Transform Skip Signaling for Low-Overhead Video Coding
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Solution Overview
Problem
Existing video coding standards face limitations in coefficient coding, particularly in transform skip mode, including inflexible transform skip dimensions, increased overhead costs, and unsupported chroma component processing, which affect encoding efficiency and complexity.
Innovation Solution
The proposed solution involves signaling maximal transform skip dimensions in various headers, optimizing context modeling for coefficient flags, supporting chroma component processing, and enhancing residual coding techniques like QR-BDPCM and LMCS to improve encoding efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If transform skip mode is applied to all video blocks, then encoding efficiency is improved, but overhead cost increases due to signaling requirements
Solution Approach 1:
The patent applies transform skip mode selectively to specific video blocks based on local characteristics such as prediction mode and block content, rather than uniformly to all blocks. This local differentiation allows encoding efficiency to be improved in suitable blocks while avoiding unnecessary overhead in blocks where transform skip is not beneficial.
Solution Approach 2:
The patent introduces dynamic signaling mechanisms where the application of transform skip mode is controlled by syntax elements that are conditionally signaled based on block characteristics. This dynamic approach allows the system to adapt to different block types and content, improving encoding efficiency only where needed while minimizing overhead.
2Quantity of substance
If transform skip mode is selectively applied, then overhead cost is reduced, but encoding flexibility is limited
Solution Approach 1:
The patent modifies key parameters such as transform skip dimensions and signaling conditions to balance overhead and flexibility. By adjusting parameters like maxTransformSkipWidth and maxTransformSkipHeight, the system can adapt to different content types while controlling overhead. The syntax element design allows flexible activation based on prediction modes and block characteristics.
Solution Approach 2:
The patent segments the video content into different types based on prediction modes and block characteristics, applying transform skip mode selectively to appropriate segments. This segmentation allows the system to maintain flexibility for different content types while reducing overall overhead by not applying transform skip uniformly.
3Productivity
If transform skip mode is applied without dimension limits, then encoding efficiency is maximized, but device complexity increases
Solution Approach 1:
The patent introduces parameter constraints including maxTransformSkipWidth and maxTransformSkipHeight to limit transform skip dimensions. These parameter changes prevent unlimited transform skip application, thereby controlling device complexity while maintaining encoding efficiency within acceptable bounds for different content types.
4Adaptability or versatility
If chroma component processing is added to transform skip mode, then adaptability is improved, but device complexity increases
Solution Approach 1:
The patent applies transform skip mode to chroma components selectively based on local characteristics such as chroma prediction mode and block size. This local application improves adaptability for chroma content while avoiding unnecessary processing complexity in blocks where chroma transform skip is not beneficial.
Data Source
AI summary
Devices, systems and methods for coefficient coding in transform skip mode are described. An exemplary method for visual media processing includes: for encoding a current video block in a video region of a visual media data into a bitstream representation of the visual media data, identifying usage of a coding mode and/or an intra prediction mode and/or a set of allowable intra prediction modes; and upon identifying the usage, making a decision of whether to include or exclude, in the bitstream representation, a syntax element indicative of selectively applying a transform skip mode to the current video block, wherein, in the transform skip mode, a residual of a prediction error between the current video block and a reference video block is represented in the bitstream representation of the visual media data without applying a transformation.