Scalable Video Coding Upsampling with Phase Offset Signaling
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Solution Overview
Problem
Scalable video coding technologies face challenges in efficiently upsampling base layer video data to match the resolution of enhancement layers, particularly in achieving accurate phase alignment and offset adjustments between layers, which affects video quality and encoding efficiency.
Innovation Solution
The proposed solution involves a three-module upsampling process that selects input samples from the base layer, chooses appropriate filters based on phase filtering, and uses phase filtering to recreate video at enhancement layer resolution, with signaling of scaled reference layer offsets and phases at the Picture Parameter Set (PPS) level for precise alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If upsampling filtering is applied to base layer to match enhancement layer resolution, then spatial scalability is achieved, but phase alignment accuracy deteriorates
Solution Approach 1:
The patent segments the upsampling process into distinct modules: a sample selector that chooses specific base layer samples, a filter selector that chooses appropriate filters, and phase filtering modules. This segmentation allows independent optimization of sample selection and phase adjustment, resolving the contradiction between resolution matching and phase alignment accuracy.
Solution Approach 2:
The patent performs preliminary phase calculation based on the ratio between base layer and enhancement layer picture resolutions before applying the upsampling filter. By pre-calculating the phase offset, the system ensures accurate phase alignment is established before the actual upsampling operation, preventing phase misalignment that would otherwise occur during resolution scaling.
2Measurement precision
If multiple filter sets with different phases are used for upsampling, then phase alignment is improved, but device complexity increases
Solution Approach 1:
The patent implements dynamic filter selection where the filter set is chosen based on calculated phase values. Rather than using all possible filters simultaneously, the system dynamically selects the appropriate filter from predefined sets according to the specific phase requirements of each upsampling operation. This dynamic approach maintains high phase alignment accuracy while reducing the effective complexity by selecting only necessary filters.
Solution Approach 2:
The patent changes the parameter of filter phase offset based on the calculated phase difference between base layer and enhancement layer. By adjusting the phase parameter of the upsampling filter according to resolution ratios, the system achieves accurate phase alignment without requiring complex manual configuration or multiple static filter sets for every possible scenario.
3Adaptability or versatility
If base layer and enhancement layer have different resolutions, then spatial scalability is enabled, but sample position mapping complexity increases
Solution Approach 1:
The patent creates a universal sample position mapping mechanism that works for any resolution combination between base layer and enhancement layer. The mapping function uses the resolution ratio as a universal parameter to calculate corresponding sample positions, making the system adaptable to different spatial scalabilities without requiring separate mapping logic for each resolution pair.
Solution Approach 2:
The patent uses resolution ratio as a dynamic parameter to determine sample position mapping. By changing the mapping calculation based on the specific resolution ratio between layers, the system handles different spatial scalability scenarios uniformly. The phase offset parameter is also adjusted based on resolution ratios, simplifying the mapping complexity through parameter-based adaptation rather than complex conditional logic.
Data Source
AI summary
A process for determining the selection of filters and input samples is provided for scalable video coding. The process provides for re-sampling using video data obtained from an encoder or decoder process of a base layer (BL) in a multi-layer system to improve quality in Scalable High Efficiency Video Coding (SHVC). In order to accommodate other applications such as interlace/progressive scalability and to increase the resolution of the alignment between layers, it is proposed that the phase offset adjustment parameters be signaled.