I created 10 trials with two conditions, each condition plays a different movie (optic flow or random flow). I loaded the mp4 movies with the function
visual.MovieStim3 and displayed the movies in my trials loop with the function
movie.draw(). Since I have 10 trials, the videos should be shown randomly 10 times, but instead, the code is only displaying the first two videos in a loop of 10 trials. After showing a second video, the window stays black for some second then closes. There is no error thrown.
I added the lines
random_flow_movie.seek(0) following the answer to my question on StackOverflow provided by @Michael, and it worked on my Linux machine that had the Python Version (3.6.4) and the PsychoPy Version (3.2.0).
Now that I am trying it on a MAC computer that has the latest Python Version (3.7.4) and PsychoPy version (PsychoPy3, version 2020.1.2 ), I am running into the same bug, and there was no error thrown. There was only the warning:
WARNING We strongly recommend you activate the PTB sound engine in PsychoPy prefs as the preferred audio engine. Its timing is vastly superior. Your prefs are currently set to use [‘sounddevice’, ‘PTB’, ‘pyo’, ‘pygame’] (in that order).
Therefore, I downgraded the PsychoPy version to 3.2.0, and it is still bugging.
Your help would be very precious because this recurrent bug is preventing me from moving forward with my experiment.
nTrials = 10 nb_conditions = np.arange(1,3) # We have two conditions : Optic flow and Random flow conditions = nb_conditions.repeat(nTrials/2) # 5 times condition_1 and 5 times condition_2 conditions_rand = np.random.permutation(conditions) # Randomize the order of the conditions # Load optic flow and random flow movies (duration of each movie is 200 frames) optic_flow_movie = visual.MovieStim3(win, 'optic_flow.mp4') random_flow_movie = visual.MovieStim3(win, 'random_flow.mp4') # iterate through trials and play movies for trialcount in range(nTrials): optic_flow_movie.seek(0) random_flow_movie.seek(0) for Nframes in range(200): if conditions_rand[trialcount] == 1: optic_flow_movie.draw() elif conditions_rand[trialcount] == 2: random_flow_movie.draw() win.flip() win.close()