I use Handbrake for converting videos. It's got useful features such as burning soft subtitles into the resulting video if needed. You can also use many of the available presets depending on your needs, or create a custom one and save it for later usage.
What I use is mediacoder, however for some weird reason MBAM picks it up as malware, however my computer works fine and nothing has happened to it(no pop ups, etc). Use at your own risk, but it works fine for me.