H.264 ( this is MP4 compression and is one of the best and the most widely used, H.264 plays on virtually any device, delivers quality video streams ) Actualy its H.264 compression wrapped in a MP4 container. How to compress videos in Adobe Media Encoder for chimps
In After Effects select “composition” in the main menu then “add to adobe media encoder”
The adobe media encoder application will open, this can sometimes take a while especially if it’s a large file. Make sure The left hand menu is set to H.264.
Click on match source
Scroll down to bitrate setting ,Dragsliders left to about 5 or 6 (MBS). Shouldn’t notice
hardly any difference at this rate but file size should go down quite a bit.
If your still unclear there is a simple you tube video here..