Weird idea for getting 23.97 fps

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Postby RadicalEd0 » Sun Sep 29, 2002 3:58 am

sweet that it worked
anyway klinky wasnt totally wrong in what he was saying, he was saying 24fps is the original that we want not 23.976. Its true that 24 fps is the original framerate and that its slowed down by like 1/10th of a second before telecine so technically ivtc only restores the frames, not the exact same speed. But nobody cares about 1/10th of a second :P

and the only (really dumb) reason premiere uses 23.98 fps is because it dosent calculate framerates into the thousanths, so it rounds 23.976 up to 23.98. :/
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Postby RadicalEd0 » Sun Sep 29, 2002 4:14 am

uh.. weird.. i posted here.. and its not here..
:/

well to summarize:
sweet that it works

klinky wasnt all wrong, he was just saying that it should really be 24fps, since that is the original framerate of film/anime. He's right, the 24fps is just sped up 1/10th of a second to get 23.976 before telecine (24 / 4 x 5 = 30, no good, but 29.976 / 4 x 5 = 29.97 exactly) but its just 1/10th of a second so nobody cares :P

also the (really dumb) reason premiere uses 23.98 fps is becuz it dosent calculate framerates into the thousandths. So it rounds 23.976 up to 23.98
:/
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Postby RadicalEd0 » Sun Sep 29, 2002 4:15 am

doh!
the second page was invisible
well there, now u get the facts twice
:P
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Postby ErMaC » Mon Sep 30, 2002 2:01 pm

Umm... Did you bother reading the guide in AD's audio guide about how to do this properly in Premiere? Your method's this one big hack that involves a whole crapload of extra work.

It's far easier to just stretch your audio, edit in 24fps (so your timecode isn't screwed up and you don't wind up with offsync previews) and then change the framerate and use your original audio.

You're making things way too complicated.
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Postby Zarxrax » Mon Sep 30, 2002 7:45 pm

Nope Ermac, I didn't read the audio guide. Anyways I find that method a little more difficult (for me) than what I've done here.
Anyways, I just found out yet another method, that is far, far easier than any other. Simply make an avisynth script with the lines:

AVISource("C:\test 23.98fps.avi")
changeFPS(23.976)

And there it is. This function will duplicate or drop frames as necessary in order to keep the framerate in sync. And since the difference between 23.98 and 23.976 is so small, it hardly has to make any changes at all, and the few it does make wont be noticable.
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Postby derobert » Tue Oct 01, 2002 1:22 pm

Zarxrax wrote:Ok klinky, we dont WANT it to be 23.98 fps, we want it to be 23.976 fps! 23.976fps is the correct fps for ntcs film.

The difference between 23.98fps and 23.976fps is 14.4 frames per hour. 345.6 frames per day! 126,144 frames per non-leap year! This is a travesty! It must be stopped!

Some may object that oscilator jitter is far greater than .004 frames per second, but we say: So what! This is a THEORETICAL problem, and that can't be ignored due to PRACTICAL concerns!
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Postby trythil » Tue Oct 01, 2002 1:52 pm

derobert wrote:
Zarxrax wrote:Ok klinky, we dont WANT it to be 23.98 fps, we want it to be 23.976 fps! 23.976fps is the correct fps for ntcs film.

The difference between 23.98fps and 23.976fps is 14.4 frames per hour. 345.6 frames per day! 126,144 frames per non-leap year! This is a travesty! It must be stopped!


Regardless of however you try to rationalize it, 23.98 is not 23.976. And that DOES make a difference when you're trying to get very tight audio/video synchronization. Especially in longer videos, where that "small" difference of 14.4 frames per hour becomes very obvious.
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Postby Zarxrax » Tue Oct 01, 2002 2:39 pm

Yes, trythil is correct. It doesnt really make much of a difference for your average AMV, but for other stuff I work on (like fansubs) it can be a problem.
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Postby ErMaC » Wed Oct 02, 2002 3:33 am

You still forget that editing in 23.98fps in Premiere itself will cause sync issues because you must select the 24fps timebase, thus all your previews will be out of sync.
When you go to export at 23.98fps and your project is 24fps, then you wind up dropping frames in Premiere which is bad because it does a crap job of it.
The best, most failsafe, and highest quality way is to use the method outlined in the guide.
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Postby Zarxrax » Wed Oct 02, 2002 7:30 am

24 fps timebase? I set that to 23.98...
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Postby klinky » Wed Oct 02, 2002 8:43 am

There is no option for a timebase of 23.98
Image


You can set the frame rate to it tho :\

Image


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Postby AbsoluteDestiny » Wed Oct 02, 2002 9:30 am

from the new video guides (will be released soon):

"Notice that Premiere does not have an option for 23.976 fps footage. This is because it sucks. This is the reason why you should change all your footage to 24fps if you have done IVTC, otherwise Premiere doesn't have a timebase for it which will mess up your edits. Editing in 23.98fps is even worse than loading 23.976fps footage into a 24fps project (confused yet?)

For progressive footage, always edit 24fps footage with a 24fps project."


from the audio guide:

"So, you have some progressive (FILM) footage all in it's non-interlaced 23.976fps glory. You'll want to edit this in Premiere and make an nice 23.976fps amv, won't you?

Well tough.

"What?!?!" I hear you say.

"Tough", I reply.

You can't make 23,976fps videos with Adobe Premiere.... is no possible. You can do 24fps video... you can do 23.98fps video but damned if you can do 23.976.

So what are your options? Well, we've come up with a fairly good solution to this dilemna. Basically the idea is that you make a slightly faster version of your audio, edit at 24fps in premiere and change the video to 23.976fps later and re-attach your original audio."


We write these things because we know what we are talking about :D
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Postby Zarxrax » Wed Oct 02, 2002 10:27 am

Well damn, there ISNT an option for 28.98 fps.
Hmmm, but I've always edited my videos at 23.98fps and had the timebase to 24 (i guess) and I've never experienced my previews being out of sync (and I think it would get WAY out of sync with such a framerate difference wouldn't it?).
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Postby trythil » Wed Oct 02, 2002 1:28 pm

Zarxrax wrote:Well damn, there ISNT an option for 28.98 fps.
Hmmm, but I've always edited my videos at 23.98fps and had the timebase to 24 (i guess) and I've never experienced my previews being out of sync (and I think it would get WAY out of sync with such a framerate difference wouldn't it?).
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Postby trythil » Wed Oct 02, 2002 1:31 pm

trythil wrote:
Zarxrax wrote:Well damn, there ISNT an option for 28.98 fps.
Hmmm, but I've always edited my videos at 23.98fps and had the timebase to 24 (i guess) and I've never experienced my previews being out of sync (and I think it would get WAY out of sync with such a framerate difference wouldn't it?).


OK, that didn't work, and I have no idea why my message didn't get tacked on there.

Anyway, the short answer is that it WILL mess up your edits, though maybe not on an obvious scale. Premiere, AFAIK, uses the timebase to determine what the time positions of each edit are. If your timebase doesn't match the video frame rate, Premiere tries to compensate, but from what I've seen and heard about the compensation algorithms, it really sucks.

So, yes, there are sync problems.
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