Mix 24 fps and 60 fps in a 60 fps timeline

[Johan5FB9]

I don't want to change the speed.

Can I get the 24 fps clip to run smooth together with 60 fps clips?

Putting the 24 fps clip in a 60 fps timeline should be as smooth as putting it in a 24 fps timeline, or am I wrong? I mean monitors are having a refreash rate of 60 fps. So it should be pretty much the same?

[Graeme Bull]

You can't. There are only 24 frames per second. You're putting it in a 60 frames per second timeline. Premiere has to find an extra 36 frames PER SECOND from somewhere to play the footage cleanly, essentially being forced to fill in with interpolated frames for 75% of the video clip. That's a tough job. There's "frame blending" in Premiere or you can try to bring that into AE to stretch it out to 60fps, but it's still going to look weird for sure. There are other options if you do a search on the internet that can possibly do a better job, but you're still having to fill in so much information.

[Johan5FB9]

Thank you for your comment.

24 fps is played back on a 60 hz screen most of the time. How is that different from putting a 24 fps in a 60 fps timeline?

I did search for more on this subject but I did not find anything. I did only find a lot information on putting a 60 fps in a 24 fps timeline. If there is more information please show me in the right direction.

Interpolated? Do you mean that software is trying to recreate missing frames? I don't think that is what is going on when you watch a movie recorded in 24 fps. My guess is that every frames just appear 2 or 3 times.

I can upload a 24 fps to youtube. Then I guess the viewers will stream/download in 24 fps and that viewers graphic cards will convert it to 60 fps.

But I just want to know what is the best way to do it in premiere so that I can combine 60 fps screen recording with 24 fps video camera recording.

[Stan Jones]

> 60 hz screen

That's not how it works. The refresh rate is how many times the monitor redraws the screen in a second. As long as it is the same or higher than the framerate, you're okay.

See this, for example:

https://www.avadirect.com/blog/frame-rate-fps-vs-hz-refresh-rate/

Your footage, sequence, export settings are dealing with framerates. Putting a 60fps source into a 24 fps timeline can be conformed by using actual frames. But putting the 24 fps source into a 60fps sequence requires that itnerpolated frames be created.

Stan

[Johan5FB9]

Your footage, sequence, export settings are dealing with framerates. Putting a 60fps source into a 24 fps timeline can be conformed by using actual frames. But putting the 24 fps source into a 60fps sequence requires that itnerpolated frames be created.

Thank you Stan for your explanation. 

I do understand that the correct frames does not exist.

But I don't understand why it's different when playing back a 24 fps clip on a 60 hz monitor.

I did read the article thank you.

I do understand that the gpu can produce lower or higher fps then the refresh rate of the monitor.

But if the screen redraw is 60 times a second with the same time interval, it should logically be the same problem with missing frames. But I'm apearantly wrong.

If you or someone else have the time to explain this I would approciate it very much.

[Stan Jones]

I can't find one of the image sequences on the web that helps explain this, so I'll try to explain it in words. My numbers are approximate, and the method used may change this.

So you  have a 24 fps video clip on a 60 fps sequence.

If you don't use some type of interpolation, these frames will just be duplicated to get to the 60 fps.

Frame 1 of the timeline: we see frame 1 of the 24 fps clip.

Frame 2 of the timeline: we still see frame 1 of the 24 fps clip.

Frame 3 of the timeline: we see frame 2 of the 24 fps clip.

Frame 4 of the timeline: we still see frame 2 of the 24 fps clip.

Frame 5 of the timeline: we still see frame 3 of the 24 fps clip.

Now export this to a 60fps file and play this on a monitor with a 60Hz refresh rate. All it does is play the frames given to it by the player. Yes, the player is sending 60 frames per second, but they are the ones exported from PR with duplicate frames. So no matter the refresh rate of the monitor, during the first 1/60 of a second, it shows your 24 fps frame 1. And in the second 1/60 of a second, it shows the same frame 1. In the thrid 1/60, it shows frame 2, etc.

Now use interpolation in PR and create frames in between the actual 24fps frames. Using "Frame Blending," every frame is blended  unless a 24 fps frame is at the exact time of a 60 fps frame. For example, 60 fps frame 5 is 24 fps frame 3.  Using "Optical Flow," we get the same thing, it just looks better.

But what the monitor "sees" is what is sent by the player: the only unchanged 24 fps frames occur every twelfth of a second, and all the ones inbetween are what PR created. The monitor can't create the in between frames any better.

Stan

[Johan5FB9]

Thank you. I understand the concept of frame dublication and interpolation. I previously asked what is the best method to be used in premiere. What I understand reading your comment, interpolation is the best.

But what I can tell, no one so far explained why dublication of frames in premiere (24 fps -> 60 fps) is different than watching an unaltered 24 fps clip on a 60 hz monitor.

[Graeme Bull]

It is truly unfortunate you are stuck on the refresh rate of your monitor. It has been explained to you over and over again and it's clear you don't understand what it means to try to get a piece of software to playback footage at a frame rate of footage of a different frame rate. It doesn't matter AT ALL what the refresh rate of your screen is unless it's UNDER the amount of the LOWEST footage frame rate. What you are asking it totally and completely irrelevant to your actual problem.

[Johan5FB9]

Ok.

[Graeme Bull]

The frequency of updates of your monitor mean nothing in this case. I sure hope somebody else can explain this concept to you of trying to force 24fps to play well in a 60fps timeline, I tried but it doesn't look like you can understand my explanation. Good luck!

[Johan5FB9]

Thank you anyway.

[Andy 1968]

I mix and match 60P, 30P,  24P and even interlaced video clips all the time. It looks fine even playing back in an interlaced sequence to broadcast complaint hardware in real-time. Most NLE can playback mixed frame rates in realtime and have done so for over ten years. I say give it a whirl and see what results you get. 

[Johan5FB9]

Ok I might give it a try thank you.