What file type do Iphone's use?

I'm trying to move a video from my computer to my iphone through itunes, but it isn't working. People a while ago say that it uses.mp4 but has it changed since then? It syncs but when I look at my camera roll, it isn't there.

Added (1). I did leave it the same and sync it, still nothing

Leave it the same and sync your iphone

IPhone does support MP4 and H.264 videos. But if the video resolution or video bitrate beyond iPhone imitation, you can't upload them to your iPhone. If the videos are in your iTunes, you can highlight the problem video in iTunes and choose Create iPod or iPhone version from the Advanced drop down menu. When the conversion process has completed, sync the new version to your iPod. If not, you can follow this guide to convert and transfer the video to your iPhone.
http://www.dvdtoiphone3gs.com/how-to-play-dvd-video-on-iphone.html
Hope it helps. Contact me if you have any other question.