VVC Reference Picture Resampling Signaling for Adaptive Resolution
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Solution Overview
Problem
Existing video coding technologies struggle with efficiently managing changes in picture size and resolution within a coded video sequence, particularly in modern codecs like VVC, where adaptive resolution changes (ARC) are not adequately signaled, leading to inefficiencies and complexity in reference picture resampling.
Innovation Solution
A method and device for decoding video bitstreams that determine a resampling ratio based on a flag indicating whether a conformance window is used for reference picture resampling, and if not, derive the ratio from signaled or output picture size, enabling efficient reference picture resampling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If adaptive resolution changes are implemented in VVC, then video coding flexibility and adaptability are improved, but signaling complexity and device complexity increase due to inadequate signaling mechanisms
Solution Approach 1:
The patent extracts the conformance window parameters (offsets and size) from the complex ARC signaling structure, allowing them to be independently signaled and processed. This separation simplifies the overall signaling by breaking down the complex ARC configuration into manageable components that can be handled separately in the bitstream.
Solution Approach 2:
The patent segments the ARC signaling into distinct components: conformance window parameters, ARC enable flags, and resampling control parameters. This segmentation allows each component to be signaled independently, reducing the overall signaling complexity while maintaining full adaptability for resolution changes.
2Adaptability or versatility
If reference picture resampling is performed, then handling of different resolutions is improved, but processing complexity and computational requirements increase
Solution Approach 1:
The patent performs preliminary actions by signaling conformance window parameters and resampling control information in advance during the parameter set configuration stage. This allows the decoder to pre-calculate resampling ratios and prepare reference pictures at appropriate resolutions before actual decoding, reducing real-time processing complexity.
Solution Approach 2:
The patent implements dynamic resampling control where the resampling behavior adapts based on the coded picture type and signaled parameters. Different resampling strategies can be applied dynamically depending on whether it's an I picture, P picture, or B picture, optimizing processing complexity for each case while maintaining versatility.
3Measurement precision
If conformance window parameters are signaled, then precision in defining resampling regions is improved, but bitstream overhead and signaling data quantity increase
Solution Approach 1:
The patent changes the parameter representation by signaling conformance window offsets and sizes relative to the picture dimensions, using compact integer encodings. This approach maintains high precision in defining resampling regions while minimizing bitstream overhead through efficient parameter encoding schemes.
Solution Approach 2:
The signaled conformance window parameters serve multiple functions: they define the resampling region, determine the active picture area, and control the reference picture selection. This multi-functionality reduces the need for separate signaling for each purpose, thereby reducing overall bitstream overhead while maintaining precision.
Data Source
AI summary
A method, device, and computer-readable medium for decoding an encoded video bitstream using at least one processor, including obtaining a flag indicating that a conformance window is not used for reference picture resampling; based on the flag indicating that the conformance window is not used for the reference picture resampling, determining whether a resampling picture size is signaled; based on determining that the resampling picture size is signaled, determining a resampling ratio based on the resampling picture size; based on determining that the resampling picture size is not signaled, determining the resampling ratio based on an output picture size; and performing the reference picture resampling on a current picture using the resampling ratio.