Decoding apparatus, encoding apparatus, and transmitting apparatus

Patent metadata

Field	Value
Publication number	US-12556712-B2
Application number	US-202418931236-A
Country	US
Kind code	B2
Filing date	Oct 30, 2024
Priority date	Jan 12, 2019
Publication date	Feb 17, 2026
Grant date	Feb 17, 2026

Abstract

A decoding apparatus for image decoding includes: a memory and at least one processor connected to the memory, the at least one processor configured to: obtain a transform skip flag of a current block from a bitstream, obtain residual information of the current block from the bitstream based on the transform skip flag, wherein the residual information is residual information on transform skip, derive a specific number of context-coded bins for context syntax elements for the current block, decode the context syntax elements for a current sub-block of the current block included in the residual information based on the specific number, derive transform coefficients for the current sub-block based on the decoded context syntax elements, derive residual samples for the current block based on the transform coefficients, and generate a reconstructed picture based on the residual samples.

First claim

What is claimed is:

1 . A decoding apparatus for image decoding, the decoding apparatus comprising:
a memory; and at least one processor connected to the memory, the at least one processor configured to:
obtain a transform skip flag of a current block from a bitstream;
obtain residual information of the current block from the bitstream based on the transform skip flag, wherein the residual information is residual information on transform skip;
derive a specific number of context-coded bins for context syntax elements for the current block;
decode the context syntax elements for a current sub-block of the current block included in the residual information based on the specific number;
derive transform coefficients for the current sub-block based on the decoded context syntax elements;
derive residual samples for the current block based on the transform coefficients; and
generate a reconstructed picture based on the residual samples;
wherein when a number of context coded bins for context syntax elements of transform coefficients reaches the specific number, a bypass syntax element for a specific transform coefficient of the current sub-block included in the residual information is decoded; wherein whether the number of the context-coded bins reaches the specific number is determined by a sum of the number of the context coded bins for the context syntax elements of the transform coefficients derived before the specific transform coefficient.

2 . The decoding apparatus of claim 1 , wherein when the number of the context coded bins reaches the specific number, decoding of context syntax elements for the specific transform coefficient is omitted; and
wherein a value of the specific transform coefficient is derived based on the bypass syntax element for the specific transform coefficient.

3 . The decoding apparatus of claim 1 , wherein the context syntax elements include a significant coefficient flag indicating whether a transform coefficient is a non-zero transform coefficient, a parity level flag for a parity of a transform coefficient level for the transform coefficient, a first transform coefficient level flag for whether the transform coefficient level is greater than a first threshold, and a second transform coefficient level flag for whether the transform coefficient level of the transform coefficient is greater than a second threshold.

4 . The decoding apparatus of claim 1 , wherein the context syntax elements include a significant coefficient flag indicating whether a transform coefficient is a non-zero transform coefficient, a sign flag indicating a sign of the transform coefficient, a first transform coefficient level flag for whether a transform coefficient level for the transform coefficient is greater than a first threshold, and a parity level flag for a parity of the transform coefficient level.

5 . The decoding apparatus of claim 1 , wherein the specific number is set based on a size of the current block.

6 . The decoding apparatus of claim 1 , wherein it is not determined whether the number of the context-coded bins reaches the specific number in a decoding process of each of the context syntax elements.

7 . An encoding apparatus for image encoding, the encoding apparatus comprising:
a memory; and at least one processor connected to the memory, the at least one processor configured to:
derive residual samples for a current block;
derive a transform skip flag for whether transform is applied to the current block;
derive transform coefficients in a current sub-block of the current block based on the residual samples;
derive a specific number of context-coded bins for context syntax elements for the current block;
encode the context syntax elements based on the specific number; and
generate a bitstream including the transform skip flag and residual information for the current block including the encoded context syntax elements, wherein the residual information is residual information on transform skip;
wherein when a number of context coded bins for context syntax elements of transform coefficients reaches the specific number, a bypass syntax element for a specific transform coefficient of the current sub-block included in the residual information is encoded; wherein whether the number of the context-coded bins reaches the specific number is determined by a sum of the number of the context coded bins for the context syntax elements of the transform coefficients derived before the specific transform coefficient.

8 . The encoding apparatus of claim 7 , wherein the context syntax elements include an significant coefficient flag indicating whether a transform coefficient is a non-zero transform coefficient, a parity level flag for a parity of a transform coefficient level for the transform coefficient, a first transform coefficient level flag regarding whether the transform coefficient level is greater than a first threshold, and a second transform coefficient level flag regarding whether the transform coefficient level of the transform coefficient is greater than a second threshold.

9 . The encoding apparatus of claim 7 , wherein when the number of the context coded bins reaches the specific number, encoding of context syntax elements for the specific transform coefficient is omitted; and
wherein a value of the specific transform coefficient is derived based on the bypass syntax element for the specific transform coefficient.

10 . The encoding apparatus of claim 7 , wherein it is not determined whether the number of the context-coded bins reaches the specific number in an encoding process of each of the context syntax elements.

11 . The encoding apparatus of claim 7 , wherein the specific number is set based on a size of the current block.

12 . A non-transitory computer readable storage medium, storing computer programs and a bitstream, wherein when executed by a processor, the computer programs cause the processor to perform an encoding method to generate the bitstream, the encoding method comprising:
deriving residual samples for a current block; deriving a transform skip flag for whether transform is applied to the current block; deriving transform coefficients in a current sub-block of the current block based on the residual samples; deriving a specific number of context-coded bins for context syntax elements for the current block; encoding the context syntax elements based on the specific number; and generating a bitstream including the transform skip flag and residual information for the current block including the encoded context syntax elements, wherein the residual information is residual information on transform skip; wherein when a number of context coded bins for context syntax elements of transform coefficients reaches the specific number, a bypass syntax element for a specific transform coefficient of the current sub-block included in the residual information is encoded; wherein whether the number of the context-coded bins reaches the specific number is determined by a sum of the number of the context coded bins for the context syntax elements of the transform coefficients derived before the specific transform coefficient.

Assignees

• Guangdong Oppo Mobile Telecommunications Corp Ltd

Inventors

• Choi Jungah
• Lim Jaehyun
• Heo Jin
• Yoo Sunmi
• Li Ling
• Choi Jangwon
• Kim Seunghwan

Classifications

• H04N19/88

  involving rearrangement of data among different coding units, e.g. shuffling, interleaving, scrambling or permutation of pixel data or permutation of transform coefficient data among different blocks · CPC title

• H04N19/70

  characterised by syntax aspects related to video coding, e.g. related to compression standards · CPC title

• H04N19/46

  Embedding additional information in the video signal during the compression process (H04N19/517, H04N19/68, H04N19/70 take precedence) · CPC title

• H04N19/18 Primary

  the unit being a set of transform coefficients · CPC title

• H04N19/176

  the region being a block, e.g. a macroblock · CPC title