Picture Encoding With Shape-Adaptive Coefficient Scanning
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Solution Overview
Problem
Existing video compression systems lack adaptive scanning orders for quantized transform coefficients, leading to suboptimal compression efficiency and increased complexity.
Innovation Solution
Adaptive scanning orders for quantized transform coefficients are determined based on block shape, prediction tool, and transform type, using methods such as vertical, horizontal, and diagonal scanning, with additional syntax elements to signal the best scanning order for improved rate-distortion performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a fixed scanning order is used for quantized transform coefficients, then the encoding complexity is reduced, but the compression efficiency deteriorates
Solution Approach 1:
The patent applies dynamics by making the scanning order adaptive rather than fixed. The scanning order is dynamically selected based on block characteristics (shape, prediction mode, transform type) to optimize compression efficiency for different content types while maintaining manageable complexity through rule-based selection
Solution Approach 2:
The patent changes the scanning order parameter based on block characteristics. Different scanning patterns (e.g., diagonal, horizontal, vertical) are selected according to block shape, prediction mode, and transform type, allowing the system to adapt to varying content characteristics and improve overall compression efficiency
2Productivity
If adaptive scanning orders are implemented based on block characteristics, then the compression efficiency is improved, but the device complexity increases
Solution Approach 1:
The patent applies local quality by selecting different scanning orders for different local block characteristics. Each block is analyzed based on its shape, prediction mode, and transform type, and the scanning order is locally optimized for that specific block rather than applying a uniform approach across all blocks
Solution Approach 2:
The patent uses preliminary action by determining the scanning order based on pre-encoded information (block shape, prediction mode, transform type) before the actual coefficient scanning process. This allows the decoder to know which scanning pattern to use without requiring complex real-time analysis
3Productivity
If multiple scanning patterns are supported for different block types, then the rate-distortion performance is improved, but the difficulty of detecting and measuring increases
Solution Approach 1:
The scanning pattern is determined in advance based on block characteristics that are already available from previous encoding steps. The block shape, prediction mode, and transform type are known before coefficient scanning, so the appropriate pattern can be selected without additional complex detection
Solution Approach 2:
The patent changes scanning parameters (pattern selection) based on block characteristics. By linking scanning pattern selection to existing block properties (shape, prediction mode, transform type), the system achieves multiple scanning patterns without requiring complex detection mechanisms
Data Source
AI summary
An encoding method is presented. Transform coefficients of a block are first obtained. They are then scanned according to a scan pattern for entropy coding. The scan pattern is determined responsive to a shape of the block.