VSDC Free Video Converter is a comprehensive and highly configurable tool for converting videos from one format to another.
The program supports a wide range of video formats: AVI, MPEG, MP4, WMV, FLV, MKV, RM/ RMVB, 3GP/ 3G2, H.264/ AVC, AVCHD/ MTS/ M2TS, TOD/ MOD, TS and more. And it handles all the usual video and audio codecs, including DivX, H.264/ AVC, MP3, AAC and so on.
Once your files have been imported, you can then choose the device where you'd like to play them: a PC, DVD, iPod, PSP, mobile phone, whatever it might be. And you're then able to choose the output formats supported for that device.
Next, you get to pick an output profile, which defines the resolution and quality of the finished video. You don't have to bother with this - a "Normal Quality" profile is selected by default - but if it's mostly just important for the file to be small, say, you might prefer to choose a "Low Quality" option.
There are other options, too. You can trim the source video in an editor, for instance. The program is able to export just the video of a clip. Or you might combine several clips together into one.
And when you're done, VSDC Free Video Converter can be set to convert your movies at a click, exporting the finished files, or even burning them to DVD.
There's a lot of power here, and sometimes it can be hard to find the precise option you need. If you choose to output to PC, for instance, the Formats tab doesn't display the MP4 option, and you have to go looking for it.
If regular video conversion tools don't satisfy your needs, though, VSDC Free Video Converter could be worth a try: it really is a very capable tool.