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New Participant
July 6, 2023
Question

Pre-comps Auto Fps

  • July 6, 2023
  • 2 replies
  • 947 views

my main compositions fps is 60, my footage's fps is 23,976, and when i precompose the footage rather than the precomp becoming 60 fps, it becomes the same as the source. before anyone says that's how it's always been, no it isn't. my prefrences got corrupted, then everything got messed up, prior to this i would make a precomp, and it would be the same fps as my main comps, not the source i'm precoming. 

2 replies

Community Expert
July 6, 2023

I have to ask why you have set the main comp to 60 fps when the footage is 23.976? YouTube and Vimeo will throttle 60 FPS uploads to 30 fps for most users because of the bandwidth. Motion Blur in the footage will not match the motion blur for elements in the main comp. Your file size will be more than twice as large as it wold be if you matched the footage frame rate. Render times will be a little more than twice as long. Full Resolution previews will be about half as long.

 

About the only thing you gain in a 60 fps comp is a little more latitude with controlling Judder (the interraction of motion with frame rate that causes things like title rolls to appear to jerk around a bit). The human eye's effective shutter speed is somewhere close to 1/50 of a second, and that's very close to the shutter speed of a motion picture camera running at 24 fps. 

 

Just make sure that you really need 60 fps. If you are going for a cinematic look, it's really hard to get it at 60 fps. 

 

 

 

New Participant
July 6, 2023

for the editing that i do, 60 fps makes it look smoother, therefore more appealing, this has nothing to do with what i needed help with. i'm well aware about those things, and frankly do not care, my point is when i precomp it becomes my footages fps, rather than my main comps fps. i could change it manually, but that's tideous, and doesn't make sense to do considering prior to my prefrences file getting corrupted it would so for me.

Community Expert
July 7, 2023

Dropping 23.976 footage does not change the frame rate of the footage. You just get duplicate frames. When you Pre-compose and move all attributes you still get 23.976 footage in a 60 fps comp and you get duplicate frames. You might be able to get some fairly decent intermediate frames if you try the different frame blending options before you pre-compose. Once you have the frame blending worked out, pre-composing will give you a new comp that matches the frame rate of the footage, but the Frame Blending options will be preserved. The long and short of that workflow is that if you setup frame blending to fix the duplicate frame problem before you pre-compose, you don't have to open up the nested comp (your pre-comp) and change the frame rate. It will propegate.

 

You can test this yourself. Interpret some footage with a very slow frame rate so you can easily see the jumps between frames. You could even use 1 or 2 fps. Scrub through the timeline and watch the footage. Now try the second frame blending option where the icon looks like a funky arrow and you should see some fairly smooth movement. Pre-compose the footage moving all attributes and check it again. You should see the same result. There is no need to open the Pre-comp and fiddle with the frame rates. 

Mylenium
Brainiac
July 6, 2023

What options are you using? Sounds like you're not using "move attributes". Nothing wrong here then. That's how it always has been - if you're moving a single footage source into a pre-comp with "keep attributes (in parent comp), AE will use the source framerate.

 

Mylenium