Movies not displaying for some users

URL of experiment: Pavlovia

Description of the problem: The task is an RSVP task with a movie displaying coherent motion in the background. I have tested this out on different computers with different operating systems, and it works on Big Sur and Catalina, on an iMac and a MacBook Pro, respectively. However, one of the students in the lab cannot see the movie in the background using a a MacBook Pro running Big Sur.

For now we are running the experiment and then surveying participants whether they saw the motion in the background. According to the participants, about 20% cannot see the motion, so this is not ideal. It seems to happen most often on PCs, but also on some Macs.


Sorry for the troubles. I see you’re videos use the right codec (see Media formats suitable for online studies — PsychoPy v2021.1). We use the same in our automated tests, and that works fine across platforms.

I do notice you’re running a rather old version of PsychoJS (2020.2). Could well be that upgrading to the newest version (2021.1.4) would help.

Best, Thomas

I notice that motion_movie is in both block_types2.csv and trial_types2.csv (according to the loop definitions). Assuming that you delted it from trial_types2.csv then it might be worth reattaching the spreadsheet to tell Pavlovia.

You also seem to be setting motion_movie twice in code

motion_movie = background.concat(direction)
motion_movie = background.concat(direction)

(with missing semi-colon) so I’m now definitely confused about your spreadsheets. trial_types2.csv seems to have a blank column called direction.

That same code is resetting a variety of parameters in Begin Routine that should be set in Begin Experiment

shuffle = util.shuffle;
stim_dur = 0.088;
isi = 0.032;
tot_dur = stim_dur + isi;
once = 0;
p = 0;
targets = ['2','3','4','5','6','7','8','9'];
letters = ["A", "B", "C", "D", "E", "F", "G", "H", "J", "K", "L", "N", "P", "Q", "R", "S", "T", "U", "V", "X", "Y", "Z"];
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Thanks- I realized the code was a little Frankenstein-like, I had used old code and was updating the javascript code directly. Hopefully updating to the latest code and going about it in a systematic way will fix the bugs.


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Thank you- I had a bunch of things left over from some old code and had been working directly on the javascript code itself. I believe I’ve cleaned it up, and we’ll see if it works more consistently.

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I strongly discourage people you from making edits to the JS files directly.

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