Video Coefficient Entropy Coding for Single-Pass Compression
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Solution Overview
Problem
Current entropy coding methods, such as CABAC, are inefficient for larger block sizes in video coding due to the need for two scanning passes and a non-systematic design, which results in reduced compression efficiency.
Innovation Solution
A systematic entropy coding approach that uses a binary arithmetic coding engine with reduced binary bins, coding coefficient values in a single scanning order, and employing flags like last_ge2_flag to indicate significant coefficients, allowing for simpler coding and higher compression efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If CABAC is used for entropy coding, then coding efficiency is improved, but two scanning passes are required which reduces productivity
Solution Approach 1:
The patent segments the coefficient coding process by introducing a flag mechanism that divides coefficients into those requiring value coding and those that do not, allowing the encoder to skip value coding for certain coefficients and thus reduce the number of passes needed
Solution Approach 2:
The patent performs preliminary action by coding the flag in the first pass that indicates whether value coding is needed, so that the second pass can skip value coding for coefficients where the flag indicates it's unnecessary, thereby improving productivity
2Loss of information
If CABAC is used for entropy coding, then coding efficiency is improved, but device complexity increases due to non-systematic implementation
Solution Approach 1:
The patent applies homogeneity by creating a systematic coding structure where all coefficients are processed through the same flag-based mechanism, making the coding process more regular and less complex compared to the non-systematic CABAC approach
3Loss of information
If CABAC is used for entropy coding, then coding efficiency is improved, but it becomes less efficient for larger block sizes
Solution Approach 1:
The patent achieves universality by designing a flag-based coding mechanism that works efficiently for both small and large block sizes, making the entropy coding method adaptable to different block dimensions without losing efficiency
Data Source
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AI summary
A signal is provided comprising video data generated by an improved entropy encoding method or apparatus. The video data comprises at least a block in a picture being, for instance, encoded by a video encoder, by transforming a residue of the block to obtain transform coefficients, quantizing the transform coefficients to obtain quantized transform coefficients, and entropy coding the quantized transform coefficients. The quantized transform coefficients are encoded using a flag to indicate that a current one of the quantized transform coefficients being processed is a last non-zero coefficient for the block having a value greater than or equal to a specified value.