// Set our source file
    $srcFile = $uploadFilm.".".$film_type;
    $destFile = $uploadFilm;
    $ffmpegPath = "ffmpeg";

    // Create our FFMPEG-PHP class
    $ffmpegObj = new ffmpeg_movie($srcFile);

    // Save our needed variables
    $srcWidth = makeMultipleTwo($ffmpegObj->getFrameWidth());
    $srcHeight = makeMultipleTwo($ffmpegObj->getFrameHeight());
    $srcFPS = $ffmpegObj->getFrameRate();
    if($ffmpegObj->hasAudio()){
        $srcAB = intval($ffmpegObj->getAudioBitRate()/1000);
        $srcAR = $ffmpegObj->getAudioSampleRate();
    }else{
        $srcAB = 0;
        $srcAR = 0;
    }

    // Call our convert using exec()
    //$command = $ffmpegPath . " -i " . $srcFile . " -ar " . $srcAR . " -ab " . $srcAB . "k -f flv -s " . $srcWidth . "x" . $srcHeight . " " . $destFile;
    //$command = "whoami";
    $command = $ffmpegPath . ' -i ' .'"'. $srcFile . '" -ar ' . $srcAR . ' -ab ' . $srcAB . 'k -f flv -s ' . $srcWidth . 'x' . $srcHeight . ' "' . $destFile . '" 2>&1';
    $outputCommand = array();
    $status = 1;
    exec($command, $outputCommand, $status);

Error while opening encoder for output stream #0.1 - maybe incorrect parameters such as bit_rate, rate, width or height

ffmpeg -i source -ar 48000 -ab 160k -f flv -s 1920x1080 destination