Patent ID: 6233017
Filing Date: 2001-05-15
Classification: H04N

Abstract:
A method for encoding a motion video image which includes two or more frames, the method comprising performing the following steps for each subject one of one or more of the frames to encode the subject frame to form an encoded frame:(i) selecting a temporally displaced one of the frames other than the subject frame;(ii) selecting one or more blocks of the subject frame;(iii) for each of the blocks of the subject frame,(a) forming a motion compensated block of the block with reference to a corresponding block of the temporally displaced frame;(b) measuring a block distortion between the block and the motion compensated block;(c) measuring a block rate of the motion compensated block in terms of an amount of data required to represent the motion compensated block;(d) for each of two or more sub-blocks of the block, performing the following steps:(1) forming a motion compensated sub-block with reference to a corresponding sub-block of the temporally displaced frame;(2) measuring a sub-block distortion between the sub-block and the motion compensated sub-block; and(3) measuring a sub-block rate of the motion compensated sub-block in terms of an amount of data required to represent the motion compensated sub-block;(e) constructing a composite sub-block distortion from the sub-block distortions;(f) constructing a composite sub-block rate from the sub-block rates;(g) measuring a relative distortion between the block distortion and the composite sub-block distortion;(h) measuring a relative rate between the block rate and the composite sub-block rate;(i) comparing the relative distortion to the relative weight according to a predetermined ratio of distortion and rate priorities to determine whether the motion compensated block or the motion compensated sub-blocks provide a better combination of distortion and rate;(j) including the motion compensated block in the encoded frame if the motion compensated block provides a better combination of distortion and rate as determined in the step of comparing; and(k) including the motion compensated sub-blocks in the encoded frame if the motion compensated sub-blocks provide a better combination of distortion and rate as determined in the step of comparing.