Removing redundant frames?

[ccarollo]

I've got a 720p (and thus 60fps) mpeg from a film source that I'd like to convert back down to its 24fps (okay, 23.976fps) roots. Single stepping through it I can see the expected 2-3-2-3-2-3 pattern of redundant frames, but this isn't consistent throughout the clip, so simple ConvertToFPS doesn't work (it gets off sync so every so often it's sampling 2-3-2-3-2-3 when the frames are actually 3-2-3-2-3-2 and the video gets all stuttery).

I think what I really want is to just remove all the redundant frames, but I'm kind of an AviSynth newbie and didn't see any filters that would let me do this. Is there such a thing? And will my plan for converting back to 24fps work, or is there a better, more accepted method?

[Mug Funky]

a couple of things:

- lots of redundancy will compress pretty well, so it's not a big problem with the right codec settings unless you're wanting a format like SVCD or DVD, where the frame rate is locked to either FILM, 29.97 or PAL.

- either decimate(2).decimate(5) or fDecimate(23.976) would work for you, i think.

fDecimate would be faster (i'm not sure... haven't worked with anything more demanding than DVD before).

[AS]

Changefps() will also handle this nicely.

[Mug Funky]

indeed it will, but as soon as there's a pattern change, you'll be getting dupes in the output, and dropped good frames.

changefps might be adequate for halving the framerate before a decimate(5), but i'd be inclined not to trust it, as the TV experts that put the clip together probably buggered it up somewhere.