Preselection Signalling Structure for Accurate Media Track Selection
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Solution Overview
Problem
Existing media file formats like ISOBMFF face issues with preselection signaling, allowing multiple tracks from the same alternate group, lack of a main track indication, optional PreselectionTrackGroupEntryBoxes, redundant preselection_tag and segment_order fields, and unclear processing order, leading to inefficiencies in video decoding and streaming.
Innovation Solution
Implement modifications to ISOBMFF preselection signaling by ensuring tracks from the same alternate group have unique track_group_id, introduce a main_track_in_preselection_flag, make PreselectionTrackGroupEntryBoxes mandatory when track_in_movie flag is set, remove preselection_tag and segment_order fields, and rely on track_order for processing order, aligning with DASH semantics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple tracks from the same alternate group are allowed in preselection, then track selection flexibility is improved, but preselection tracking accuracy deteriorates
Solution Approach 1:
The patent segments the preselection tracking by assigning unique track_group_id values to each track within an alternate group. This segmentation ensures that tracks from the same alternate group are distinguished by their individual track_group_id, preventing confusion and maintaining accurate tracking while still allowing multiple tracks to be selected. The segmentation is implemented through the track_group_id field which uniquely identifies each track's preselection group.
2Device complexity
If PreselectionTrackGroupEntryBoxes are made optional, then device complexity is reduced, but preselection signaling reliability deteriorates
Solution Approach 1:
The patent extracts and removes the redundant preselection_tag and segment_order fields from the PreselectionGroupBox structure. By taking out these unnecessary fields, the signaling structure becomes simpler and less complex, while the remaining fields (track_group_id, track_order) provide sufficient information for reliable preselection tracking. This extraction eliminates the complexity without sacrificing reliability.
3Ease of operation
If segment_order field is included in PreselectionGroupBox, then processing order specification is improved, but data redundancy increases
Solution Approach 1:
The patent extracts and removes the segment_order field from the PreselectionGroupBox structure. The processing order information is instead conveyed through the track_order field which is already present in the structure. By taking out the redundant segment_order field, the patent eliminates data redundancy while maintaining the ability to specify processing order through the existing track_order mechanism.
4Measurement precision
If preselection_tag field is retained, then preselection identification is improved, but signaling redundancy increases
Solution Approach 1:
The patent extracts and removes the preselection_id field from the PreselectionGroupBox structure. The preselection identification function is maintained through the combination of track_id and track_group_id fields, which together provide sufficient identification without requiring the redundant preselection_id field. This extraction eliminates signaling redundancy while preserving identification accuracy.
Data Source
AI summary
A mechanism for processing video data is disclosed. The mechanism determines information from a Preselection Group Box. A segment_order field is omitted from the Preselection Group Box and sub-boxes thereof. A conversion is performed between a visual media data and the media data file based on the Preselection Group Box.