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Randomization of video sequences

Dear all,

my name is David and I am completely new to working with OpenSesame.
I am working on an experiment with video based decision making, and I am planning to use circa 160 short video clips of 3-6 seconds each. After every clip the participants should answer three short multiple choice questions. I got two questions regarding this.

1) How is it possible to randomize all the videos with each new participant? Is it possible to get a script in which a folder is preselected and the system randomizes all the videos from 001 to 160 and runs them after another?

2) Will I have trouble with the size of an experiment containing 160 videos?

I would be super happy, if someone could help me with my questions!

Greetings, David


  • Hi David,

    actually you can do that quite easily. I am sure that there are several ways to tackle this, but what I did was to have the all the videos as part of a loop. If you have the videoname as a variable, you can simply have the program run through all of them. In addition, you can choose whether Opensesame should grab the vids from your list sequentially or in a random order. If you choose the second, you are good to go ;)

    Regarding performance, it strongly depends on the computer you will be using. If you have a fast pc with a good graphics card, you will be absolutely fine. Since I was running my experiment on notebook with onboard graphics, I had to play close attention to the codec used (divx work great for me) and also on which backend the experiment used (pygame had the best performance for me, though quality was slightly worse)

    hope that helps!


  • Thanks a lot, I finally figured it out!

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