Last Coefficient Position Coding Across Symmetrical Scan Orders

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Solution Overview

Problem

Existing video coding techniques face inefficiencies in coding last significant coefficient position information, leading to increased complexity and bitrates due to the need for separate statistics for each scanning order, which results in reduced coding efficiency and increased system complexity.

Innovation Solution

The techniques involve coding x- and y-coordinates indicating the position of the last significant coefficient based on the scanning order, using common statistics for symmetrical scanning orders, and updating these statistics to improve accuracy and efficiency, allowing for context adaptive entropy coding that reduces system complexity and bit savings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If separate statistics are maintained for each scanning order, then coding accuracy is improved, but system complexity and bitrate increase

Engineering Contradiction:
Improvecoding accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the statistics for symmetrical scanning orders into a single shared statistics structure. When the current scanning order is symmetrical to a previous scanning order, the encoder reuses the statistics from the previous order instead of maintaining separate statistics, thereby reducing system complexity while preserving coding accuracy through the symmetry relationship.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent makes statistics universal across symmetrical scanning orders. A single statistics structure serves multiple scanning orders that are symmetrical to each other, allowing the same statistics to be used for encoding last significant coefficient position information across different but symmetrical scanning patterns, thus reducing overall system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Measurement precision

If separate statistics are maintained for each scanning order, then coding precision is improved, but bitrate increases

Engineering Contradiction:
Improvecoding precisionVSAvoidbitrate
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent combines statistics for symmetrical scanning orders into a single representation, reducing the total amount of statistical data that needs to be stored and transmitted. This merging reduces the bitrate overhead associated with transmitting last significant coefficient position information while maintaining coding precision through the symmetry relationship.

Inventive Principle:
Principle #5Merging (Combining)

3Device complexity

If common statistics are used for symmetrical scanning orders, then system complexity is reduced, but coding efficiency may be compromised

Engineering Contradiction:
Improvesystem complexityVSAvoidcoding efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent applies asymmetry in the opposite direction - it identifies when scanning orders ARE symmetrical and exploits this symmetry. By detecting symmetrical relationships between scanning orders and applying common statistics only in those cases, the patent reduces system complexity without compromising coding efficiency for non-symmetrical cases where separate statistics are maintained.

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP2647204B1Coding the position of a last significant coefficient within a video block based on a scanning order for the block in video coding
Publication Date: 2018.04.04 VELOS MEDIA INT LTD
  • EP2647204B1 patent drawingFigure 1
  • EP2647204B1 patent drawingFigure 2
  • EP2647204B1 patent drawingFigure 3

AI summary

In one example, an apparatus is disclosed for coding coefficients associated with a block of video data during a video coding process, wherein the apparatus includes a video coder configured to code x- and y-coordinates that indicate a position of a last non-zero coefficient within the block according to a scanning order associated with the block when the scanning order comprises a first scanning order, and code interchanged x- and y-coordinates that indicate the position of the last non-zero coefficient within the block according to the scanning order when the scanning order comprises a second scanning order, wherein the second scanning order is different than the first scanning order.