Boundary Sub-Picture Sizing for Flexible CTU Video Decoding
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Solution Overview
Problem
Existing video coding systems constrain sub-pictures to have heights and widths that are multiples of CTU size, preventing them from operating correctly with many picture layouts, leading to decoding errors and inefficient resource usage.
Innovation Solution
Allow sub-pictures to have heights and widths that are not multiples of CTU size when positioned at the right or bottom boundaries of the picture, enabling their use with any picture layout without decoding errors, and enhancing encoder and decoder functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sub-pictures are constrained to have heights and widths that are multiples of CTU size, then decoding accuracy is maintained, but adaptability to different picture layouts is reduced
Solution Approach 1:
The patent applies local quality by differentiating the constraints on sub-picture dimensions based on their position within the picture. Specifically, sub-pictures at the right boundary are allowed to have widths that are not multiples of CTU size, while other sub-pictures maintain the standard multiple-of-CTU constraint. This localized relaxation enables better adaptability to various picture layouts without compromising decoding accuracy in the affected regions.
2Adaptability or versatility
If sub-picture constraints are relaxed to allow non-multiple CTU sizes at boundaries, then adaptability to picture layouts is improved, but decoding complexity increases
Solution Approach 1:
The patent implements parameter changes by modifying the dimensional constraints on sub-pictures based on their spatial position. The constraint parameter (whether width must be a multiple of CTU size) is changed from a uniform requirement to a position-dependent requirement. This allows the system to maintain simplicity in most cases while providing flexibility where needed, balancing adaptability and complexity.
3Device complexity
If uniform CTU multiple constraints are applied to all sub-pictures, then encoder and decoder simplicity is maintained, but resource efficiency is reduced
Solution Approach 1:
The patent applies segmentation by dividing the picture into different regions based on sub-picture position, particularly identifying sub-pictures at the right boundary as a special segment. This segmentation allows different constraint rules to be applied to different segments, enabling more efficient resource utilization in boundary regions while maintaining simplicity in interior regions, thereby improving overall resource efficiency.
Data Source
AI summary
A video coding mechanism is disclosed. The mechanism includes receiving a bitstream comprising one or more sub-pictures partitioned from a picture such that each sub-picture includes a sub-picture width that is an integer multiple of a coding tree unit (CTU) size when the each sub-picture includes a right boundary that does not coincide with a right boundary of the picture. The bitstream is parsed to obtain the one or more sub-pictures. The one or more sub-pictures are decoded to create a video sequence. The video sequence is forwarded for display.