US 6,983,018 B1 | ||
Efficient motion vector coding for video compression | ||
Chih-Lung (Bruce) Lin, Redmond, Wash. (US); and Ming-Chieh Lee, Bellevue, Wash. (US) | ||
Assigned to Microsoft Corporation, Redmond, Wash. (US) | ||
Filed on Nov. 30, 1998, as Appl. No. 9/201,278. | ||
Int. Cl. H04N 7/12 (2006.01) |
U.S. Cl. 375—240.16 | 20 Claims |
1. In a video coder for coding video images in a block format, a method for improving compression of the video images comprising:
predicting x and y motion vector components for a current block of pixels based on a motion vector of at least one neighboring
block of pixels to compute x and y components of a predictor motion vector;
computing differential x and y components from the x and y components of the predictor and x and y components of a motion
vector for the current block; and
assigning a single variable length code to joint x and y differential motion vector components, wherein the single variable
length code is assigned from a variable length code table, the table comprising a list of pairs of joint differential motion
vector components and a corresponding variable length code for each pair, such that shorter variable length codes are assigned
to joint differential motion vector components that have a higher probability of occurrence in the video images, and longer
variable length codes are assigned to joint differential motion vector components that have a lower probability of occurrence,
wherein the table includes the most probable pairs of joint differential motion vector components as computed by statistical
analysis of example video sequences.
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