Lossless Video Coding via Prediction Residual Entropy Encoding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current video compression technologies, such as those in the High Efficiency Video Coding (HEVC) standard, lack an efficient lossless coding mode, which limits their coding efficiency and speed, especially for high-quality videos like those with YUV subsampling of 4:4:4, leading to potential image quality issues and eye fatigue in applications like computer screen sharing.
Innovation Solution
The implementation of a transform bypass lossless coding scheme that bypasses the transform and quantization steps, directly encoding prediction residuals of a residual block, using adaptive scanning and context modeling to efficiently encode residual blocks with large values, and employing level inversion flags for efficient encoding of residual levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If transform and quantization steps are used in video compression, then compression ratio is improved, but image quality is degraded due to lossy compression
Solution Approach 1:
The patent extracts and removes the transform and quantization steps from the traditional video compression pipeline, keeping only the prediction residual encoding. This extraction eliminates the source of information loss while preserving compression functionality through direct entropy encoding of residuals.
Solution Approach 2:
Instead of following the conventional approach of transform→quantization→encoding, the patent inverts the methodology by bypassing transform and quantization entirely, directly encoding prediction residuals in the spatial domain. This inversion achieves lossless compression where traditional methods achieve lossy compression.
2Manufacturing precision
If traditional lossless coding modes are used, then image quality is maintained, but coding efficiency and speed are reduced
Solution Approach 1:
The patent segments the encoding process into prediction block generation and direct residual encoding, eliminating intermediate transform and quantization stages. This segmentation simplifies the workflow and improves coding efficiency while maintaining lossless image quality.
Solution Approach 2:
The patent skips the transform and quantization steps entirely, rushing directly from prediction residual calculation to entropy encoding. This skipping of unnecessary intermediate steps significantly improves coding speed and efficiency while maintaining lossless compression.
3Quantity of substance
If compression is applied to reduce data quantity, then bandwidth requirements are reduced, but image quality deteriorates
Solution Approach 1:
The patent changes the fundamental parameters of the compression approach by working directly in the spatial domain with prediction residuals rather than transforming to frequency domain and applying quantization. This parameter change enables data reduction while preserving exact original image quality through lossless entropy encoding.
Data Source
AI summary
An apparatus used in video encoding comprising a processor configured to generate a prediction block for a current block, compute a difference between the current block and the prediction block to generate a residual block, wherein the residual block comprises a plurality of residual values, and if the plurality of residual values include at least one non-zero residual value comprising at least one sign and at least one residual level, perform entropy encoding on the at least one sign; and perform entropy encoding on the at least one residual level, wherein one non-residual value comprises one sign and one residual level.