I am using Psychtoolbox 3 for Matlab R2019b on Windows 10.
For a while, the script would run fine until connected to a second monitor (required for the study). At that point, I would get the error message pasted below and the task would terminate. Now, the error message is showing up even when not connected to a second monitor.
It seems there are two different errors here, and we initially thought they were unrelated, but now are not so sure.
I am new to Psychtoolbox (and to Matlab), but have been unsuccessful in identifying a solution through more experienced people or this forum. Help would be hugely appreciated! I would especially appreciate ideas about the source of the problem, potential solutions, or troubleshooting strategies.
Zak
PS: Apologies if I pasted an excessive amount of the error message, but I am not sure where the key information is and don’t want to risk excluding it.
PTB-INFO: This is Psychtoolbox-3 for Microsoft Windows, under Matlab 64-Bit (Version 3.0.16 - Build date: Dec 16 2019).
PTB-INFO: OS support status: Windows 10 (Version 10.0) supported and tested to some limited degree.
PTB-INFO: Type ‘PsychtoolboxVersion’ for more detailed version information.
PTB-INFO: Most parts of the Psychtoolbox distribution are licensed to you under terms of the MIT License, with
PTB-INFO: some restrictions. See file ‘License.txt’ in the Psychtoolbox root folder for the exact licensing conditions.
PTB-INFO: The detected endline of the vertical blank interval is equal or lower than the startline. This indicates
PTB-INFO: that i couldn’t detect the duration of the vertical blank interval and won’t be able to correct timestamps
PTB-INFO: for it. This will introduce a very small and constant offset (typically << 1 msec). Read ‘help BeampositionQueries’
PTB-INFO: for how to correct this, should you really require that last few microseconds of precision.
PTB-INFO: Btw. this can also mean that your systems beamposition queries are slightly broken. It may help timing precision to
PTB-INFO: enable the beamposition workaround, as explained in ‘help ConserveVRAMSettings’, section ‘kPsychUseBeampositionQueryWorkaround’.
PTB-INFO: OpenGL-Renderer is Intel :: Intel® UHD Graphics 620 :: 4.6.0 - Build 26.20.100.7810
PTB-INFO: VBL startline = 1080 , VBL Endline = 1080
PTB-INFO: Measured monitor refresh interval from beamposition = 16.650435 ms [60.058492 Hz].
PTB-INFO: Will use beamposition query for accurate Flip time stamping.
PTB-INFO: Measured monitor refresh interval from VBLsync = 16.670686 ms [59.985534 Hz]. (50 valid samples taken, stddev=0.595100 ms.)
PTB-INFO: Reported monitor refresh interval from operating system = 16.666667 ms [60.000000 Hz].
PTB-INFO: Small deviations between reported values are normal and no reason to worry.
PTB-INFO: ==============================================================================================================================
PTB-INFO: WINDOWS DWM DESKTOP COMPOSITOR IS ACTIVE. On this Windows-10 or later system, Psychtoolbox can no longer reliably detect if
PTB-INFO: this will cause trouble for timing and integrity of visual stimuli or not. You might be just fine, or you could be in trouble.
PTB-INFO: Use external measurement equipment and independent procedures to verify reliability of timing if you care about proper timing.
PTB-INFO: ==============================================================================================================================
WARNING: Couldn’t compute a reliable estimate of monitor refresh interval! Trouble with VBL syncing?!?
----- ! PTB - ERROR: SYNCHRONIZATION FAILURE ! -----
One or more internal checks (see Warnings above) indicate that synchronization
of Psychtoolbox to the vertical retrace (VBL) is not working on your setup.
This will seriously impair proper stimulus presentation and stimulus presentation timing!
Please read ‘help SyncTrouble’ for information about how to solve or work-around the problem.
You can force Psychtoolbox to continue, despite the severe problems, by adding the command
Screen(‘Preference’, ‘SkipSyncTests’, 1); at the top of your script, if you really know what you are doing.
Error using Screen
See error message printed above.
Error in main_PC_scanner_REW31_v1 (line 172)
w=Screen(‘OpenWindow’,0,[0 0 0]);