Moving Picture Coding With Clipped Motion Vector Precision
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Solution Overview
Problem
The multiplication involved in the temporal direct mode of H.264 motion vector scaling increases processing load in coding and decoding, necessitating higher bit precision handling which can lead to inefficiencies.
Innovation Solution
A method for coding and decoding moving pictures that involves selectively adding motion vectors from spatially or temporally neighboring blocks, performing a scaling process to calculate a second motion vector within a predetermined magnitude range, and limiting motion vectors to a certain bit precision by clipping or excluding those outside this range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temporal direct mode with motion vector scaling multiplication is used, then prediction accuracy is improved, but processing load increases and bit precision requirements increase
Solution Approach 1:
The patent changes the parameter of motion vector precision by clipping motion vectors to a predetermined bit precision (e.g., 16 bits). This reduces the processing load and complexity associated with handling high-precision motion vectors while maintaining adequate prediction accuracy for video coding applications.
Solution Approach 2:
The patent extracts and removes the excessive precision components from motion vectors by applying clipping to a predetermined bit precision. This eliminates the unnecessary high-precision handling while preserving the essential prediction functionality, thereby reducing processing load.
2Measurement precision
If temporal direct mode with motion vector scaling multiplication is used, then prediction accuracy is improved, but processing load increases
Solution Approach 1:
The patent modifies the precision parameter of motion vectors by clipping to a fixed bit width, which streamlines processing operations and improves productivity by reducing the computational burden of handling variable-precision high-bit motion vectors.
Solution Approach 2:
The patent uses a simplified, fixed-precision motion vector representation that is easier and faster to process. This disposable approximation approach maintains sufficient prediction accuracy while significantly reducing processing load and improving coding/decoding efficiency.
3Measurement precision
If motion vectors are handled at higher bit precision, then prediction accuracy is improved, but coding efficiency decreases
Solution Approach 1:
The patent optimizes the bit precision parameter of motion vectors by clipping to a predetermined width, achieving the best balance between prediction accuracy and coding efficiency. This prevents excessive precision from degrading coding performance while maintaining sufficient accuracy for quality video reproduction.
Data Source
AI summary
A moving picture coding apparatus includes an intra-inter prediction unit which calculates a second motion vector by performing a scaling process on a first motion vector of a temporally neighboring corresponding block, when selectively adding, to a list, a motion vector of each of one or more corresponding blocks each of which is either a block included in a current picture to be coded and spatially neighboring a current block to be coded or a block included in a picture other than the current picture and temporally neighboring the current block, determines whether the second motion vector has a magnitude that is within a predetermined magnitude or not within the predetermined magnitude, and adds the second motion vector to the list when the intra-inter prediction unit determines that the second motion vector has a magnitude that is within the predetermined magnitude range.