Video Picture Encoding and Decoding for Panoramic Sub-region Filtering
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Solution Overview
Problem
In visual angle-based VR encoding and transmission, content discontinuity occurs due to independent encoding of sub-regions, leading to blocking artifacts and encoding/decoding mismatches, especially when assembling sub-bitstreams into a complete rectangle.
Innovation Solution
A method that includes obtaining a primary sub-region bitstream from secondary sub-region bitstreams, performing cross-sub-region-boundary out-loop filtering, and adjusting sub-region locations to resolve content discontinuity, using sub-region information and an out-loop filtering identifier to accurately filter boundaries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If independent encoding of sub-regions is applied to save bandwidth and reduce decoding capability requirements, then encoding bandwidth is saved and terminal decoding capability requirement is reduced, but content discontinuity and blocking artifacts occur at sub-region boundaries
Solution Approach 1:
The panoramic picture is divided into multiple sub-regions (tiles or slices), each independently encoded to reduce decoding complexity and bandwidth requirements. This segmentation allows parallel processing and reduces the capability requirements for terminal decoders while maintaining efficient bandwidth utilization.
Solution Approach 2:
Different filtering strategies are applied to different regions: strong filtering at in-loop (within sub-region boundaries) and out-loop (across sub-region boundaries) to selectively smooth blocking artifacts only where needed, preserving overall picture quality while managing the trade-off between bandwidth efficiency and visual continuity.
2Productivity
If block-based encoding policy is used in standard HEVC video encoding, then encoding efficiency is improved, but blocking artifacts appear at block edges due to independent quantization errors
Solution Approach 1:
Filtering operations are performed in advance during the encoding process (in-loop filtering) and after decoding (out-loop filtering) to preemptively remove blocking artifacts before they affect the final picture quality, allowing block-based encoding to maintain both efficiency and visual quality.
Solution Approach 2:
Filtering mechanisms act as intermediaries between the block-based encoding process and the final reconstructed picture, smoothing the transition at block edges and eliminating the harmful blocking artifacts while preserving the encoding efficiency benefits of block-based processing.
3Manufacturing precision
If cross-sub-region in-loop filtering is enabled on the decoder to smooth boundaries, then boundary continuity is improved, but encoding and decoding mismatch occurs because decoders must separately decode sub-region bitstreams
Solution Approach 1:
The filtering process is segmented into two independent stages: in-loop filtering performed during encoding on each sub-region separately, and out-loop filtering performed after decoding across sub-region boundaries. This segmentation allows each decoder to independently process its assigned sub-region bitstream while still achieving boundary continuity through the out-loop filtering stage.
Solution Approach 2:
The out-loop filtering mechanism serves as an intermediary that operates after independent decoding of sub-region bitstreams, smoothing boundaries without requiring the decoders to have knowledge of or coordination with each other, thus maintaining encoding-decoding consistency while achieving boundary continuity.
4Shape
If sub-bitstreams are assembled into a complete rectangle with re-arranged locations, then a complete rectangular picture is formed, but content discontinuity occurs because original adjacent sub-regions are no longer adjacent
Solution Approach 1:
Out-loop filtering is applied in advance after assembly but before final picture output, anticipating and correcting the content discontinuity that results from re-arranging sub-regions into a complete rectangle, thereby restoring visual continuity without requiring the original spatial adjacency of sub-regions.
Solution Approach 2:
The out-loop filtering process acts as an intermediary between the assembled sub-bitstreams and the final reconstructed picture, smoothing the discontinuities introduced by re-arrangement and ensuring content continuity is restored despite the changed spatial relationships among sub-regions.
Data Source
AI summary
A video picture encoding and decoding method, including obtaining a primary sub-region bitstream corresponding to a target sub-picture of a panoramic picture, where the primary sub-region bitstream includes N secondary sub-region bitstreams, and N is a positive integer, parsing the primary sub-region bitstream to obtain a reconstructed picture, performing cross-sub-region-boundary out-loop filtering on the reconstructed picture when an out-loop filtering identifier instructs to perform cross-sub-region-boundary out-loop filtering on the reconstructed picture, to obtain a filtered reconstructed picture, and adjusting a location of at least one of N sub-regions in the filtered reconstructed picture to obtain a picture having no sub-region boundary.