240fps Render After Effects CS5

[Walter Soyka]

Slow motion footage is shot overcranked in the camera (at a high frame rate like 240 fps), but then played back at normal speed. If you played it back at the same rate at which it was shot, it would play in real time, not slow motion.

Render to whatever your native frame rate should be — perhaps 24 fps for a 10x slowdown.

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

[Gino Brugman]

I used Twixtor in AAE to slow it down by the use of keyframes. Does it matter if i render the final composition at 30fps? Will it affect the not slowed down pieces.

[Walter Soyka]

Let’s back up. What did you shoot, and what do you need to make?

Do you have footage from a high-speed camera that was originally shot at 240 fps? If so, you can simply interpret the footage at 30 fps for an 8x slowdown. No need for optical flow from Twixtor. In fact, you will get better results from a straight re-interpretation of the footage.

If you did not shoot at high speed (or a speed high enough to get you the slowdown you need), then Twixtor is an appropriate choice.

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

[Gino Brugman]

I got 240 FPS Footage, Captured with Fraps(Gameplay-recorder) I need to make a slow-motion video using a plugin called twixtor. When i want to render the final product, After effects tell’s me i can only render it to a max. of 99FPS but i need 240.

[Walter Soyka]

[Gino Brugman] “I got 240 FPS Footage, Captured with Fraps(Gameplay-recorder)”

Like Dave asked — is it really 240 fps? If you have repeated frames, you won’t get smooth slow motion. As Dave suggested, you’ll need to get rid of them, either through re-capture or decimation.

[Gino Brugman] “I need to make a slow-motion video using a plugin called twixtor.”

Not necessarily. Twixtor works by estimating the motion of each pixel from one real frame to the next, then generating intermediate frames based on these vectors.

You’ve got 240 fps media, but there’s no video standard that plays at a frame rate that fast. You’ll top out at 60 (59.94 for video) frames per second, and 30 (29.97) or 24 (23.976) are also possibilities.

To get slow motion from your footage, and play it back on a regular video device, you DON’T WANT to use Twixtor, because there’s no need to generate new frames. You just need to play the frames you’ve already got back at a slower rate.

Select your 240 fps footage in the Project panel, then right-click and Interpret footage [link]. Choose “Conform to frame rate” and enter one of the values above (depending on which video standard you are delivering for). Doing the math, 24fps will be 10x slower than 240; 30 with be 8x slower; 60 will be 4x slower.

Now drag your re-interpreted footage to the new comp button. Bam! Instant slow mo.

[Gino Brugman] “When i want to render the final product, After effects tell’s me i can only render it to a max. of 99FPS but i need 240.”

AE tops out at 99fps. It can’t go higher. There is no video standard that supports 240 fps. Why do you think you need 240 fps? How can you use 240 fps footage?

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

[Walter Soyka]

[Dave LaRonde] “The concept was solid, but unfortunately TV monitors aren’t exactly Phantom cameras.”

I don’t use the software he mentioned, but it’s since it’s for gamers, I figured it was possible that it grabs data directly from the GPU instead of recording a frame at a time like we would be accustomed to with our video backgrounds.

My question is why he thinks he needs 240 fps on the way out of this process — of course it won’t be playable anywhere.

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

[Gino Brugman]

We’re not talking about any camera… I use a program to record gameplay at 240fps. And wanted to put some part’s in slow-motion. So after the final product is done, the only thing left is rendering. Do I have to render it at 240 fps? Or can i render it as 60fps, maybe even 30fps without affecting the speed?

[Gino Brugman]

Now I get it 🙂 And yes my game put’s out a 240fps, As i raised the the com_maxFPS “90” to 240 in the config file. Thanks for helping, I think ill just render it out as 30fps and see the result 🙂

[Erik Lindahl]

Sometimes I hate these ancient forums, do a replay > get need to log in and loose all my text. Thanks mr Cow!

Anyhow, to try and recap what I wrote. Video games on Mac/PC don’t always follow set standards in terms of frame-rate or frame size. Often the optimal settings for best performance simply output as many frame per second as possible at a given resolution – i.e. this can be anything from 0 fps to over 200 fps and it can variate a lot.

So, say you do have a frap-recording at 240fps the best thing you can do is the following.

1. Note that After Effects is limited to 99 fps comps and probably footage as well. Because of this you can’t edit in “native” 240 fps.
2. To overcome the above limitation I’d recommend converting your fraps footage to an image sequence. I.e. every single frame in the fraps-file should be a seperate image.
3. Import the image sequence and state it should be run at 30 fps.
4. Your recording should now run at 1/8th of realtime. For realtime you need to increase the speed by 800% or 8 frames per frame.

Makes sense?

Sadly I’m not sure how you would do #2.

I personally record game-footage on the Mac and editing can be an issues as you end up with variable frame-rate an a non-standard resolution. My solution is to limit in-game frame-rate to 50 and then converting the video-file to 25 fps after it’s been recorded. This doesn’t allow me any nifty things like slow-motion or anything however.

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Erik Lindahl
Freecloud Post Production Services
http://www.freecloud.se

[Erik Lindahl]

Note that the output frame rate from a game can differ from the the refresh-rate of your screen. This will in general cause screen-tearing. But it’s not uncommon you have games running at say 50 fps in-game and menus roaring by at 200 fps cause cause they are easier for the GPU to render.

If you have a powerful enough system you will enable double / tripple buffer. This will sync the frame-rate with your output device (at the cost of some performance).

All in all editing game-footage can be a pain because of this.

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Erik Lindahl
Freecloud Post Production Services
http://www.freecloud.se