Quote Originally Posted by abeez
Convert Error or converted video is less than 1 kb in size, try upload a big
video. If that do not work, verify convert command works on the server.
This is probably because you have an older mplayer version. They made a major change to mplayer a couple of months back (installs via SVN), and many servers still have the older (RPM installed) version. I had the same problem, and here's what worked for me:

Open include/settings/video_conversion.php

Look for
Code:
// For rpm (old) version of mplayer
// $cmd_mencoder = "$config[mencoder] '$video_src' -o $video_flv -of lavf -oac mp3lame -lameopts abr:br=56 -ovc lavc -lavcopts vcodec=flv:vbitrate=500:mbd=2:mv0:trell:v4mv:cbp:last_pred=3 -srate 22050 -lavfopts i_certify_that_my_video_stream_does_not_use_b_frames";

// For latest svn version of mplayer
$cmd_mencoder = "$config[mencoder] '$video_src' -o $video_flv -of lavf -oac mp3lame -lameopts abr:br=56 -ovc lavc -lavcopts vcodec=flv:vbitrate=500:mbd=2:mv0:trell:v4mv:cbp:last_pred=3 -srate 22050 -ofps 24 -vf harddup";
and change it to
Code:
// For rpm (old) version of mplayer
$cmd_mencoder = "$config[mencoder] '$video_src' -o $video_flv -of lavf -oac mp3lame -lameopts abr:br=56 -ovc lavc -lavcopts vcodec=flv:vbitrate=500:mbd=2:mv0:trell:v4mv:cbp:last_pred=3 -srate 22050 -lavfopts i_certify_that_my_video_stream_does_not_use_b_frames";

// For latest svn version of mplayer
// $cmd_mencoder = "$config[mencoder] '$video_src' -o $video_flv -of lavf -oac mp3lame -lameopts abr:br=56 -ovc lavc -lavcopts vcodec=flv:vbitrate=500:mbd=2:mv0:trell:v4mv:cbp:last_pred=3 -srate 22050 -ofps 24 -vf harddup";
In other words, remove the two //'s from in front of the top "$cmd_mencoder =" command, and put them in front of the bottom one. This forces the converter to use the top command instead of the bottom one. It's possible you've got an older version of mplayer that needs the "-lavfopts i_certify_that_my_video_stream_does_not_use_b_fram es" option.