Video Reference Picture Scheme for Temporal Switching and Error Resilience
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Solution Overview
Problem
Conventional video coding methods using hierarchical coding structures face inefficiencies and error propagation when switching from lower to higher temporal levels due to restrictive referencing structures, leading to sub-optimal coding efficiency and increased error resilience issues.
Innovation Solution
A resilient picture referencing scheme is introduced, defining boundary pictures and using a predetermined scheme for reference picture list construction to minimize bit signaling and enable efficient inter-picture prediction, allowing for switching points between frame rates in a temporally scalable coded video bitstream.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a temporal nesting scheme is used to enable switching from lower to higher temporal levels, then adaptability is improved, but coding efficiency deteriorates due to highly restrictive referencing structure
Solution Approach 1:
The patent introduces dynamic reference picture list construction that adapts to the current temporal level. The reference picture list is constructed differently depending on whether the current picture is at a lower or higher temporal level, allowing flexible switching without the rigid constraints of temporal nesting. This dynamic approach maintains adaptability while improving coding efficiency.
Solution Approach 2:
The patent changes the parameter of reference picture selection criteria based on temporal level. By modifying how reference pictures are selected and ordered in the reference picture list according to the current temporal level, the system achieves efficient coding while maintaining the ability to switch temporal levels dynamically.
2Adaptability or versatility
If restrictive referencing structure is used for temporal nesting, then temporal level switching is enabled, but error resilience deteriorates due to error propagation
Solution Approach 1:
The patent segments the reference picture list into different groups based on temporal level. By separating reference pictures into distinct groups that can be independently managed, errors in one temporal level do not propagate to other temporal levels, thereby improving error resilience while maintaining temporal scalability.
Solution Approach 2:
The patent introduces an intermediary mechanism in the form of a reordering process that acts as a buffer between different temporal levels. This reordering process prevents direct error propagation paths while still enabling temporal level switching, thus improving reliability without sacrificing adaptability.
3Productivity
If conventional reference picture list construction is used, then inter-picture prediction is performed, but bit signaling efficiency deteriorates due to lack of optimization for temporal levels
Solution Approach 1:
The patent applies local quality optimization by constructing the reference picture list with different ordering criteria for different temporal levels. Lower temporal level pictures use one ordering strategy while higher temporal level pictures use another, reducing the average bit signaling overhead across all pictures while maintaining prediction efficiency.
Solution Approach 2:
The patent performs preliminary reordering of the reference picture list based on temporal level before the actual prediction process. This preliminary action optimizes the reference picture selection in advance, reducing the need for additional bit signaling during decoding while maintaining high prediction efficiency.
Data Source
AI summary
A video encoding method using a plurality of reference pictures includes: selecting whether or not a resilient picture referencing scheme is to be used for encoding video; writing a parameter indicating the selection into a header of an encoded video bitstream; and encoding a picture using inter-picture prediction using a result of the selection.