Composition speeds up when I change Framerate.

[Alexander5EA9]

Hello!

it used to be like this: If I have a Composition with 25 fps and I want to have a "stop motion" effect, I can either use the effect "posterize time" - OR I change the composition fps to 12 fps.

Today I noticed that if I do that (lower the FPS of the composition) it speeds up the animation accordingly. I tried changing the "preserve framerate" in the advanced setting. 

Basically it behaves like changing how to interpret the footage itself.
I am pretty sure this behaviour is not like it used to be, or I changed some setting I can't find.

I would be really grateful to the community to help me in this matter.

Cheers,
Alexander

[Alexander5EA9 · Accepted solution]

I reset the preferences :
To reset preferences and plug-in cache at the same time, hold down Control-Shift-Alt (Windows) or Command-Shift-Option (Mac OS) while the application is starting.

Now it behaves like before. 

[Rick Gerard]

The timeline and all keyframes are time-based, not frame rate based. Changing the composition's frame rate does not change the speed of the playback. It just changes the number of frames per second. Never has. Never will. 

Changing the frame rate of footage does change the speed of playback. If the original footage was shot at 30 fps and you interpret (change) the frame rate to 60, one second of real-time (original footage time) becomes 1/2-second of screen time. 

Nested compositions (pre-comps) are essentially footage. If you change the frame rate of a nested comp, the playback speed will change just as it changes when you change the interpreted frame rate of the source footage. It has always been that way. It always should be that way.

I'm not sure what you are doing, but I think you are changing the frame rate of a nested composition, turning on Preserve Frame Rate When Nested, and then collapsing transformations. That will always turn off Preserve Frame Rate. It always has.

[Alexander5EA9]

The timeline and all keyframes are time-based, not frame rate based. Changing the composition's frame rate does not change the speed of the playback. It just changes the number of frames per second. Never has. Never will. 

Changing the frame rate of footage does change the speed of playback. If the original footage was shot at 30 fps and you interpret (change) the frame rate to 60, one second of real-time (original footage time) becomes 1/2-second of screen time. 

Nested compositions (pre-comps) are essentially footage. If you change the frame rate of a nested comp, the playback speed will change just as it changes when you change the interpreted frame rate of the source footage. It has always been that way. It always should be that way.

I'm not sure what you are doing, but I think you are changing the frame rate of a nested composition, turning on Preserve Frame Rate When Nested, and then collapsing transformations. That will always turn off Preserve Frame Rate. It always has.

By @Rick Gerard

Thank you for replying! No, it did exactly what I described. It did change the speed of the playback. I also did a test at a colleagues computer. Change framerate to 12 - it stuttered. Then saved the file, send to me and opened on my computer. And it was having faster playback. The question is not if it happened. The question is if it was a bug or a new option I am not aware of. I solved the problem by resetting the preferences.

[Alexander5EA9]

Just to clarify: for my tests I animated a simple shape layer from left to right (no nested compositions). When I changed framerate from 25 to 1 fps, the shape layer moved extremely quickly instead of changing the frame each second.

[Rick Gerard · Accepted solution]

I cannot reproduce your bug. I suggest you reset your preferences and/or reinstall. That kind of a bug makes absolutely no sense at all.

I created a comp, changed the frame rate several times, and found no problems. The comp always remained 4 seconds long. If your comp duration is not changing, your preview is fouled up. I can't make mine foul-up. 

Comp and demo video uploaded.

[Alexander5EA9]

Thanks Rick. I am working with After Effects for 7 years and also have never ever had that problem. That is why i posted here. I am not surprised that you can't reproduce the problem because I wouldn't know how to reproduce it. Like I have stated, it works like in your preview video again, after I had reset the preferences.

Now I wish I had made a video of my problem like you did, like some kind of proof. 😉 It must have been some kind of bug - I have recently installed Overlord and I have recently made a default preset project layout to load each time. No idea if there is a correlation.

And finally, I have been consulting these Forums as a reader for years and I want to thank you for being so helpful to so many people, because I have seen and read your posts many times. 🙂

[vegard26173324egod]

I had this problem and the fix i found was to make sure the fps selected in the preview menu matched the fps in the comp settings.

[silverk6935462]

Hah. Had The same problem as described above. In preview by default the selection is probably on "Auto". This is why u never see that problem. Until it is switches to something else. Good call! Tahnks.