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US 7,116,831 B2Granted
Chrominance motion vector rounding
AssigneeMicrosoft Corporation
InventorsKunal Mukerjee, Sridhar Srinivasan
Life of this patent
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Abstract
Various techniques and tools for chrominance motion vector rounding are described. For example, during motion compensation, a video encoder or decoder converts luminance motion vectors into chrominance motion vector having quarter-pixel accuracy. Or, during motion compensation, a video encoder or decoder converts luminance motion vectors into chrominance motion vectors using one of multiple available chrominance motion vector rounding modes.
Claims36
In a computer system, a computer-implemented method comprising:
- buffering a reference video frame;
- and
- performing motion compensation for at least part of a current video frame relative to the reference video frame, the motion compensation including,
- computing a luminance motion vector with quarter-pixel accuracy in luminance space;
- and
- converting the luminance motion vector to a chrominance motion vector with quarter-pixel accuracy in chrominance space,
- wherein if the luminance motion vector has a quarter-pixel offset in a given dimension, the chrominance motion vector has an integer-pixel offset or half-pixel offset in the given dimension;
- if the luminance motion vector has a half-pixel offset in the given dimension, the chrominance motion vector has a quarter-pixel offset or three-quarters-pixel offset in the given dimension;
- and
- if the luminance motion vector has a three-quarters-pixel offset in the given dimension, the chrominance motion vector has a half-pixel offset or integer-pixel offset in the given dimension.
7 more elements
In a computer system, a computer-implemented method comprising:
- buffering a reference video frame;
- and
- performing motion compensation for at least part of a current video frame relative to the reference video frame, the motion compensation including,
- computing a luminance motion vector with quarter-pixel accuracy in luminance space;
- and
- converting the luminance motion vector to a chrominance motion vector with quarter-pixel accuracy in chrominance space,
- wherein the luminance motion vector has a half-pixel value in one dimension in luminance space, and wherein the chrominance motion vector has a corresponding quarter-pixel value or three-quarters-pixel value in the one dimension in chrominance space.
4 more elements
In a computer system, a computer-implemented method comprising:
- buffering a reference video frame;
- and
- performing motion compensation for at least part of a current video frame relative to the reference video frame, the motion compensation including,
- computing a luminance motion vector in luminance space;
- and
- converting the luminance motion vector to a chrominance motion vector, the converting being performed in one of multiple available chrominance motion vector rounding modes,
- wherein compared to a first mode of the multiple available chrominance motion vector rounding modes, a second mode of the multiple available chrominance motion vector rounding modes decreases chrominance motion vector precision and thereby reduces computational complexity of subsequent motion compensation.
4 more elements
A system comprising:
- means for computing luminance motion vectors with quarter-pixel accuracy for a predicted video frame relative to a reference video frame;
- and
- means for converting the luminance motion vectors into chrominance motion vectors with quarter-pixel accuracy in chrominance space, wherein for a given luminance motion vector of the luminance motion vectors and for a corresponding chrominance motion vector of the chrominance motion vectors,
- if the luminance motion vector has a quarter-pixel offset in a given dimension, the corresponding chrominance motion vector has an integer-pixel offset or half-pixel offset in the given dimension;
- if the luminance motion vector has a half-pixel offset in the given dimension, the corresponding chrominance motion vector has a quarter-pixel offset or three-quarters-pixel offset in the given dimension;
- and
- if the luminance motion vector has a three-quarters-pixel offset in the given dimension, the corresponding chrominance motion vector has a half-pixel offset or integer-pixel offset in the given dimension.
4 more elements
A system comprising:
- means for computing luminance motion vectors for a predicted video frame relative to a reference video frame;
- means for selecting one of multiple available chrominance motion vector rounding modes;
- and
- means for converting the luminance motion vectors into chrominance motion vectors according to the selected chrominance motion vector rounding mode,
- wherein a first mode of the multiple available chrominance motion vector rounding modes emphasizes motion compensation quality over computational simplicity, and wherein a second mode of the multiple available chrominance motion vector rounding modes emphasizes computational simplicity over motion compensation quality.
2 more elements
Dependencies are inferred from the claim text.