Video Slice Height Indication in Subpictures
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current video coding standards, such as VVC Draft 7, lack a mechanism to specify the height of rectangular slices in CTU units within a subpicture, leading to suboptimal tile size constraints and inefficient use of the tiles structure design.
Innovation Solution
Introduction of new syntax elements, including rect_slice_height_in_subpic_only_flag and slice_height_in_ctu_in_subpic_minus1, to indicate slice heights in units of CTU rows, allowing flexible specification of slice heights within subpictures and tiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If slice height is not specified for subpicture partitioning, then the tiles structure design is simplified, but the flexibility in organizing video pictures is reduced
Solution Approach 1:
The patent introduces dynamic syntax elements that allow the slice height specification mechanism to adapt based on the subpicture configuration. The rect_slice_height_in_subpic_only_flag and slice_height_in_ctu_in_subpic_minus1 enable flexible slice organization within subpictures while maintaining a clean interface with the tiles structure when not needed, resolving the contradiction between flexibility and complexity.
2Productivity
If tile size is constrained, then the decoding process is simplified, but the efficiency in utilizing the tiles structure is reduced
Solution Approach 1:
The patent segments the picture into subpictures, and within each subpicture, segments into slices with independently specifiable heights. This segmentation allows each slice to be optimized independently while maintaining the overall tiles structure, improving productivity without requiring complex global tile size management.
3Adaptability or versatility
If slice height specification is added for subpictures, then the organization of video pictures is improved, but the bitstream size increases
Solution Approach 1:
The patent applies slice height specification locally within subpictures rather than globally across the entire picture. The rect_slice_height_in_subpic_only_flag and slice_height_in_ctu_in_subpic_minus1 are only active when subpicture-based slice organization is needed, providing local optimization without globally increasing bitstream complexity.
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
Methods, apparatus and systems for video bitstream generation and parsing are described. One example bitstream decoding method includes parsing a portion of a video bitstream at a video unit level for a first field indicative of whether a slice height is specified for a subpicture partitioning or for a tile partitioning at the video unit level, parsing, due to determining that the first field indicates that the slice height is specified for the subpicture partitioning, N second fields in the portion of the video bitstream to obtain heights for rectangular slices in the video unit, wherein the heights are indicated in multiple of coding tree unit (CTU) heights, and wherein each rectangular slice comprises one or more CTU rows that belong to a same subpicture, wherein N is a positive integer, and decoding, based on the first field and/or the N second fields, the video bitstream to generate a video.