Constraint Flag Signaling for Efficient Last Significant Coefficient Coding
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Solution Overview
Problem
Existing video coding technologies face inefficiencies in representing less likely intra prediction directions and motion vector directions, leading to increased bit usage and reduced compression ratios.
Innovation Solution
Implementing a syntax element for coding control that disables or enables tools for coding the position of last significant coefficients during entropy coding, constraining the use of these tools in certain scopes of coded video data to optimize bit usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional intra coding without intra prediction is used, then device complexity is reduced, but coding efficiency deteriorates due to increased bit usage for representing directions
Solution Approach 1:
The patent changes the parameter representation method by introducing a constraint flag that modifies how intra prediction directions are coded. When the constraint flag is set, the encoder uses a simplified coding mechanism that assumes certain directional constraints, reducing the bits needed to represent less likely directions while maintaining decoding accuracy through the constraint information.
Solution Approach 2:
Instead of explicitly coding all possible prediction directions with full precision, the patent inverts the approach by coding the constraint flag that indicates which directions are limited. This inversion allows the system to represent less likely directions with fewer bits by implicitly assuming the constraint rather than explicitly stating all possibilities.
2Productivity
If coding tools for last significant coefficient position are enabled, then coding efficiency improves through better compression, but bit usage increases for representing less likely directions
Solution Approach 1:
The constraint flag changes the parameter coding strategy by indicating when the last significant coefficient position should be constrained. When constrained, the system uses a simplified coding approach that reduces bit usage for less likely directions while maintaining compression effectiveness through the implicit directional constraints.
Solution Approach 2:
The patent applies partial action by selectively enabling the coding tool for last significant coefficient position only when the constraint flag indicates it is appropriate. This partial application avoids unnecessary bit usage for directions where the constraint would not provide benefit, while still achieving good compression ratios for the cases where the constraint is active.
3Quantity of substance
If constraint flag is used to control coding tool invocation, then bit usage is optimized for likely directions, but complexity increases for managing multiple coding scenarios
Solution Approach 1:
The patent segments the coding process into distinct scenarios based on the constraint flag value. When the constraint flag is set, a simplified coding path is taken; when unset, a more complex but more flexible coding path is used. This segmentation allows the system to optimize bit usage for likely directions while managing complexity by having clear, distinct coding paths for different scenarios rather than a single complex unified approach.
Data Source
AI summary
Aspects of the disclosure provide methods and apparatuses for video data processing. In some examples, an apparatus for video data processing includes processing circuitry. For example, the processing circuitry determines a first syntax element for coding control in a first scope of coded video data in a bitstream. The first syntax element is associated with a coding tool for coding a position of a last significant coefficient during an entropy coding of transform coefficients. Then, in response to the first syntax element being a first value indicative of disabling of the coding tool in the first scope, the processing circuitry decodes the first scope of coded video data in the bitstream that includes one or more second scopes of coded video data without invoking the coding tool.