September 18, 2018 at 11:14AM, Edited September 18, 11:15AM

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How do I combine 24fps and 25fps footage.

I am from the UK so we use PAL and i'm often changing my DSLR in between 24 and 25 fps as well as 50 and 60 fps for stuff I want to slow down. I recently shot two very important workshops for my company and made the school boy error of filming one in NTSC 24fps and one in PAL 25fps. Now I think I probably can combine the footage without too much trouble but I just want some clarification and reassurance that everything will turn out alright. Will it?!!

4 Comments

I'm by no mean an authority, but I recall people just recommend slowing down the 25 to 24 and then fixing the audio with a pitch shifter that doesn't affect speed. There's probably a bunch of other ways to do this (especially since I haven't kept up on the newest tech), but that's the first thing I thought of. Hope this helps.

September 18, 2018 at 11:25AM

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Josh Molen
Music Composer for TV and Film
81

There's multiple ways you can go about this. You can put both in a 29.97i timeline with upper field first. That way a pulldown gets added to you footage but retains the framerates. That way isn't my favorite. Only use this way if you need to retain the time of the clips for sync purposes or multi cam.

The other way is to reinterpret your footage. In premiere when something is in your bin you can right click it and go to modify. There you can reinterpret the framerate. What this does is reorder the frames so the duration will change. Like if you're going from 24 to 25 fps, the clip will be shorter because there are more frames per second. Since it's such a mild change in framerate the audio should only change a little bit.

I work with a lot of archival footage at my job, and these are the two ways my company goes about different frame rates.

I don't reccommend just slowing down the footage or just exporting a 24fps file in a PAL timeline because you'll most definitely get some dropped frames.

*BTW 24fps isn't NTSC, 29.97fps is.*

September 18, 2018 at 5:22PM

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Alex Alva
966

Thanks for the help.

I might have complicated things further by recording the audio of both workshop sessions to a Zoom H4N audio recorder. So if I reinterpret the footage I think the audio won't sync properly. Or can I speed up the audio a pinch (I only need one frame) and balance the pitch?

Also on the point of reinterpreting footage. Wouldn't I be better reinterpreting the 25fps to 24fps so I lose a frame, rather than going from 24fps to 25fps and creating a new frame?

Sorry i'm still a bit of a newb.

Sam

September 19, 2018 at 9:28AM

No worries. When you reinterpret the framerate it just takes all the existing frames and just reorders them. It doesn't drop frames or adds them. Like if you have one second of 25fps and you reinterpret it to 24 your runtime will go from 00:00:01:00 to 00:00:01:01. It really doesn't matter which way you convert to be honest.

Now since you have audio to sync to and reinterpreting will change the length, there's a couple ways you can go about it. There's the first way I mentioned about where you edit in a 29.97i timeline with upper field first. This way a pulldown get added but retains the framerates.(Side note: one time heard this theory that everything can be put into a 120fps timeline and it'll soon be the universal delivery standard. Just something I saw at a trade show before and obviously I'm grossly simplifying it. Just thought it was interesting.)
You can also download JES Deinterlacer, which is a free app that does some pretty solid framerate conversions. It'll allow you to convert your PAL to 23.98 and then you should be able to cut together the 23.98 and the 24 with little to no issues.

I'm sure there's some other ways I'm not thinking of but this is all I conjure up at the moment.

Alex Alva

September 19, 2018 at 10:31AM, Edited September 19, 10:31AM

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