Adaptive frame-skipping for video transcoding

In video transcoding, the compressed video bitstream is often converted to the reduced frame-rate video bitstream in order to reduce bit-rate or implement fast forward and reverse video playback. One way to perform this is to decompress the compressed video bitstream and drop several specific frames, then compress those nonskipped frames to another compressed video bitstream. This method has heavy computation complexity. In this paper, we propose two new methods to reduce the complexity. The first method is simple frame-skipped video transcoder architecture which can reduce frame rate of recompressed video bitstream adaptively and quickly. The second method is bidirection dominant vector selection method which converts the popular I-B-P frame structure of video bitstream to be the I-P frame structure quickly through reusing the decoded incoming motion vectors. Experimental results are reported in this paper to show the efficacy of the proposed methods.