Patent ID: 7079578

Claim:
A transcoder system for compressed digital video bitstreams comprising packets within the three frame types: I-frames and P-frames (reference frames); and B-frames (non-reference frames), the system comprising: a picture reader decoder to ascertain the type of each packet, to select packets of B-frames (non-reference frames) and to select one of the following parameters prior to transcoding: the estimated quality of each packet; the size of each packet; and DSP processing power; a T.sub. 1 transcoder for processing said selected packets; a picture decision block for separating all said packets according to said one parameter; and a remerge block for recombining the output of said T.sub. 1 transcoder and said packets not selected into a reconstituted output bitstream, such that said selected packets are B-frames (non-reference frames) processed by said T.sub. 1 transcoder, and reference frames (I-frames, P-frames) remain untouched, thereby overcoming drift error, improving the focus of transcoded images and achieving substantial improvement in the transcoding throughput speed.