Introducing variance to the playback speed of a clip, using expressions and time remapping

[Darby Edelen]

The temporalWiggle() function will get closest to what you’re describing without having to write a lot of code. This may still cause your clip to play backwards (especially at higher amplitudes) but you can check your time remap property in the graph editor while varying the values to get something that works for you.

Darby Edelen

[Perry Kroll]

This is a great function, which I did not know about, but I’m finding that it still causes backwards playback no matter how I tweak it.

I’ve got a pre-comp with a bunch of text scrolling one line at a time, at a set interval, and I’m trying to simulate a computer terminal readout where it sometimes slows down or speeds up, so with scrolling text it’s really obvious when this doubles back on itself for a moment.

Does anyone know of an example script that someone has written somewhere which demonstrates the ‘a lot of code’ method for approaching something like this?

[Perry Kroll]

Well, I did some more fussing, and I ended up with this, which is a modified script I found posted on this site by Dan Ebberts:

Adder = thisComp.layer("speed controller").effect("Slider Control")("Slider");
f = timeToFrames(time);
Cumulo = 0;
for (i = 0; i <= f; i++){
t = framesToTime(i);
Cumulo += Math.max(0,((Adder.valueAtTime(t)+1.6)/30));
}
Cumulo%38.9

The speed controller is a null slider with a wiggle on it.

wiggle(8,6)

This line
Cumulo += Math.max(0,((Adder.valueAtTime(t)+1.6)/30));

Does some hardcoded tweaking to effect how that number from the wiggler is used. Whenever the value+1.6 is below 0 the scrolling text simply pauses. The whole thing is also divided by 30. All arbitrary numbers that just looked good.

This was, of course, abysmally slow once out into the 1-2 minute range, and I ended up baking the expression to keyframes.

[Dan Ebberts]

I love it when my old posts beat me to the punch. Good job!

Dan