Affine Motion Prediction Refinement With Optical-Flow Block Sizing
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Solution Overview
Problem
Existing video coding standards face challenges in efficiently managing deblocking filters and quantization parameters, leading to inefficiencies in bandwidth usage and decoding processes, particularly in advanced codecs like VVC.
Innovation Solution
Implementing a set of rules and syntax elements to govern the application of deblocking filters and quantization parameters at various levels of video coding, including picture, slice, and sequence levels, based on specific syntax elements and flags, to optimize filtering and reduce computational complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If deblocking filter application is controlled at multiple levels (picture, slice, block), then filtering precision is improved, but device complexity increases
Solution Approach 1:
The patent segments the deblocking filter control into multiple hierarchical levels: picture-level syntax elements (deblocking_filter_override_enabled_flag, pps_deblocking_filter_disabled_flag), slice-level syntax elements (slice_deblocking_filter_override_flag, slice_chroma_deblocking_filter_disabled_flag), and block-level decisions. This segmentation allows precise control at different granularities while managing complexity through structured organization of control parameters.
Solution Approach 2:
The patent enables local quality control by allowing different deblocking filter settings for different regions within a picture. Through slice-level overrides and block-level decisions, specific areas can have customized filtering applied or disabled independently, allowing local optimization of filtering precision without uniformly increasing complexity across the entire picture.
2Manufacturing precision
If multiple syntax elements are used to control deblocking filters, then manufacturing precision is improved, but ease of operation deteriorates
Solution Approach 1:
The patent implements dynamic control mechanisms where syntax elements can be conditionally present or absent based on higher-level flags. For example, slice-level override flags are only processed if picture-level override is enabled, and block-level decisions depend on slice-level settings. This dynamic structure allows precise control when needed while simplifying operation through conditional simplification when uniform settings suffice.
Solution Approach 2:
The patent uses preliminary action by establishing default deblocking filter settings at the picture parameter set level that apply to all slices and blocks. These default settings are pre-configured, and only when specific conditions are met do additional syntax elements override them. This allows most cases to operate with simple default settings while enabling precise control when required.
3Adaptability or versatility
If deblocking filter parameters are signaled at slice level, then adaptability is improved, but loss of information increases due to additional bitstream data
Solution Approach 1:
The patent changes parameters conditionally based on content characteristics. Slice-level deblocking parameters (beta_offset_div2, tc_offset_div2, chroma_beta_offset_div2, chroma_tc_offset_div2) are only signaled when slice_deblocking_filter_override_flag is set to 1, allowing adaptability when needed while avoiding unnecessary bandwidth consumption when uniform picture-level settings suffice.
Solution Approach 2:
The patent applies partial action by selectively applying slice-level override mechanisms only to specific slices that require customized filtering, rather than applying it uniformly to all slices. This partial application of the override mechanism provides adaptability where needed while minimizing the bandwidth overhead associated with signaling additional syntax elements.
Data Source
AI summary
A method includes determining, for a conversion between a video block of a video and a bitstream of the video, a size of prediction block corresponding to the video block according to a rule. The method also includes performing the conversion based on the determining. The rule specifies that a first size of the prediction block is determined responsive to whether a prediction refinement using optical flow technique is used for coding the video block. The video block has a second size and is coded using an affine merge mode or an affine advanced motion vector prediction mode.