MeGUI + AVISynth settings recommendation: 50 fps progressive source

[U2Joshua]

I have this 720p HD music video, and it's 50fps progressive. However, inspecting the clip seems to indicate that it was likely deinterlaced, and resulted in going from 25 fps to 50 fps?

Clip: https://www.sendspace.com/file/j2y8xy

Not having encountered this before, I tried a simple AVISynth script of Srestore in MeGUI, and it resulted in a 23.976 fps final render.

Is there any way of knowing whether this was originally a 23.976 fps source for certain? Or, if by some chance this would have been a 25 fps original source that simply got doubled?

What would you recommend for encoding? Srestore, etc?

thanks in advance~

[manono]

SRestore will always give 23.976fps by default, when beginning with a 50fps source. I wouldn't take that as any indication of what the source really is. The scenes on the boat were originally 25fps, I think. The bit from the air is considerably less, maybe shot using a 16mm camera. I'd leave it alone unless, maybe, you intend to make a DVD of it. Then I'd make the whole thing 25fps using BlendBob. I'm not positive about any of that, though.

[KarMa]

The video itself was shot on film back in what looks like the 80s, can even see a hair on one of frames. So that would mean that it was probably shot at 24fps (standard film frame rate) and then sped up to 25fps for PAL. Or it could have been telecined to 25fps from 24fps. The fact that this video was bob deinerlaced (I'm assuming) kinda hints that there was combing in the source and so to get rid of it they just bob deinterlaced instead of a field matching detelecining. Which would of given you back 24 unique frames per second.

If this video was originally shot on a PAL camera, then that would of given you 50 fields per second and bob deinterlacing to get 50 fps would be acceptable. But since this was shot on film, this 50fps video you posted is half duplicates (maybe even slightly more than half if it's a telecine video).

[jagabo]

The video was 25i at some point. The latter part was 25p (probably PAL film speed up) but the aerial shot at the start was slowed a bit so there are more duplicate fields -- probably why it was encoded 25i. If it's just that one shot I'd decimate it to 25p. But I suspect there will be lots of sped or slowed shots.

[U2Joshua]

The video was 25i at some point. The latter part was 25p (probably PAL film speed up) but the aerial shot at the start was slowed a bit so there are more duplicate fields -- probably why it was encoded 25i. If it's just that one shot I'd decimate it to 25p. But I suspect there will be lots of sped or slowed shots.

Fun stuff!

what's the best way to simply decimate duplicate fields without altering anything else?

[manono]

what's the best way to simply decimate duplicate fields...

I already told you how I'd do it - using BlendBob. Or you could just use a SelectEven (or SelectOdd). If you decide you want it slowed to 23.976fps afterwards, then add an AssumeFPS(23.976) and slow the audio to match. I think first, though, you should decide if the audio is supposed to be slowed. The answer will also tell you whether or not it was 23.976fps (or 24fps) to begin with. KarMa says it was.

...without altering anything else?

You're reencoding, right? So everything else gets altered anyway.