How do I normalize the audio volume of a bunch of MOV and MP4 files?
The "Sound Check" option in iTunes works passably well for MP3 files, but doesn't do anything for videos. This makes it annoying to use a playlist full of music videos as a source of ambient entertainment, since the volume fluctuates wildly.
I think that a solution involving manually pulling the audio out of the movie files, normalizing it as a WAV, and re-inserting it into the movie is probably doomed to synchronization errors. So let's not.
I have tried using the "Get Info / Options / Volume Adjustment" slider manually on a few videos, but that is far too manual and annoying to do for all of them. Perhaps an approach would be to compute the volume boost desired of each movie, then set whatever ID3 tag corresponds to that slider? Or failing that, do it with Applescript?
Update: I kinda got something working with Applescript here. It fails if any video requires a volume increase of more than 100% (~6dB), but I only have a few videos of which that is true.