RMVB (Real Media Variable Bitrate).
sudo apt-get install mplayer mencoder librte librte-dev
mencoder -oac mp3lame -lameopts cbr=128 -ovc xvid -xvidencopts bitrate=1200 video_input.rmvb -o video_output.avi
For Codec error refer HERE
mencoder-ovc divx4-Copy-oac filmname.avi filmname.rmvb
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