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Weird frame rate problem

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Anh Minh Truong
Weird frame rate problem
on May 11, 2010 at 5:13:59 pm

Hello,
I'm working on a compo of 2800x1380, frame rate: 23.976. ( After effects CS4- mac)

I exported a QT ProresHQ with the same specs. Then I wanted to make a QT Animation but with a frame rate of 29.97, so I compressed it using Compressor with the new frame rate.

Now the weird part :
Quicktime X, Final Cut Pro, and Cinema Tools see the new QT Animation as 23.976 fps.
While After Effects, Compressor, Premiere Pro and Mpeg Streamclip see it as 29.97 fps.

Which one should I trust ?

The problem doesn't occur when I compressed from 24p to 29.97fps in the ProresHQ format...they all see it in 29.97fps. But I need to have a QT animation..

Any ideas ?

Thanks for your help!

Anh Minh



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Dave LaRonde
Re: Weird frame rate problem
on May 11, 2010 at 6:51:48 pm

[Anh Minh Truong] "...I'm working on a compo of 2800x1380"

That's an odd sort of resolution... something to dovetail with RED footage, perhaps? What is the footage in your comp, and what are you doing with the rendered AE file?




[Anh Minh Truong] "...compressed it using Compressor with the new frame rate...
Quicktime X, Final Cut Pro, and Cinema Tools see the new QT Animation as 23.976 fps.
While After Effects, Compressor, Premiere Pro and Mpeg Streamclip see it as 29.97 fps. "


Are you SURE you were looking at the same file in both instances? I don't think so.

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


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Anh Minh Truong
Re: Weird frame rate problem
on May 11, 2010 at 7:03:34 pm

I'm creating videos for a live multimedia show... we are edge blending multiple projector to create huge frame (and projection surface). I have another compo of 7000 x 1850.... can't wait to work to migrate on CS5.... I am using all sort of media in my compo : some red footage, mainly photoshop layers that we animate..

Yes I am sure I looked at the same file in both instances... I also double checked with other files that have been through the same process.

it's weird... is it possible that Compressor adds a Pull-down in the footage that some software recognize and some don't ? That's my theory..

I've tried putting the Prores24p footage in a new compo with a frame rate of 29.97 , and export it in Animation, but After Effects don't seem to add that "smooth" pull-down... I see some jitter in the motion at every second.. like if it duplicated 6 frames at every 24 frames...



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Dave LaRonde
Re: Weird frame rate problem
on May 11, 2010 at 8:18:03 pm

[Anh Minh Truong] "I've tried putting the Prores24p footage in a new compo with a frame rate of 29.97 , and export it in Animation, but After Effects don't seem to add that "smooth" pull-down... I see some jitter in the motion at every second.. like if it duplicated 6 frames at every 24 frames... "

Oh... you want EVERYTHING at 29.97! Now I understand! Well, AE won't be able to do it without introducing interlacing to the image. Here's how it's done:

• Add the 23.976 comp to the Render Queue
• In the Render Settings, select Add 3:2 pulldown
• Select any of the five pulldown patterns; It shouldn't make a bit of difference

You may be better off using Compressor.

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


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Dave LaRonde
Re: Weird frame rate problem
on May 11, 2010 at 10:40:39 pm

Ooh! Ooh! Something else to try:
Nest that 23.976 comp in a 59.94 ProRes comp and render. No 3:2 pulldown necessary. If you're not using progressive-scan in the rest of the project, it might work. If you can change the project's frame rate to 59.94, it WILL work.

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


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Walter Soyka
Re: Weird frame rate problem
on May 12, 2010 at 4:48:53 am

[Anh Minh Truong] "I've tried putting the Prores24p footage in a new compo with a frame rate of 29.97 , and export it in Animation, but After Effects don't seem to add that "smooth" pull-down... I see some jitter in the motion at every second.. like if it duplicated 6 frames at every 24 frames..."

Are you using actual ProRes video footage in your comp, or are you referring to the ProRes render you've already created?

If your comp entirely generated within AE, don't pre-render before you put the 23.976 material in the 29.97 timeline. Instead, nest your master 23.976 comp in a 29.97 comp, and AE will smoothly re-interpret all your keyframed and animated motion and effects in the new frame rate.

If you do have other 24p video footage...

[Dave LaRonde] "Ooh! Ooh! Something else to try: Nest that 23.976 comp in a 59.94 ProRes comp and render. No 3:2 pulldown necessary. If you're not using progressive-scan in the rest of the project, it might work. If you can change the project's frame rate to 59.94, it WILL work."

This is a great idea to try. Your blended projection system is progressive, so a 3:2 pulldown that relies on interlacing won't help you. You'll still sort of get a pull-down here, but it will use progressive frames instead of interlaced fields, so it won't get clobbered by your progressive displays.

Just make sure of these two things:

1) the playback system can handle progressive media at 59.94 fps. The data rate will be twice as high as 29.97.

2) the widescreen switcher is running at a refresh rate of 59.94 Hz. For example, a Spyder may need to drop down to 29.97 to handle a pixel space of that size (I don't remember offhand what the system's total bandwidth is to tell you for sure.)

Walter Soyka
Principal & Designer at Keen Live
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
RenderBreak Blog - What I'm thinking when my workstation's thinking
Creative Cow Forum Host: Live & Stage Events


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Dave LaRonde
Re: Weird frame rate problem
on May 12, 2010 at 2:59:14 pm

[Walter Soyka] "nest your master 23.976 comp in a 29.97 comp, and AE will smoothly re-interpret all your keyframed and animated motion and effects in the new frame rate. "

Actually, it won't. At 29.97, you need to have interlaced footage and add 3:2 pulldown... and it's normally done on SD footage, which contains interlacing... even if it's progressive scan.

People who place 23.976 footage in a 29.97 FCP edit timeline -- essentially the same thing as you suggest doing in AE -- discover that the cadence turns out to be 2-2-2-4 instead of the proper 3-2-3-2 cadence. So every fourth frame, you'd see a little hitch in your git-along.

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


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Walter Soyka
Re: Weird frame rate problem
on May 12, 2010 at 3:04:13 pm

[Dave LaRonde] "Actually, it won't. At 29.97, you need to have interlaced footage and add 3:2 pulldown... and it's normally done on SD footage, which contains interlacing... even if it's progressive scan.

People who place 23.976 footage in a 29.97 FCP edit timeline -- essentially the same thing as you suggest doing in AE -- discover that the cadence turns out to be 2-2-2-4 instead of the proper 3-2-3-2 cadence. So every fourth frame, you'd see a little hitch in your git-along."


Sorry I didn't make myself clear -- I was talking about comps with no external footage. If everything is generated from within AE (all stills, illustrations, solids, masks, effects, etc.) with keyframed animation, and you nest it in a comp with a different frame rate, it will smoothly reinterpret all your animation in the new frame rate.

Walter Soyka
Principal & Designer at Keen Live
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
RenderBreak Blog - What I'm thinking when my workstation's thinking
Creative Cow Forum Host: Live & Stage Events


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Dave LaRonde
Re: Weird frame rate problem
on May 12, 2010 at 3:15:07 pm

Ah. Difference noted. Read for understanding, Dave!

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


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Walter Soyka
Re: Weird frame rate problem
on May 12, 2010 at 3:47:27 pm

Not at all -- my original post definitely needed clarification.

Walter Soyka
Principal & Designer at Keen Live
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
RenderBreak Blog - What I'm thinking when my workstation's thinking
Creative Cow Forum Host: Live & Stage Events


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