Mixed IRAP Sub-Picture Decoding With Reference Picture Lists
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Solution Overview
Problem
Conventional video coding techniques do not permit intra random access point (IRAP) pictures to reference and utilize a reference picture list (RPL), limiting the efficiency and flexibility of video compression and decompression, particularly in applications like VR coding.
Innovation Solution
The techniques allow mixed IRAP pictures to reference and utilize an RPL, enabling improved video coding by permitting IRAP and non-IRAP sub-pictures to utilize the RPL, even when the mixed IRAP picture contains an IRAP sub-picture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If IRAP pictures are used for random access points, then random access capability is improved, but the ability to reference and utilize RPL is lost
Solution Approach 1:
The picture is divided into multiple sub-pictures, where each sub-picture can have different IRAP properties. This allows selective application of IRAP constraints to specific regions while other regions can utilize RPL for more efficient coding.
Solution Approach 2:
Different regions (sub-pictures) of the same picture are assigned different properties: some sub-pictures are marked as IRAP while others are not. This local differentiation allows the system to optimize for random access in critical regions while maintaining coding efficiency in other regions.
2Reliability
If conventional coding techniques are used for IRAP pictures, then random access is supported, but reference to RPL is prohibited limiting flexibility
Solution Approach 1:
The system dynamically determines RPL usage based on sub-picture type and decoding context. The decoder checks whether the current sub-picture is an IRAP sub-picture and whether reference pictures are available, making adaptive decisions about RPL utilization rather than applying rigid constraints.
Solution Approach 2:
The RPL mechanism is designed to serve multiple functions: it can be used for both IRAP and non-IRAP sub-pictures under appropriate conditions. This multi-functionality allows the same reference structure to support both random access requirements and efficient predictive coding.
3Ease of manufacture
If mixed IRAP pictures are decoded without RPL for non-IRAP sub-pictures, then decoding simplicity is maintained, but compression efficiency is reduced
Solution Approach 1:
The decoder periodically checks conditions (sub-picture type, availability of reference pictures, syntax flags) to determine whether to use RPL. This conditional, periodic evaluation allows the system to switch between simple and efficient decoding modes as appropriate.
Solution Approach 2:
The decoding process automatically determines whether to use RPL based on the properties of the current sub-picture and available reference pictures, without requiring external control. The system self-adjusts its decoding strategy based on the encoded information in the bitstream.
Data Source
AI summary
A method of decoding a coded video bitstream implemented by a video decoder is provided. The method includes receiving, by a receiver of the video decoder, a mixed intra random access point (IRAP) picture including a first sub-picture and a second sub-picture, wherein the first sub-picture is an IRAP picture and the second sub-picture is a non-IRAP sub-picture; receiving, by the receiver; a reference picture list (RPL) for the mixed IRAP picture; decoding, by a processor of the video decoder, the second sub-picture using the RPL; and generating, by the processor, an image based on the second sub-picture as decoded. A corresponding encoding method is also provided.