TypeError: Cannot read properties of null (reading 'width') - video stimuli

Online experiments
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1

URL of experiment: DOT_MOV [PsychoPy]

Description of the problem:
I am running a study which includes videos, I have successfully ran an identical study but using images instead. However, I seem to run into an error when using video stimuli.
When I try to run my experiment online, it runs normally for a few trials but then eventually I encounter an error that says ‘TypeError: Cannot read properties of null (reading ‘width’)’. I would really appreciate some advice on how to solve this issue.
Thank you!

2

That sounds like you might have a blank row in your spreadsheet.

3

I just finished deleting all blank rows and columns and still continue to get the same error.

4

Try an incognito tab

5

Hi there, I have also just tried that and again encountered the same error.

6

If you have a loop set to random and an error appearing at a random point, try setting the loop to sequential to identify which trial is causing the issue. My assumption was that it was a blank row, but it could, for example, be a problem with one of the video files themselves.

7

Okay thank you, I will try that

8

I have just tried running each set of video files individually and sequentially and they work perfectly with no issues. The error seems to arise when I set the experiment to combine the files and randomise the order they are shown to participants.