You might try posting your response in the same thread that you got this information from, the original posters may have more information for you.

This is the thread that I used to increase my video quality:

viewtopic.php?f=4&t=312

All I did was change the default 500 vbitrate to 512 and then later changed it to 768. Here's what my current include/settings/video_conversion.php looks like:

Code:
<?php

$cmd_ffmpeg = "$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=768: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_mencoder;


$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;
Please be sure to post any comments or questions in the original post, not here.
Good Luck!