Adaptive Transform Skip Mode Coding for Video Blocks
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Solution Overview
Problem
Conventional High Efficiency Video Coding (HEVC) techniques assume a two-dimensional transform for video blocks, which may not be the most efficient when transforms are skipped, leading to suboptimal coding of significant coefficient information.
Innovation Solution
The proposed solution involves selecting a transform skip mode for a video block, which allows for choices between two-dimensional, horizontal one-dimensional, vertical one-dimensional, or no transform modes, and uses specific coding procedures to efficiently code the position of the last non-zero coefficient and significance map based on the selected mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional two-dimensional transform coding procedures are used, then the coding is simple and consistent, but the compression efficiency is suboptimal when transforms are skipped
Solution Approach 1:
The patent applies dynamics by making the coding procedure adaptive to the transform mode. Different coding procedures are selected based on whether a two-dimensional transform or transform skip mode is used. This allows the system to optimize compression efficiency for each specific case rather than using a fixed procedure, directly resolving the contradiction between simplicity and efficiency.
Solution Approach 2:
The patent changes the parameters of the coding procedure based on the transform mode. When transform skip mode is detected, specific parameters such as significance map coding and last non-zero coefficient positioning are adjusted to match the statistical characteristics of the transformed data, improving compression efficiency without requiring complete procedural overhaul.
2Productivity
If transform skip mode is implemented with mode-specific coding procedures, then compression efficiency improves, but the complexity of implementing and maintaining multiple coding procedures increases
Solution Approach 1:
The patent segments the coding procedure into distinct paths based on transform mode. One path handles two-dimensional transform coding while another handles transform skip mode coding. This segmentation allows each procedure to be optimized independently for its specific case, improving overall efficiency while making the complexity manageable through clear separation of concerns.
Solution Approach 2:
The patent applies preliminary action by detecting the transform mode before proceeding with coefficient coding. This early detection allows the system to select the appropriate coding procedure in advance, avoiding the need to implement and switch between multiple procedures during the actual coding process, thus reducing operational complexity.
3Productivity
If conventional significance map coding is used, then the implementation is straightforward, but the coding is not optimal for transform skip mode statistics
Solution Approach 1:
The patent applies local quality by tailoring the significance map coding procedure to the local characteristics of transform skip mode data. Instead of using a universal coding approach, the patent adjusts the coding strategy to match the specific statistical properties of coefficients generated when transforms are skipped, thereby improving efficiency without requiring complete statistical analysis.
Data Source
AI summary
This disclosure describes techniques for coding significant coefficient information for a video block in a transform skip mode. The transform skip mode may provide a choice of a two-dimensional transform mode, a horizontal one-dimensional transform mode, a vertical one-dimensional transform mode, or a no transform mode. In other cases, the transform skip mode may provide a choice between a two-dimensional transform mode and a no transform mode. The techniques include selecting a transform skip mode for a video block, and coding significant coefficient information for the video block using a coding procedure defined based at least in part on the selected transform skip mode. Specifically, the techniques include using different coding procedures to code one or more of a position of a last non-zero coefficient and a significance map for the video block in the transform skip mode.