Video Slice Header Weight Signaling for Faster Parsing
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Solution Overview
Problem
The overhead of slice header parsing in video coding is excessive, particularly in high-definition video decoding, leading to processing bottlenecks and pipeline delays, even when implemented in hardware or software.
Innovation Solution
Constrain the number of weighting factors signaled in a slice header for weighted prediction to a predetermined threshold and separate the signaling of weight flags from weighting factors to improve processing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of weighting factors in slice header is increased to support more reference pictures for weighted prediction, then prediction accuracy is improved, but parsing overhead and processing time increase significantly
Solution Approach 1:
The patent changes the parameter of weighting factor count from unlimited to constrained (maximum 4 per slice header). This parameter change directly reduces parsing overhead while maintaining adequate prediction accuracy for most practical scenarios, resolving the contradiction between precision and time loss.
Solution Approach 2:
The patent applies partial action by limiting weighting factors to the most essential cases (up to 4 reference pictures) rather than supporting all possible reference pictures. This partial approach achieves sufficient prediction accuracy for typical video content while avoiding the excessive parsing overhead of supporting every possible reference picture scenario.
2Adaptability or versatility
If slice header parsing is implemented in software for flexibility and error resiliency, then adaptability is improved, but processing speed and productivity decrease
Solution Approach 1:
By changing the parameter of weighting factor count to a small fixed maximum (4), the patent enables the parser to use optimized lookup tables and simplified logic, allowing software implementation to achieve both flexibility and acceptable processing speed.
Solution Approach 2:
The patent applies preliminary action by pre-defining the maximum number of weighting factors (4) during standard development. This preliminary constraint allows decoder implementations to pre-compute and store parsing logic and lookup tables, improving runtime processing speed while maintaining software flexibility.
3Productivity
If large slice headers are decoded in hardware to improve processing speed, then productivity is improved, but pipeline bubbles and delays increase
Solution Approach 1:
The patent changes the header size parameter by constraining weighting factors to maximum 4 per slice, which directly reduces slice header size. This enables hardware decoders to process headers faster and reduces pipeline bubble time, resolving the contradiction between productivity and time loss.
4Adaptability or versatility
If the maximum number of weighting factors is allowed for all reference pictures, then prediction flexibility is improved, but device complexity and parsing overhead increase
Solution Approach 1:
The patent changes the parameter of weighting factor count to a constrained maximum (4) that balances prediction flexibility with manageable parsing complexity. This parameter change allows the device to handle most practical video scenarios without requiring complex parsing logic for large numbers of reference pictures.
Data Source
AI summary
A method for encoding a picture of a video sequence in a bit stream that reduces slice header parsing overhead is provided. The method includes determining weighting factors that may be used for weighted prediction in encoding at least one slice of the picture, wherein a total number of the weighting factors is constrained to not exceed a predetermined threshold number of weighting factors, wherein the threshold number is less than a maximum possible number of weighting factors, and signaling weighted prediction parameters including the weighting factors in a slice header in the bit stream.