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J
Jesse Toula
Inspiring
June 20, 2015
Question

Expression Evaluation Issue in CC 2015

  • June 20, 2015
  • 2 replies
  • 1477 views

Hi,

I have a script that applies the sampleImage expression to a layer in order to find its boundaries. In all previous versions of After Effects, this script could evaluate a layer in less then a second. In AE CC 2015, the script was failing completely. I found the problem was that the value of the applied script was not being updated fast enough.

In order to get things working i have to add a half second delay each time the expression is changed, so a function that used to take half a second now takes almost 2 minutes.

Has anyone came accross any similar issues or have any ideas for fixing the problem without hurting the performance so much?

Thanks,

Jesse

This topic has been closed for replies.

2 replies

T
techsupp006
Known Participant
October 6, 2016

Hi,

I know this is kinda old thread but I just encountered this issue as well.

I wrote a script with a bi-section sampleImage loop that scans a layer for the alpha channel value to find its bounds.

This script works perfectly and in literally 0 milliseconds in After Effects 2014 CC.

In AE 2015 (any version including the most recent one), I get the an AE internal error and a sorry!  Haven't debugged this thoroughly yet but I'm sure it has everything to do with the new way in which sampleImage is processed asynchronously and I the script doesn't get the correct results when harvesting the sampleImage expression value.

Did you manage to overcome this issue in AE 2015? Is there a way to force run sampleImage synchronously?

using .sleep(1000)  is not an option because that means the scripts takes around 2 minutes per layer because of the sampleImage loop.

I can't figure out why would someone ever need an asynchronous sampleImage anyway... This should maybe be a boolean parameter passed to sampleImage...

I found this thread that addresses the same problem:

Re: Problem with sampleImage in After Effects CC 2015 (Extendscript / Expressions)

but I thought I'd check here first to see if you managed to solve this in 2015 versions.

Thanks

Roy.

Dan Ebberts
Community Expert
Dan EbbertsCommunity Expert
Community Expert
June 20, 2015

Just curious--what does the expression look like?

Dan

J
Jesse ToulaAuthor
Inspiring
June 20, 2015

var theArray = thisComp.layer("theLayer").sampleImage([960,540],[960,50], true, time);

Dan Ebberts
Community Expert
Dan EbbertsCommunity Expert
Community Expert
June 20, 2015

So you've got a loop looking at comp-wide, 100-pixel strips of the layer, looking for non-zero alpha? If you get a hit, then you zero in at finer precision--something like that? So how many times do you have to apply the expression and harvest the results to get the info you need? I assume the target layer is not text or shape because you're not using sourceRectAtTime(), is that correct?

Dan

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