Residual DPCM for Lossy Video Coding Without Transform

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Solution Overview

Problem

Current video coding techniques, such as those in the HEVC standard, experience precision loss due to the application of transforms and quantization in lossy coding, which can degrade performance, especially when sign data hiding is attempted in blocks using lossy coding without transforms and planar or DC intra prediction modes.

Innovation Solution

The implementation of residual differential pulse code modulation (DPCM) techniques without applying transforms to residual data, combined with disabling sign data hiding for blocks using lossy coding without transforms, to enhance throughput and maintain precision in video encoding and decoding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If transforms and quantization are applied in lossy coding, then compression efficiency is improved, but precision loss occurs which degrades performance

Engineering Contradiction:
Improvecompression efficiencyVSAvoidprecision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies transforms and quantization selectively rather than uniformly across all blocks. By identifying specific block types (e.g., smooth regions, specific prediction modes) where transforms provide benefit, the system applies them only where needed, thereby improving compression efficiency while minimizing precision loss in blocks where transforms would be harmful.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent dynamically adjusts coding parameters based on block characteristics. By changing parameters such as transform type, quantization step size, or even switching between transform and non-transform coding modes based on local image content and prediction mode, the system optimizes the trade-off between compression efficiency and precision for each block individually.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If sign data hiding is attempted in blocks using lossy coding without transforms, then throughput is improved, but precision loss and errors occur

Engineering Contradiction:
ImprovethroughputVSAvoidprecision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent prevents sign data hiding from being applied in blocks where it would cause errors. By identifying blocks coded without transforms (where residual values are not transformed) and disabling sign data hiding for these blocks, the system avoids the precision loss and errors that would result from applying sign data hiding inappropriately, while still enabling it in blocks where it is safe and beneficial.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The patent applies different coding strategies to different blocks based on their specific characteristics. By disabling sign data hiding only in blocks coded without transforms while allowing it in other blocks, the system maintains high precision where needed while achieving good throughput overall, rather than applying a uniform strategy to all blocks.

Inventive Principle:
Principle #3Local quality

3Productivity

If residual DPCM is applied without transforms, then throughput is improved, but precision loss occurs

Engineering Contradiction:
ImprovethroughputVSAvoidprecision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies residual DPCM selectively to specific blocks rather than uniformly. By identifying blocks where residual DPCM provides benefit (such as blocks with smooth gradients or specific prediction modes) and applying it only to those blocks, the system improves throughput while minimizing precision loss in blocks where DPCM would be less effective.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP2979450B1Intra prediction modes for lossy coding when transform is skipped
Publication Date: 2020.10.07 QUALCOMM INC
  • EP2979450B1 patent drawingFigure 1
  • EP2979450B1 patent drawingFigure 2
  • EP2979450B1 patent drawingFigure 3

AI summary

A video coder applies a residual differential pulse code modulation technique to a residual data of a block coded using lossy coding. The block may be coded without application of a transform to the residual data.