Problem with playing mp4 online - moving dots movies

URL of experiment:

Description of the problem: I am trying to load some mp4 movies of moving dots and for some reason I am not able to see it on pavlovia. It runs fine locally, and when I try to run it on Pavlovia it doesn’t give me any error but simply does not show up. Any pointers will be very very helpful.

Thanks in advance

Hi Maha,

I ran your experiment on my computer and I also didn’t see the video. Next, I made a simple test experiment that only presents on of your MP4 file, which did work:

I don’t have a solution though (sorry), but I’d like to know what the problem is, hence this reply.

Cheers, Thomas

Hi Thomas,

I can’t pinpoint what the problem is either - it works perfectly fine locally on my device - when I tried a single file it didn’t work but it is good to know that it works for you.

1 Like

@Ram-Maha, try giving your movie a start time of zero, rather than leaving it blank. I think the issue is that your movie start condition is never satisfied when you leave the start time blank, because then the start time is undefined. In the JS code, the start condition of t >= undefined is never true.

1 Like

Hi @dvbridges - Thanks, that was the problem - it works fine now - but the video quality is not great - since these are moving dots - is there a prescription to render videos - in a way where speed information is not compromised?? Any suggestion will help a lot!

Thanks again

Hi all - So my movie component shows up but i am having trouble successfully running all the trials - even with one movie, with the right speed etc… please the new version here: [ ]

around 3-4 trials it pauses and all I see is a static image - ideally i would like to have 240 trials with each having its unique RDK dots …any suggestion on how go about this? and any thoughts on how to do this without overloading memory?


Are you trying to play the same clips multiple times? Cause then your movies will play once and the next time it has to play it will freeze and only show a static image. You can use a code component to reset your videos so they will continue to play multiple times. This link may help you.

Hope this helps!