Rice Parameter Update for Video Coefficient Coding

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Solution Overview

Problem

Existing video coding techniques face inefficiencies in adapting to large coefficient values and transform skipping or bypass scenarios, particularly in coding coefficient levels for screen content and natural content, due to limitations in the Rice parameter update scheme of the HEVC standard.

Innovation Solution

The proposed solution involves updating the Rice parameter used for Golomb codes based on a variable increment determined by the absolute value of the coefficient level, allowing the parameter to increase up to a maximum value, and adjusting the parameter based on whether a transform is applied to the block, enabling faster adaptation to large coefficient values and improving computational efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the Rice parameter is updated using the HEVC standard scheme, then coding performance is maintained, but adaptation to large coefficient values is slow

Engineering Contradiction:
ImproveAdaptation speed to large coefficient valuesVSAvoidCoding efficiency
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The Rice parameter update mechanism is made dynamic by introducing multiple update modes (first mode with faster increment for large coefficients, second mode with standard increment for normal cases). The system adapts the parameter value dynamically based on the magnitude of coefficient values encountered during encoding, allowing rapid adaptation when needed while maintaining stability during normal operation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the Rice parameter values based on the absolute values of transform coefficients. When large coefficient values are detected, the parameter is increased more aggressively using a first update mode, whereas standard update modes are used for normal cases. This parameter adaptation enables the coding scheme to handle different coefficient distributions effectively.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If the Rice parameter update scheme is simplified, then computational efficiency improves, but handling of transform skipping and bypass scenarios deteriorates

Engineering Contradiction:
ImproveComputational efficiencyVSAvoidHandling of transform skipping and bypass scenarios
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

Different Rice parameter update strategies are applied locally based on the coding scenario. For transform skipping and bypass scenarios, the invention uses specific update rules that account for the absence of transform coefficients or direct coefficient usage. For normal transformed blocks, standard update modes are applied. This localized adaptation ensures optimal performance for each specific coding case.

Inventive Principle:
Principle #3Local quality

3Device complexity

If conditional operations are reduced, then device complexity decreases, but adaptation precision worsens

Engineering Contradiction:
ImproveNumber of conditional operationsVSAvoidParameter adaptation precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The invention uses simple increment operations instead of complex conditional logic. Rather than implementing multiple nested conditionals to determine parameter updates, the system applies straightforward increment rules that are computationally inexpensive. The precision is maintained through the mathematical relationship between coefficient magnitudes and parameter increments, rather than through complex decision trees.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Data Source

PatentEP2984830B1Rice parameter update for coefficient level coding in video coding process
Publication Date: 2021.04.07 QUALCOMM INC
  • EP2984830B1 patent drawingFigure 1
  • EP2984830B1 patent drawingFigure 2
  • EP2984830B1 patent drawingFigure 3

AI summary

Techniques are described for updating a value of a Rice parameter used to define Golomb codes for coefficient level coding. The Golomb codes defined by the Rice parameter may be used to code a remaining absolute value of a coefficient level for at least one coefficient in a coefficient group (CG). According to the techniques, the value of the Rice parameter is updated based on a selection of a minimum of either a maximum value of the Rice parameter or a variable increment of the value of the Rice parameter. The variable increment is determined based on the value of the Rice parameter and an absolute value of the coefficient level for the current coefficient being coded. Techniques are also described for adjusting the value of the Rice parameter used to define Golomb codes for coefficient level coding based on whether a transform is applied to a transform block.