VVC Video File Encapsulation for Parser-Independent Layer Metadata
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Solution Overview
Problem
The encapsulation of VVC bitstreams into ISOBMFF files does not adequately describe the composition of independent layers, leading to issues with parsers that rely on decoding SEI NAL units for composition information, which is format-specific and inefficient.
Innovation Solution
A method is introduced to generate metadata structures in the ISOBMFF file that describe the composition of VVC bitstreams independently of the encoding format, using new structures like 'ropi' to indicate filtered or recommended operation points, ensuring the metadata accurately reflects the available layers and sub-layers in the bitstream.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If SEI NAL units are used to describe composition information, then composition data can be conveyed, but parsers must decode format-specific SEI NAL units which is inefficient and complex
Solution Approach 1:
The patent creates a simplified copy of composition information in the metadata structure that mirrors the essential data from SEI NAL units but in a parser-friendly format. This allows parsers to access composition data without decoding the original format-specific SEI NAL units, reducing complexity while preserving information.
Solution Approach 2:
The patent introduces an intermediary metadata structure that sits between the SEI NAL units and the parser. This intermediary translates and presents composition information in a standardized, easily accessible format, eliminating the need for parsers to directly interpret format-specific SEI NAL unit structures.
2Loss of information
If SEI NAL units are decoded for composition information, then accurate composition data is obtained, but processing time increases
Solution Approach 1:
The patent performs preliminary extraction and organization of composition information during the metadata generation phase. By pre-processing the SEI NAL unit data into a ready-to-use format in the metadata structure, the system eliminates the need for time-consuming decoding operations during parser execution, thus reducing processing time while maintaining accuracy.
3Loss of information
If format-specific SEI NAL units are used, then VVC bitstream composition is described, but the solution is not adaptable to other formats
Solution Approach 1:
The patent designs the metadata structure with universal, format-agnostic fields that can represent composition information from VVC bitstreams while being accessible to parsers regardless of the original encoding format. This universal structure maintains the ability to describe VVC-specific composition data while enabling broader adaptability and compatibility across different video formats.
Data Source
AI summary
A method of encapsulating a bitstream of encoded video data in a media file, the method comprising: obtaining the bitstream comprising a second plurality of operating points, video data in the bitstream being organized into NAL units; the bitstream being filtered from an original bitstream, the original bitstream comprising a first plurality of operating points, the first plurality of operating points comprising at least the second plurality of operating points; obtaining from the bitstream a first NAL unit describing the first plurality of operating points; obtaining form the bitstream a second NAL unit describing the second plurality of operating points; generating the media file comprising the bitstream and comprising at least one metadata structure describing the second plurality of operating points; wherein the at least one metadata structure is generated based on both the first and second NAL units.