Update 2013-04-11: Thanks to Felix Paul Kühne, lead developer of VLC for Mac, this feature has been added to VLC 2.0.6 without the need for the user to make any changes to the app. If you use that version, or later, you do not need to take the steps below.
The article below remains only for reference. -- TjL
Lately I have been ripping a bunch of DVDs using RipIt which has an option to save the rips as ".dvdmedia" files. For those who aren't familiar with ".dvdmedia" files, they are a special kind of folder, similar to ".app" or some ".pkg" files which aren't "files" but look and act like them. Inside of a .dvdmedia file is a VIDEO_TS folder as you'd expect from a DVD rip.
The good thing about .dvdmedia files is that you can double-click on them and have them open. The bad thing about them is that the only app that I had which recognized the .dvdmedia file extension was Apple's DVD Player.app. In particular, VLC does not recognize it as a valid format.
If you are a Mac "power user" you might think, "No problem, I'll just use the 'Open With...' menu and tell Finder to open .dvdmedia files with VLC. That will work." However, if you choose "Change All" to set all .dvdmedia files to open with VLC, not only will it not work, but it will make it so that .dvdmedia files are no longer shown as files at all! (If that happened to you, Tantek Çelik has the solution: use
SetFile -a B /path/to/file.dvdmedia and it will undo the change.)
The good news is that you can very easily add .dvdmedia as a recognized extension to VLC. You just have to add the appropriate information to the file VLC.app/Contents/Info.plist. Specifically, you have to add this:
section. (Note: I found that via the VLC forums and tested that it worked for me in VLC version 2.0.5.)
If you'd rather not try to edit the file yourself, you can download my Info.plist file and replace the existing file in the app. To do so, download the file to your Desktop (or wherever you will easily be able to find it) and then locate the VLC.app. Make sure the app is not running, and then Control-Click on the app and choose "Show Package Contents" from the context menu.
Inside you will find a "Contents" folder. Open it and you will see a file named "Info.plist" which you can delete (rename to something like "Info.plist.original") and then drag the Info.plist file which you downloaded into the "Contents" folder.
After that you will need to log out and then log back in to see VLC offered as an option to open .dvdmedia files. Once it is set as a recognized app for .dvdmedia you can set it to "Change All" so that other .dvdmedia files you have or create in the future will also open with VLC. If you ever decide you don't want to use .dvdmedia anymore, simply rename the files and remove the extension, and it will immediately appear as a folder once again.
Caveat: Because you are replacing an app inside the VLC app wrapper, you may need to fix the Info.plist file again when VLC.app is updated. Hopefully VLC will eventually include this feature by default.
Alternative fix via Terminal.app
If you are comfortable with the command line, you can do all of the above much more easily. Again, be sure that VLC.app is not running before making this change.
(Note: I assume VLC.app is installed in /Applications/. If you have installed it somewhere else, change the "cd" line below.)
These four lines will: a) change directory to the correct folder, b) rename the existing "Info.plist" file to "Info.plist.original," c) download the new "Info.plist" file and d) register VLC as an application capable of opening .dvdmedia files:
Make sure that last command (which starts with /System/Library/) is all one long line. If you use that command, you don't have to log out and back in to open .dvdmedia files with VLC.
(Hat tip to Mac OSX Hints for that one!)