Abstract: A preprocess（post-process） method of video encoding（decoding） to decrease the transmission bitrate is proposed in this paper．By true motion estimation‚those frames with motion vector less than a threshold will be removed from the video sequence and should not be transmitted‚but the frame number must be transmitted．After being decoded. The removed frames can be reconstructed by the corresponding reference-frames according to the frame number．In order to improve the visual effect some intermediary frames may be inserted into the image sequence according to the motion vector．The intermediate frames may be produced by interpolation algorithm． 

Key words: video segmentation, motion estimation, removing frame, inserting frame, transmission bitrate