I have managed to convert one format to another (PHP) as long as the files are images. But is it possible to convert GIF to MP4 format? Is there also anyway to display a GIF as video? I am trying to find a way to display a large GIF file as video because they are more faster and smaller in size.
Take a look at gfycat. There is a subreddit that realy loves it. So this might be suitable for you. You can use PHP to interact with their API. This will not work if you don't want to depend on the tough.
As an alternative to Gfycat, try the gifs.com API.