MPEG TRANSCODING SYSTEM AND METHOD USING MOTION INFORMATION

摘要

An open loop system and method of transcoding a stream of compressed video data to a required lower bit rate. The invention includes the steps of: examining motion vectors for each of a set of macroblocks in the stream; determining an importance of each of the set of macroblocks based the motion vectors; and selectively modifying DCT blocks in the set of macroblocks to reduce the bit rate, wherein the modification to each DCT block is based on the determined importance of the macroblock. High coefficient dropping or re-quantization may be utilized.