Sublayer-Wise Output Layer Set Derivation for VVC Decoding
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Solution Overview
Problem
Existing video coding technologies struggle with efficiently signaling adaptive picture size changes in video bitstreams, particularly in modern codecs like VVC, leading to inefficiencies and increased complexity in decoding multiple layers with varying qualities.
Innovation Solution
The proposed solution involves constraining the value of a temporal sublayer identifier in a video coding layer network abstraction layer unit to be less than or equal to a maximum number of temporal sublayers specified in the video parameter set, allowing for efficient derivation of sublayer-wise output layer sets and inter-layer prediction, thereby simplifying the decoding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If adaptive picture size changes are implemented in video bitstreams, then video quality and resolution flexibility are improved, but decoding complexity and computational load increase
Solution Approach 1:
The video picture is divided into multiple layers with different resolutions and qualities. Each layer represents a different level of detail, allowing the decoder to process and reconstruct the image progressively from coarse to fine details, reducing overall decoding complexity while maintaining quality
Solution Approach 2:
Multiple layers of varying resolutions are merged together during decoding to form the final high-quality picture. The decoder combines information from different resolution layers through interpolation and fusion techniques, achieving high video quality without requiring the full computational load of processing only high-resolution data
2Adaptability or versatility
If multiple layers with varying qualities are decoded, then adaptability and versatility are improved, but processing time and computational resources increase
Solution Approach 1:
Reference pictures are pre-processed and stored in a reference picture buffer before being needed for prediction. The decoder prepares multiple reference layers in advance, allowing faster access during inter-layer prediction without increasing real-time processing delays
Solution Approach 2:
The decoding process dynamically adjusts which layers are processed based on current picture type, motion complexity, and quality requirements. The decoder can selectively skip processing certain layers for low-motion or low-complexity scenes, reducing processing time while maintaining adaptability for complex scenes
3Productivity
If inter-layer prediction is used, then compression efficiency is improved, but derivation complexity increases
Solution Approach 1:
The decoder derives output layer sets and reference picture lists automatically from the coded bitstream without requiring explicit signaling. The derivation processes use readily available syntax elements from the parameter sets and picture data structures, reducing signaling overhead while maintaining compression efficiency through self-service derivation
Data Source
AI summary
A method and system for decoding a coded video sequence may include obtaining the coded video sequence, and decoding the coded video sequence. A a value of a temporal sublayer identifier of a video coding layer (VCL) network abstraction layer (NAL) unit in the coded video sequence is constrained to be less than or equal to a value of vps_max_sublayers_minus1, that specifies a maximum number of temporal sublayers that may be present in a layer in each coded video sequence referring to the video parameter set (VPS), in the VPS referred to by the VCL NAL unit.