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Frame shift of two comps. Why???

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Katherine Landgrebe
Frame shift of two comps. Why???
on Nov 18, 2009 at 10:26:09 am

Hi, maybe I'm just blind, but...

I have two compositions. Both have 24fps, both are 2 minutes in length. One is placed into the other.
But: When I place the timeline-thingy to, say, 1 minute in the subComp, it's at 1:06 in the main comp. Also the values of my expression that I use in the SubComp are shifted timewise 2 frames/second. So, I lose the synchronization, and at the end of 2 minutes, I have 12 seconds difference. I did not use time remap.

What can this be?


P.S.: I just tried out a copy of the SubComp, this one is perfect. Strange, strange, strange.


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Dave LaRonde
Re: Frame shift of two comps. Why???
on Nov 18, 2009 at 2:02:42 pm

[Katherine Landgrebe] "I have two compositions. Both have 24fps, both are 2 minutes in length."

I doubt very much that the frame rate should be 24. Unless you're working with an image sequence taken from the source celluloid film or footage a RED camera set to shoot an actual 24fps, your comp's frame rate should be 23.976.

This is because your footage's frame rate is probably 23.976. 24p and 23.98 are simply nicknames for this frame rate. You can double check by highlighting the footage in the project window, and looking at the footage information at the top.

It's possible to work with a close-to-film frame rate when dealing with footage shot on a TV camera. But it is NOT the no-brainer of a normal TV frame rate. You have to follow certain procedures.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


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Katherine Landgrebe
Re: Frame shift of two comps. Why???
on Nov 18, 2009 at 2:17:04 pm

Thanks, Dave, for your response.
I forgot to mention, that there is no original video footage in my project. It's an AE animation, the only thing I imported are Illustrator files. So, it's a FullHD 1920x1080 composition in HDTV, 24 frames. I set them all up like this, but I always get confused with all these standards. I used that one that AE has as a preset in the comp-preferences.


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Dave LaRonde
Re: Frame shift of two comps. Why???
on Nov 18, 2009 at 5:21:32 pm

What are you trying to deliver? Who gets this next, and for what purpose? What frame rate do THEY specify? It sounds like you may have been using two DIFFERENT frame rates in those comps, and that's typically never a good idea.

In NTSC, the frame rate is 29.97, and since it's 1080, the field order is upper field first. OR -- if you happen to think that a film frame rate is just toooooooo cool to ignore -- it's 23.976, no set field order, and you may or may not want to add the 3:2 pulldown at render time, depending on what you have to deliver.

In PAL, it's 25.

And only under EXTREMELY limited circumstances is the frame rate EVER 24 fps. You would know about that frame rate because you would be doing work for a film production company.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


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Katherine Landgrebe
Re: Frame shift of two comps. Why???
on Nov 18, 2009 at 6:47:09 pm

Well, for I'm more a designer than a technician, I'm not too familiar with each and every detail of all these things. Sorry about that. I try do do my very best to get it right. Thanks for your suggestions.

I set this project up for myself, first of all (free study project). I'm gonna burn it on BluRay later and show it as a QTmov from my computer. If I'm lucky, it's shown on festivals in movie theaters in Germany or somewhere else in Europe. Then there will be a PAL DVD in 25 frames as a preview version. Then there will be a NTSC DVD for non European film festivals. Then there might be a BetaSP PAL tape for broadcasting. You see, I have to set something up and change it later anyways. I can't build 3 different versions, I have to re-render it.

The 24 frames may be wrong, and I promise, my next project will be in 23.976. :)
If I did it wrong, I have to live with it for now or change my project carefully step by step, but actually, I did not use different frame rates in one project. I double-checked it all, it's all set to 24.00. Anyways, which frame rate ever I use, inside the project it should be synchrone when two comps have the same frame rate, shouldn't it?

I might just switch to 25fps, then at least Europe is happy :)


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Dave LaRonde
Re: Frame shift of two comps. Why???
on Nov 18, 2009 at 7:08:26 pm

[Katherine Landgrebe] "...I'm gonna burn it on BluRay later and show it as a QTmov from my computer. If I'm lucky, it's shown on festivals in movie theaters in Germany or somewhere else in Europe...."

Ah, well, that makes a difference! My compliments on your excellent English, by the way. You would need to check on the delivery requirements for various festivals; they all seem to have different requirements.


If this is STRICTLY for Europe, I recommend working in 1920x1080 and at 25fps. You can then make a 25fps blu-ray, a 25fps quicktime movie, etc. If a delivery requirement involves 24fps for cinema, you could conform a duplicated 25fps file to 24. Yes, it will slow down a bit, but it is hardly noticeable, and it is much, MUCH cheaper than the alternative of having a frame rate conversion done at a post house. You could easily spend 2000 euros on such a conversion.

If you had realistic hopes for both North America and Europe, I would have recommended a frame rate of 23.976. It's easy to convert to 29.97 through the common process of adding 3:2 pulldown, It's easy to conform to 24, and conforming to 25 isn't all that bad, either.


But this doesn't answer your original question: why are times off in your comps? In the comp settings, check the frame rate. I think we agree on that one: 25. Then either in AE Preferences or Project Settings, check the Time Display: it should also be set to 25.



Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


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Katherine Landgrebe
Re: Frame shift of two comps. Why???
on Nov 18, 2009 at 7:25:25 pm

>>My compliments on your excellent English, by the way.<<

Haha, thanks. I studied in the US for a (way too short) while.

Yep, I guess I'll go for the 25 frames then. Oh dear.

>>If you had realistic hopes for both North America and Europe, I would have recommended a frame rate of 23.976<<

Hm, that happened before, but I'm not sure if this would happen again. I think, in case they want the film, I'll have some fun converting it. :)

What I like even more than frame rates is the pixel ratio ;) Yay, squash and stretch.

Dave, I appreciate your help. Thank you very much!
I'll get back to work and let you know how this frame shift issue reacts to 25 frames.

Best,
Katherine


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Katherine Landgrebe
Re: Frame shift of two comps. Why???
on Nov 18, 2009 at 8:58:02 pm

I now got rid of the "Auto" Framerate in the project presets to 24 (I haven't started switching to 25 yet). Then I reboot AE and made a new composition and copy-pasted the layers in it (which I tried before), and it worked now! Cool. This might have done the trick. But with the pingpong-problem (see http://forums.creativecow.net/readpost/202/884005), unfortunately the trick did not work out. Well, I'll keep on trying to find out a solution.


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