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24fps 3:2 and 2:3 pulldown?

MooiTV.com

MooiTV.com

Can anybody explain to me in the simplest terms possible what pulldown is and if I should select it and which one?

I'm editing in Premiere and exporting a 25fps movie to a 24fps master file. There's a setting that says Pulldown which I assume has something to do with the frame conversion but the "explanations" I've found online are too complicated.

There are 3 options to choose in export settings, of no pulldown or 2:3 or 3:2.

To get the best 25fps to 24fps conversion, which is best here? I've selected none for now.
 
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Unfortunately, although frame rates appears like a fairly simple subject it can get pretty complex when you need to get into the guts of it. Some/Many NLEs try to simplify this area while still providing all the functions which may be required.

Simply: Pulldown is the act of turning TV/video into film or occasionally vice versa. Film is 24 individual frames per second. TV/Video does not generally use individual frames as such, it uses (interlaced) fields, where two fields are equivalent to one frame. The 2:3 and 3:2 pulldown means this relationship of 2 fields to 1 frame is deliberately changed in order to account for a different speed. Not using a pulldown will simply play the 25fps footage at 24fps, IE. Your footage will run 4.1% slower than you actually filmed it and the duration of your film will therefore be 4.1% longer.

Unfortunately, with the advent of HD video the situation has become more complex as not all the HD video formats use interlaced fields rather than progressive frames and also the nomenclature has become quite confused by manufacturers using oversimplified terminology for the benefit of consumers. For example, 24p can mean either true 24fps in the case of film or 23.976fps in the case of video.

MooiTV.com said:
To get the best 25fps to 24fps conversion, which is best here?
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Changing/Converting frame rates should always be avoided, there is almost always a price to pay with picture quality plus it often causes serious problems with audio synchronisation. If there were one best way to achieve a conversion, there would be no need of any alternate choices/options. Which is best therefore depends on exactly what you want to convert to and what you want to use your converted film for.

The obvious first question you should ask yourself is, do you really need to convert your footage? What platform are you looking at which won't allow 25fps? If you're absolutely certain you do need to covert then your best bet is to spend some time researching frame rates, fields, film and video speeds, because to get the best results you're going to have to be able to answer questions such as, do you really want 24fps or is it really 23.976 you're after and, how are you going to deal with audio sync?

G
 
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Well I've exported it and there's no audio sync problems.

It seems what Premiere did is simply drop the last frame from every second.

The result is good and the frame rate is exactly what I was looking for - it's lovely!, but a very critical eye like mine does notice that for example where there is a panning shot, that one dropped frame does cause a slight jump in the smooth continuous motion. This bothers me but probably won't others.

I'm going to leave it as is for now because time has run out, but for future reference, do you think perhaps choosing 2:3 or 3:2 might have smoothened it out so there wouldn't be jumps?
 
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The 3:2 pulldown is something that is used to make 29,97fps interlaced footage (60i) look like 24fps progressive (24p).

It is a useless procedure to convert 25fps into 24fps.
That is why you just have an export with dropped frames.

There is a way to interpolate new frames in After Effects, but that procedure is pretty complicated and one I don't know from the top of my head. It takes a mathematical brain and quite some experience with After Effects to get how it works.
It entails several nested compositions where every step needs to be in the right order and uses effects like timestretching and timewarp. Plus you need 2 layers: pixelmotion to create new frames with the correct timing, the second one with frameblending (which needs to be used where pixelmotion created artifacts, like on cuts, fades or complicated non-lineair movements). And then you need to check EVERY frame for artifacts.
In the end you will have a file that has the exact same length in seconds (if the original length has a few frames after the whole second, that might be a little different offcourse, but not larger that 1 frame: 25 and 24 a close to each other)
Than you add the original sound again in a 24fps timeline in your NLE and export it.

BTW, I can't guarantee the quality of this procedure as I never use it like this. I used it to convert 25fps to 29,97fps before and it worked very well. But this way every second has 5 frames that are more or less spot on, so only the 4 inbetween frames need to be changed into 5 smooth frames.
When going from 25 to 24, there is only 1 frame that is spot on in every second. The other 24 frames have to be converted into 23 smooth frames.

The timestretching APE proposes is for sure the easiest and quickest way to convert it without framedropping. Make sure you have the calculus right.

And you will not be the only one to notice the dropped frames. Many will notice.
It will feel like a bike with a front wheel where the axis is not in the center: a rhythm of hickups.
 
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The explaination of 3:2 or (2:3) pull down is that (if I'm not mistaken):
60i is being deinterlaced first.
Next step is that the first 3 of the 60 'frames' are the same.
Then the 4th is used twice.
The 6th 3 times again.
The 9th twice again. (and so on)
So 10 interlaced fields are converted into 4 frames using a 3:2 (or 2:3) repetition.
10 fields is 1/6th of (roughly) 60 (59,97 to be precise).
4 times 6 = 24.
That is how 60i is made to look like 24p.
 
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I'm editing in Premiere and exporting a 25fps movie to a 24fps master file.

To get the best 25fps to 24fps conversion, which is best here? I've selected none for now.
Click to expand...

From my understanding, with PP CS5, you don't.

By todays standards, Interpolation is what you need.

interpolate new frames in After Effects
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This used to be required, but it's no longer the case. I think it changed in CC2015, maybe 2014. Premiere Pro now has interpolation built into its render engine. The software does all the heavy lifting for you.

Your best bet now may be FFmpeg. It's freeware so the price is right and as a bonus it's multi-platform. Most people aren't used to using command line programs anymore so it might take you a while to work it out. You'll have to do your own reading/testing to see if it drops frames or interpolates and create a workflow that suits you best.
 
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Sweetie said:
From my understanding, with PP CS5, you don't.

By todays standards, Interpolation is what you need.

This used to be required, but it's no longer the case. I think it changed in CC2015, maybe 2014. Premiere Pro now has interpolation built into its render engine. The software does all the heavy lifting for you.
...................
Click to expand...

Haven't converted frames in years, so that might indeed be the case.
I have no time to test it now.
Just make sure to check the render for artifacts. In AE I had to, because interpolating between cuts created the wildest pixelated artwork ever :P
That is why I used frameblending for such frames: get the quality of interpolation, unless it fails: blend those frames. :)
 
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Ok so basically I have done it the best way I'm going to get it for now, unless I buy a new Adobe Premiere. Would you all pitch in? Dunno how much because adobe.com is now so damn complicated I've surfed 4 pages already and don't know how in heaven's name to just buy the thing so I'm giving up for now.

Anyway, actually my current 24fps results don't look bad at all. I mean to post a video test for you but I probably won't get around to it. But it looks good enough I think.

Thanks y'all for your inputs!
 
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Just make sure to check the render for artifacts.
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That's always the case with each render. Always check the render. It's good practice. The render engine in PP is surprisingly good these days. I haven't seen it do anything funky for a long time.

blend those frames
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If memory serves me right, that's an option.

Would you all pitch in?
Click to expand...
I mean to post a video test for you but I probably won't get around to it.
Click to expand...
Sure. We'd mean to but we probably won't get around to it. You know how it is.
 
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MooiTV.com said:
Ok so basically I have done it the best way I'm going to get it for now, unless I buy a new Adobe Premiere. ..............
Click to expand...

That really depends on the version of the software you are using.
To me framedrops will never be the best way.
But you have no more time left, so it is not the best way, but the way you'll have to live with for now. :P
 
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Lol, fine. Before you feel unloved or something, I exported you these random shots with emphasis on motion & panning & handheldness, to see the effect of the frame rate change from 25fps to 24fps.

Of course the real test is if you see it in full HD on a big screen TV.
 
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