Alpha Channel Indicator for Video Transparency Handling
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Solution Overview
Problem
Current video coding standards, such as VSEI, do not effectively decouple alpha blending post-decoding processing from other types of post-decoding processing, leading to ambiguity in alpha channel signalling, especially for transparent screens, and result in inefficient compression and interoperability issues.
Innovation Solution
Incorporating an alpha channel indicator in the bitstream to specify the intended post-processing type, allowing for separate handling of alpha channel information for transparency adjustment on transparent screens, which includes determining a transparency information mask and adjusting pixel transparency accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If alpha channel information is always processed using alpha blending post-decoding, then compatibility with existing standards is maintained, but flexibility for transparent screen applications is lost
Solution Approach 1:
The patent segments the alpha channel processing into distinct types by introducing an indicator that specifies whether alpha blending or transparency adjustment should be applied. This segmentation allows the system to handle different post-processing types separately rather than using a single unified approach, thereby improving adaptability to transparent screens while maintaining manageable complexity through structured classification.
Solution Approach 2:
The patent makes the post-processing type dynamic by using an indicator in the bitstream that can specify different processing modes (alpha blending or transparency adjustment). This dynamic approach allows the system to adapt the processing method based on the specific application requirements, enabling flexibility for transparent screens while maintaining compatibility with traditional applications through the same indicator mechanism.
2Loss of information
If all alpha channel parameters are transmitted in the bitstream, then complete information is available for all processing types, but compression efficiency deteriorates
Solution Approach 1:
The patent extracts only the necessary alpha channel parameters based on the indicated processing type. When transparency adjustment is specified, only the transparency information mask is transmitted rather than all alpha channel parameters. This selective extraction maintains complete information for the required processing while improving compression efficiency by excluding irrelevant parameters.
Solution Approach 2:
The patent applies local quality by transmitting different amounts of alpha channel information depending on the specific processing requirement. The indicator enables the system to provide full alpha channel information when alpha blending is used, while providing only transparency information masks when transparency adjustment is used, optimizing the information quality to match the local processing needs.
3Ease of operation
If alpha channel information is decoded without type specification, then decoding is simplified, but ambiguity arises in transparent screen applications
Solution Approach 1:
The patent performs preliminary action by including an alpha channel indicator in the bitstream before the actual alpha channel data. This indicator pre-specifies the processing type (alpha blending or transparency adjustment), allowing the decoder to prepare the appropriate processing path in advance. This maintains decoding simplicity while eliminating ambiguity by providing clear instructions before the data is processed.
Solution Approach 2:
The patent introduces an alpha channel indicator as an intermediary element between the encoded video data and the post-processing stage. This intermediary carries the type specification information that disambiguates the intended processing, allowing the decoder to correctly interpret the alpha channel information without increasing operational complexity. The indicator acts as a mediator that bridges the gap between generic encoding and specific processing requirements.
Data Source
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AI summary
The present application relates to a methods and apparatus of encoding/decoding a video sequence associated with alpha channel information. An alpha channel indicator is signalled as part of the alpha channel information. The alpha channel indicator indicates for which type of post-decoding processing the alpha channel information associated with the video sequence is intended for.