US-12627824-B2 - Systems and methods for entropy coding for recursive intra region partitioning

US12627824B2US 12627824 B2US12627824 B2US 12627824B2US-12627824-B2

Abstract

An example method of video coding includes receiving a video bitstream including a plurality of coding blocks; identifying a coding region that includes two or more coding blocks of the plurality of coding blocks that are encoded in a first prediction mode. The method also includes entropy decoding a signaled flag indicating a prediction mode for the coding region, the entropy decoding using coded information including one or more of: previous instances of the signaled flag, a block size of a current coding block, a block size group of the current coding block, respective block sizes of a set of neighboring coding blocks, respective block size groups of the set of neighboring coding blocks, and signaled flags for the set of neighboring coding blocks; and reconstructing the two or more coding blocks according to a value of the signaled flag for the coding region.

Inventors

Liang Zhao
Xin Zhao
Madhu PERINGASSERY KRISHNAN
Yushin Cho
Han Gao
Jing Ye
Shan Liu

Assignees

Tencent America LLC

Dates

Publication Date: 20260512
Application Date: 20240411

Claims (16)

1 . A method of video decoding performed at a computing system having memory and one or more processors, the method comprising: receiving a video bitstream comprising a plurality of coding blocks; identifying a coding region that comprises two or more coding blocks of the plurality of coding blocks that are encoded in a first prediction mode; entropy decoding a signaled flag indicating the first prediction mode for the coding region, the entropy decoding using coded information comprising one or more of: previous instances of the signaled flag, a block size of a current coding block, a block size group of the current coding block, respective block sizes of a set of neighboring coding blocks, respective block size groups of the set of neighboring coding blocks, and signaled flags for the set of neighboring coding blocks; and reconstructing the two or more coding blocks according to a value of the signaled flag for the coding region, wherein the coded information comprises flags from the set of neighboring coding blocks that are a same type of flag as the signaled flag for the coding regio and the signaled flag is a region type flag, and wherein the coded information comprises a count of signaled region type flags from coding blocks within the coding region.
2 . The method of claim 1 , wherein the coded information comprises flags from the set of neighboring coding blocks that are a different type of flag than the signaled flag for the coding region.
3 . The method of claim 2 , wherein the signaled flag for the coding region is entropy coded using coded information based on signaled flags from the set of neighboring coding blocks indicating a respective prediction mode of the set of neighboring coding blocks.
4 . The method of claim 3 , wherein the coded information further comprises one or more of: a partition type of the current coding block, a partition depth of the current coding block, and signaled flags from the set of neighboring coding blocks indicating a respective partition type of the set of neighboring coding blocks.
5 . The method of claim 1 , further comprising partitioning a current frame of the video bitstream to obtain the coding region, wherein the coded information further comprises one or more of: a quantization step size or a quantization parameter index for the current frame, a base quantization parameter index for a current video sequence that comprises the current frame, a picture type, and a partitioning series.
6 . The method of claim 1 , further comprising partitioning a current frame of the video bitstream to obtain the coding region, wherein, when the current frame corresponds to an inter frame, the coded information that further comprises a position of the current frame in a pyramid structure of video frames.
7 . The method of claim 1 , further comprising: when the current coding block meets one or more criteria, partitioning chroma blocks within a coding region encoded in an intra prediction mode using a restricted set of partitioning modes.
8 . The method of claim 1 , further comprising: when a partition type of the current coding block meets one or more criteria, parsing a region type flag from the video bitstream; and when the partition type of the current coding block does not meet the one or more criteria, forgoing parsing the region type flag from the video bitstream.
9 . The method of claim 1 , further comprising: when the current coding block meets one or more criteria, partitioning the current coding block within a first depth.
10 . The method of claim 1 , wherein the signaled flag is entropy coded using one of a plurality of contexts.
11 . A computing system, comprising: control circuitry; memory; and one or more sets of instructions stored in the memory and configured for execution by the control circuitry, the one or more sets of instructions comprising instructions for: receiving video data comprising a plurality of coding blocks; identifying a coding region that comprises two or more coding blocks of the plurality of coding blocks that are to be encoded in a first prediction mode; entropy encoding a flag indicating the first prediction mode for the coding region using information comprising one or more of: previous instances of the flag, a block size of a current coding block, a block size group of the current coding block, respective block sizes of a set of neighboring coding blocks, respective block size groups of the set of neighboring coding blocks, and signaled flags for the set of neighboring coding blocks; signaling the entropy encoded flag in a video bitstream; and encoding the two or more coding blocks into the video bitstream according to a value of the entropy encoded flag for the coding region, wherein the signaled flags for the set of neighboring coding blocks comprise flags that are a same type of flag as the entropy encoded flag for the coding region and the signaled flag is a region type flag, and wherein the information comprises a count of signaled region type flags from coding blocks within the coding region.
12 . The computing system of claim 11 , wherein the signaled flags for the set of neighboring coding blocks comprise flags from the set of neighboring coding blocks that are a different type of flag as the entropy encoded flag for the coding region.
13 . The computing system of claim 11 , wherein the information further comprises one or more of: a quantization step size or a quantization parameter index for a current frame, a base quantization parameter index for a current video sequence that comprises the current frame, a picture type, a partitioning series, and a position of the current frame in a pyramid structure of video frames.
14 . A non-transitory computer-readable storage medium storing a video bitstream that is generated by a video encoding method, the video bitstream comprising: coded information for a plurality of pictures of video data, including a first picture having a coding region comprising two or more coding blocks; and a flag indicating the first prediction mode for the coding region using information comprising one or more of: previous instances of the flag, a block size of a current coding block, a block size group of the current coding block, respective block sizes of a set of neighboring coding blocks, respective block size groups of the set of neighboring coding blocks, and signaled flags for the set of neighboring coding blocks; the signaled flags for the set of neighboring coding blocks, including region-type flags that are a same type of flag as the flag for the coding region, wherein the information comprises a count of signaled region type flags from coding blocks within the coding region; wherein the video encoding method comprises: entropy encoding the flag indicating the first prediction mode for the coding region; and encoding the two or more coding blocks into the video bitstream according to a value of the entropy encoded flag for the coding region.
15 . The non-transitory computer-readable storage medium of claim 14 , wherein the coded information comprises flags from the set of neighboring coding blocks that are a different type of flag as the signaled flag for the coding region.
16 . The non-transitory computer-readable storage medium of claim 14 , wherein the information further comprises one or more of: a quantization step size or a quantization parameter index for a current frame, a base quantization parameter index for a current video sequence that comprises the current frame, a picture type, a partitioning series, and a position of the current frame in a pyramid structure of video frames.

Description

RELATED APPLICATIONS This application claims priority to U.S. Provisional Patent Application No. 63/603,056, entitled “Entropy Coding for Recursive Intra Region Partitioning” filed Nov. 27, 2023, which is hereby incorporated by reference in its entirety. TECHNICAL FIELD The disclosed embodiments relate generally to video coding, including but not limited to systems and methods for using coded information as context for entropy coding signaled flags. BACKGROUND Digital video is supported by a variety of electronic devices, such as digital televisions, laptop or desktop computers, tablet computers, digital cameras, digital recording devices, digital media players, video gaming consoles, smart phones, video teleconferencing devices, video streaming devices, etc. The electronic devices transmit and receive or otherwise communicate digital video data across a communication network, and/or store the digital video data on a storage device. Due to a limited bandwidth capacity of the communication network and limited memory resources of the storage device, video coding may be used to compress the video data according to one or more video coding standards before it is communicated or stored. The video coding can be performed by hardware and/or software on an electronic/client device or a server providing a cloud service. Video coding generally utilizes prediction methods (e.g., inter-prediction, intra-prediction, or the like) that take advantage of redundancy inherent in the video data. Video coding aims to compress video data into a form that uses a lower bit rate, while avoiding or minimizing degradations to video quality. Multiple video codec standards have been developed. For example, High-Efficiency Video Coding (HEVC/H.265) is a video compression standard designed as part of the MPEG-H project. ITU-T and ISO/IEC published the HEVC/H.265 standard in 2013 (version 1), 2014 (version 2), 2015 (version 3), and 2016 (version 4). Versatile Video Coding (VVC/H.266) is a video compression standard intended as a successor to HEVC. ITU-T and ISO/IEC published the VVC/H.266 standard in 2020 (version 1) and 2022 (version 2). AOMedia Video 1 (AV1) is an open video coding format designed as an alternative to HEVC. On Jan. 8, 2019, a validated version 1.0.0 with Errata 1 of the specification was released. SUMMARY The present disclosure describes amongst other things, a set of methods for video (image) compression, more specifically related to block partitioning, intra prediction, and coding of signaled flags. Some embodiments include using coded information (e.g., relating to the current block and/or neighboring blocks) as a context for a probability model used to entropy encode a signaled flag. Using coded information as context for the probability model may improve accuracy and efficiency of entropy coding as compared to systems in which the coded information is not used as the context for the probability model. The use of coded information as the context for entropy coding a signaled flag helps to reduce the amount of overhead required for signaling flags that indicate a characteristic of a coding region. In accordance with some embodiments, a method of video decoding includes (i) receiving a video bitstream including a plurality of coding blocks; (ii) identifying a coding region that comprises two or more coding blocks of the plurality of coding blocks that are encoded in a first prediction mode; (iii) entropy decoding a signaled flag indicating a prediction mode for the coding region, the entropy decoding using coded information comprising one or more of: previous instances of the signaled flag, a block size of a current coding block, a block size group of the current coding block, respective block sizes of a set of neighboring coding blocks, respective block size groups of the set of neighboring coding blocks, and signaled flags for the set of neighboring coding blocks; and (iv) reconstructing the two or more coding blocks according to a value of the signaled flag for the coding region. In accordance with some embodiments, a method of video encoding includes (i) receiving video data comprising a plurality of coding blocks; (ii) identifying a coding region that comprises two or more coding blocks of the plurality of coding blocks that are to be encoded in a first prediction mode; (iii) entropy encoding a flag indicating the first prediction mode for the coding region using information comprising one or more of: previous instances of the flag, a block size of a current coding block, a block size group of the current coding block, respective block sizes of a set of neighboring coding blocks, respective block size groups of the set of neighboring coding blocks, and signaled flags for the set of neighboring coding blocks; (iv) signaling the entropy encoded flag in a video bitstream; and (v) encoding the two or more coding blocks into the video bitstream according to a value of the entropy coded flag for the coding region. In