Transform Skip Block Coding Constraints for Lossless Video Integrity
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Solution Overview
Problem
In video coding, the use of dependent quantization (DQ) and sign data hiding (SDH) with transform skip residual coding (TSRC) can lead to lossy coding scenarios, even when a lossless mode is desired, as these tools are implicitly lossy and can be invoked for transform skip blocks, compromising the integrity of the encoded video data.
Innovation Solution
Configuring video encoders and decoders to disallow the use of DQ and SDH when transform skip residual coding is disabled, ensuring that both DQ and SDH are only enabled if TSRC is also enabled, thereby preventing lossy coding operations on transform skip blocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If dependent quantization and sign data hiding are enabled for transform skip blocks, then coding flexibility and compression efficiency are improved, but lossless coding integrity is compromised
Solution Approach 1:
The patent applies different coding characteristics to different blocks by checking the transform skip flag for each block individually. When the transform skip flag is set, DQ and SDH are disabled for that specific block while allowing them for non-transform-skip blocks, achieving local quality control rather than global restriction
Solution Approach 2:
The patent performs preliminary checking of the transform skip flag before applying DQ or SDH operations. By evaluating the flag status in advance (before the actual coding operation), the system prevents lossy operations from being applied to transform skip blocks, ensuring lossless coding integrity is maintained proactively
2Reliability
If transform skip residual coding is disabled, then lossless coding is maintained, but coding versatility is reduced
Solution Approach 1:
The patent dynamically adjusts the coding mode for each block based on the transform skip flag and the enabled status of DQ/SDH. The system can switch between transform skip residual coding and regular residual coding on a block-by-block basis, providing dynamic adaptability rather than static restriction
Solution Approach 2:
Different residual coding methods are applied to different blocks based on local characteristics indicated by the transform skip flag. Blocks with the flag enabled use transform skip residual coding while others use regular residual coding with DQ/SDH, achieving local optimization of coding versatility
Data Source
AI summary
An example device includes memory and one or more processors implemented in circuitry and communicatively coupled to the memory. The one or more processors are configured to receive a first slice header syntax element for a slice of the video data and determine a first value for the first slice header syntax element, the first value being indicative of whether dependent quantization is enabled. The one or more processors are configured to receive a second slice header syntax element for the slice of the video data and determine a second value for the second slice header syntax element, the second value being indicative of whether sign data hiding is enabled. The one or more processors are configured to determine whether transform skip residual coding is disabled for the slice based on the first value and the second value and decode the slice based on the determinations.