http://www.boonex.com/unity/forums/#topic/found-problem-video-comments-and-fix-sort-of.htm
1st) problem is codec of flv don't fit in mpeg4 (then we can't use -acodec copy)...this is the solution i've tryed:
$sSound = $bSound ? " -acodec libmp3lame -ar 44100 " : " -an ";
in file \flash\modules\video_comments\inc\functions.inc.php, it work but video and audio aren't sync.
2nd) audio and video aren't sync.:
Further investigations reveal that the original flv audio aren't sync..
Please Boonex create a video comment, then open the flv (I think created by rms) file in the folder flash/modules/video_comments/files/ yu'll see it isn't sync.
I think it's an RMS bug, and after fixed functions.inc.php and the sync bug all work good...
luca_it