Dear Valsecchimat,
Make sure the screen grab happens after objects are drawn on the screen (otherwise it will be grabbing stuff that doesn’t exist yet).
Also some other fixes are: Exporting experiment to a .mov or mp4 file - #8 by Michael .
Also, with a trial that has fixed durations and object placements, you are better off just having a pre-recorded version of it, then overlaying your eye data post experiment for data analysis/presentation.
Issac