360-Degree Video Geometry Conversion for Chroma-Luma Alignment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing video coding technologies for 360-degree videos fail to efficiently align chroma and luma components, leading to boundary misalignment and inefficient compression due to chroma subsampling, particularly in geometric conversions like equirectangular to cubemap formats.
Innovation Solution
A method for aligning unaligned chroma and luma components by applying geometric conversion processes, including chroma upsampling and downsampling filters, to maintain the phase relationship between chroma and luma sampling grids during conversion from equirectangular to cubemap formats, ensuring proper alignment and reducing bandwidth requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If chroma subsampling is applied to reduce data量, then compression efficiency is improved, but chroma and luma components become misaligned leading to visual artifacts
Solution Approach 1:
The patent applies preliminary action by performing chroma component alignment before geometry conversion. The chroma components are realigned to match luma component positions using phase shift filters and resampling operations, ensuring proper alignment is established before the conversion process begins, thereby preventing misalignment artifacts from occurring in the first place
Solution Approach 2:
The patent introduces an intermediary process of chroma upsampling and phase alignment between the chroma subsampling and geometry conversion steps. This intermediary realignment process acts as a mediator that restores the spatial relationship between chroma and luma components that was disrupted by subsampling, allowing both compression efficiency and alignment precision to be maintained
2Adaptability or versatility
If geometry conversion is performed to switch between equirectangular and cubemap formats, then format flexibility is improved, but boundary misalignment and visual artifacts occur
Solution Approach 1:
The patent applies preliminary action by realigning chroma components to luma component positions before performing geometry conversion. This ensures that the chroma-luma spatial relationship is properly established in advance, preventing boundary misalignment artifacts from occurring during the format conversion process
Solution Approach 2:
The patent implements feedback by detecting boundary misalignment issues during geometry conversion and applying corrective phase shift filters and resampling operations. The system monitors for misalignment artifacts and dynamically adjusts the chroma component positioning to compensate for boundary issues, thereby maintaining precision while enabling format flexibility
3Manufacturing precision
If phase shift filters and resampling filters are applied to align chroma components, then alignment precision is improved, but processing complexity increases
Solution Approach 1:
The patent applies preliminary action by performing chroma component alignment using phase shift filters and resampling operations before geometry conversion. This preliminary realignment ensures that chroma and luma components are properly positioned in advance, achieving high alignment precision through a single dedicated processing stage rather than requiring complex continuous adjustments
Solution Approach 2:
The patent segments the alignment process into distinct, manageable operations: phase shift filtering, resampling, and realignment. By breaking down the complex alignment task into separate sequential steps, each handling a specific aspect of the positioning problem, the overall processing complexity is reduced while maintaining high alignment precision
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
Processing a 360-degree video content for video coding may include receiving the video content in a first geometry. The video content may include unaligned chroma and luma components associated with a first chroma sampling scheme. The unaligned chroma and luma components may be aligned to a sampling grid associated with a second chroma sampling scheme that has aligned chroma and luma components. A geometric conversion to the video content may be performed. The video content, that may comprise the aligned chroma and luma components, in the first geometry may be converted to a second geometry. The first geometry may be a stitched geometry, and the second geometry may be a coding geometry. The converted video content in the second geometry may include the chroma and luma components aligned to the sampling grid associated with the second chroma sampling scheme.