i just found two $video_src:

$cmd_ffmpeg = "$config[ffmpeg] -i '$video_src' -acodec mp3 -ar 22050 -ab 32 -f flv $video_flv";
$cmd_mencoder = "$config[mencoder] '$video_src' -o $video_flv -of lavf -oac mp3lame -lameopts abr:br=56 -ovc lavc -lavcopts....

and already put the ''. is it correct?