SAO Edge Offset Interpolation for Parallel Video Decoding

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Sample Adaptive Offset (SAO) in video coding often causes visual artifacts due to its dependency on future deblocked pixels, making it difficult to integrate into parallel deblocking processes, and can result in quality loss by adding offset values that are not suitable for all pixel statistics.

Innovation Solution

The method involves selecting an edge offset type and sub-class for SAO, generating an interpolated pixel value related to the current pixel, and applying an offset value to form an SAO compensated value, which reduces the dependency on future deblocked pixels and limits the offset to prevent increased contrast between current and neighboring pixels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If SAO is applied using future deblocked pixels, then pixel reconstruction accuracy is improved, but integration into parallel deblocking process becomes difficult

Engineering Contradiction:

Improvepixel reconstruction accuracyVSAvoidprocess integration complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies SAO filtering before the deblocking filter in the video decoding process, rather than after. This preliminary action allows SAO to operate on original block boundaries without requiring future deblocked pixels, enabling parallel processing while maintaining reconstruction accuracy through subsequent deblocking refinement

Inventive Principle:

Principle #10Preliminary action

2Ease of manufacture

If global offset values are applied to all pixels in a region, then processing simplicity is improved, but visual artifacts increase due to mismatched pixel statistics

Engineering Contradiction:

Improveprocessing simplicityVSAvoidvisual artifacts

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent divides the picture into multiple regions and applies different offset values to each region based on local pixel statistics. This local quality approach ensures that offset values match the characteristics of each specific region, reducing visual artifacts while maintaining processing efficiency through systematic regional classification

Inventive Principle:

Principle #3Local quality

3Productivity

If offset values are applied to all pixels uniformly, then processing speed is improved, but quality loss increases due to inappropriate offsets for different pixel statistics

Engineering Contradiction:

Improveprocessing speedVSAvoidreconstruction quality

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent dynamically adjusts offset values based on local pixel statistics and region characteristics. By changing the offset parameters according to local conditions rather than applying uniform values, the system maintains high processing speed through efficient regional classification while improving reconstruction quality through statistically appropriate offset selection

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentEP2801195B1Devices and methods for sample adaptive offset coding and selection of edge offset parameters

Publication Date: 2018.03.07 GOOGLE TECHNOLOGY HOLDINGS LLC

Figure 1A
Figure 1B
Figure 2A~2B

AI summary

In one embodiment, a method for encoding sample adaptive offset (SAO) values in a video encoding process is provided, the method comprising: selecting an edge offset type; selecting one of one or more edge offset sub-classes; within at least one of the edge offset sub-classes, generating an interpolated pixel value that is related to a current pixel value; generating an offset value that is related to the interpolated pixel value; and optionally applying the offset value to at least the current pixel value to form an SAO compensated value.