Video Container Subpicture Tracks for Flexible Bitstream Reconstruction
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Solution Overview
Problem
Existing video encoding and decoding technologies face challenges in efficiently managing subpicture tracks and reconstructing video bitstreams, particularly in advanced video coding standards like VVC, leading to inefficiencies in storage and transmission.
Innovation Solution
The method involves writing and parsing subpicture tracks in a container file, including a base track with a layout of subpictures and sample group description entries, to facilitate the reconstruction of video bitstreams by selecting appropriate subpicture tracks for each position, enhancing the efficiency of video encoding and decoding processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple subpicture tracks are written in the container file for each subpicture position, then the flexibility and adaptability of video bitstream reconstruction is improved, but the device complexity and storage requirements increase
Solution Approach 1:
The video picture is segmented into multiple subpictures, with each subpicture positioned at specific locations. Multiple subpicture tracks are created in the container file, where each track corresponds to a specific subpicture position. This segmentation allows flexible reconstruction by selecting appropriate tracks while maintaining manageable complexity through structured organization.
Solution Approach 2:
The patent introduces a temporal dimension to subpicture management by creating multiple subpicture tracks that can be selected based on timing information. Instead of managing all subpictures in a single track, the solution distributes them across multiple tracks with associated timing metadata, adding a time-based dimension to the organization structure that enhances flexibility without proportionally increasing complexity.
2Measurement precision
If sample group description entries are added to indicate subpicture track selection, then the precision of video reconstruction is improved, but the data overhead and processing complexity increase
Solution Approach 1:
Sample group description entries are written in advance during the encoding phase, establishing the mapping between subpicture positions and their corresponding tracks before decoding occurs. This preliminary organization of track selection information eliminates the need for complex runtime decisions, improving reconstruction precision while keeping the additional data volume manageable through efficient pre-computation.
3Productivity
If the base track is resolved into a video bitstream with subpicture layout, then the video encoding efficiency is improved, but the decoding complexity and processing time increase
Solution Approach 1:
The base track is segmented into multiple subpicture tracks during encoding, with each subpicture positioned and tracked separately. This segmentation enables parallel processing during decoding, where different subpicture tracks can be processed independently and then composited, improving encoding efficiency while managing decoding complexity through modular processing.
Solution Approach 2:
The container file structure is designed to be self-describing, with metadata and timing information embedded within the file itself. The decoder can autonomously reconstruct the video bitstream by reading the embedded subpicture layout and track selection information without requiring external configuration, improving encoding efficiency while keeping the decoder design manageable through self-contained data structures.
Data Source
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AI summary
The embodiments relate to a method for writing, in a container file, two or more subpicture tracks; writing, in the container file, a base track, which is intended to be resolved into a video bitstream; indicating, in the base track, a layout of subpictures; writing, in the container file, a sample group description entry indicative of a first subpicture track or a group of subpicture tracks for each subpicture position in the layout of subpictures, wherein the first subpicture track comprises the subpicture sequence for the respective subpicture position and wherein any track among the group of subpicture tracks comprises a valid subpicture sequence for the respective subpicture position; and indicating in the container file, samples of the base track for which the sample group description entry is intended to be used for reconstructing the video bitstream. The embodiments also relate to a method for parsing, as well as technical equipment for implementing the method for writing and the method for parsing.