Intra-Slice Filtering for HEVC Video Coding Boundary Artifacts
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Solution Overview
Problem
In video coding, the application of deblocking filtering and adaptive loop filtering at slice boundaries in HEVC causes loss of independent processing feature, leading to noticeable artifacts and long processing latency due to dependency on neighboring slices.
Innovation Solution
Intra-slice deblocking filtering, adaptive loop filtering, and adaptive offset algorithms that only rely on data within the slice, along with a slice boundary filter, are developed to maintain independent slice processing and reduce artifacts at slice boundaries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If deblocking filtering and adaptive loop filtering are applied at slice boundaries using data from neighboring slices, then filtering quality is improved, but independent slice processing is lost and processing latency increases
Solution Approach 1:
The patent applies segmentation by introducing a dedicated slice boundary filter that processes only the boundary pixels between slices. This separates the filtering operation into two independent parts: intra-slice filtering (using data within the slice) and inter-slice boundary filtering (using a specialized filter at boundaries). This allows the majority of slice processing to remain independent and parallelizable, while still applying enhanced filtering at critical boundary regions to maintain quality.
Solution Approach 2:
The patent introduces an intermediary mechanism by using previously filtered boundary pixels from adjacent slices as reference data for the slice boundary filter. Instead of requiring full access to neighboring slice data, the intermediary approach uses already-processed boundary information to perform accurate boundary filtering without creating data dependencies that would block parallel processing.
2Manufacturing precision
If deblocking filtering and adaptive loop filtering are applied at slice boundaries using data from neighboring slices, then filtering quality is improved, but slice independent processing is lost
Solution Approach 1:
The patent applies segmentation by introducing a dedicated slice boundary filter that processes only the boundary pixels between slices. This separates the filtering operation into two independent parts: intra-slice filtering (using data within the slice) and inter-slice boundary filtering (using a specialized filter at boundaries). This allows the majority of slice processing to remain independent and parallelizable, while still applying enhanced filtering at critical boundary regions to maintain quality.
Solution Approach 2:
The patent applies local quality by using different filtering approaches for different regions: standard intra-slice filters for interior regions and a specialized slice boundary filter for boundary regions. The slice boundary filter is specifically designed to handle the unique characteristics of boundary pixels while maintaining independence from neighboring slice data, thus preserving parallel processing capability while improving boundary filtering quality.
3Productivity
If intra-slice filtering only using data within the slice is used, then independent slice processing is maintained, but artifacts at slice boundaries become noticeable
Solution Approach 1:
The patent applies local quality by using different filtering approaches for different regions: standard intra-slice filters for interior regions and a specialized slice boundary filter for boundary regions. The slice boundary filter is specifically designed to handle the unique characteristics of boundary pixels while maintaining independence from neighboring slice data, thus preserving parallel processing capability while improving boundary filtering quality.
Solution Approach 2:
The patent introduces an intermediary mechanism by using previously filtered boundary pixels from adjacent slices as reference data for the slice boundary filter. Instead of requiring full access to neighboring slice data, the intermediary approach uses already-processed boundary information to perform accurate boundary filtering without creating data dependencies that would block parallel processing.
Data Source
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AI summary
An apparatus and method for video coding having intra-slice deblocking, intra-slice adaptive loop filter, and intra-slice adaptive offset are disclosed. In a video coding system, a picture is often divided into slices and each slice is independently processed so that errors or missing data from one slice cannot propagate to any other slice within the picture. In the recent high efficiency video coding (HEVC) development, deblock filtering (DF), adaptive loop filter (ALF) and adaptive offset (AO) may be applied to reconstructed slices. When the processing is applied across slice boundaries, it may rely on pixels outside the current slice and cause dependency of the current slice on other slice(s). Consequently, the DF/ALF/AO processing on a reconstructed slice may have to wait until the reconstructed slices that it is dependent from complete the DF/ALF/AOprocessing. To overcome the slice boundary issue, intra-slice DF/ALF/AO is developed that does not rely on any pixel outside the currently slice. An optional slice boundary filter may be applied to slice boundaries after all slices are processed by the intra-slice DF/ALF/AO.