OS (e.g. Win10): Windows 11 Education
PsychoPy version (e.g. 2024.2.4 Py 3.8): 2026.1.1
Standard Standalone Installation? (y/n) If not then what?: Y
Do you want it to also run online? (y/n) N
What are you trying to achieve?:
I have a simple task where I play short video clips (0.5 secs) of faces and then participants must press a key to indicate the emotion. Between video clips I want a fixation cross to appear for 0.5 secs.
At the moment the videos seem to be causing a lag to the fixation cross routine (the fixation cross is appearing for 3-5 secs before the video starts, rather than 0.5 secs). The video clips are already in the preferred format for PsychoPy (Format: MP4; Video codec: H.264; Resolution: 800 × 600; Frame rate: 30 fps), and the videos played fine in previous versions of PsychoPy, when I could use the moviepy backend rather than ffpyplayer, but none of the backends other than ffpyplayer will work at all with my videos in the new version.
What did you try to make it work?: I added in code to check the timing of the fixation and video routines, and PsychPy reports that they are running for the correct amount of time (~0.5 sec), but this is objectively not the case when I use a stopwatch to time the routines. The fixation routine is taking much longer (3-5 secs).
The culprit is definitely the videos, because when I disable the video component or replace with an image instead, the issue goes away.
What specifically went wrong when you tried that?:
It seems like it might be a PsychoPy/ffpyplayer rendering problem. I am using a 60 Hz display, but when I ask PsychoPy to report on the frame rate, it tells me the following:
8.1582 WARNING t of last frame was 2281.06ms (=1/0)
13.5228 WARNING t of last frame was 2626.02ms (=1/0)
18.1835 WARNING t of last frame was 2701.08ms (=1/0)
34.9154 WARNING t of last frame was 2557.55ms (=1/0)
40.2914 WARNING Multiple dropped frames have occurred - I’ll stop bothering you about them!
I would be grateful for any suggestions as to how I can fix this issue to make my experiment run without the lag between trials.