Video coding based on true motion estimation
A new approach for MC-DCT (motion compensated-discrete cosine transform) hybrid video coding based on true motion estimation is proposed. The true motion estimation technique employs the least-median-squares (LMedS) matching criterion in block matching process for motion estimation. The rationale for using such true motion estimator is that at low bit-rates, very few bits are available for coding the motion-compensated DCT errors, and thus the detection of the true underlying motion of the picture block becomes much more important than just trying to find a block-match that satisfies the traditional least-mean-squares (LMS) matching criterion. Without detecting the true motion of the picture block, the errors due to insufficient bits for coding the motion-compensated DCT errors will be propagated to succeeding inter-frames, resulting in a progressive degeneration on perceptual quality of the pictures. An important advantage of using true motion estimation is that it results in better perceptual video quality compared to the conventional block-matching algorithm that utilizes least-mean-squares matching criterion. Experimental results obtained had supported our proposition on using the LMedS-based matching criterion in block-matching motion estimation for low bit rate video coding.