Coded Video Sub-bitstream Extraction for Adaptive Resolution
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Solution Overview
Problem
Current video coding technologies face challenges in efficiently signaling and managing adaptive picture size changes within a video bitstream, particularly in scenarios requiring different resolution settings for semantically independent pictures, such as 360-degree video or surveillance applications, which can lead to increased complexity and bandwidth requirements.
Innovation Solution
The method involves extracting a sub-bitstream from an encoded video bitstream by removing specific NAL units not included in an output layer set list, such as those with higher temporal IDs, scalable or non-scalable SEI messages, and certain parameter sets, to enable adaptive picture size signaling and resampling, allowing for independent resolution settings for different picture parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If adaptive picture size changes are implemented in video coding, then flexibility in handling diverse scene activities and resolutions is improved, but device complexity increases
Solution Approach 1:
The video bitstream is segmented into multiple output layer sets, each corresponding to different picture sizes or resolutions. The encoder divides the coded video sequence into base layer and enhancement layer sets, allowing selective extraction and processing of different resolution layers independently, thereby managing complexity through structured segmentation
Solution Approach 2:
The system dynamically adjusts picture size and resolution based on scene activity and application requirements. The encoder can switch between different output layer sets during video coding, and the extractor can selectively retrieve specific resolution layers in real-time, enabling adaptive resolution changes without fixed predetermined configurations
2Adaptability or versatility
If multiple output layer sets with different resolutions are coded, then adaptability for different applications is improved, but bandwidth requirements increase
Solution Approach 1:
Multiple resolution layers are nested within a single coded video bitstream using a hierarchical structure. The base layer contains information decodable on its own, while enhancement layers contain additional detail information that depends on the base layer. This nested structure allows a single bitstream to contain multiple resolution representations without requiring separate independent encodings for each resolution
Solution Approach 2:
A single coded video bitstream with multiple output layer sets serves multiple functions and applications simultaneously. The same bitstream can be used for high-resolution applications when bandwidth is available, or downsampled to lower resolutions for bandwidth-constrained applications, making the system universally applicable across different scenarios without requiring separate encoding for each use case
3Adaptability or versatility
If reference pictures are resampled for different resolutions, then picture size adaptability is improved, but processing time increases
Solution Approach 1:
Reference pictures are pre-resampled and prepared in multiple resolutions during the encoding phase and stored in the reference picture buffer. When decoding, the decoder can directly use the pre-prepared reference pictures at the required resolution without performing resampling operations in real-time, thereby reducing processing time during playback
Data Source
AI summary
A method of extracting a sub-bitstream from an encoded video bitstream using at least one processor includes: obtaining an encoded video bitstream, the encoded video bitstream including a plurality of Network Abstraction Layer (NAL) units; obtaining an output layer set list; comparing the NAL units with the output layer set list; and removing NAL units that are not included in the output layer set list.