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50 fps sequence to 25 fps Movie

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Dennis Squadrazzino
50 fps sequence to 25 fps Movie
on Jul 30, 2018 at 2:10:26 pm

Hi!

There are a lot of threads about converting 50fps to 25 fps clips, but here i have a different question:

I got a project which is almost completed and just needs small small adjustment.
The source material is 1080 50p (50 fps), the final movie must be 1080 50p (25 fps).

I just discovered, that everything was edited in a 50 fps sequence, but the final movie has to be in 25 fps.

What is the best solution now? Should i continue editing in this 50 fps sequence and just render it with the normal settings (1080p 50 fps)?
Or make a new sequence with 25 fps, copy everything from the 50 fps sequence (timeline turns red) and pre-render the whole sequence to be able see the edited sequence?


I also want to include a few slow-motion clips in the sequence.

Thanks for your help!


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Jeff Pulera
Re: 50 fps sequence to 25 fps Movie
on Jul 30, 2018 at 2:19:22 pm

Hi Dennis,

I'm a bit confused with the posting:

"source material is 1080 50p (50 fps), the final movie must be 1080 50p (25 fps)."

Perhaps a typo in saying "1080 50p (25fps)" and you meant "1080 25p" ?

Or does the export need to be 1080i? Which is 50 fields/25 frames?

If the source is 50p, and export must be 25p, you have no worries at all - edit in the 50p sequence and export as 25p. The output clip simply uses every other frame from source clip and will look fine. You could also edit the 50p clips in 25p timeline, also would work fine. Premiere automatically handles the difference in frame rate - you don't need to do anything special.

In the U.S. I will shoot 60p and export as 30p all the time. In fact, I often edit 60p in a 30p sequence to get the benefits of smooth 50% slow motion (using extra frames from 60p source), and then also export as 30p.

Thanks

Jeff Pulera
Safe Harbor Computers


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Dennis Squadrazzino
Re: 50 fps sequence to 25 fps Movie
on Jul 30, 2018 at 2:32:28 pm

Hi Jeff!

Thanks for your answer. Sorry, i typed something wrong.

These are the correct facts:

The source material is 1920x1080p with 50 fps.
Output should be 1920x1080p with 25fps.
Everything was edited in a sequence with 1920x1080 but 50 fps.

I am now a bit confused, whether i should continue editing in this 50fps sequence and later in the render option just set the framerate to 25 fps or make a new sequence in 25 fps, copy the clips from the 50fps sequence, pre render everything and continue working in the 25fps sequence.

I also wonder if there will be problems with Premiere having to skip frames in order to match the clips to the new framerate.


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Roger Averdahl
Re: 50 fps sequence to 25 fps Movie
on Jul 30, 2018 at 3:09:32 pm

I also wonder if there will be problems with Premiere having to skip frames in order to match the clips to the new framerate.

Yes there will be some issues depending on the original footage you have. If you pan with the camera it will look smooth in the original footage but will look stuttey/nervous when converting 50p to 25p. All motion will suffer when converting 50p to 25p. The conversion Premiere Pro does is simply to throw away 25 of the original 50 frames to get a 25p output. Using hardware to convert is way better, but it comes at a cost to say the least.


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Roger Averdahl
Re: 50 fps sequence to 25 fps Movie
on Jul 30, 2018 at 3:10:53 pm

...continue to edit in a 50p sequence. :)


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Jeff Pulera
Re: 50 fps sequence to 25 fps Movie
on Jul 30, 2018 at 3:28:49 pm

Roger is correct that camera pans will look less smooth as 25p...however, if you had shot at 25p to begin with, you'd have the same issue! Now we could argue about the different shutter speeds used for shooting 50p versus 25p making some difference in "the look" but in reality, it doesn't matter at this point because you are required to deliver at 25p. Period. So that's that.

If I have footage at 30p and need to convert to 25p or 24p, that gets complicated because the math doesn't work out very well for dropping frames to get where we need to be. But if I shoot 60p and deliver 30p, no problem with weird cadences of frame drops - Premiere just uses every other frame and no one is the wiser. Same for you going from 50p to 25p, will look just fine. Fast motion will have a bit more judder, but on a lock-down shot it will look the same to an untrained eye (the average viewer).

Don't overthink it and worry yourself. If you are not applying slow-motion to any clips, just continue editing the 50p clips in 50p sequence, and just export as 1080p25. Do a short test right now - export a short clip as 25p then view it to put yourself at ease.

Thanks

Jeff Pulera
Safe Harbor Computers


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Ann Bens
Re: 50 fps sequence to 25 fps Movie
on Jul 30, 2018 at 3:36:26 pm

When exporting 50p to 25p set it to Optical Flow in the export settings.

-----------------------------------------------
Adobe Certified Expert Premiere Pro CS2/CS6/CC
Adobe Community Professional


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Roger Averdahl
Re: 50 fps sequence to 25 fps Movie
on Jul 30, 2018 at 4:04:35 pm

Ann, i tested this now and the export look exactly the same.

I exported 1080p50 from a 1080p50 sequence to 1080p25 (CineForm) and selected Optical Flow under Time Interpolation down in the Export Settings dialog. Did i select it in the wrong place? ☺


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Dennis Squadrazzino
Re: 50 fps sequence to 25 fps Movie
on Jul 31, 2018 at 7:51:14 am

Thank you all for your generous help! I will continue working in the 50fps sequence and then render it with 25 fps.

This is really a great and helpful website!


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Ann Bens
Re: 50 fps sequence to 25 fps Movie
on Aug 9, 2018 at 5:38:35 pm

Nope, then it does not need OF.

-----------------------------------------------
Adobe Certified Expert Premiere Pro CS2/CS6/CC
Adobe Community Professional


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