Intra Prediction Mode Signaling for Video Encoding
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Solution Overview
Problem
As video resolution increases, the efficiency of intra prediction mode signaling in video encoding and decoding is compromised due to the need to transmit more intra modes, leading to reduced compression efficiency and increased complexity in representing most probable modes (MPMs) using truncated unary form.
Innovation Solution
The method involves determining and encoding intra modes for a current block by identifying most probable modes (MPMs) and non-MPMs, grouping non-MPMs, and signaling the index of the group to which the intra mode belongs, rather than explicitly signaling each mode, to optimize encoding and decoding processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of intra prediction modes is increased to handle higher video resolution, then prediction accuracy is improved, but the complexity of signaling and compression efficiency deteriorates
Solution Approach 1:
The patent segments the set of intra prediction modes into two distinct groups: MPM (Most Probable Mode) candidates and non-PM modes. This segmentation allows the encoder to selectively signal only the necessary subset of modes based on their probability of occurrence, thereby reducing signaling complexity while maintaining prediction accuracy for high-resolution video
Solution Approach 2:
The patent changes the parameter of mode representation by using an MPM indicator to select from a limited set of most probable modes, rather than signaling all available intra prediction modes. This parameter change reduces the bitrate required for mode signaling while preserving the ability to accurately predict high-resolution video blocks
2Reliability
If the number of MPMs is increased to improve prediction efficiency, then prediction quality is improved, but the compression efficiency deteriorates due to truncated unary representation
Solution Approach 1:
The patent applies partial action by signaling only the most probable modes (a subset of all possible modes) using the MPM mechanism. Instead of exhaustively representing all intra prediction modes, the system performs partial signaling focused on the most likely candidates, improving compression efficiency while maintaining prediction efficiency through selective mode representation
3Measurement precision
If explicit indication of non-MPM modes is transmitted, then mode precision is improved, but the overhead in signaling increases
Solution Approach 1:
The patent extracts and separates the MPM candidates from the complete set of intra prediction modes. By taking out only the most probable modes for explicit signaling and handling the remaining modes differently (through implicit derivation or limited signaling), the system reduces signaling overhead while maintaining the precision needed to accurately represent the actual intra mode used
Data Source
AI summary
The present invention relates to efficient signaling of an intra prediction mode for predicting a current block in intra prediction coding. According to an aspect of the present invention, a video encoding apparatus divides dozens of intra modes into groups, selects a group to which an actual intra mode of the current block to be encoded belongs, and signals a value corresponding to the group. The video decoding apparatus acquires information on the group to which the actual intra mode of the current block belongs from a bit-stream and then evaluates intra modes belonging to the group to select a final intra mode.