Video Coding Syntax Signaling with SPS Flag Inference Across Slices
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Solution Overview
Problem
Current video coding standards face issues with redundant signaling of syntax elements in the picture header, leading to inefficiencies and potential decoding errors due to improper value settings for coding tools, particularly in bi-predictive slices.
Innovation Solution
Implement methods to conditionally signal disable flags for coding tools in the picture header based on enable flags in the sequence parameter set, inferring flag values when not explicitly present to ensure consistent and efficient decoding across slices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If disable flags are always explicitly signaled in the picture header, then decoding reliability is improved, but bit rate increases due to redundant signaling
Solution Approach 1:
The patent extracts only the necessary disable flag signaling to the picture header level, removing redundant signaling from slice headers. The disable flag is included in the picture header only when sps_bdof_enabled_flag equals 1, eliminating unnecessary repetition while maintaining decoding reliability.
Solution Approach 2:
Instead of always signaling the disable flag explicitly, the patent inverts the approach by allowing the decoder to infer the flag value from SPS-level enable flags when the picture header does not contain an explicit disable flag. This reduces bit rate while preserving reliability through logical inference.
2Quantity of substance
If disable flags are inferred from SPS enable flags, then bit rate is reduced, but decoding complexity increases
Solution Approach 1:
The SPS-level enable flags (sps_bdof_enabled_flag) are set in advance during encoding, preparing the information needed for inference. The decoder uses these pre-established flags to infer picture header disable flags without requiring complex real-time analysis, reducing decoding complexity while maintaining bit rate efficiency.
3Productivity
If disable flags are conditionally signaled based on enable flags, then signaling efficiency is improved, but risk of inconsistent values increases
Solution Approach 1:
The patent establishes a feedback mechanism where the decoder checks the sps_bdof_enabled_flag value and uses it to either explicitly read the disable flag from the picture header or infer it based on SPS-level flags. This feedback loop ensures that the inferred values are consistent with the enable flags, preventing value inconsistency while improving signaling efficiency.
Data Source
AI summary
Methods and apparatuses for video encoding are provided. The method includes signaling one or more enable flags in a sequence parameter set (SPS) of a picture; and selectively signaling a disable flag in a picture header (PH) associated with a picture, wherein the disable flag specifies whether a coding tool is disabled for one or more slices associated with the PH; wherein in response to the disable flag being determined not to be signaled in the PH, a value of the disable flag is inferred according to one or more enable flags at the SPS level; and wherein in response to a first enable flag at the SPS level being determined to be equal to 1 and a second enable flag at the SPS level being determined to be equal to 0, the value of the disable flag is inferred to be 0.