Shooting in 30FPS and Converting to 24FPS in post edit [ HOW ? ]

[Isaac94]

Hi, so I've looked through several videos about how to convert 30 FPS to 24FPS in post edit, using premiere pro. But I am still tad bit confuse on how about to do that, first off I would hope to know these step by step, as I open premiere pro, I click on New Project, so I just click Ok from there ? Or is there any settings that I have to set before hitting Ok ?

After that, I'm in the project timeline, so from here onwards, after importing my 30FPS clips in, how do I then go about converting both my clips and the project timeline to 24FPS ?

 

[johnmeyer]

I don't know about Premiere Pro, but in most NLEs you simply specify the output frame rate you want, and the NLE takes care of both synthesizing new frames, and also decimating frames in order to get to the desired frame rate.

I am not a big fan of doing 24<-->30 fps conversions because if you go through the math, a huge percentage of the resulting frames will have to be created by either interpolating or blending adjacent frames. This leads to artifacts, some of which can be pretty significant.

If you have a choice when shooting, always try to keep all cameras at the same frame rate or, if you must convert, try to keep the conversions between these frame rates:

60 fps progressive
30 fps progressive
30 fps interlaced

 

[Maviac]

Hi, so I've looked through several videos about how to convert 30 FPS to 24FPS in post edit, using premiere pro. But I am still tad bit confuse on how about to do that, first off I would hope to know these step by step, as I open premiere pro, I click on New Project, so I just click Ok from there ? Or is there any settings that I have to set before hitting Ok ?

After that, I'm in the project timeline, so from here onwards, after importing my 30FPS clips in, how do I then go about converting both my clips and the project timeline to 24FPS ?

In Premiere Pro CC, when you go to export, click on "Video" about halfway down the window and you'll have the option to change the resolution and frame rate. By default it will "match source" which I believe is set by the first clip in the timeline. You'll need to uncheck the box by the relevant setting, then you can select a different frame rate (or resolution if you want).

Whether it's a good idea or not I can't say. I typically stick with footage at 30 or 60 fps and output to at least an even multiple.

 

[Harro]

Why change from 30 to 24 fps? Doing that you discard 6 frames each second, do you really want that? 30 fps is far better quality than 24 fps, given a choice of 60, 30 and 24 fps, I would choose 60 pretty well all the time.

 

[Isaac94]

I see, well ok so for example, if I shoot in 30FPS, then I want a slow motion video, so I have to shoot in 1080P 120FPS, how do I then post edit these 2 clips ? Do I create a sequence for 30FPS or 120FPS ?

Also, just a side question, would it be better to film everything in 4K or 2.7K ? As with the question about smaller file size for 2.7K, and quality wise is closely about the same, people go for 2.7K, I would love some advice on that please.

 

[johnmeyer]

... if I shoot in 30FPS, then I want a slow motion video, so I have to shoot in 1080P 120FPS, how do I then post edit these 2 clips ?

To get slow motion from 120 fps video, you put that on your NLE timeline and then tell your NLE to play that video at a slower speed. If your planned final output is 30 fps, then you can slow down the 120 fps to exactly 50% or to 25% and you will get slow motion without your NLE having to create any intermediate frames. While you can slow down by other amounts, the resulting video will not be as perfect because of the intermediate frames that must be synthesized.

Also, just a side question, would it be better to film everything in 4K or 2.7K ?

I don't quite understand your question. My usual advice is to film at 4K, because most people deliver in HD (1920x1080) and filming in significantly higher resolution lets you perform zooming and cropping in your NLE without ending up with something that is any lower resolution than 1920x1080.

Both 2.7K and 4K will let you do what I just described. However, in the Mavic 2 line 2.7K lets you film at 60p, whereas 4K only goes to 30p. There is a massive difference in fluidity between these two. Also, you will probably see some judder when filming 30p, especially with rapid horizontal movements.

Everything depends, of course, on what you are actually trying to do. Absent any information on that, I'd recommend filming in 2.7K if you have a Mavic 2 Pro.

 

[Isaac94]

To get slow motion from 120 fps video, you put that on your NLE timeline and then tell your NLE to play that video at a slower speed. If your planned final output is 30 fps, then you can slow down the 120 fps to exactly 50% or to 25% and you will get slow motion without your NLE having to create any intermediate frames. While you can slow down by other amounts, the resulting video will not be as perfect because of the intermediate frames that must be synthesized.
I don't quite understand your question. My usual advice is to film at 4K, because most people deliver in HD (1920x1080) and filming in significantly higher resolution lets you perform zooming and cropping in your NLE without ending up with something that is any lower resolution than 1920x1080.

Both 2.7K and 4K will let you do what I just described. However, in the Mavic 2 line 2.7K lets you film at 60p, whereas 4K only goes to 30p. There is a massive difference in fluidity between these two. Also, you will probably see some judder when filming 30p, especially with rapid horizontal movements.

Everything depends, of course, on what you are actually trying to do. Absent any information on that, I'd recommend filming in 2.7K if you have a Mavic 2 Pro.

I see, so you mean that if I film put a 30FPS clip in the timeline of my editing software, and I create a New Sequence of 30FPS, then I drag my 30FPS clip into the timeline, after that I drag my 120FPS slow motion clip into the same timeline as well, but for the slow motion clip I'll be right clicking it and select Speed, and type in 50% directly ? That's the way to do it ?

I personally own a Mavic Air. What I meant about 4K or 2.7K is that, most people shoot in 4K, but due to the huge file size, they opt to go for 2.7K, without losing any much of image / film quality, hence I was wondering if I should ignore the file size, and always shoot in 4K, or shoot in 2.7K would be a better ideal choice, or alternative.

 

[johnmeyer]

I wouldn't worry so much about file size. The differences aren't that much and storage has gotten awfully inexpensive. Instead, base your decision on what will give you the best results for what you're trying to do.

As for the slo-mo, it sounds like you've got it. My advice is to try it, see what happens, and then ask more questions, if you need to.

 

[Isaac94]

I wouldn't worry so much about file size. The differences aren't that much and storage has gotten awfully inexpensive. Instead, base your decision on what will give you the best results for what you're trying to do.

As for the slo-mo, it sounds like you've got it. My advice is to try it, see what happens, and then ask more questions, if you need to.

Will do, thank you so much for your help and information. It really helps me a great deal, would ask further questions here if I have any, cheers mate ! Oh yes, one question, 1080P 120FPS by default is already in it's own slow motion, by reducing it a further 50% in post editing, wouldn't it be even slower ? Or should I just leave it be as it is ?

 

[brett8883]

Hi, so I've looked through several videos about how to convert 30 FPS to 24FPS in post edit, using premiere pro. But I am still tad bit confuse on how about to do that, first off I would hope to know these step by step, as I open premiere pro, I click on New Project, so I just click Ok from there ? Or is there any settings that I have to set before hitting Ok ?

After that, I'm in the project timeline, so from here onwards, after importing my 30FPS clips in, how do I then go about converting both my clips and the project timeline to 24FPS ?

Click control n to bring up your sequence settings.

Before dragging a dragging a clip onto the timeline consider that you want to do with it. There a two ways to convert a 30FPS clip to 24FPS. You can either drop frames or slow down the play back.

So if you have a 3 second clip at 30fps you have 90 frames. So if this 90 frames are played back at 24 FPS it will take 3.75 seconds to play it back and this will slow down the footage just enough to make it look smoother but not like it’s in slow motion. This is my preferred why to do it.

The other way to do it is to drop frames which in this cause will be unnoticeable just going from 30 to 24, however, if you were to slow part of the sequence down you would have more frames to work with when it’s slowed down.

In a nut shell if you want to slow the whole thing down use option #1. If you only want to slow down part of the clip use option #2

To do option #1 you would right click the clip and go to properties and select “interpret footage” and then change it to 24 FPS this will play all the frames but just at the slower rate

To do option# 2 simply drag the clip onto the timeline and Premier will automatically drop frames to get it to fit on the 24fps timeline

 

[Harro]

Do your editing in 29.97 fps (30 is most likely an approximation to this), as that is what you are going to view on your TV in the US. Placing the 120 fps clip in that (29.97 fps project) timeline will slow that clip down to quarter speed, if that is what you want, i.e. slow motion.

 

[johnmeyer]

... one question, 1080P 120FPS by default is already in it's own slow motion, by reducing it a further 50% in post editing, wouldn't it be even slower ? Or should I just leave it be as it is ?

Another person just posted that it would, so maybe some NLEs work that way. In my NLE (Vegas Pro) each clip plays at its normal speed and is adjusted to fit the project's frame rate. To get it to play at slower speed, I have to tell Vegas to slow it down. If the video was 30 fps to begin with, and if my project is set to play at 30 fps, then Vegas has to synthesize new frames in order to still have 30 frames each second once the video is slowed down. However, if you slow down a video that contains 120 frames each second, Vegas doesn't have to create any new frames until you slow it down to less than 25% of normal speed, or unless you choose a slow down percentage other than 50% or 25%.

The way in which your NLE performs slow down makes a huge difference in the quality of the end results. Here is a comparison I posted years ago, showing three different ways to create slow motion from 60i material (30 frames per second, interlaced):

Slow Mo Comparision

Here's another one I did ten years ago:

If you use 120 fps and slow it to exactly 50% or 25%, your slow motion should look absolutely perfect, without any of the artifacts shown in these examples, both of which required the NLE to artificially synthesize the needed extra frames.

 

[Isaac94]

Another person just posted that it would, so maybe some NLEs work that way. In my NLE (Vegas Pro) each clip plays at its normal speed and is adjusted to fit the project's frame rate. To get it to play at slower speed, I have to tell Vegas to slow it down. If the video was 30 fps to begin with, and if my project is set to play at 30 fps, then Vegas has to synthesize new frames in order to still have 30 frames each second once the video is slowed down. However, if you slow down a video that contains 120 frames each second, Vegas doesn't have to create any new frames until you slow it down to less than 25% of normal speed, or unless you choose a slow down percentage other than 50% or 25%.

The way in which your NLE performs slow down makes a huge difference in the quality of the end results. Here is a comparison I posted years ago, showing three different ways to create slow motion from 60i material (30 frames per second, interlaced):

Slow Mo Comparision

Here's another one I did ten years ago:

If you use 120 fps and slow it to exactly 50% or 25%, your slow motion should look absolutely perfect, without any of the artifacts shown in these examples, both of which required the NLE to artificially synthesize the needed extra frames.

I see, so basically if I shoot slow-mo in 120FPS, and then post edit I slow it down by typing in 50%, it'll be a perfect slow motion video, would I be correct to say that ?

 

[johnmeyer]

I see, so basically if I shoot slow-mo in 120FPS, and then post edit I slow it down by typing in 50%, it'll be a perfect slow motion video, would I be correct to say that ?

You're asking the same questions over and over. I already gave you that same advice. Just go ahead and start editing.

 

[brett8883]

Will do, thank you so much for your help and information. It really helps me a great deal, would ask further questions here if I have any, cheers mate ! Oh yes, one question, 1080P 120FPS by default is already in it's own slow motion, by reducing it a further 50% in post editing, wouldn't it be even slower ? Or should I just leave it be as it is ?

@Isaac94 i thought we went over this already...https://mavicpilots.com/threads/could-i-shoot-slow-motion-in-intelligence-flight-mode.69712/#post-790371

120 FPS is not its own slow motion it’s just a frame rate... it get slow motion you have to put it on a time line that is less than 120 FPS for it to be slow motion.

 

[brett8883]

I actually have two videos to demonstrate this conversion from 30 to 24 FPS by using the interpret footage option in Premier. Both videos are the same both have the same number of frames.

The first one is the video shot in 30 frames per second on a 30fps timeline. Pressing play on both videos simultaneously will best display the differences between them .

The next one is the same video interpreted as a 24fps video

 

[Isaac94]

I actually have two videos to demonstrate this conversion from 30 to 24 FPS by using the interpret footage option in Premier. Both videos are the same both have the same number of frames.

The first one is the video shot in 30 frames per second on a 30fps timeline. Pressing play on both videos simultaneously will best display the differences between them .

The next one is the same video interpreted as a 24fps video

I see, after looking closely on both videos, I realized the 30FPS clip that is interpreted to 24FPS maintains the same smoothness, but also slower and more "cinematic" feel to it, thanks a lot !

 

[brett8883]

I see, after looking closely on both videos, I realized the 30FPS clip that is interpreted to 24FPS maintains the same smoothness, but also slower and more "cinematic" feel to it, thanks a lot !

Yep exactly and remember in the other thread how I was talking about how the greater the difference between the time line frame rate and the clip frame rate is going to determine the amount of slow motion? So here the difference is only 6 frames per second but if I had shot this in 60fps it would have been much slower when interpreting because 36 is much greater than 6.

So this is the best way to do this conversion from 30 to 24 because the speed difference is subtle enough that had you just watched the interpreted clips above you wouldn’t have thought it was slowed down or anything and then also get that “cinematic gloss” feel.

 

[iatroGen]

Yep exactly and remember in the other thread how I was talking about how the greater the difference between the time line frame rate and the clip frame rate is going to determine the amount of slow motion? So here the difference is only 6 frames per second but if I had shot this in 60fps it would have been much slower when interpreting because 36 is much greater than 6.

So this is the best way to do this conversion from 30 to 24 because the speed difference is subtle enough that had you just watched the interpreted clips above you wouldn’t have thought it was slowed down or anything and then also get that “cinematic gloss” feel.

This is just what I wanted to know, thanks!

 

[FlyingFilmmaker]

IMO the best way to convert from 30-24 fps (as long as you aren't dealing with audio or something that needs to happen in real time) is to interpret 30 to 24 as others have mentioned., In other words, slow it down to 80%.