Entropy Coding Adaptation for Video Compression Complexity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing video compression systems face challenges in achieving real-time transmission of high-quality video over bandwidth-limited connections while maintaining low complexity in entropy coding and decoding processes.
Innovation Solution
A method for entropy coding and decoding of quantized transform coefficients that balances low complexity with high performance by using a simplified approach similar to Context Adaptive Variable Length Coding (CAVLC), focusing on efficient coding of block patterns and coefficient positions, and adapting VLC tables based on block sizes and macroblock information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If complex entropy coding methods like CABAC are used to achieve high compression ratios, then video quality is improved, but computational complexity increases making real-time transmission difficult
Solution Approach 1:
The patent applies different VLC table strategies to different blocks within a macroblock based on their specific characteristics. Different VLC tables are selected based on the number of non-zero coefficients and their positions, allowing each block to be coded with optimally suited tables rather than using a uniform complex method throughout, thus reducing overall complexity while maintaining quality.
Solution Approach 2:
The patent segments the entropy coding process into multiple stages: first coding the number of non-zero coefficients, then coding their positions, and finally coding the coefficient values themselves. This segmentation allows the use of simpler VLC tables at each stage rather than requiring a single complex coding scheme, enabling real-time processing while achieving good compression.
2Productivity
If more bits are allocated for entropy coding to improve compression efficiency, then data transmission efficiency is improved, but the complexity of the coding process increases
Solution Approach 1:
The patent dynamically selects different VLC tables based on the actual content of each block (number of non-zero coefficients, their positions). This dynamic adaptation allows the system to achieve high compression efficiency by matching the coding strategy to the data characteristics, while avoiding the fixed complexity of always using the most complex tables.
Solution Approach 2:
The patent changes the parameters of the VLC tables based on block characteristics. Different VLC tables are constructed with different code assignments based on the number of non-zero coefficients and their positions, allowing optimal parameter selection for each coding scenario without requiring a single complex universal table.
Data Source
AI summary
The invention is related to entropy coding/decoding of transform coefficient data in video compression systems. For entropy coding coefficients representing a block in a video image, a preferred embodiment of the present invention introduces events combining the position of the last non-zero coefficient in the block with whether the absolute value is greater than 1. Further, no information from outside the macroblock is used to decide what VLC to use. Coefficients are typically coded by starting in a Run-mode and continuing in Level-mode when the first coefficient with absolute value >1 is found.