I'd start looking at
http://www.videohelp.com and
http://www.doom9.org. The container format is likely MPEG4 so I am thinking you'll you need to demux (separate) the streams (h.264 video and any audio) and then remux them into the AVI or MKV container formats. Doing it that way will preserve the quality.
The only tool that comes to mind atm is
Videora it will re-encode so there will be a reduction in quality.