Video coding based on true motion estimation

In this paper, 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 leastmedian-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 motioncompensated 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 blockmatch 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 bitrate video coding.