Sub-Picture Sizing for Non-CTU Boundary Video Layouts
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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, particularly at the right or bottom boundaries of the picture, to accommodate various picture layouts without causing decoding errors, thereby enhancing encoder and decoder functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If sub-pictures are constrained to have heights and widths that are multiples of CTU size, then decoding simplicity is maintained, but compatibility with various picture layouts is lost
Solution Approach 1:
The patent applies local quality by differentiating the treatment of sub-pictures based on their position within the picture. Sub-pictures that do not extend to the picture boundary maintain the CTU multiple constraint, while sub-pictures that extend to the right or bottom boundary are allowed to have non-CTU-multiple dimensions. This localized differentiation resolves the contradiction by maintaining simplicity where possible while enabling compatibility where needed.
2Stability of the object's composition
If sub-picture size constraints are enforced, then processing consistency is improved, but functionality with diverse picture layouts is reduced
Solution Approach 1:
The patent introduces dynamic constraints for sub-picture sizing. The CTU multiple requirement is applied conditionally based on the sub-picture's spatial relationship with picture boundaries. This dynamic approach allows the system to maintain processing consistency for standard cases while adapting to diverse picture layouts when sub-pictures extend to boundaries, thereby resolving the contradiction between stability and adaptability.
3Loss of energy
If sub-pictures are limited to CTU-multiple dimensions, then resource usage is optimized, but decoding errors occur with certain picture layouts
Solution Approach 1:
The patent modifies the dimensional parameters of sub-pictures based on their position within the picture. By changing the constraint parameter from a fixed CTU-multiple requirement to a conditional requirement (CTU-multiple for internal sub-pictures, flexible for boundary sub-pictures), the system maintains resource efficiency for standard layouts while ensuring decoding reliability for diverse picture configurations.
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.