Adaptive Resolution Video Decoding via Early APS NAL Units
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Solution Overview
Problem
Current video coding and decoding technologies face challenges in efficiently adapting to changes in picture resolution within a coded video sequence, leading to suboptimal compression and decoding performance, especially in scenarios requiring adaptive resolution changes.
Innovation Solution
The method involves decoding an encoded video bitstream by obtaining a picture header, video coding layer, and adaptation parameter set Network Abstraction Layer (NAL) units, with the adaptation parameter set being available before the video coding layer, allowing for adaptive resolution changes and improved scalability in video decoding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If video coding operates on a fixed picture size for a coded video sequence, then decoding complexity is reduced and processing is simplified, but adaptability to changing scene activity and resolution requirements is limited
Solution Approach 1:
The patent enables dynamic picture size changes within a coded video sequence by introducing adaptive resolution change mechanisms. The decoder can adjust the picture size based on scene activity and resolution requirements, transitioning from a static fixed-size approach to a dynamic adaptive approach that responds to content characteristics.
Solution Approach 2:
The patent changes the picture size parameter dynamically during decoding by introducing an adaptive resolution change flag and associated control mechanisms. This allows the system to modify resolution parameters on-the-fly based on scene activity, enabling flexible adaptation without requiring complete re-encoding.
2Adaptability or versatility
If reference pictures are resampled to accommodate different resolutions, then adaptability to resolution changes is improved, but only parts of the picture canvas are utilized resulting in wasted bandwidth
Solution Approach 1:
The patent extracts and transmits only the necessary portion of the picture data at the target resolution rather than transmitting entire resampled reference pictures. By identifying and removing unnecessary data (unused parts of the picture canvas), the system achieves better bandwidth utilization while maintaining resolution adaptability.
Solution Approach 2:
The patent applies partial action by processing and transmitting only the required portion of picture data needed for the current resolution requirement, rather than processing the entire picture. This avoids the excessive action of transmitting full-resolution reference pictures when only a portion is needed, thereby improving bandwidth efficiency.
3Adaptability or versatility
If the picture size is changed within a coded video sequence, then adaptability to different resolutions is improved, but decoding complexity and processing overhead increase
Solution Approach 1:
The patent performs preliminary actions by preparing resolution change parameters and control information in advance before actual picture size changes occur. The adaptive resolution change flag and related control data are encoded ahead of time, allowing the decoder to prepare for resolution transitions without sudden complexity spikes during playback.
Solution Approach 2:
The patent segments the video sequence into sections with different resolution characteristics, allowing independent processing of each segment. By dividing the overall decoding task into smaller manageable segments with specific resolution requirements, the system reduces processing overhead compared to handling the entire sequence at maximum resolution.
Data Source
AI summary
A method of decoding an encoded video bitstream using at least one processor, including: obtaining from the encoded video bitstream a coded video sequence including a picture unit corresponding to a coded picture; obtaining a picture header (PH) network abstraction layer (NAL) unit included in the picture unit; obtaining at least one video coding layer (VCL) network abstraction layer (NAL) unit included in the picture unit; decoding the coded picture based on the PH NAL unit, the at least one VCL NAL unit, and an adaptation parameter set (APS) included in an APS NAL unit obtained from the coded video sequence; and outputting the decoded picture, wherein the APS NAL unit is available to the at least one processor before the at least one VCL NAL unit.