It's a very simple utility. You can choose one or several folders, or even drag 'n' drop them on the app's icon. Once you're done, just hit the return key to quit and close the app.
One side effect of fixing the filenames, at least on a case-sensitive NAS: the PRIVATE, AVCHD, and BDMV folders will not appear as "AVCHD Content" objects any more, but as plain folders (why? Don't ask me, ask Apple). Using Finder, you'll have to drill down into the BDMV folder and open INDEX.BDM to browse the media. FCP will still work fine looking at the root of the folder structure, though.
- Written on OS X 10.8.3, tested on OS X 10.6.3, 10.6.8, and 10.8.3. It should work on any version from 10.6.0 on up, but I haven't tested it on 10.7 at all.
- avchd2AVCHD only works with AVCHD media copied off the camera's storage to your local disks or a file server. Camera media names always appear to be in uppercase to OS X's file system routines, so avchd2AVCHD won't fix anything on camera media such as SD or CF cards.
- Start at the root folder for your media: avchd2AVCHD looks for the PRIVATE and/or AVCHD folders to verify it's working on the right thing. Choose the PRIVATE folder (if present), the AVCHD folder, or a higher-level folder containing them. Do not choose a folder deeper in the file structure, like the BDMV folder: it won't work.
- Warning: avchd2AVCHD will try to fix any seemingly valid file or folder it finds inside any folder named "private" or "avchd" whether it's an AVCHD media file or not! The program checks that "private" has an "/avchd/bdmv/stream" subfolder tree; that "avchd" has a "/bdmv/stream" folder inside it; and that other folders and files appear to have the proper parent folders. However, this error checking is not guaranteed to work in every possible situation, and all sorts of things can break when you're trying to change filenames over a network connection, like yanked cables or power failures.
- Drag 'n' drop works on the app's dock icon in 10.8, but not in 10.6 (it works on the app's Finder icon, just not when it's in the dock).
- Error handling is very basic: you get a system error message for each error encountered (and you can look up details in avchd2AVCHD's window when it's finished). For example, if your AVCHD media are on a read-only filesystem, or the folders are locked, you'll get an alert for every filename avchd2AVCHD wants to fix, but can't.
You use avchd2AVCHD at your own risk: avchd2AVCHD is not guaranteed to work as expected; it is not warranted to be fit or suitable for any purpose whatsoever. I wrote it for my own needs and I've used it on my own local disk and Netgear ReadyNAS server, but that's it: there's not been any formal beta-testing. Back up your media before running avchd2AVCHD!
avchd2AVCHD is not code-signed, nor is it sandboxed; if you're on 10.8, you may get the message:
"avchd2AVCHD" can't be opened because it is from an unidentified developer.
How to open apps from an unidentified developer in OS X Mountain Lion
explains how to deal with this.