Panoramic Video Compression Motion Search Optimization
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Solution Overview
Problem
Conventional video compression methods for panoramic video face inefficiencies due to pixel distortion in panoramic formats like equirectangular, leading to unreliable motion search results, especially in vertical directions, which wastes processing time and resources.
Innovation Solution
The method involves skewing motion searches around co-located blocks according to direction, limiting vertical searches, and allocating more weight to horizontal search results, while adjusting the quantization parameter as the search moves away from the equator, to improve compression efficiency and reduce distortion-related errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If motion search is performed in all directions (including vertical) around co-located blocks, then motion compensation coverage is improved, but processing time and power consumption increase due to unreliable vertical search results caused by pixel distortion
Solution Approach 1:
The patent applies local quality by making the motion search strategy direction-dependent. Horizontal motion searches are performed with full search range and complexity, while vertical motion searches are limited or skipped in distorted regions (areas far from the equator in equirectangular projection). This localized adaptation of search quality based on spatial position and direction resolves the contradiction by maintaining reliability where it matters (horizontal directions) while reducing processing time in problematic areas (vertical directions in distorted regions).
Solution Approach 2:
The patent changes the motion search parameters dynamically based on the spatial location and direction. The search window size, search range, and search complexity are adjusted as parameters according to the block's distance from the equator and the search direction. This parameter adaptation allows the system to maintain high prediction reliability in reliable directions/regions while reducing processing overhead in unreliable directions/regions, thus resolving the time-reliability tradeoff.
2Reliability
If motion search is performed in all directions around co-located blocks, then motion compensation coverage is improved, but power consumption increases due to processing unreliable vertical search results
Solution Approach 1:
The patent applies local quality by making the motion search strategy direction-dependent. Horizontal motion searches are performed with full search range and complexity, while vertical motion searches are limited or skipped in distorted regions (areas far from the equator in equirectangular projection). This localized adaptation of search quality based on spatial position and direction resolves the contradiction by maintaining reliability where it matters (horizontal directions) while reducing processing time in problematic areas (vertical directions in distorted regions).
Solution Approach 2:
The patent changes the motion search parameters dynamically based on the spatial location and direction. The search window size, search range, and search complexity are adjusted as parameters according to the block's distance from the equator and the search direction. This parameter adaptation allows the system to maintain high prediction reliability in reliable directions/regions while reducing processing overhead in unreliable directions/regions, thus resolving the time-reliability tradeoff.
3Productivity
If uniform compression is applied across all regions of panoramic video, then encoding simplicity is maintained, but compression efficiency decreases in distorted regions far from the equator
Solution Approach 1:
The patent applies local quality by implementing region-dependent motion search strategies. Different encoding parameters, search ranges, and prediction methods are used in different regions of the panoramic video. Specifically, regions near the equator use standard encoding, while regions far from the equator use adapted parameters and limited vertical search. This localized approach improves overall compression efficiency by optimizing for each region's characteristics while adding minimal encoding complexity through systematic parameter adaptation.
Solution Approach 2:
The patent segments the panoramic video encoding process into different regions based on their distortion characteristics. By dividing the video into zones (e.g., near-equator regions vs. pole regions) and applying different encoding strategies to each segment, the system achieves better overall compression efficiency. The segmentation is implemented through conditional logic that divides the search space and parameter selection based on spatial coordinates, managing complexity through structured regional processing.
Data Source
AI summary
A processing device is provided which includes memory configured to store data and a processor. The processor is configured to receive a plurality of panoramic video images representing views around a point in a three dimensional (3D) space and warp the plurality of panoramic video images, using a panoramic format, into a plurality of formatted warped images. The processor is also configured to store, in the memory, the plurality of formatted warped images and perform a motion search around each co-located pixel block of a reference panoramic frame by limiting the motion searches in a vertical direction around the co-located pixel blocks.