cpp-lln-lab / CPP_PTB

a set of function to make it easier to create behavioral, EEG, fMRI experiment with psychtoolbox
https://cpp-ptb.readthedocs.io/en/latest/index.html#
MIT License
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[BUG]: Trial duration changes across OS and/or if using a second screen or not #169

Open marcobarilari opened 2 years ago

marcobarilari commented 2 years ago

Is there an existing issue for this?

Expected Behavior

If I inputs

% Speed in visual angles / second
cfg.dot.speed = 15;

cfg.timing.eventDuration = 0.30; % second

I expect the same behavior in both OS.

At least in Liege machine and on Marco's Mac this is not the case. In order to have a trial of .6 seconds in xxx (check in which machine) it needs to input .03 cause it is calculated as slower trial.

Current Behavior

No response

Error message

No response

Environment

- OS:
- Matlab:
- SPM:

Anything else?

No response

marcobarilari commented 2 years ago

Ok this seems to be a universal problem not just with dots, also @yyang1234 and @avanaudenhaege need (sometimes?) to double or divide by 2 the stim duration across OS and/or while using a second screen or not.

@Remi, could it be the refresh rate of different screens?

Remi-Gau commented 2 years ago

yeah I saw that issue with @avanaudenhaege as well.

no idea what is going on here because clearly the refresh rate we get from PTB seems correct.