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time remapping expressions taking FOREVER to render

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Anna Hahn
time remapping expressions taking FOREVER to render
on Dec 23, 2018 at 6:45:21 pm

Hello

So I am relatively new to working with time remapping expressions but I have been receiving advice from some people on this forum as well as others and currently have a set of expressions for jumping between random points in a clip and creating fades between the jump cuts- the expressions are working beautifully BUT are taking FOOORREEEVERRR to render~~~ I'm confused because jumping between random points in the timeline and creating opacity fades seems like it wouldn't be particularly computationally taxing- however for some reason these take forever to render with codec settings that take just a few seconds to render out anything else


My setup is this:

two copies of the same clip stacked ontop of each other

TOP LAYER
time remap expression=

segDur = .69;// duration of each "segment" of random time
minVal = inPoint;
maxVal = outPoint - segDur;
seed = Math.floor(time/segDur);
segStart = seed*segDur;
seedRandom(seed,true);
startVal = random(minVal,maxVal);
endVal = startVal + segDur;
linear(time,segStart,segStart + segDur, startVal, endVal);

opacity expression=
segDur = .69;
fadeDur = .77;
t = time%segDur;
linear(t,0,fadeDur,0,100);


BOTTOM LAYER

time remap expression=
fadeDur = .77;
thisComp.layer(index-1).timeRemap.valueAtTime(time - fadeDur) + fadeDur



I have even tried converting all expressions to keyframes and it still produces ridiculously large render times- 1 hour + for 1 minute of footage

Any tips on how to revamp the expression to make it more efficient or any other approach to speeding up the renders? Right now it is impossible for me to even preview the clips in after effects with these scripts because they are so slow they must be rendered out.

Any tips would be infinitely appreciated. Thank you so so much!


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Kalleheikki Kannisto
Re: time remapping expressions taking FOREVER to render
on Dec 24, 2018 at 10:47:05 am

IF your footage is in mpeg format, that can slow things down as AE constructs the current frame from keyframes and changes thereafter. I would try converting it to an uncompressed format where the full image is included at each frame.

On the other hand, in AE 1 hour render time for 1 minute of footage is not unusual. In fact, that's my general expectancy with animations rendered out of AE.

Kalleheikki Kannisto
Senior Graphic Designer


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Anna Hahn
Re: time remapping expressions taking FOREVER to render
on Dec 27, 2018 at 6:04:40 pm

Thank you so much for this- this was incredibly helpful, I switched to cineform and all of the renders sped up dramatically THANK YOU!!

One question~ with the source footage as cineform the renders go much faster AS LONG AS I TURN OFF THE AUDIO FOR THOSE LAYERS- if the audio is on then the renders take quite a long time still~ any way to speed this up and keep audio on?

THANKS!!


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Kalleheikki Kannisto
Re: time remapping expressions taking FOREVER to render
on Dec 28, 2018 at 3:04:23 pm

Since you are not fading the audio, you will get a crazy double audio if you keep it on.

I would try exporting audio only for the two layers SEPARATELY (i.e. with just one of the layers enabled at a time.) Then you can combine them in an editing software.

However, you will still get two layers of audio, which won't make much sense, unless you're after a cacophonic result. I suspect you'll be happier using just one of the audio outputs.

Kalleheikki Kannisto
Senior Graphic Designer


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Anna Hahn
Re: time remapping expressions taking FOREVER to render
on Dec 28, 2018 at 3:35:21 pm

Hi thank you for this!

I actually am after cacophonous sound.

But my issue is more technical than this~ anytime I render with the sound on the renders take 5-10 times as long. My source footage is in a cineform codec. Is there any way to speed this up? Would it make a difference if the audio on the cineform footage were AAC vs WAV?


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Kalleheikki Kannisto
Re: time remapping expressions taking FOREVER to render
on Dec 28, 2018 at 7:52:49 pm

I would try rendering audio only, one layer at a time, and then combine with video in edit. That way the expression only have to deal with the time remapping of one layer at a time.

Kalleheikki Kannisto
Senior Graphic Designer


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