Intra-Prediction Mode Signaling in Video Coding

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Solution Overview

Problem

Current video coding techniques face inefficiencies in signaling intra-prediction modes for video data, leading to increased bit usage due to the lack of optimized coding methods for variable-length codewords based on context likelihoods.

Innovation Solution

The proposed solution involves determining the most probable intra-prediction modes for video blocks based on encoding contexts and using variable-length codewords that are inversely proportional to their likelihoods, allowing for a more efficient signaling of intra-prediction modes by modifying the index values and codeword lengths.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If variable-length codewords are used for signaling intra-prediction modes, then bit usage efficiency is improved, but codeword selection complexity increases

Engineering Contradiction:
Improvebit usageVSAvoidcodeword selection complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by dynamically adjusting codeword lengths based on the probability of intra-prediction modes. More probable modes are assigned shorter codewords while less probable modes receive longer codewords, optimizing the overall bit usage for the bitstream without requiring complex selection mechanisms.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If context-based probability estimation is used for intra-prediction modes, then coding efficiency is improved, but computational complexity increases

Engineering Contradiction:
Improvecoding efficiencyVSAvoidcomputational complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent employs preliminary action by pre-determining the most probable intra-prediction mode based on context information from neighboring blocks before actual encoding. This allows the encoder to select optimal codewords in advance, improving coding efficiency while minimizing computational complexity during the encoding process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent applies local quality by using context-specific probability estimates for different spatial locations in the video frame. Each block's intra-prediction mode probability is determined based on local characteristics of neighboring blocks, allowing adaptive optimization without requiring global analysis of the entire frame.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2622864B1Indicating intra-prediction mode selection for video coding
Publication Date: 2018.09.05 QUALCOMM INC
  • EP2622864B1 patent drawingFigure 1
  • EP2622864B1 patent drawingFigure 2
  • EP2622864B1 patent drawingFigure 3

AI summary

For a block of video data, a video encoder can signal to a video decoder a selected intra-prediction mode using a codeword that is mapped to a modified intra- prediction mode index. The video decoder can receive the codeword, determine the modified intra-prediction mode index corresponding to the codeword, determine most probable modes based on a context, map the modified intra-prediction mode index to an intra-prediction mode index by comparing the modified intra-prediction mode index to the mode indexes of the most probable modes, and determine the selected intra- prediction mode used to encode the block of video data based on the intra-prediction mode index.