US 6,208,690 B1Granted

Method of motion-compensated interframe-prediction in a video-coding device

AssigneeSharp Kabushiki Kaisha

InventorNaoki Tomizawa

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Abstract

Motion-compensated interframe-prediction can be realized by affine-transformation of suitably divided areas of an object image with a reduced amount of calculations and an improved coding efficiency. A motion-compensated interframe-prediction method obtains a predictive video-frame from motion-vectors of an input video-frame and a reference video-frame by translating blocks of processable area, determines a prediction-error estimation value of the predictive frame from an input video-frame, compares the determined prediction-error estimation value with a preset threshold value, selects a predictive video-frame obtained by translation (parallel displacement of coordinates) and encodes the prediction-error information when the prediction-error estimation value is smaller than the threshold, or, with the prediction-error estimation value exceeding the threshold, previously prepares a plurality of area-division pattern types, obtains affine transformations of each type starting from the type having the least number of divisions, calculates a prediction-error estimation value of each type, determines the suitable type which prediction-error estimation value is smaller than the threshold, applies a predictive frame by affine-transformation, encodes the prediction-error information and outputs the predictive frame together with side-information such as motion-vectors and area-dividing information.

Claims5

Dependent claims

A method of motion-compensated interframe-prediction in a video-coding device for encoding prediction-error information of a difference between an input video-frame and a predictive video-frame obtained by performing motion-compensated interframe-prediction, which comprises the steps of:

determining a predictive video-frame by translating a block of a processable area from motion-vectors and a reference video-frame;
determining a prediction-error estimation value of the predictive video-frame from an input video-frame;
comparing the determined prediction-error estimation value with a preset threshold value;
selecting the predictive video-frame obtained by translation and encoding a prediction-error information of the predictive video-frame when the determined prediction-error estimation value by translation is smaller than the threshold value;
or
selecting a predictive video-frame obtained by affine transformation with a processable area divided into divisions suitable for the input video-frame from motion-vectors and a reference video-frame, and encoding a prediction-error information of the predictive video-frame when the determined prediction-error estimation value exceeds the threshold value;
and
outputting the predictive video-frame and side-information such as motion-vectors and area-division information,
wherein suitable divisions of a processable area of the input video-frame is obtainable by:
dividing a video-frame in advance into a plurality of blocks,
preparing a plurality of types to divide a block into triangular divisions, calculating a prediction-error estimation value of each division type, starting from the division-type having the least number of divisions,
comparing the calculated prediction-error estimation value with the threshold, and
selecting it as a suitable division-type of area-dividing when the prediction-error estimation value is smaller than the threshold.

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