Mp4 converter

Have you looked at Handbrake?

http://handbrake.fr/

You can also try AVS Video Converter.

Find a good converter tool is very difficult,I use ddvideo flv video converter gain,It can convert any videos files to flv,mp4,avi,wmv,mpeg,3gp,mov etc many video format.some videos or musics volume is too high or too low.with a volume gain option in the tool.very useful. you can try it.