The power of Avisynth: restoring old 8mm films.

[johnmeyer]

If you want to put this on DVD, which only accepts 30 fps (29.97), what you can do is duplicate (or interpolate) frames to 32 fps, and then use AssumeFPS(29.97) to change the speed of playback. All this does is change the playback speed, like slowing down the film projector speed. I doubt you will notice that change in speed and indeed, most PAL films are sped up from 24 to 25 fps without any adjustment, and people don't notice or complain.

FWIW, my advice is to not use interpolation to go from 16 to 30 or 32 fps. I do film transfers and have spent a LOT of time with motion estimation, tweaking all the settings to get the best possible results. The problem: motion estimation always fails at some point. You can count on it. And, when it fails, it does so spectacularly.

Having said that, I did use interpolation for some 1940s parade footage I posted on YouTube. You'll probably recognize the footage because StainlessS and others have used it a lot for testing various scripts. The problem is that at 16 fps, the temporal gap between frames is huge and therefore the motion estimation has a really hard time predicting where all those little blocks should be moved in order to synthesize the new frame. Even though I knew I'd create some problems, I used it on this clip because there was so much horizontal movement that the judder effect you get from slow frame rates was overwhelming (we were taught to never do horizontal pans with a movie camera).

Things to look for when watching this clip:

• Artifacts when objects get revealed as the parade float moves down the street.
  
• Artifacts from people legs moving back-and forth
  
• Artifacts from waving flags.
  
• The moose antlers (by far the worst artifact)
  
• Rotating spokes on wheels
  
• Object moving across the frame, close to the camera

I can go on, but you get the idea.

Here's the clip:

1940 Flint Michigan Parade