FFmpeg PHP too slow

Hello Guys,
I am looking to convert a video codec and change bitrate etc. It is taking a lot of time for the same. I want a expert to jump in and help me find a quick solution to this

I am using core php, below is the code attached.
ffmpeg = FFMpeg\FFMpeg::create();
$video = $ffmpeg->open($videopath);

$format = new FFMpeg\Format\Video\X264();
$format
->setKiloBitrate(1500)
->setAudioChannels(2)
->setAudioKiloBitrate(256);

$video->save($format, destination)