Assuming you have VLC installed in /Applications, try executing the following at the Terminal (the following is based off of the VLC wiki page
here):
Code:
/Applications/VLC.app/Contents/MacOS/VLC --vout-filter=transform --transform-type=hflip /path/to/file
Replace /path/to/file with the path and name of the file. So, for example, if you had a file on your Desktop called example.mp4, execute the following:
Code:
/Applications/VLC.app/Contents/MacOS/VLC --vout-filter=transform --transform-type=hflip ~/Desktop/example.mp4
~ is shorthand for your home directory.
There may be an easier way through the UI but I have yet to find it. All of the explanations online do not work for VLC 1.0. My guess is that things have moved around or been removed.
This flipped a regular movie upside down for me so I'm guessing it will flip upside down movies for you to a regular orientation.
EDIT: Terminal.app can be found in /Applications/Utilities in case you didn't know.