If you are using latest version, edit

include/settings/video_conversion.php


Put following code in that file


Code:
<?php

# Allowed File Types

$file_types = array("flv","3gp","mp4","mov","asf","mpg","avi","mpeg","wmv","rm","dat");

$cmd_ffmpeg = "$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 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";

$cmd_all = $cmd_ffmpeg;


$convert_3gp = $cmd_all;
$convert_mp4 = $cmd_all;
$convert_mov = $cmd_all;
$convert_asf = $cmd_all;
$convert_mpg = $cmd_all;
$convert_avi = $cmd_all;
$convert_mpeg = $cmd_all;
$convert_wmv = $cmd_all;
$convert_rm = $cmd_all;
$convert_dat = $cmd_all;