Video stimulus is not playing/ stimulus is playing but experiment hangs afterwards

OS: Win10
PsychoPy version: 2021.1.2

I am creating a perception experiment with video stimuli, after every stimulus a question appears on screen corresponding to the video.

The files exist in an unedited version, an edited version where parts of the video are blurred and an edited version with no video but audio only. All files are in mp4 format. Now when I’m running the experiment, the blurred videos and raw video files are playing and the questions appear, but the audio versions cause problems:

I tried two things:

  1. the video as an audio-only file in mp4 format: the files are not played and the experiment ends (error message below)

  2. the video as a black screen with the audio (also mp4 format): the file is played but after the file has been played the experiment hangs and the corresponding questions do not appear. I need to press esc to close the window.

Has anyone here encountered a similar problem and knows how to make the files work?

the error message:

Running: C:\Users\Desktop\PsychoPy folder\

190.4711 INFO Loaded monitor calibration from [‘2021_03_23 11:31’]
pygame 1.9.6
Hello from the pygame community.
Traceback (most recent call last):
File “C:\Users\Desktop\PsychoPy folder\”, line 437, in
File “C:\Program Files\PsychoPy3\lib\site-packages\psychopy\visual\”, line 140, in init
File “C:\Program Files\PsychoPy3\lib\site-packages\psychopy\visual\”, line 182, in loadMovie
if os.path.isfile(filename):
File “C:\Program Files\PsychoPy3\lib\”, line 30, in isfile
st = os.stat(path)
TypeError: stat: path should be string, bytes, os.PathLike or integer, not NoneType
Exception ignored in: <bound method MovieStim3.del of <psychopy.visual.movie3.MovieStim3 object at 0x0000029504A19A58>>
Traceback (most recent call last):
File “C:\Program Files\PsychoPy3\lib\site-packages\psychopy\visual\”, line 499, in del
File “C:\Program Files\PsychoPy3\lib\site-packages\psychopy\visual\”, line 476, in _unload
File “C:\Program Files\PsychoPy3\lib\site-packages\psychopy\visual\”, line 1141, in clearTextures
GL.glDeleteTextures(1, self._texID)
OSError: exception: access violation reading 0x0000000000000000

Experiment ended.

Try changing the opacity to 1 (or upgrading your version).

Thank you for the suggestions! Opacity was already set to 1 before, so that wasn’t the problem I guess. I also just upgraded my version and I’m still encountering the same problems. It’s weird because they all have the same format and two versions are working only the third one doesn’t.