Implicit Transform Settings for Video Coding Blocks
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Solution Overview
Problem
High-Efficiency Video Coding (HEVC) faces challenges in efficiently encoding and decoding video data due to the complexity of transform settings, particularly in inter prediction modes, where explicit signaling of transform settings increases bitstream syntax and computational overhead.
Innovation Solution
The proposed solution involves a video coder that implicitly determines transform settings based on block processing settings, eliminating the need for explicit signaling of transform flags and indices by using predefined rules to select transform modes from DCT/DST families, such as DCT-II, DST-VII, DCT-VIII, and DST-I, for both intra and inter coded blocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If explicit signaling of transform settings is used in inter prediction modes, then transform mode selection flexibility is improved, but bitstream syntax complexity increases
Solution Approach 1:
The patent extracts the transform setting information from explicit bitstream signaling and derives it implicitly from block processing settings (such as motion prediction mode, block size, and gradient information). This removes the need for separate syntax elements to signal transform flags and indices, thereby reducing bitstream complexity while maintaining transform mode flexibility through derivation rules based on block characteristics.
Solution Approach 2:
Instead of explicitly signaling transform settings and then selecting transform modes, the patent inverts the approach by first determining block processing settings and then deriving the transform settings from them. This inversion allows the transform mode to be implicitly determined by the block's processing characteristics, reducing the need for explicit signaling while preserving adaptability.
2Manufacturing precision
If explicit signaling of transform settings is used, then transform coding precision is improved, but computational overhead increases
Solution Approach 1:
The transform setting derivation process uses self-service by automatically determining transform modes based on intrinsic block processing characteristics (motion prediction mode, block size, gradient calculations) without requiring external explicit signaling. The system serves itself by deriving transform settings from its own processing state, maintaining coding precision through context-adaptive selection while reducing computational overhead from explicit signaling and processing.
3Productivity
If multiple transform modes from DCT/DST families are supported, then coding efficiency is improved, but syntax element requirements increase
Solution Approach 1:
The patent applies preliminary action by pre-defining derivation rules that map block processing settings to specific transform modes from the DCT and DST families. These rules are established in advance based on block characteristics (size, shape, motion complexity), allowing the encoder to select from multiple transform modes without requiring additional syntax elements to signal the selection, thus maintaining coding efficiency while avoiding increased syntax requirements.
Data Source
AI summary
A video coder that implicitly signals a transform setting for coding a block of pixels is provided. The video coder derives a transform setting for a block of pixels based on a block processing setting. The video coder processes the block of pixels according to the block processing setting. For encoding, the video coder transforms a set of residual pixels to generate a set of transform coefficients according to the transform setting. For decoding, the video coder inverse transforms the transform coefficients to generate a set of residual pixels according to the transform setting.