A New Motion Vector Composition Algorithm for Fast-forward Video Playback in H.264

With the rapid growth of streaming digital videos, it is desirable to access video segments of interest by searching through the video contents with a faster speed than a normal playback. Fast-forward playback is the key function that enables quick browsing of videos. It can be realized by a frame-skipping transcoder which transcodes only the frames required for playback at the desired fast speed. Various motion vector (MV) composition algorithms aim at reducing the computational complexity of the transcoder. They only perform fairly in limited skipped frames scenarios. In this paper, a new vector selection algorithm is proposed to compose a new motion vector (MV) from a set of candidate MVs for minimizing prediction errors due to a larger frame-skipping factor. Experimental results show that the proposed algorithm can deliver a remarkable improvement on the rate-distortion performance over other algorithms.