Motion Vector Precision Reduction for Video Buffer Storage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current video coding technologies face significant storage requirements for motion vectors (MVs) due to high precision, which can lead to increased storage needs for MV buffers, especially in advanced video coding standards like HEVC and next-generation codecs, without adequately addressing the performance impact in fast motion scenarios.
Innovation Solution
The method involves reducing the precision or resolution of MVs before storage and restoring it when necessary for motion compensation, using precision reduction and restoration operations, and encoding the scaling factors in the bitstream to maintain performance and reduce storage requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high precision motion vectors are stored in MV buffers, then motion compensation performance is improved, but storage requirements increase significantly
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the precision of motion vectors based on motion characteristics. The system switches between high precision (e.g., 1/4 pixel) and reduced precision (e.g., 1/8 pixel) representations of motion vectors, allowing the storage requirement to be reduced while maintaining motion compensation performance for most scenarios.
Solution Approach 2:
The patent implements dynamics by making the motion vector precision adaptive rather than fixed. The system dynamically selects the precision level based on motion activity in different regions of the video frame, using higher precision only where necessary and reduced precision where motion is minimal or stationary, thus optimizing the storage-performance trade-off.
2Quantity of substance
If reduced precision motion vectors are stored, then storage requirements are reduced, but motion compensation accuracy degrades
Solution Approach 1:
The patent uses parameter changes to transform motion vectors between different precision representations. When storing, motion vectors are converted to reduced precision to save space. When retrieving and using for motion compensation, the system adjusts the precision parameter to maintain accuracy, thus resolving the contradiction between storage efficiency and measurement precision.
Solution Approach 2:
The patent applies copying by creating a reduced-precision representation of motion vectors that captures the essential motion information while using fewer bits. This copy is sufficient for storage and can be reconstructed or adjusted when needed for accurate motion compensation, avoiding the need to store full precision data continuously.
3Quantity of substance
If precision reduction scaling factors are encoded in bitstream, then storage efficiency is improved, but bitstream complexity increases
Solution Approach 1:
The patent applies taking out by extracting only the necessary precision information (scaling factors) from the full motion vector data and encoding just these parameters in the bitstream. This allows the decoder to reconstruct the appropriate precision levels without transmitting the complete high-precision motion vector data, reducing bitstream size while maintaining functionality.
Solution Approach 2:
The patent uses partial action by encoding only the precision reduction scaling factors rather than all motion vector data. This partial encoding approach transmits only the necessary control information needed to reconstruct motion vectors at the required precision levels, avoiding the excessive data transmission that would occur if full precision data were always encoded.
Data Source
AI summary
Apparatus and methods are described for a video encoder that uses reference motion vectors (MVs) with reduced precision to generate predicted MVs. The video encoder receives a block of pixels of a video frame and generates a MV for encoding the block of pixels by motion compensation. The video encoder creates a reduced-precision MV by reducing a precision of the generated MV based on a precision reduction scaling factor. The video encoder also stores the reduced-precision MV in a MV buffer as a reference MV for temporal or spatial MV prediction.