Implicit Transform Mode Mapping in Video Coding
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Solution Overview
Problem
High-Efficiency Video Coding (HEVC) lacks an efficient method to implicitly signal transform settings based on intra prediction settings, leading to suboptimal compression and decoding processes.
Innovation Solution
A video encoder and decoder that implicitly determine transform settings by mapping intra prediction modes to target transform modes using predefined rules and schemes like Adaptive Multiple Transform (AMT) and Multiple Transform Selection (MTS), eliminating the need for explicit signaling of transform settings in the bitstream.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If explicit transform settings are signaled in the bitstream, then transform accuracy is improved, but bitstream overhead increases
Solution Approach 1:
The patent extracts the transform setting information from explicit bitstream signaling and derives it implicitly from intra prediction mode information that is already present in the bitstream. This removes the redundant explicit signaling while maintaining the necessary transform configuration data.
Solution Approach 2:
The decoder uses the intra prediction mode information (which is already decoded for prediction purposes) to self-determine the transform settings without requiring additional signaling. The same intra prediction mode that guides prediction also guides transform selection, making the system self-sufficient.
2Productivity
If multiple transform modes are supported, then compression efficiency is improved, but device complexity increases
Solution Approach 1:
The patent applies different transform modes locally based on the specific intra prediction mode used for each block. Instead of universally applying one transform mode, the transform type is adapted to match the local prediction characteristics, optimizing compression for each block's specific content.
Solution Approach 2:
The patent changes the transform parameter (transform type) based on the intra prediction mode parameter. By linking transform selection to prediction mode selection, the system dynamically adjusts transform characteristics to match the content being encoded, improving efficiency without requiring complex independent transform decision logic.
Data Source
AI summary
A video coder that implicitly signals or decides transform settings based on intra prediction settings is provided. The video coder receives input data associated with a current block. The video coder determines a current intra prediction mode for the current block and maps the current intra prediction mode to a target transform mode. In one example, the video coder encodes the current block by performing a transform operation according to the target transform mode on the prediction residuals of the current block generated according to the current intra prediction mode. In another example, the video coder decodes the current block by performing an inverse transform operation according to the target transform mode on the coded prediction residuals of the current block, in which the coded prediction residuals is derived from the bitstream and is generated according to the current intra prediction mode.