JVET Intra Prediction Template Matching for Lower Bitstream Overhead
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Solution Overview
Problem
Existing video coding standards like JVET face challenges in efficiently decoding intra prediction modes without explicit indication in the bitstream, leading to increased bitstream overhead and computational complexity.
Innovation Solution
Implementing a template matching scheme within the decoder to generate candidate prediction templates using different intra prediction modes, calculating matching costs, and selecting the mode with the lowest cost to reconstruct CUs, thereby omitting the need for explicit intra prediction mode signaling in the bitstream.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If explicit intra prediction mode indication is included in the bitstream, then decoding accuracy is improved, but bitstream overhead increases
Solution Approach 1:
The patent extracts the intra prediction mode information from the bitstream by using template matching to infer the mode from the decoded picture data itself. Instead of transmitting mode indicators, the decoder derives the mode by comparing templates from different prediction directions against the actual decoded block, thereby removing the overhead while preserving decoding accuracy.
Solution Approach 2:
The decoder performs self-service by autonomously determining the intra prediction mode through template matching operations on the decoded picture data. The system uses its own decoded output to infer the encoding parameters without requiring external signaling, thus eliminating bitstream overhead while maintaining accurate reconstruction.
2Quantity of substance
If template matching scheme is implemented to infer intra prediction modes, then bitstream overhead is reduced, but computational complexity increases
Solution Approach 1:
The patent segments the computational task by dividing the picture into multiple blocks and performing template matching independently for each block. By processing smaller units separately rather than analyzing the entire picture globally, the computational complexity per processing unit is reduced while still achieving accurate mode inference through localized template comparisons.
3Measurement precision
If multiple CU templates spaced by different reference lines are used, then decoding accuracy is improved, but device complexity increases
Solution Approach 1:
The patent applies local quality by using multiple CU templates spaced at different reference lines to capture local variations in the picture content. Different reference lines provide different local contexts, and by selecting the template that yields the best match for each local block, the system adapts to local picture characteristics, improving decoding accuracy while managing complexity through localized processing.
Data Source
AI summary
A method of decoding JVET video, comprising defining a coding unit (CU) template within a decoded area of a video frame, the CU template being positioned above and/or to the left of a current decoding position for which data was intra predicted, defining a search window within the decoded area, the search window being adjacent to the CU template, generating a plurality of candidate prediction templates based on pixel values in the search window, each of the plurality of candidate prediction templates being generated using different intra prediction modes, calculating a matching cost between the CU template and each of the plurality of candidate prediction templates, selecting an intra prediction mode that generated the candidate prediction template that had the lowest matching cost relative to the CU template, and generating a prediction CU for the current decoding position based on the intra prediction mode.