HandBrake
A few weeks ago I updated my desktop from Ubuntu 8.04 to 8.10 and preformed a clean instal. I was following the MTS to AVI how to guide that I made a while ago and found that some of the links were dead. I tried to find the new location for some of the downloads, but eventually gave up. I decided I would see if another program had come along that could do the task better. Enter HandBrake
This is an awesome conversion program that runs on Windows, Mac, and Linux that was originality designed to rip DVDs to your hard drive. This open source gem also has a knack for transcoding h.264 video files. Even beter it does so using multiple threads, unlike the script that I was using before. If you have a need to convert AVCHD (or .MTS) files, I seriously recommend it.