Scalable Video Coding Weight Prediction Syntax Adaptation

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Solution Overview

Problem

The H.264 standard does not specify which weights to use for the enhancement layer when different weighting parameters are applied in the base and enhancement layers during scalable video coding, leading to lower coding efficiency and bit waste due to the frequent absence of residue_prediction_flag when different weights are used.

Innovation Solution

The solution involves reusing the base layer weights for the enhancement layer by modifying the semantics of motion_prediction_flag_lx and simplifying the residual_prediction_flag syntax, allowing the same weighting parameters to be applied across layers without adding new syntax, and indicating this through rephrased weighted_pred_flag and weighted_bipred_idc values.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If different weighting parameters are used in the enhancement layer and base layer for a given macroblock, then the H.264 standard allows flexibility in weight selection, but residual prediction becomes impractical and bits are wasted due to frequent absence of residue_prediction_flag

Engineering Contradiction:

Improveweight selection flexibilityVSAvoidbit waste

Core Design Contradiction:

Adaptability or versatilityVSLoss of information

Solution Approach 1:

The patent makes the residue_prediction_flag syntax self-adaptive by automatically determining whether to be present or absent based on weight comparison between layers. When weights are identical, the flag is present enabling residual prediction; when weights differ, the flag is absent avoiding bit waste. This self-service mechanism eliminates the need for explicit signaling while maintaining optimal coding efficiency.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent changes the parameter state of the residue_prediction_flag syntax from always-present to conditionally-present based on the weighting parameter comparison. This parameter change allows the system to adapt its behavior (flag presence/absence) based on the relationship between base layer and enhancement layer weights, resolving the contradiction between flexibility and bit efficiency.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If the H.264 standard does not specify which weights to use for the enhancement layer, then weight flexibility is maintained, but coding efficiency decreases due to ambiguity in weight application

Engineering Contradiction:

Improveweight application flexibilityVSAvoidcoding efficiency

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent performs preliminary comparison of weighting parameters between base layer and enhancement layer before the actual encoding/decoding process. This preliminary action determines whether residual prediction should be applied, eliminating ambiguity about which weights to use. By deciding the weight application strategy in advance, the patent improves coding efficiency while maintaining flexibility in weight selection.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces dynamic behavior to the weight application process by making the residue_prediction_flag syntax dynamically present or absent based on weight comparison results. This dynamic adaptation allows the system to switch between different prediction modes (residual prediction enabled/disabled) based on the specific coding situation, resolving the contradiction between flexibility and efficiency.

Inventive Principle:

Principle #15Dynamics

3Loss of substance

If residue_prediction_flag is frequently absent due to different weights, then bitstream size is reduced, but residual prediction capability is lost when it should be used

Engineering Contradiction:

Improvebitstream sizeVSAvoidresidual prediction reliability

Core Design Contradiction:

Loss of substanceVSReliability

Solution Approach 1:

The residue_prediction_flag syntax serves itself by automatically determining its own presence based on the weight comparison outcome. This self-service mechanism ensures that the flag is present only when residual prediction is actually beneficial (when weights are identical), maintaining both bitstream efficiency and prediction reliability without manual intervention or explicit signaling.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS8867618B2Method and apparatus for weighted prediction for scalable video coding

Publication Date: 2014.10.21 INTERDIGITAL MADISON PATENT HLDG

AI summary

There are provided scalable video encoders, scalable video decoders, and corresponding scalable video encoding and decoding methods. A scalable video encoder includes an encoder for encoding a block in an enhancement layer of a picture by using a motion vector that corresponds to a block in a lower layer of the picture as a motion vector predictor for the block in the enhancement layer, and using a weighting parameter that was applied to a particular lower layer reference picture to encode the block in the lower layer for motion compensation of the block in the enhancement layer. The block in the enhancement layer corresponds to the block in the lower layer.