motion compensation unit 224 may interpolate values ​​for the prediction block based on one or more interpolation filters. Furthermore, for bidirectional inter prediction, motion compensation unit 224 may retrieve data for two reference blocks identified by their respective motion vectors and combine the retrieved data, for example, by sample-by-sample averaging or a weighted average.

[0149] As another example, for intra prediction or intra prediction decoding, the intra prediction unit 226 can generate a prediction block based on samples adjacent to the current block. For example, for directional mode, the intra prediction unit 226 can generally mathematically combine the values ​​of the adjacent samples and pad these calculated values ​​across the current block in a defined direction to produce a prediction block. As another example, for DC mode, the intra prediction unit 226 can calculate the average of the adjacent samples of the current block and generate a prediction block to include the obtained average for each sample of the prediction block.

[0150] 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 calculates 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 may also determine the difference between sample values ​​in the residual block to generate the residual block using residual differential pulse coded modulation (RDPCM). In some examples, residual generation unit 204 may be formed using one or more subtractor circuits that perform binary subtraction.

[0151] In the example where the mode select unit 202 partitions the CU into PUs, each PU may be associated with a luma prediction unit and a corresponding chroma prediction unit. The video encoder 200 and the video decoder 300 may support PUs of various sizes. As noted above, the size of a CU may refer to the size of the luma coding block of the CU, and the size of a PU may refer to the size of the luma prediction unit of the PU. Assuming a particular CU size of 2Nx2N, the video encoder 200 may support PU sizes of 2Nx2N or NxN for intra prediction, and symmetrical PU sizes of 2Nx2N, 2NxN, Nx2N, NxN, or similar sizes for inter prediction. The video encoder 200 and the video decoder 300 may also support asymmetric partitioning for PU sizes of 2NxnU, 2NxnD, nLx2N, and nRx2N for inter prediction.

[0152] In an example where the mode select unit does not further split the CU into PUs, each CU can be associated with a luma coding block and a corresponding chroma coding block. As described above, the size of a 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.

[0153] For other video coding techniques (such as intra-block copy mode coding, affine mode coding, and linear model (LM) mode coding, to name a few), mode selection unit 202 generates a prediction block for the current block being encoded via the respective units associated with the coding technique. In some examples (such as palette mode coding), mode selection unit 202 may not generate a prediction block, but instead generate syntax elements that indicate how to reconstruct the block based on the selected palette. In such a mode, mode selection unit 202 may provide these syntax elements to entropy coding unit 220 for encoding.

[0154] As described above, the residual generation unit 204 receives video data for a current block and a 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 sample-by-sample difference between the prediction block and the current block.

[0155] The transform processing unit 206 applies one or more transforms to the residual block to generate a block of transform coefficients (referred to herein as a "transform coefficient block"). The transform processing unit 206 may apply various transforms to the residual block to form the coefficient block. For example, the transform processing unit 206 may apply a discrete cosine transform (DCT), a directional transform, a Karhunen-Loeve transform (KLT), or a conceptually similar transform to the residual block. In some examples, the transform processing unit 206 may perform multiple transforms on the residual block, such as a primary transform and a secondary transform (such as a rotation transform). In some examples, the transform processing unit 206 does not apply a transform to the residual block. For blocks of video data decoded in transform skip mode, the transform processing unit 206 may be considered a pass-through unit that does not alter the residual block.

[0156] Quantization unit 208 may quantize the coefficients in the coefficient block to produce a quantized coefficient block. Quantization unit 208 may quantize the coefficients of the coefficient block according to a quantization parameter (QP) value associated with the current block. Video encoder 200 (e.g., via mode select unit 202) may adjust the degree of quantization applied to the coefficient block associated with the current block by adjusting the QP value associated with the CU. Quantization may result in a loss of information, and therefore, the quantized coefficients may have lower precision than the original coefficients output by transform processing unit 206.

[0157] The inverse quantization unit 210 and the inverse transform processing unit 212 may apply inverse quantization and inverse transform, respectively, to the quantized coefficient block to reconstruct a residual block from the coefficient block. For blocks of video data coded in transform skip mode, the inverse transform processing unit 212 may be considered a pass-through unit that does not alter the dequantized coefficient block. The reconstruction unit 214 may generate a reconstructed block corresponding to the current block (albeit potentially with some degree of distortion) based on the reconstructed residual block and the prediction block generated by the mode selection unit 202. For example, the reconstruction unit 214 may add samples of the reconstructed residual block to corresponding samples from the prediction block generated by the mode selection unit 202 to generate the reconstructed block.

[0158] Filter unit 216 may perform one or more filter operations on the reconstructed block. For example, filter unit 216 may perform a deblocking operation to reduce blocking artifacts along the edges of the CU. In some examples, the operations of filter unit 216 may be skipped.

[0159] The video encoder 200 stores the reconstructed block in the DPB 218. For example, in an example where the operation of the filter unit 216 is performed, the reconstruction unit 214 may store the reconstructed block in the DPB 218. In an example where the operation of the filter unit 216 is not performed, the filter unit 216 may store the filtered reconstructed block in the DPB 218. The motion estimation unit 222 and the motion compensation unit 224 may retrieve a reference picture formed by the reconstructed (and potentially filtered) block from the DPB 218 to perform inter-frame prediction on blocks of subsequently encoded pictures. In addition, the intra-frame prediction unit 226 may use the reconstructed block of the current picture in the DPB 218 to perform intra-frame prediction on other blocks in the current picture.

[0160] In general, entropy coding unit 220 may entropy encode syntax elements received from other functional components of video encoder 200. For example, entropy coding unit 220 may entropy encode quantized coefficient blocks from quantization unit 208. As another example, entropy coding unit 220 may entropy encode prediction syntax elements (e.g., motion information for inter-frame prediction or intra-frame mode information for intra-frame prediction) from mode selection unit 202. Entropy coding unit 220 may perform one or more entropy encoding operations on syntax elements, another example of video data, to generate entropy-encoded data. For example, entropy coding unit 220 may perform a context-adaptive variable length coding (CAVLC) operation, a CABAC operation, a variable-to-variable (V2V) length coding operation, a syntax-based context-adaptive binary arithmetic coding (SBAC) operation, a probability interval partitioning entropy (PIPE) coding operation, an exponential Golomb coding operation, or another type of entropy coding operation on the data. In some examples, entropy coding unit 220 may operate in a bypass mode in which syntax elements are not entropy encoded.

[0161] According to the technology of the present disclosure, the transform skip syntax processing unit 221 of the entropy coding unit 220 can be configured to signal the level of the quantized residual value of the block by determining the range of the level of the quantized residual value of the block of video data based on the quantization parameter and dividing the range into k intervals. Then, the transform skip syntax processing unit 221 can signal the level of the quantized residual value of the block based on the k intervals by: generating one or more syntax elements indicating a specific interval including the level of the quantized residual value, for inclusion in the bitstream of the encoded video data; and generating a syntax element indicating a difference value, for inclusion in the bitstream of the encoded video data, the difference value being the difference between the reference level value in the specific interval and the level of the quantized residual value of the block.

[0162] The video encoder 200 may output a bitstream including entropy-encoded syntax elements required for reconstructing blocks of a slice or picture. Specifically, the entropy encoding unit 220 may output a bitstream.

[0163] The above operations are described with respect to blocks. Such descriptions should be understood as operations for luma coding blocks and / or chroma coding blocks. As described above, in some examples, the luma coding blocks and chroma coding blocks are the luma components and chroma components of a CU. In some examples, the luma coding blocks and chroma coding blocks are the luma components and chroma components of a PU.

[0164] In some examples, the operations performed for luma coding blocks do not need to be repeated for chroma coding blocks. As an example, the operations for identifying the motion vector (MV) and reference picture for the luma coding block do not need to be repeated to identify the MV and reference picture for the chroma blocks. Specifically, the MV for the luma coding block can be scaled to determine the MV for the chroma blocks, and the reference picture can be the same. As another example, the intra prediction process can be the same for luma coding blocks and chroma coding blocks.

[0165] The video encoder 200 also represents an example of a device configured to encode video data, the device including: a memory configured to store the video data; and one or more processing units implemented in circuitry and configured to: determine whether a block of the video data is encoded in a transform skip mode; determine a quantization parameter for the block of the video data; determine a range of residual values ​​for the block of the video data based on the determined quantization parameter; divide the range into k intervals, where k is an integer value; and determine values ​​of one or more syntax elements based on the k intervals. The syntax elements include, for example, the abs_level_gtTX_flag and abs_remainder syntax elements described above.

[0166] Figure 4 is a block diagram illustrating an example video decoder 300 that may perform the techniques of this disclosure. Figure 4 This is provided for purposes of explanation and does not limit the techniques broadly illustrated and described in this disclosure. For purposes of explanation, this disclosure describes the video decoder 300 based on the techniques of JEM, VVC, and HEVC. However, the techniques of this disclosure can be performed by video decoding devices configured for other video decoding standards.

[0167] exist Figure 4In the example of FIG, video decoder 300 includes a coded picture buffer (CPB) memory 320, an entropy decoding unit 302, a prediction processing unit 304, an inverse quantization unit 306, an inverse transform processing unit 308, a reconstruction unit 310, a filter unit 312, and a decoded picture buffer (DPB) 134. Entropy decoding unit 302 includes a transform skip syntax processing unit 303. 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 134 may be implemented in one or more processors or processing circuitry. Furthermore, video decoder 300 may include additional or alternative processors or processing circuitry to perform these and other functions.

[0168] The prediction processing unit 304 includes a motion compensation unit 316 and an intra prediction unit 318. The prediction processing unit 304 may include an addition unit 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.

[0169] CPB memory 320 may store video data, such as an encoded video bitstream, to be decoded by components of video decoder 300. For example, the video data may be encoded from computer readable medium 110 ( Figure 1 ) obtains video data stored in CPB memory 320. CPB memory 320 may include a CPB that stores coded video data (e.g., syntax elements) from a coded video bitstream. Furthermore, CPB memory 320 may store video data other than syntax elements for decoded pictures, such as temporary data representing outputs from various units of video decoder 300. DPB 314 typically stores decoded pictures, which video decoder 300 may output and / or use as reference video data when decoding subsequent data or pictures in the coded video bitstream. CPB memory 320 and DPB 314 may be formed from any of a variety of memory devices, such as DRAM, including SDRAM, MRAM, RRAM, or other types of memory devices. CPB memory 320 and DPB 314 may be provided by the same memory device or separate memory devices. In various examples, CPB memory 320 may be on-chip with other components of video decoder 300 or off-chip relative to those components.

[0170] Additionally or alternatively, in some examples, video decoder 300 may retrieve the video from memory 120 ( Figure 1 ) to retrieve the decoded video data. That is, memory 120 may utilize CPB memory 320 to store data as discussed above. Similarly, when some or all of the functionality of video decoder 300 is implemented in software to be executed by processing circuitry of video decoder 300, memory 120 may store instructions to be executed by video decoder 300.

[0171] Shown Figure 4 The various units shown in FIG. 300 help understand the operations performed by the video decoder 300. These units can be implemented as fixed function circuits, programmable circuits, or a combination thereof. Figure 3 , fixed-function circuits refer to circuits that provide specific functions and are pre-set with respect to the operations that can be performed. Programmable circuits refer to circuits that can be programmed to perform various tasks and provide flexible functionality in terms of 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 (e.g., to receive parameters or output parameters), but the types of operations performed by the fixed-function circuits are generally immutable. In some examples, one or more of these units may be different circuit blocks (fixed-function or programmable), and in some examples, one or more units may be integrated circuits.

[0172] The video decoder 300 may include an ALU, an EFU, digital circuits, analog circuits, and / or a programmable core formed from programmable circuits. In an example where the operation of the video decoder 300 is performed by software executed on the programmable circuits, on-chip or off-chip memory may store instructions (e.g., object code) of the software that the video decoder 300 receives and executes.

[0173] The entropy decoding unit 302 may receive the encoded video data from the CPB and perform entropy decoding on the video data to regenerate syntax elements. The prediction processing unit 304, the inverse quantization unit 306, the inverse transform processing unit 308, the reconstruction unit 310, and the filter unit 312 may generate decoded video data based on the syntax elements extracted from the bitstream.

[0174] Typically, the video decoder 300 reconstructs a picture on a block-by-block basis. The video decoder 300 may perform a reconstruction operation on each block individually (where the block currently being reconstructed (ie, decoded) may be referred to as a "current block").

[0175] The entropy decoding unit 302 may entropy decode syntax elements defining the quantized coefficients of the quantized coefficient block and transform information such as a quantization parameter (QP) and / or a transform mode indication. The inverse quantization unit 306 may use the QP associated with the quantized coefficient block to determine a degree of quantization and, similarly, determine a degree of inverse quantization for the inverse quantization unit 306 to apply. The inverse quantization unit 306 may, for example, perform a bitwise left shift operation to inverse quantize the quantized coefficients. The inverse quantization unit 306 may thereby form a coefficient block comprising the coefficients.

[0176] According to the technology of the present disclosure, for a video data block decoded in a transform skip mode, the transform skip syntax processing unit 303 of the entropy decoding unit 302 can be configured to determine a range of levels of quantized residual values ​​of the block of video data based on a determined quantization parameter, and divide the range into k intervals. Then, the transform skip syntax processing unit 303 can determine the levels of the quantized residual values ​​of the block based on the k intervals by the following operations: receiving information indicating that the levels of the quantized residual values ​​are within a specific interval among the k intervals; receiving information indicating a difference value, the difference value indicating a difference between a reference level value in the specific interval and the level of the quantized residual value of the block; and determining the level of the quantized residual value based on the reference level value and the difference value.

[0177] After the inverse quantization unit 306 forms the coefficient block, the inverse transform processing unit 308 may apply one or more inverse transforms to the coefficient block to generate a residual block associated with the current block. For example, the inverse transform processing unit 308 may apply an inverse DCT, an inverse integer transform, an inverse Karhunen-Loeve transform (KLT), an inverse rotational transform, an inverse directional transform, or another inverse transform to the coefficient block. For blocks coded in transform skip mode, the inverse transform processing unit 308 may be considered a pass-through unit that does not alter the dequantized coefficient block.

[0178] In addition, prediction processing unit 304 generates a prediction block based on the prediction information syntax element entropy decoded by entropy decoding unit 302. For example, if the prediction information syntax element indicates that the current block is inter-predicted, motion compensation unit 316 may generate a prediction block. In this case, the prediction information syntax element may indicate a reference picture in DPB 314 from which to retrieve the reference block, and a motion vector that identifies the position of the reference block in the reference picture relative to the position of the current block in the current picture. Motion compensation unit 316 may generally generate a prediction block in the same manner as described for motion compensation unit 224 ( Figure 3 ) is performed in a manner substantially similar to that described in the foregoing.

[0179] As another example, if the prediction information syntax element indicates that the current block is intra-predicted, the intra-prediction unit 318 may generate a prediction block according to the intra-prediction mode indicated by the prediction information syntax element. Again, the intra-prediction unit 318 may generally generate a prediction block in the same manner as described with respect to the intra-prediction unit 226 ( Figure 3 The intra prediction process is performed in a manner substantially similar to that described in the preceding claims. The intra prediction unit 318 may retrieve data of neighboring samples of the current block from the DPB 314.

[0180] The reconstruction unit 310 may reconstruct the current block using the prediction block and the residual block. For example, the reconstruction unit 310 may add samples of the residual block to corresponding samples of the prediction block to reconstruct the current block.

[0181] The filter unit 312 may perform one or more filter operations on the reconstructed block. For example, the filter unit 312 may perform a deblocking operation to reduce blocking artifacts along the edges of the reconstructed block. The operations of the filter unit 312 may not necessarily be performed in all examples.

[0182] The video decoder 300 may store the reconstructed blocks in the DPB 314. As discussed above, the DPB 314 may provide reference information (such as samples of the current picture for intra prediction and previously decoded pictures for subsequent motion compensation) to the prediction processing unit 304. In addition, the video decoder 300 may output decoded pictures from the DPB for use in, for example, Figure 1 Subsequent presentation on the display device 118 of the display device.

[0183] In this manner, video decoder 300 represents an example of a video decoding device that includes a memory configured to store video data, and one or more processing units implemented in circuitry and configured to: determine whether a block of video data is coded in transform skip mode; determine a quantization parameter for the block of video data; determine a range of residual values ​​for the block of video data based on the determined quantization parameter; divide the range into k intervals, where k is an integer value; and determine values ​​of coefficients of the residual data based on the k intervals. For example, video decoder 300 may interpret values ​​of one or more syntax elements based on the determined intervals.

[0184] In some implementations, the video decoder 300 may also receive a syntax element indicating that a coefficient has a value greater than zero, a syntax element indicating that a coefficient has a value greater than one, and / or a syntax element indicating the sign of the coefficient.

[0185] The video decoder 300 may receive, for a first interval among the k intervals, a syntax element indicating that the value of a coefficient is greater than the value included in the first interval; receive, for a second interval among the k intervals, a syntax element indicating that the value of the coefficient is included in the second interval; and receive a syntax element indicating a difference between an initial value of the second interval and the value of the coefficient. The syntax element indicating the difference may be bypass-coded.

[0186] The video decoder 300 may receive, for each interval, a flag indicating that the value of the coefficient is greater than the value included in the respective interval for the flag, until receiving the flag indicating that the value of the coefficient is within the interval for the flag. The video decoder 300 may then receive a syntax element indicating the difference between the initial value for the interval for the flag and the value of the coefficient. For example, the syntax element indicating the difference may be bypass-decoded.

[0187] The k intervals may, for example, include an interval from 0 to 0, an interval from 1 to 1, an interval from 2 to a first threshold, an interval from the first threshold plus 1 to a second threshold, and an interval from the second threshold plus 1 to a third threshold. The video decoder 300 may determine the first threshold, the second threshold, and the third threshold based on the quantization parameter, as described above. The k intervals may also include an interval from the third threshold plus 1 to the maximum value of the range.

[0188] The video decoder 300 may be configured to receive a syntax element indicating an index of one of the k intervals, wherein the one of the k intervals indicated by the index corresponds to an interval of the k intervals including the value of the coefficient. The video decoder 300 may then receive a syntax element indicating a difference between a start value of the one of the k intervals and the value of the coefficient.

[0189] Figure 5 1 is a flowchart illustrating an example method for encoding a current block. The current block may include a current CU. Although with respect to the video encoder 200 ( Figure 1 and 3 ) is described, but it should be understood that other devices may be configured to perform the same Figure 5 A similar approach to the one in the previous section.

[0190] In this example, the video encoder 200 initially predicts a current block (350). For example, the video encoder 200 may form a prediction block for the current block. The video encoder 200 may then calculate a residual block for the current block (532). To calculate the residual block, the video encoder 200 may calculate the difference between the original, unencoded block and the prediction block for the current block. The video encoder 200 may then transform and quantize the coefficients of the residual block (354). For blocks coded in transform skip mode, at step 354, only the residual block may be quantized without being transformed. Next, the video encoder 200 may scan the quantized coefficients of the residual block (356). During or after the scan, the video encoder 200 may entropy encode the coefficients (358). For example, the video encoder 200 may encode the coefficients using CAVLC or CABAC. The video encoder 200 may then output the entropy coded data for the block (360).

[0191] Figure 6 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 4 ) is described, but it should be understood that other devices may be configured to perform the same Figure 6 A similar approach to the one in the previous section.

[0192] The video decoder 300 may receive entropy-coded data for a current block (e.g., entropy-coded prediction information and entropy-coded data for coefficients of a residual block corresponding to the current block) (370). The video decoder 300 may entropy decode the entropy-coded data to determine prediction information for the current block and regenerate coefficients of the residual block (372). The video decoder 300 may predict the current block (374), for example, using an intra-prediction mode or an inter-prediction mode indicated by the prediction information of the current block to calculate a prediction block for the current block. The video decoder 300 may then inverse scan the regenerated coefficients (376) to create a block of quantized coefficients. The video decoder 300 may then inverse quantize and inverse transform the coefficients to generate a residual block (378). For blocks coded in transform skip mode, at step 378, the video decoder 300 may only inverse quantize the block of quantized coefficients without inverse transforming them. Finally, the video decoder 300 may decode the current block by combining the prediction block and the residual block ( 380 ).

[0193] Figure 7 1 is a flowchart illustrating an example method for encoding a current block. The current block may include a current CU. Although with respect to the video encoder 200 ( Figure 1 and 3 ) is described, but it should be understood that other devices may be configured to perform the same Figure 7 A similar approach to the one in the previous section.

[0194] Video encoder 200 determines whether a block of video data was encoded without performing a transform on residual data for the block (400). For example, the block may be encoded in a transform skip mode. Video encoder 200 determines a level of a quantized residual value for the block (402). To determine the level of the quantized residual value for the block, video encoder 200 may, for example, be configured to determine the level of the residual value and quantize the level of the residual value to determine the level of the quantized residual value.

[0195] Video encoder 200 determines a quantization parameter for the block of video data (404). Video encoder 200 determines a range of levels of quantized residual values ​​for the block of video data based on the determined quantization parameter (406).

[0196] The video encoder 200 divides the range into k intervals, where k represents an integer value (408). The k intervals may include, for example, the following intervals:

[0197] [X,t1],[t1+1,t2],[t2+1,t3],…[t k-2 +1,t k-1 ],[t k-1 +1,maxTsLevel], where maxTsLevel represents the maximum possible level among the levels of the quantized residual values ​​of the block based on the quantization parameter of the block, t n represents the upper threshold of the nth interval, where n is from 0 to k-1, and X represents the minimum value of the first interval (eg, interval 0). As explained elsewhere, X can be equal to 0, 1, 2, or some other value.

[0198] The video encoder 200 determines a specific interval of the k intervals that includes the level of the quantized residual value (410). The video encoder 200 determines a difference value representing the difference between the reference level value in the specific interval and the level of the quantized residual value of the block (412).

[0199] The video encoder 200 signals a level of quantized residual values ​​for the block based on the k intervals (414). As part of signaling the level of quantized residual values ​​for the block based on the k intervals, the video encoder 200 generates one or more syntax elements indicating a particular interval for inclusion in a bitstream of the encoded video data (416) and generates a syntax element indicating a difference value for inclusion in the bitstream of the encoded video data (418). For example, the video encoder 200 may bypass encoding the syntax element indicating the difference value.

[0200] For example, the video encoder 200 may generate a flag for each of the k intervals to be included in the bitstream of the encoded video data, the flag indicating that the level of the quantized residual value is greater than the value included in the respective interval for the flag, until a flag is generated for inclusion in the bitstream of the encoded video data, the flag indicating that the level of the quantized residual value is within the interval associated with the flag. In addition, the video encoder 200 may generate a syntax element representing a sign of the residual value to be included in the bitstream of the encoded video data.

[0201] For example, the video encoder 200 may generate a syntax element (e.g., a 1-bit flag) for a first interval of the k intervals to be included in the bitstream of the encoded video data, the syntax element indicating that the level of the quantized residual value is greater than the value included in the first interval; and generate a syntax element (e.g., another 1-bit flag) for a second interval of the k intervals to be included in the bitstream of the encoded video data, the syntax element indicating that the level of the quantized residual value is included in the second interval. For the syntax element indicating the difference value, the video encoder 200 may generate a syntax element set to the difference between the reference level value of the second interval and the level of the quantized residual value of the block.

[0202] In some examples, a first interval of the k intervals may include values ​​from 1 to a first threshold, and the video encoder 200 may be configured to generate a syntax element indicating that the level of the quantized residual value is greater than zero for inclusion in the bitstream of the encoded video data. In the case where the level of the quantized residual value is equal to zero, the video encoder 200 does not need to signal any additional information indicating the quantized residual value. That is, the video encoder does not need to generate one or more syntax elements indicating a particular interval or a syntax element indicating a difference value for inclusion in the bitstream of the encoded video data.

[0203] In some examples, a first interval of the k intervals may include values ​​from 2 to a first threshold, and the video encoder 200 may generate a syntax element indicating that the level of the quantized residual value is greater than zero and a syntax element indicating that the level of the quantized residual value is greater than one for inclusion in the bitstream of the encoded video data. In the case where the level of the quantized residual value is equal to one, the video encoder 200 does not need to signal any additional information indicating the quantized residual value. That is, the video encoder does not need to generate one or more syntax elements indicating a particular interval or a syntax element indicating a difference value for inclusion in the bitstream of the encoded video data.

[0204] As part of signaling the level of the quantized residual value of the block based on the k intervals, the video encoder 200 also outputs a bitstream of encoded video data (420). For example, the video encoder 200 can output the bitstream of the encoded video by storing the bitstream in a memory device or by transmitting the bitstream of the encoded video data to another device.

[0205] Figure 8 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 4 ) is described, but it should be understood that other devices may be configured to perform the same Figure 5 A similar approach to the one in the previous section.

[0206] The video decoder 300 determines that a block of video data was encoded without performing a transform on residual data for the block (430). For example, the block may have been encoded in a transform skip mode. The video decoder 300 determines a quantization parameter for the block of video data (432). For example, the video decoder 300 may receive an indication of the quantization parameter in the video data.

[0207] The video decoder 300 determines a range of levels of quantized residual values ​​for the block of video data based on the determined quantization parameter (434). The range of levels of quantized residual values ​​is typically less than the bit depth of the video data. For example, if 8-bit video data has a range from 0 to 2 8 -1, the quantized residual value has a range from 0 to less than 2 8 The maximum value is a function of the particular quantization parameter used for the video data. The video decoder 300 divides the range into k intervals (436).

[0208] Video decoder 300 determines the level of the quantized residual value of the block based on the k intervals (438). The k intervals may, for example, include the following intervals:

[0209] [X,t1],[t1+1,t2],[t2+1,t3],…[t k-2 +1,t k-1 ],[t k-1 +1,maxTsLevel], where maxTsLevel represents the maximum possible level among the levels of the quantized residual values ​​of the block based on the quantization parameter of the block, t n represents the upper threshold of the nth interval, where n is from 0 to k-1, and X represents the minimum value of the first interval (eg, interval 0). As explained elsewhere, X can be equal to 0, 1, 2, or some other value.

[0210] In the example where X is equal to 0, the k intervals include the interval from 0 to the first threshold, the interval from the first threshold plus 1 to the second threshold, the interval from the second threshold plus 1 to the third threshold, and other intervals. In the example where X is equal to 1, the k intervals include the interval from 1 to the first threshold, the interval from the first threshold plus 1 to the second threshold, the interval from the second threshold plus 1 to the third threshold, and other intervals. In the example where X is equal to 2, the k intervals include the interval from 2 to the first threshold, the interval from the first threshold plus 1 to the second threshold, the interval from the second threshold plus 1 to the third threshold, and other intervals. The k intervals also include the interval that includes the maximum value of the range.

[0211] As part of determining the level of the quantized residual value for the block based on the k intervals, the video decoder 300 receives information indicating that the level of the quantized residual value is within a particular interval among the k intervals (440) and receives information indicating a difference value representing a difference between a reference level value in the particular interval and the level of the quantized residual value for the block (442). For example, the video decoder 300 may bypass decoding a syntax element indicating the difference value. The video decoder 300 then determines the level of the quantized residual value based on the reference level value and the difference value (444).

[0212] For example, the video decoder 300 may receive a flag for each of the k intervals, the flag indicating that the level of the quantized residual value is greater than the value included in the respective interval for the flag, until the flag is received indicating that the level of the quantized residual value is within the interval associated with the flag.

[0213] In the example where X is equal to 1, the video decoder 300 may receive a syntax element indicating that the level of the quantized residual value is greater than zero before receiving information indicating that the level of the quantized residual value is within a specific interval among the k intervals or information indicating a difference value. If the level of the quantized residual value is equal to zero, the video decoder 300 does not need to receive any additional information indicating the quantized residual value. That is, the video decoder 300 does not need to receive information indicating that the level of the quantized residual value is within a specific interval among the k intervals or information indicating a difference value.

[0214] In the example where X is equal to 2, the video decoder 300 may receive a syntax element indicating that the level of the quantized residual value is greater than zero and a syntax element indicating that the level of the quantized residual value is greater than one before receiving information indicating that the level of the quantized residual value is within a specific interval among the k intervals or information indicating a difference value. If the level of the quantized residual value is equal to one, the video decoder 300 does not need to receive any additional information indicating the quantized residual value. That is, the video decoder 300 does not need to receive information indicating that the level of the quantized residual value is within a specific interval among the k intervals or information indicating a difference value.

[0215] The video decoder 300 outputs decoded video data based on the level of the quantized residual value (446). For example, the video decoder 300 may output the decoded video data for display or output the decoded video data for storage. As part of decoding the video data, the video decoder 300 may, for example, dequantize the level of the quantized residual value to determine a level of a dequantized residual value, receive a syntax element indicating a sign of the dequantized residual value, and determine the dequantized residual value based on the level of the dequantized residual value and the sign of the dequantized residual value. The video decoder 300 may also determine a residual block for the block of video data, add the residual block to a prediction block for the block of video data to determine a reconstructed block for the block of video data, and generate a picture of the decoded video data based on the reconstructed block. In addition, the video decoder 300 may perform one or more filtering operations on the reconstructed block.

[0216] It will be appreciated that, depending on the example, certain actions or events of any of the techniques described herein may be performed in a different order, may be added, combined, or omitted entirely (e.g., not all described actions or events are necessary to implement the techniques). Furthermore, in some examples, actions or events may be performed concurrently rather than sequentially, such as through multithreading, interrupt handling, or multiple processors.

[0217] In one or more examples, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or transmitted through a computer-readable medium as one or more instructions or codes and executed by a hardware-based processing unit. Computer-readable media may include computer-readable storage media, which corresponds to tangible media such as data storage media or communication media, such as 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 may generally correspond to (1) non-transitory tangible computer-readable storage media, or (2) communication media such as signals or carrier waves. Data storage media may be any available medium 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 may include computer-readable media.

[0218] By way of example and not limitation, such computer-readable storage media may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, flash memory, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer. In addition, any connection is appropriately referred to as a computer-readable medium. For example, if instructions are transmitted from a website, server or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL) or wireless technology (e.g., infrared, radio and microwave), the coaxial cable, fiber optic cable, twisted pair, DSL or wireless technology (e.g., infrared, radio and microwave) is included in the definition of 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 are instead directed to non-temporary tangible storage media. As used herein, disks and optical disks include compact discs (CDs), laser discs, optical discs, digital versatile discs (DVDs), floppy disks and Blu-ray discs, wherein disks typically copy data magnetically, while optical discs use lasers to copy data optically. Combinations of the above should also be included within the scope of computer-readable media.

[0219] Instructions may be executed by one or more processors, such as one or more digital signal processors (DSPs), general-purpose microprocessors, application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other equivalent integrated or discrete logic circuits. Thus, the terms "processor" and "processing circuitry" as used herein may refer to any of the aforementioned structures or any other structure suitable for implementing the techniques described herein. Additionally, in some aspects, the functionality described herein may be provided within dedicated hardware and / or software modules configured for encoding and decoding, or incorporated into a combined codec. Furthermore, the techniques may be fully implemented in one or more circuits or logic elements.

[0220] The techniques of this disclosure may 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 chipset). Various components, modules, or units are described in this disclosure to emphasize functional aspects of a device configured to perform the disclosed techniques, but they do not necessarily need to be implemented by different hardware units. Rather, as described above, the various units may be combined in a codec hardware unit in conjunction with appropriate software and / or firmware, or provided by a collection of interoperating hardware units including one or more processors as described above.

[0221] 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 that a block of video data is encoded without transforming residual data for the block; determining a quantization parameter for the block of video data; determining a range of levels of quantized residual values ​​for the block of video data based on the determined quantization parameter, wherein the range is from zero to a maximum possible level of the levels of quantized residual values ​​for the block of video data; dividing the range into k intervals, where k is an integer value, each interval comprising a plurality of levels for quantized residual values, and each interval having an associated index value between 0 and k-1; Determining a level of a quantized residual value for the block of video data based on the k intervals, wherein determining the level of the quantized residual value for the block of video data based on the k intervals comprises: receiving information indicating an index corresponding to a specific interval into which the level of the quantized residual value among the k intervals falls; receiving information indicating a difference value, wherein the difference value represents a difference between a reference level value in the specific interval and the level of the quantized residual value of the block of video data; and determining the level of the quantized residual value based on the reference level value and the difference value; and Decoded video data is output based on the level of the quantized residual value.

2. The method according to claim 1, further comprising: dequantizing the level of the quantized residual value to determine a level of a dequantized residual value; receiving a syntax element indicating a sign of the dequantized residual value; as well as The dequantized residual value is determined based on the level of the dequantized residual value and the sign of the dequantized residual value.

3. The method according to claim 2, further comprising: determining a residual block for the block of video data, wherein the residual block comprises the dequantized residual values; adding the residual block to a prediction block for the block of video data to determine a reconstructed block for the block of video data; generating a picture of decoded video data based on the reconstructed block; and The picture of the decoded video data is output.

4. The method according to claim 1, wherein A first interval of the k intervals includes values ​​from 1 to a first threshold, and the method further includes: A syntax element is received that indicates that the level of the quantized residual value is greater than zero.

5. The method according to claim 1, wherein A first interval of the k intervals includes values ​​from 2 to a first threshold, the method further comprising: receiving a syntax element indicating that the level of the quantized residual value is greater than zero; A syntax element is received that indicates that the level of the quantized residual value is greater than one.

6. The method according to claim 1, further comprising: receiving, for a first interval of the k intervals, a syntax element indicating that the level of the quantized residual value is greater than a value included in the first interval; receiving, for a second interval of the k intervals, a syntax element indicating that the level of the quantized residual value is included in the second interval; Therein, the syntax element indicating the difference value indicates a difference between a reference level value of the second interval and the level of the quantized residual value of the block of video data.

7. The method according to claim 1, further comprising: A flag is received for each of the k intervals, the flag indicating that the level of the quantized residual value is greater than a value included in the respective interval for the flag, until the flag is received indicating that the level of the quantized residual value is within the interval associated with the flag.

8. The method according to claim 1, wherein The k intervals include an interval from 0 to a first threshold, an interval from the first threshold plus 1 to a second threshold, and an interval from the second threshold plus 1 to a third threshold. The method further includes: The first threshold, the second threshold, and the third threshold are determined based on the quantization parameter.

9. The method according to claim 1, wherein: The k intervals include an interval from 1 to a first threshold, an interval from the first threshold plus 1 to a second threshold, and an interval from the second threshold plus 1 to a third threshold. The method further includes: The first threshold, the second threshold, and the third threshold are determined based on the quantization parameter.

10. The method according to claim 1, wherein The k intervals include an interval from 2 to a first threshold, an interval from the first threshold plus 1 to a second threshold, and an interval from the second threshold plus 1 to a third threshold. The method further includes: The first threshold, the second threshold, and the third threshold are determined based on the quantization parameter.

11. The method according to claim 10, wherein: The k intervals include intervals from the third threshold plus 1 to the maximum possible level of the level of the quantized residual value of the block of video data.

12. The method according to claim 1, wherein The k intervals include the following intervals: [2,t1],[t1+1,t2],[t2+1,t3],…[t k-2 +1,t k-1 ],[t k-1 +1,maxTsLevel], wherein maxTsLevel represents the maximum possible level among the levels of quantized residual values ​​for the block of video data based on the quantization parameter for the block of video data, and wherein t n Indicates the upper threshold of the nth interval, where n ranges from 0 to k-1.

13. The method according to claim 1, wherein The syntax element indicating the difference value is bypass coded.

14. The method according to claim 1, wherein The k intervals include the following intervals: [X,t1],[t1+1,t2],[t k-2 +1,t k-1 ],[t k-1 +1,maxTsLevel], wherein X represents the minimum value for the interval K=0, wherein maxTsLevel represents the maximum possible level among the levels of quantized residual values ​​of the block of video data based on the quantization parameter for the block of video data, and wherein t n Indicates the upper threshold of the nth interval, where n ranges from 0 to k-1.

15. A method of generating a bitstream of encoded video data, the method comprising: determining that a block of video data is encoded without transforming residual data for the block; determining a level of a quantized residual value for the block of video data; determining a quantization parameter for the block of video data; determining a range of levels of quantized residual values ​​for the block of video data based on the determined quantization parameter, wherein the range is from zero to a maximum possible level of the levels of quantized residual values ​​for the block of video data; dividing the range into k intervals, where k is an integer value, each interval comprising a plurality of levels for quantized residual values, and each interval having an associated index value between 0 and k-1; determining a specific interval of the k intervals that includes the level of the quantized residual value; determining a difference value, wherein the difference value represents a difference between a reference level value in the particular interval and the level of the quantized residual value of the block of video data; and Signaling the level of the quantized residual value for the block of video data based on the k intervals, wherein signaling the level of the quantized residual value for the block of video data based on the k intervals comprises: generating one or more syntax elements indicating an associated index value of the particular interval for inclusion in a bitstream of the coded video data; generating a syntax element indicating the difference value for inclusion in a bitstream of the coded video data; and A bitstream of the encoded video data is output.

16. The method according to claim 15, wherein Determining the level of the quantized residual value for the block of video data comprises: Determine the level of residual values; and The level of the residual value is quantized to determine the level of the quantized residual value.

17. The method according to claim 16, further comprising: A syntax element indicating a sign of the residual value is generated for inclusion in a bitstream of the encoded video data.

18. The method according to claim 15, wherein A first interval of the k intervals includes values ​​from 1 to a first threshold, and the method further includes: A syntax element indicating that the level of the quantized residual value is greater than zero is generated for inclusion in a bitstream of the encoded video data.

19. The method according to claim 15, wherein A first interval of the k intervals includes values ​​from 2 to a first threshold, the method further comprising: generating, for inclusion in a bitstream of the coded video data, a syntax element indicating that the level of the quantized residual value is greater than zero; A syntax element indicating that the level of the quantized residual value is greater than one is generated for inclusion in a bitstream of the encoded video data.

20. The method of claim 15, further comprising: generating, for a first interval of the k intervals, a syntax element indicating that the level of the quantized residual value is greater than a value included in the first interval for inclusion in a bitstream of the coded video data; generating, for a second interval of the k intervals, a syntax element indicating that the level of the quantized residual value is included in the second interval, for inclusion in a bitstream of the encoded video data; Therein, the syntax element indicating the difference value indicates a difference between a reference level value of the second interval and the level of the quantized residual value of the block of video data.

21. The method of claim 15, further comprising: A flag is generated for each of the k intervals for inclusion in the bitstream of the encoded video data, the flag indicating that the level of the quantized residual value is greater than the value included in the respective interval for the flag, until the flag is generated for inclusion in the bitstream of the encoded video data indicating that the level of the quantized residual value is within the interval associated with the flag.

22. The method according to claim 15, wherein The k intervals include an interval from 0 to a first threshold, an interval from the first threshold plus 1 to a second threshold, and an interval from the second threshold plus 1 to a third threshold. The method further includes: The first threshold, the second threshold, and the third threshold are determined based on the quantization parameter.

23. The method according to claim 15, wherein The k intervals include an interval from 1 to a first threshold, an interval from the first threshold plus 1 to a second threshold, and an interval from the second threshold plus 1 to a third threshold. The method further includes: The first threshold, the second threshold, and the third threshold are determined based on the quantization parameter.

24. The method according to claim 15, wherein The k intervals include an interval from 2 to a first threshold, an interval from the first threshold plus 1 to a second threshold, and an interval from the second threshold plus 1 to a third threshold. The method further includes: The first threshold, the second threshold, and the third threshold are determined based on the quantization parameter.

25. The method according to claim 24, wherein The k intervals include intervals from the third threshold plus 1 to the maximum possible level of the level of the quantized residual value of the block of video data.

26. The method according to claim 15, wherein The k intervals include the following intervals: [2,t1],[t1+1,t2],[t2+1,t3],…[t k-2 +1,t k-1 ],[t k-1 +1,maxTsLevel], wherein maxTsLevel represents the maximum possible level among the levels of quantized residual values ​​of the block of video data based on the quantization parameter of the block of video data, and wherein t n Indicates the upper threshold of the nth interval, where n ranges from 0 to k-1.

27. The method according to claim 15, wherein The syntax element indicating the difference value is bypass coded.

28. A device for decoding video data, the device comprising: a memory configured to store video data; as well as One or more processors configured to: determining that a block of video data is encoded without transforming residual data for the block; determining a quantization parameter for the block of video data; determining a range of levels of quantized residual values ​​for the block of video data based on the determined quantization parameter, wherein the range is from zero to a maximum possible level of the levels of quantized residual values ​​for the block of video data; dividing the range into k intervals, where k is an integer value, each interval comprising a plurality of levels for quantized residual values, and each interval having an associated index value between 0 and k-1; determining a level of a quantized residual value of the block of video data based on the k intervals, wherein, to determine the level of the quantized residual value of the block of video data based on the k intervals, the one or more processors are further configured to: receiving information indicating an index corresponding to a specific interval into which the level of the quantized residual value among the k intervals falls; receiving information indicating a difference value, wherein the difference value represents a difference between a reference level value in the specific interval and the level of the quantized residual value of the block of video data; and determining the level of the quantized residual value based on the reference level value and the difference value; and Decoded video data is output based on the level of the quantized residual value.

29. The apparatus of claim 28, wherein The one or more processors are further configured to: dequantizing the level of the quantized residual value to determine a level of a dequantized residual value; receiving a syntax element indicating a sign of the dequantized residual value; as well as The dequantized residual value is determined based on the level of the dequantized residual value and the sign of the dequantized residual value.

30. The apparatus of claim 29, wherein: The one or more processors are further configured to: determining a residual block for the block of video data, wherein the residual block comprises the dequantized residual values; adding the residual block to a prediction block for the block of video data to determine a reconstructed block for the block of video data; generating a picture of decoded video data based on the reconstructed block; and The picture of the decoded video data is output.

31. The apparatus of claim 28, wherein A first interval of the k intervals includes values ​​from 1 to a first threshold, wherein the one or more processors are further configured to: A syntax element is received that indicates that the level of the quantized residual value is greater than zero.

32. The apparatus of claim 28, wherein A first interval of the k intervals includes values ​​from 2 to a first threshold, wherein the one or more processors are further configured to: receiving a syntax element indicating that the level of the quantized residual value is greater than zero; A syntax element is received that indicates that the level of the quantized residual value is greater than one.

33. The apparatus of claim 28, wherein The one or more processors are further configured to: receiving, for a first interval of the k intervals, a syntax element indicating that the level of the quantized residual value is greater than a value included in the first interval; receiving, for a second interval of the k intervals, a syntax element indicating that the level of the quantized residual value is included in the second interval; Therein, the syntax element indicating the difference value indicates a difference between a reference level value of the second interval and the level of the quantized residual value of the block of video data.

34. The apparatus of claim 28, wherein The one or more processors are further configured to: A flag is received for each of the k intervals, the flag indicating that the level of the quantized residual value is greater than a value included in the respective interval for the flag, until the flag is received indicating that the level of the quantized residual value is within the interval associated with the flag.

35. The apparatus of claim 28, wherein The k intervals include an interval from 0 to a first threshold, an interval from the first threshold plus 1 to a second threshold, and an interval from the second threshold plus 1 to a third threshold, wherein the one or more processors are further configured to: The first threshold, the second threshold, and the third threshold are determined based on the quantization parameter.

36. The apparatus of claim 28, wherein The k intervals include an interval from 1 to a first threshold, an interval from the first threshold plus 1 to a second threshold, and an interval from the second threshold plus 1 to a third threshold, wherein the one or more processors are further configured to: The first threshold, the second threshold, and the third threshold are determined based on the quantization parameter.

37. The apparatus of claim 28, wherein The k intervals include an interval from 2 to a first threshold, an interval from the first threshold plus 1 to a second threshold, and an interval from the second threshold plus 1 to a third threshold, wherein the one or more processors are further configured to: The first threshold, the second threshold, and the third threshold are determined based on the quantization parameter.

38. The apparatus of claim 37, wherein The k intervals include intervals from the third threshold plus 1 to the maximum possible level of the level of the quantized residual value of the block of video data.

39. The apparatus of claim 28, wherein The k intervals include the following intervals: [2,t1],[t1+1,t2],[t2+1,t3],…[t k-2 +1,t k-1 ],[t k-1 +1,maxTsLevel], wherein maxTsLevel represents the maximum possible level among the levels of quantized residual values ​​for the block of video data based on the quantization parameter for the block of video data, and wherein t n Indicates the upper threshold of the nth interval, where n ranges from 0 to k-1.

40. The apparatus of claim 28, wherein The syntax element indicating the difference value is bypass coded.

41. The apparatus of claim 28, wherein The device comprises a wireless communication device and further comprises a receiver configured to receive encoded video data and a display configured to display the decoded video data.

42. The apparatus of claim 41, 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.

43. The apparatus of claim 28, wherein The k intervals include the following intervals: [X,t1],[t1+1,t2],[t k-2 +1,t k-1 ],[t k-1 +1,maxTsLevel], wherein X represents the minimum value for the interval K=0, wherein maxTsLevel represents the maximum possible level among the levels of quantized residual values ​​of the block of video data based on the quantization parameter for the block of video data, and wherein t n Indicates the upper threshold of the nth interval, where n ranges from 0 to k-1.

44. An apparatus for encoding video data, the apparatus comprising: a memory configured to store video data; as well as One or more processors configured to: determining that a block of video data is encoded without transforming residual data for the block; determining a level of a quantized residual value for the block of video data; determining a quantization parameter for the block of video data; determining a range of levels of quantized residual values ​​for the block of video data based on the determined quantization parameter, wherein the range is from zero to a maximum possible level of the levels of quantized residual values ​​for the block of video data; dividing the range into k intervals, where k is an integer value, each interval comprising a plurality of levels for quantized residual values, and each interval having an associated index value between 0 and k-1; determining a specific interval of the k intervals that includes the level of the quantized residual value; determining a difference value, wherein the difference value represents a difference between a reference level value and the level of the quantized residual value of the block of video data in the particular interval; signaling the level of the quantized residual value of the block of video data based on the k intervals, wherein to signal the level of the quantized residual value of the block of video data based on the k intervals, the one or more processors are further configured to: generating one or more syntax elements indicating an associated index value of the particular interval for inclusion in a bitstream of coded video data; generating a syntax element indicating the difference value for inclusion in a bitstream of the coded video data; and A bitstream of the encoded video data is output.

45. The apparatus of claim 44, wherein To determine the level of the quantized residual value for the block of video data, the one or more processors are further configured to: Determine the level of residual values; and The level of the residual value is quantized to determine the level of the quantized residual value.

46. ​​The device of claim 45, wherein the one or more processors are further configured to: A syntax element indicating a sign of the residual value is generated for inclusion in a bitstream of the encoded video data.

47. The apparatus of claim 44, wherein: A first interval of the k intervals includes values ​​from 1 to a first threshold, wherein the one or more processors are further configured to: A syntax element indicating that the level of the quantized residual value is greater than zero is generated for inclusion in a bitstream of the encoded video data.

48. The apparatus of claim 44, wherein A first interval of the k intervals includes values ​​from 2 to a first threshold, wherein the one or more processors are further configured to: generating, for inclusion in a bitstream of the coded video data, a syntax element indicating that the level of the quantized residual value is greater than zero; A syntax element indicating that the level of the quantized residual value is greater than one is generated for inclusion in a bitstream of the encoded video data.

49. The apparatus of claim 44, wherein The one or more processors are further configured to: generating, for a first interval of the k intervals, a syntax element indicating that the level of the quantized residual value is greater than a value included in the first interval for inclusion in a bitstream of the coded video data; generating, for a second interval of the k intervals, a syntax element indicating that the level of the quantized residual value is included in the second interval, for inclusion in a bitstream of the encoded video data; Therein, the syntax element indicating the difference value indicates a difference between a reference level value of the second interval and the level of the quantized residual value of the block of video data.

50. The apparatus of claim 44, wherein The one or more processors are further configured to: A flag is generated for each of the k intervals for inclusion in the bitstream of the encoded video data, the flag indicating that the level of the quantized residual value is greater than the value included in the respective interval for the flag, until the flag is generated for inclusion in the bitstream of the encoded video data indicating that the level of the quantized residual value is within the interval associated with the flag.

51. The apparatus of claim 44, wherein The k intervals include an interval from 0 to a first threshold, an interval from the first threshold plus 1 to a second threshold, and an interval from the second threshold plus 1 to a third threshold, wherein the one or more processors are further configured to: The first threshold, the second threshold, and the third threshold are determined based on the quantization parameter.

52. The apparatus of claim 44, wherein The k intervals include an interval from 1 to a first threshold, an interval from the first threshold plus 1 to a second threshold, and an interval from the second threshold plus 1 to a third threshold, wherein the one or more processors are further configured to: The first threshold, the second threshold, and the third threshold are determined based on the quantization parameter.

53. The apparatus of claim 44, wherein The k intervals include an interval from 2 to a first threshold, an interval from the first threshold plus 1 to a second threshold, and an interval from the second threshold plus 1 to a third threshold, wherein the one or more processors are further configured to: The first threshold, the second threshold, and the third threshold are determined based on the quantization parameter.

54. The apparatus of claim 53, wherein The k intervals include intervals from the third threshold plus 1 to the maximum possible level of the level of the quantized residual value of the block of video data.

55. The apparatus of claim 44, wherein The k intervals include the following intervals: [2,t1],[t1+1,t2],[t2+1,t3],…[t k-2 +1,t k-1 ],[t k-1 +1,maxTsLevel], wherein maxTsLevel represents the maximum possible level among the levels of quantized residual values ​​for the block of video data based on the quantization parameter for the block of video data, and wherein t n Indicates the upper threshold of the nth interval, where n ranges from 0 to k-1.

56. The apparatus of claim 44, wherein The syntax element indicating the difference value is bypass coded.

57. The apparatus of claim 44, wherein The apparatus comprises a wireless communication device and also includes a transmitter configured to transmit encoded video data.

58. The apparatus of claim 57, wherein The wireless communication device comprises a telephone handset, and wherein the transmitter is configured to modulate a signal comprising the encoded video data in accordance with a wireless communication standard.

59. A non-transitory computer-readable storage medium storing instructions that, when executed by one or more processors, cause the one or more processors to: determining that a block of video data is encoded without transforming residual data for the block; determining a quantization parameter for the block of video data; determining a range of levels of quantized residual values ​​for the block of video data based on the determined quantization parameter, wherein the range is from zero to a maximum possible level of the levels of quantized residual values ​​for the block of video data; dividing the range into k intervals, where k is an integer value, each interval comprising a plurality of levels for quantized residual values, and each interval having an associated index value between 0 and k-1; determining a level of a quantized residual value of the block of video data based on the k intervals, wherein to determine the level of the quantized residual value of the block of video data based on the k intervals, the instructions cause the one or more processors to: receiving information indicating an index corresponding to a specific interval into which the level of the quantized residual value among the k intervals falls; receiving information indicating a difference value, wherein the difference value represents a difference between a reference level value in the specific interval and the level of the quantized residual value of the block of video data; and determining the level of the quantized residual value based on the reference level value and the difference value; and Decoded video data is output based on the level of the quantized residual value.

60. An apparatus for decoding video data, the apparatus comprising: for determining that a block of video data is a unit that is coded without transforming residual data for the block; means for determining a quantization parameter for said block of video data; means for determining a range of levels of quantized residual values ​​for the block of video data based on the determined quantization parameter, wherein the range is from zero to a maximum possible level of the levels of quantized residual values ​​for the block of video data; means for partitioning the range into k intervals, wherein k is an integer value, each interval comprising a plurality of levels for quantized residual values, and each interval having an associated index value between 0 and k-1; means for determining a level of a quantized residual value for the block of video data based on the k intervals, wherein the means for determining the level of the quantized residual value for the block of video data based on the k intervals comprises: means for receiving information indicating an index corresponding to a particular interval within which the level of the quantized residual value among the k intervals falls; means for receiving information indicating a difference value, wherein the difference value represents a difference between a reference level value in the particular interval and the level of the quantized residual value of the block of video data; and means for determining the level of the quantized residual value based on the reference level value and the difference value; and Means for outputting decoded video data based on the level of the quantized residual value.

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