Unknown error when running experiment in Pavlovia

URL of experiment: Pavlovia

Description of the problem: I have designed an experiment in psychopy which I now need to run in pavlovia as part of a University thesis project. The experiment involves a series of videos with slider responses playing in a randomised loop. The following error appears when I try to run my experiment in pilot mode on pavlovia:

Unfortunately we encountered the following error:

  • when setting the movie of MovieStim: practice_movie
  • he argument: RIFF �AVI LIST�hdrlavih8V�x����LISTtstrlstrh8vidsd�x�strf((��dvsd��Cr8rT���TorPPrPRC.prproj/LAdobe Premiere Pro CS6 (WindowsLISTJINFOICRD2016-02-03T10:21:44ISFT!Adobe Premiere Pro CS6 (Windows)LIST,Tdattc_O00:00:00:00tc_A00:00:00:00JUNK.

Try to run the experiment again. If the error persists, contact the experiment designer.

The experiment works perfectly in psychopy, and I have tried a variety of things to solve this problem but the error message persists. If anyone can help explain this error message to me, it would be greatly appreciated, as I am an absolute beginner when it comes to programming experiments. I have also attached a photo of the error message, unfortunately, I cannot read the entire message as unknown symbols are appearing as boxes on my computer.

Thank you,


What format is your practice movie in?


The videos are in “.avi” format

Use H.264 encoded MP4 files with AAC audio encoding. d.govan

(Quote is from my crib sheet)

Hi, there is actually no audio on the videos, do I still need to change the format in that case?

Definitely try mp4 instead of avi

Hi, I converted the videos to mp4 successfully, and my experiment is now starting up, but after my introduction text shows, there is just a blank white screen when the videos should begin playing. No error message is appearing but the videos still aren’t playing for me. I have tried changing the start time of the video to 1 second from zero seconds, and the size of the video to [1,2] as is recommended in psychopy. The videos are followed by a slider response. Any advice on further changes I may need to make? Thank you for your help!