Affine Motion Compensation for Current Picture Referencing in 360 Video
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Solution Overview
Problem
Conventional technologies fail to support affine motion compensation mode, particularly in current picture referencing and 360° projection formats like cube map projection, leading to inefficiencies and discontinuities in video coding, especially in frames like I-frames.
Innovation Solution
The implementation of affine motion compensation for current picture referencing, which allows for sub-pel motion vector resolution and adaptive motion vector prediction, enabling efficient encoding and decoding of video data by targeting cube face edges and using locally adaptive motion vector resolution to manage discontinuities in cube map projections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional motion compensation techniques are used, then implementation is simple, but affine motion compensation mode is not supported and video quality deteriorates
Solution Approach 1:
The patent segments the motion compensation process into multiple components: affine transformation module, current picture referencing module, and cube face discontinuity handling module. Each component addresses a specific aspect of the problem, allowing complex affine motion compensation to be implemented through coordinated simpler sub-functions.
Solution Approach 2:
The patent extends traditional 2D motion compensation by incorporating affine transformation parameters that operate in an extended parameter space. This includes adding rotational and scaling dimensions to the conventional translational motion model, enabling more accurate representation of complex motion patterns while maintaining a systematic implementation approach.
2Manufacturing precision
If current picture referencing is implemented without affine motion compensation, then processing is faster, but video quality and coding efficiency deteriorate
Solution Approach 1:
The patent performs preliminary actions by pre-calculating affine transformation parameters and pre-identifying valid reference blocks in the current picture before the actual motion compensation process. This preparation work enables faster processing during encoding while maintaining high video quality through accurate affine motion modeling.
Solution Approach 2:
The patent dynamically adjusts motion vector precision parameters based on the complexity of the current block and the availability of reference samples. By adaptively changing parameter precision rather than using fixed high-precision parameters throughout, the system achieves high video quality where needed while maintaining overall coding efficiency.
3Adaptability or versatility
If cube map projection is used for 360° video, then omnidirectional coverage is achieved, but discontinuities at cube faces cause inefficiency
Solution Approach 1:
The patent introduces an intermediary validation mechanism that checks reference block positions against cube face boundaries before performing motion compensation. This intermediary step identifies and handles discontinuities at cube faces, preventing invalid reference sample access and maintaining coding efficiency while preserving omnidirectional coverage capability.
Solution Approach 2:
The patent applies different processing strategies to different regions of the cube map projection. Blocks near cube face boundaries receive special handling with adjusted reference search constraints, while blocks in interior regions use standard affine motion compensation. This local differentiation maintains coding efficiency by avoiding unnecessary complexity in regions where it is not needed.
Data Source
AI summary
Embodiments are generally directed to affine motion compensation for current picture referencing. An embodiment of an apparatus includes one or more processors for processing of data; a memory for storage of data including video data; and an encoder for encoding of video data to generate encoded video data, wherein the encoder includes a component to provide affine motion compensation for current picture references in the video data.