Here is the Matlab output on Windows from the play_movie.m code above:
PTB-INFO: This is Psychtoolbox-3 for Microsoft Windows, under Matlab 64-Bit (Version 3.0.18 - Build date: Feb 2 2022).
PTB-INFO: OS support status: Windows 11 (Version 11.0) is not supported.
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: For information about paid priority support, community membership and commercial services, please type
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 NVIDIA Corporation :: NVIDIA GeForce RTX 3080 Laptop GPU/PCIe/SSE2 :: 4.6.0 NVIDIA 472.88
PTB-INFO: VBL startline = 2160 , VBL Endline = 2159
PTB-INFO: Measured monitor refresh interval from beamposition = 502.942388 ms [1.988299 Hz].
PTB-INFO: Will use beamposition query for accurate Flip time stamping.
PTB-INFO: Measured monitor refresh interval from VBLsync = 16.697138 ms [59.890502 Hz]. (39 valid samples taken, stddev=0.471611 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: 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.
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.
PTB-WARNING: Mismatch between measured monitor refresh intervals! This indicates problems with rasterbeam position queries.
----- ! PTB - WARNING: SYNCHRONIZATION TROUBLE ! -----
One or more internal checks (see Warnings above) indicate that
queries of rasterbeam position are not properly working for your setup.
Psychtoolbox will work around this by using a different timing algorithm,
but it will cause Screen(‘Flip’) to report less accurate/robust timestamps
for stimulus timing.
Read ‘help BeampositionQueries’ for more info and troubleshooting tips.
PTB-INFO: There are still 2 movies open. Screen(‘CloseAll’) will auto-close them.
PTB-INFO: This may be fine for studies where you only use a single movie, but a large number of open
PTB-INFO: movies can be an indication that you forgot to dispose no longer needed movie objects
PTB-INFO: via a proper call to Screen(‘CloseMovie’, moviePtr); , e.g., at the end of each trial. These
PTB-INFO: stale movies linger around and can consume significant memory and cpu ressources, causing
PTB-INFO: degraded performance, timing trouble and ultimately out of memory or out of ressource
PTB-INFO: conditions or even crashes of Matlab/Octave (in rare cases). Please check your code.
WARNING: This session of your experiment was run by you with the setting Screen(‘Preference’, ‘SkipSyncTests’, 1).
WARNING: This means that some internal self-tests and calibrations were skipped. Your stimulus presentation timing
WARNING: may have been wrong. This is fine for development and debugging of your experiment, but for running the real
WARNING: study, please make sure to set Screen(‘Preference’, ‘SkipSyncTests’, 0) for maximum accuracy and reliability.