Adaptive Coefficient Sign Prediction for Transform-Skip Video Coding
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Solution Overview
Problem
Existing video coding technologies face inefficiencies in transform coefficient sign prediction, particularly when transform skip is applied, leading to suboptimal compression ratios and increased computational complexity.
Innovation Solution
Implementing a method for transform coefficient sign prediction that adapts based on the use of one-dimensional or two-dimensional transform skips, enabling differential prediction strategies for different block dimensions and modes, including disabling or modifying the prediction process when transform skip is used.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If transform skip is applied in video coding, then computational complexity is reduced, but coding efficiency deteriorates due to suboptimal sign prediction
Solution Approach 1:
The patent applies different sign prediction strategies to different coefficient positions within the transform block. Specifically, it uses neighboring sample-based prediction for certain coefficients while using default or simplified prediction for others, optimizing the local prediction quality where it matters most while maintaining overall efficiency.
Solution Approach 2:
The patent dynamically selects prediction modes based on the transform block characteristics and neighboring available samples. The sign prediction method adapts its approach depending on whether transform skip is applied and what neighboring samples are available, transitioning between different prediction strategies to maintain coding efficiency.
2Productivity
If transform coefficient sign prediction is performed using traditional methods, then coding efficiency is maintained, but bit usage increases
Solution Approach 1:
The patent performs sign prediction only for a subset of transform coefficients rather than all coefficients. By selectively applying prediction to coefficients where it provides the most benefit and using simplified or default prediction for others, it reduces the total number of bits required while maintaining adequate coding efficiency.
3Speed
If transform skip is applied, then processing speed is improved, but compression ratio deteriorates
Solution Approach 1:
The patent performs sign prediction using neighboring samples before the actual coefficient encoding process. By preparing the sign predictions in advance based on available neighboring information, it enables faster processing during the main encoding/decoding pipeline while maintaining compression efficiency through accurate sign prediction.
Data Source
AI summary
Aspects of the present disclosure provide methods and apparatuses for video encoding/decoding. In some examples, an apparatus includes processing circuitry that is configured to receive a coded video stream including a current block that is associated with a transform block, and determine whether a transform skip is used in the transform block. In response to a determination that the transform skip is not used in the transform block, the processing circuitry is configured to perform a first transform coefficient sign prediction in which (i) first signs of a first plurality of transform coefficients are predicted based on a first plurality of neighboring samples, and (ii) second signs of a second plurality of transform coefficients are predicted based on a second plurality of neighboring samples. The processing circuitry is further configured to reconstruct the current block based on the first plurality of transform coefficients and the second plurality of transform coefficients.