Chroma Transform Skip Mode Derivation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current video coding standards, such as HEVC, require explicit syntax elements for indicating transform skip mode in chroma transform blocks, leading to increased signaling overhead, especially when not all transform units are the smallest size, which can reduce coding efficiency for certain types of video content.
Innovation Solution
The proposed method derives the transform skip flag for chroma transform blocks based on the sub-sampling format and the corresponding luma transform blocks, eliminating the need for explicit syntax elements in the encoded bitstream by determining the transform skip mode based on the number of luma blocks using the transform skip mode, thereby reducing signaling overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If explicit syntax elements are used to indicate transform skip mode in chroma transform blocks, then the transform skip mode can be accurately signaled, but the signaling overhead increases
Solution Approach 1:
The patent extracts the transform skip mode indication for chroma blocks from explicit syntax elements and derives it implicitly from luma block information. This removes the redundant signaling overhead while maintaining the necessary information through the derivation relationship between luma and chroma blocks.
Solution Approach 2:
The patent makes the luma transform block information serve multiple functions: it is used for both luma coding and for deriving the chroma transform skip mode indication. This multi-functionality eliminates the need for separate chroma-specific syntax elements, reducing overall signaling overhead.
2Adaptability or versatility
If transform skip mode is explicitly signaled for all chroma transform blocks, then coding flexibility is maintained, but the bitstream size increases
Solution Approach 1:
The patent removes the explicit chroma transform skip mode syntax elements from the bitstream and extracts the necessary information from the luma block indicators. This maintains coding flexibility through the derivation mechanism while reducing bitstream size by eliminating redundant data.
Solution Approach 2:
Instead of explicitly signaling chroma transform skip mode directly, the patent inverts the approach by having the chroma mode derived from luma mode information. This inversion reduces bitstream size while preserving the ability to adapt to different coding scenarios.
3Adaptability or versatility
If separate syntax elements are used for luma and chroma transform skip modes, then each component can be independently controlled, but the processing complexity increases
Solution Approach 1:
The patent merges the transform skip mode control for luma and chroma by deriving chroma mode from luma mode information. This reduces processing complexity by eliminating separate chroma-specific syntax element handling while maintaining independent control capability through the derivation relationship.
Solution Approach 2:
The luma transform block information is given universal application, serving both as the direct coding parameter for luma and as the basis for deriving chroma transform skip mode. This multi-functionality reduces processing complexity by consolidating the information source.
Data Source
AI summary
A device for coding video data includes a video coder configured to: determine for a chroma transform block (TB) a sub-sampling format for the chroma TB; based on the sub-sampling format for the chroma TB, identify one or more corresponding luma TBs; determine, for each of the one or more corresponding luma TBs, if the corresponding luma TB is coded using a transform skip mode; and, based on a number of the one or more corresponding luma TBs coded using the transform skip mode being greater than or equal to a threshold value, determine that the chroma TB is coded in the transform skip mode.