Transform Skip Residual Coding for Video Compression
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Solution Overview
Problem
Current video coding technologies face challenges in efficiently compressing video data, particularly in reducing redundancy and managing high bitrates, which leads to increased storage requirements and bandwidth consumption.
Innovation Solution
The proposed solution involves a method for video coding at a decoder, where a bit stream including syntax elements corresponding to coefficients of a transform skipped block is received. These syntax elements include flags indicating the absolute coefficient level and its parity, which are decoded in specific passes to optimize coding efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional video coding techniques are used, then video data can be compressed, but the compression ratio is insufficient and bitrate requirements remain high
Solution Approach 1:
The patent segments the transform coefficients into multiple groups (e.g., DC coefficient group and AC coefficient groups) and applies different coding strategies to each group. The DC coefficients are coded with one pass of binary arithmetic decoding while AC coefficients use multiple passes, allowing optimized compression for different coefficient types and improving overall compression ratio while reducing bitrate.
Solution Approach 2:
The patent changes the coding parameters by introducing multiple passes of binary arithmetic decoding with different context models for different coefficient groups. It also introduces syntax elements like `abs_level_gt0_flag` and `par_level_flag` that provide more granular control over the decoding process, enabling more efficient parameter representation and higher compression ratios.
2Measurement precision
If more syntax elements are decoded to improve coding precision, then the number of bits required increases
Solution Approach 1:
The patent applies partial action by using different numbers of decoding passes for different coefficient groups. The DC coefficient group uses one pass while AC coefficient groups use multiple passes (e.g., two or more passes). This selective approach provides sufficient precision for each coefficient type without unnecessarily increasing the total bit count for all coefficients.
Solution Approach 2:
The patent applies local quality by using different context models and decoding strategies for different spatial locations and coefficient types. Specifically, different context models are used for DC and AC coefficients, and different passes are used for different coefficient groups, allowing each region to be decoded with the appropriate level of precision while minimizing overall bit consumption.
Data Source
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AI summary
A method of video decoding performed in a video decoder is provided. A bit stream including bins of syntax elements is received. The syntax elements correspond to coefficients of a region of a transform skipped block in a coded picture. The syntax elements include a first flag indicating whether an absolute coefficient level of one of the coefficients is greater than a first threshold value, and a second flag indicating a parity of the absolute coefficient level. The second flag is decoded in a pass. The pass satisfies at least one of: (1) no other syntax elements is decoded in the pass; (2) a third flag indicating whether the absolute coefficient level is greater than a second threshold value is decoded in the pass; and (3) a fourth flag indicating sign information of the coefficient level of the one of the coefficients is decoded in the pass.