This is a little trick I figured out recently to automatically convert my AVCHD files to ProRes just by dropping them into a folder. It's works by using Folder Actions in OSX to launch an ridiculously simple Automator script. Now, since I think Mountain Lion is the first version of OSX to include the ability to natively play AVCHD files, this my not work on older versions of OSX. Please let me know below if this works in older version.
Here's the step by step instructions:
[b][i]I've updated this to reflect the "Actual" way to do this instead of the old one that wa