Flexible MPEG-4 to H.264 Transcoder for Video Transmission with Effective Motion Information Reusing
Toan Nguyen Dinh, JaeMyung Yoo, Sungchan Park, Guee-Sang Lee, Young Hwan Chang, Han‐Jin Cho · ITC-CSCC :International Technical Conference on Circuits Systems, Computers and Communications · 2007
In this paper, we present a flexible MPEG-4@SP (with Simple Profile) to H.264 transcoder for transmitting video over a system which has different kinds of networks, various types of devices and video formats. From decision modes and motion vectors in MPEG-4 decoder, a set of prediction motion vectors (PMV) and limited decision modes are considered in H.264 encoder to reduce the transcoding time. To maintain a reasonable video quality, we apply an adaptive integer search range based on video picture characteristics to find the optimal motion vectors. We also present a novel spatial downscaling transcoding method in the transcoder for reducing bit rate and spatial resolution to meet the constrained transmission bandwidths and terminal devices capabilities. The simulation results show that our transcoder considerably reduces transcoding time compare to other methods while video quality is kept almost optimal.