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Noise Stim Error: 2021.1.4

OS (e.g. Win10): Win10
PsychoPy version (e.g. 1.84.x): V2021.1.4
Standard Standalone? (y/n) If not then what?:
What are you trying to achieve?:
I am trying to add a mask stimulus after showing participants a video of a two dimensional object moving across the screen. The mask is to prevent after-images of the object’s stopping point.
What did you try to make it work?:
I added the mask stimulus and did not change any of the defaults because I wanted to see what the mask looked like to start.

What specifically went wrong when you tried that?: PsychopyProblems
I’ve uploaded the error message that appears after the experiment crashes. Everything in my experiment runs smoothly until I added the mask stimulus. Without making any adjustments, the experiment will open to the ID pop up, load on a black screen and then crash. Then I see the attached message. I’ve looked through other posts that seem to mention similar problems, but the solution I found (to go into the coder and change the texture resolution value to the integer value 128 instead of the decimal value of 128.0) does not work for me. When I do this, the experiment opens the ID pop up, loads and then gets stuck on the black screen until I’m forced to close the program.

Hi There,

Please can I check how you implemented a “mask stimulus” do you mean that you had an image component and added a value to the parameter Mask in the texture tab?


Sorry for the confusion I meant the noise stimuli (pictures attached). I’ve been referring to it as a mask, since i’ve been using it as a mask for the experiment.

Hi There,

OK that looks like a bug specific to the version you are using. Are you able to download 2021.2.3 ? That produces the noise grating with defaults.

I just updated my psychopy version to 2021.2.3. The same error code came up after the experiment crashed, just like before.

Hi There,

This might sound small but please can I check you definitely launched the newly installed version? PsychoPy 2021.1.4 launches as PsychoPy3 but 2021.2.3 launches as PsychoPy - so it is easy to accidentally open the prior app on a windows 10.


Here is a screen shot of the top left of my Psychopy window. I opened the program without opening any experiment first. If this isn’t the best way to show the version please let me know, and thank you for your help so far!

Hmm ok yes that does indeed look correct! this is a tricky one as I am also on windows 10 running same version and cannot replicate. Please could you try this demo and let me know if it works for you?
basic_noise.psyexp (7.2 KB)


The demo you sent worked perfectly. I’ll try to find any differences between the demo and my experiment.

I’m still getting the same error despite making sure all of the settings in the stimulus pop-up window are the same. Is there possibly an experiment setting that could cause an issue like this?

Sorry for the multiple replies. I think I figured it out. I still don’t understand the connection between the error code and my solution, but it works now. I have my units in pixels. The default from your demo was height. I changed the noise element size in my experiment to match the pixels. My screen is 1920x1080, so I took the height default value of 0.0625 from the demo, multiplied it by 1920, and put that value in. After that the experiment worked properly.
Thank you for your help and thoroughness!

Aha ok ! Well done figuring it out - I think the link must be that there was a floating point value used in some parameter but the units used was pixels which threw an error (because pixels can only be whole numbers.

Pleased you found your solution!