Wavefront Parallel Processing Video Coding Slice Alignment
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Solution Overview
Problem
Existing video coding techniques face delays and inefficiencies due to slice spillover issues, where slices start within a wavefront and cross boundaries, disrupting parallel processing in video encoding and decoding.
Innovation Solution
Implementing techniques that restrict wavefront-slice interaction by ensuring slices either start and end within a wavefront, allowing for efficient parallel processing by ensuring access to necessary information without relying on subsequent slice headers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If slices are allowed to cross wavefront boundaries, then flexibility in slice placement is improved, but parallel processing efficiency deteriorates due to delays caused by slice spillover
Solution Approach 1:
The patent divides the picture into wavefronts (rows of CTUs) and further segments slices to ensure they align with wavefront boundaries. This segmentation prevents slices from crossing wavefront boundaries, allowing each wavefront to be processed independently in parallel without waiting for slice header information from subsequent wavefronts.
Solution Approach 2:
The patent requires that slice headers be decoded before the corresponding wavefront processing begins. By ensuring slice headers are available in advance (preliminarily decoded), the system eliminates delays caused by slice spillover and enables immediate parallel processing of each wavefront.
2Stability of the object's composition
If slices start within a wavefront and cross boundaries, then slice continuity is improved, but access to necessary information is delayed
Solution Approach 1:
The patent segments slices at wavefront boundaries rather than allowing them to cross boundaries. This ensures that all information needed for a wavefront (including slice headers) is available within or before that wavefront, eliminating information access delays while maintaining slice integrity within each wavefront segment.
Solution Approach 2:
The patent introduces wavefront boundaries as intermediaries that mediate between slice continuity requirements and parallel processing needs. By aligning slice boundaries with wavefront boundaries, the system ensures that slice information is available as an intermediary resource before wavefront processing begins, preventing delays.
3Reliability
If slice headers are required from subsequent wavefronts, then accurate decoding is improved, but parallel processing is disrupted
Solution Approach 1:
The patent requires that all slice header information be decoded preliminarily before wavefront processing begins. This preliminary decoding ensures that accurate decoding information is available in advance, eliminating the need to wait for subsequent wavefronts while maintaining decoding reliability.
Solution Approach 2:
The patent inverts the traditional approach by requiring slice headers to be available before wavefront processing rather than allowing access during processing. This inversion ensures that decoding accuracy is maintained while parallel processing continuity is preserved, as no wavefront needs to wait for subsequent wavefront information.
Data Source
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AI summary
In one example, a video coder may be configured to determine that a slice of a picture of video data begins in a row of coding tree units (CTUs) in the picture at a position other than a beginning of the row. Based on the determination, the video coder may be further configured to determine that the slice ends within the row of CTUs. The video coder may be further configured to code the slice based on the determination that the slice ends within the row of CTUs.