I would like to share you a best converter i have used:
Video Download Studio
Click here to see the full reviews and have a free trial:http://www.downloadvideos-convert.com/download-videos-music
It can convert almost any the video format to another with high output quality.
This full-featured video converter software also can help you:
1.convert between all mainstream video and audio formats,such as(mp4, mov, m4v, vob, XviD, avi, flv, 3gp, 3g2, mpg,wmv,etc;m4v, mp3, wav, ac3,etc)
2.extract audio tracks from video files to other audio formats
3.support all popular portable multimedia players
4.edit video-Merge, Trim, Crop and Snapshot
It is very easy to use,just follow the instructions on it you can convert your videos and make your movies and music taken easily on PSP, PS3, iPod, iPhone, Apple TV, Xbox or other digital devices.
Hope this can help you.