Video Bitstream Switching with Parameter Set Initialization
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Solution Overview
Problem
In video coding environments, particularly with adaptive HTTP streaming, issues arise during bitstream, track, or representation switching, especially when using open GOP structures, which can lead to inefficiencies and incorrect decoding due to mismatched initialization parameters.
Innovation Solution
A file parser and method for reconstructing a video bitstream that retrieves switching information and initialization parameters from a video file, allowing seamless switching between different tracks or representations by ensuring the decoder is initialized correctly for both the current and potential candidate tracks, even in open GOP scenarios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If out-of-band parameter set integration is used, then parameter sets are stored separately in sample entries, but incorrect parameters may be selected during track switching
Solution Approach 1:
The system performs preliminary actions by storing switching information that indicates which sample entries are switch-to candidates before actual switching occurs. This allows the decoder to be pre-configured with the correct parameter sets, ensuring reliable parameter selection during track switching without needing to search for correct parameters at the moment of switching.
2Adaptability or versatility
If in-band parameter sets are used, then parameter sets are stored with samples in AUs, but parameter sets cannot be efficiently shared across tracks
Solution Approach 1:
The sample entry structure is designed with multi-functionality to serve both in-band and out-of-band parameter set integration. The same sample entry can store parameter sets that are either embedded with samples or referenced separately, allowing efficient parameter sharing across tracks while maintaining flexibility in storage location. This universal structure eliminates the need for separate parameter set storage mechanisms.
3Productivity
If open GOP structure is used, then coding efficiency is improved, but decoding reliability during switching deteriorates
Solution Approach 1:
The system implements feedback mechanisms by using switching information to indicate which sample entries are appropriate switch-to candidates. This feedback loop ensures that during track switching, the decoder receives the correct parameter set references, maintaining decoding reliability even within the open GOP structure that enables higher coding efficiency.
4Adaptability or versatility
If track switching is enabled, then adaptability is improved, but decoding correctness deteriorates due to mismatched initialization parameters
Solution Approach 1:
The system performs preliminary actions by pre-storing switching information that identifies correct sample entries for switching before actual track switching occurs. This ensures that when switching happens, the decoder already has the correct initialization parameters ready, maintaining decoding correctness while enabling flexible track switching capability.
Data Source
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AI summary
The present invention concerns file parsers, file generators encoders, decoders, clients, servers and methods using parameter sets for coded video sequences. Said parameter sets may comprise decoding parameter information and may be conveyed in-band or out-of band. Some embodiments provide solutions to problems being related with correctly initializing a decoder for decoding coded video sequences in open GOP switching scenarios. Some embodiments may provide for hierarchical track switching levels.