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Video Stimuli Recommended Format

Description of the problem:

I am intending to use Pavlovia for my experiment. The study contains about 200 video stimuli. I have tested a mini experiment with only 5 videos. Everything seemed to be working. However, when I added more videos (n = 20), the experiment kept crashing/the page froze at the end of the first video/or the screen went blank as soon as I started the experiment.

I believe the culprit is my videos which are very large (~10-15MB each).

I have made these videos in Blender and I have some time to re-render them again. However, before re-rendering them, I want to make sure, what is the best file format/size for Pavlovia to use video stimuli? Like, what is the most compatible codec (H.264, QT, …), video format (AVI, FFmpeg), …?

Thank you so much.

1 Like

How many videos does each participant need? Could you just download the files you need for each participant?

Unfortunately, each participant needs around 120 files.
I managed to downsize the videos from 15MB to 1.3MB by changing the output quality from “lossless” to “mediuam quality”.

Hopefully, Pavlovia will be happy with me now.

Using Pavlovia for online experimentation, I have found the best cross-browser compatibility is achieved by using H.264 encoded MP4 with AAC audio encoding.


Thank you so much. I will get back to y’all if that didn’t work.

Thank you! I am able to run 160 MP4 files with H.264 codec without crashing Pavlovia. Each video is about 1-2.5MB.