Hi- According to , it's a silent film from 1927. Therefore the original frame rate was almost certainly less than 24fps. I think your first instinct is the best-decimate it by 3. Then look carefully through parts of it for any more duplicate frames. Silent films were made with many different frame rates, 18fps being perhaps the most common. It wasn't until sound came in that 24fps became the standard. However, if you use the AssumeFPS(30) to begin with, the audio will become slightly asynch, so you'll have to resynch it with a WAV editor. Sounds like an interesting movie.