On the methods and applications of arbitrarily downsizing video transcoding

Video transcoding is a common technique for adapting the bitrate or spatial/temporal resolution of a compressed video to suit different transmission bandwidths or receiving devices. To reduce the computational complexity, many fast methods have been proposed to estimate the motion vectors required for downsizing a pre-coded video by an integer factor. We develop and compare several fast video transcoding methods for downsizing a pre-coded video by an arbitrary factor Methods which out-perform others under different conditions are identified and discussed. To exploit fully the advantages of arbitrarily downsizing video transcoding, we also design a scheme to determine the reduced frame size that can sustain the best possible video quality for a given target bitrate. Experimental results are presented to show the performance of the proposed video transcoding methods.