Inter-Layer Reference Picture Signaling for Multi-Layer VVC
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Solution Overview
Problem
The existing design of reference picture lists in the Versatile Video Coding (VVC) standard faces issues such as incorrect flag signaling, empty reference picture lists, and inefficient inter-layer reference picture handling, which affect coding efficiency and decoder flexibility, especially in multi-layer video coding scenarios.
Innovation Solution
The proposed solutions include conditional signaling of flags, modifying the inference of reference picture list indices, treating certain picture types as long-term references, and signaling inter-layer reference picture indices in a reverse-ordered list, thereby ensuring proper construction and utilization of reference picture lists across multiple video layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If inter-layer reference picture indices are signaled in a reverse-ordered list, then decoder flexibility is improved, but device complexity increases
Solution Approach 1:
The patent applies inversion by signaling inter-layer reference picture indices in a reverse-ordered list rather than the conventional forward-ordered list. This inversion allows the decoder to flexibly select reference pictures from any layer without being constrained by layer ordering, thereby improving decoder flexibility while managing construction complexity through systematic reordering
2Productivity
If conditional flag signaling is implemented, then coding efficiency is improved, but device complexity increases
Solution Approach 1:
The patent implements partial action by conditionally signaling flags only when necessary. Specifically, certain syntax flags are signaled only under specific conditions (e.g., when inter-layer reference pictures are actually used), avoiding redundant signaling and improving coding efficiency while limiting the increase in syntax structure complexity to only the essential conditional elements
3Adaptability or versatility
If reference picture lists are constructed with multiple layers, then adaptability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies segmentation by dividing the reference picture list construction into distinct segments for different video layers. Each layer's reference pictures are organized separately with layer-specific indexing, allowing the system to handle multiple layers adaptively while maintaining precise index derivation through structured segmentation that reduces cross-layer interference and derivation complexity
Data Source
AI summary
Examples of video encoding methods and apparatus and video decoding methods and apparatus are described. An example method of video processing includes performing a conversion between a video and a bitstream of the video according to a rule. At least one of the one or more parameter sets of the bitstream includes a general syntax structure including timing and hypothetical reference decoder (HRD) parameters. The rule specifies that a first syntax flag is not included in the general syntax structure in response to (1) a second syntax flag specifying that network abstraction layer (NAL) HRD parameters are not present in the general syntax structure, and (2) a third syntax flag specifying that video coding layer (VCL) HRD parameters are not present in the general syntax structure, where the first syntax flag specifies that same picture-level timing information applies to all output layer sets in the bitstream.