I had my host install the ffmpeg binary for site but I don't know how to execute the binary using PHP HELP would be greatly appreciated

Could I please get some examples or maybe a PHP class or some examples it is already installed but I was wondering how to use it with PHP

I have a linux server

I found this script (BOTTOM OF POST) does anybody know how to make a dynamic version that will create the flv file then automatically write information to the database after it is done encoding the flv?
More like an upload form with with writing to a mysql DATABASE

PHP Code:

<?php
// Set our source file
$srcFile = "/path/to/clock.avi";
$destFile = "/path/to/clock.flv";
$ffmpegPath = "/path/to/ffmpeg";
$flvtool2Path = "/path/to/flvtool2";
// Create our FFMPEG-PHP class
$ffmpegObj = new ffmpeg_movie($srcFile);
// Save our needed variables
$srcWidth = makeMultipleTwo($ffmpegObj->getFrameWidth());
$srcHeight = makeMultipleTwo($ffmpegObj->getFrameHeight());
$srcFPS = $ffmpegObj->getFrameRate();
$srcAB = intval($ffmpegObj->getAudioBitRate()/1000);
$srcAR = $ffmpegObj->getAudioSampleRate();
// Call our convert using exec()
exec($ffmpegPath . " -i " . $srcFile . " -ar " . $srcAR . " -ab " . $srcAB . " -f flv -s " . $srcWidth . "x" . $srcHeight . " " . $destFile . " | " . $flvtool2Path . " -U stdin " . $destFile);
// Make multiples function
function makeMultipleTwo ($value)
{
    $sType = gettype($value/2);
    if($sType == "integer")
    {
        return $value;
    } else {
        return ($value-1);
    }
}
?>