"PTB - ERROR: SYNCHRONIZATION FAILURE"

30 Ansichten (letzte 30 Tage)
Taylor
Taylor am 24 Dez. 2014
Bearbeitet: Taylor am 21 Feb. 2017
Hi,
I am a research assistant who studies sustained attention using transcranial magnetic stimulation (TMS). I am new to MATLAB, and wish to become acquainted with its features. On my laptop (running MATLAB 8.4 (2014b) in OS X Yosemite), I tried running a script used routinely in our laboratory. (The script uses Psychtoolbox.)
I am getting an error "PTB - ERROR: SYNCHRONIZATION FAILURE" and the script does not proceed further. I would like to know if anybody has any advice on how I could circumvent this. My screen resolution is 1440 x 900 on my Macbook Pro Retina (2012 summer release).
I have pasted the output generated from MATLAB below.
Thank you for your time,
Taylor
>> show_scenes
PTB-INFO: Connection to Psychtoolbox kernel support driver instance #0 (Revision 1) established.
PTB-INFO: Connection to Psychtoolbox kernel support driver instance #1 (Revision 1) established.
PTB-INFO: Disconnecting from kernel driver instance #1 for detected Intel GPU for safety reasons. setenv('PSYCH_ALLOW_DANGEROUS', '1') to override.
PTB-INFO: Running on OSX 10.9+ - Enabling protection against AppNap and other evils.
PTB-INFO: Retina display. Enabling panel fitter for scaled Retina compatibility mode.
PTB-INFO: This is Psychtoolbox-3 for Apple OS X, under Matlab 64-Bit (Version 3.0.12 - Build date: Dec 19 2014).
PTB-INFO: Support status on this operating system release: OSX 10.10 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: Always using Cocoa for fullscreen windows to work around graphics driver bugs in OSX.
PTB-INFO: Presentation timing precision is not yet known for this configuration on most machines. Check your results.
PTB-INFO: OpenGL-Renderer is NVIDIA Corporation :: NVIDIA GeForce GT 650M OpenGL Engine :: 2.1 NVIDIA-10.0.43 310.41.05f01
PTB-INFO: Renderer has 1024 MB of VRAM and a maximum 1024 MB of texture memory.
PTB-INFO: VBL startline = 1800 , VBL Endline = 1851
PTB-INFO: Measured monitor refresh interval from beamposition = 16.669372 ms [59.990264 Hz].
PTB-INFO: Will use beamposition query for accurate Flip time stamping.
PTB-INFO: Measured monitor refresh interval from VBLsync = 16.714368 ms [59.828766 Hz]. (281 valid samples taken, stddev=0.710503 ms.)
PTB-INFO: Small deviations between reported values are normal and no reason to worry.
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 show_scenes (line 43)
window=Screen(Screen_no,'OpenWindow');
  1 Kommentar
Matthew Johnson
Matthew Johnson am 2 Jan. 2015
Hi, I had the same issue with a similar MacBook Air, and it looks like this is not uncommon with PTB and Yosemite. See the release notes:
and the following thread:
https://github.com/Psychtoolbox-3/Psychtoolbox-3/issues/214
... for more information.
I have gotten my setup working, more or less, by enabling the kernel extension (as discussed in the GitHub thread) and doing the trick where you plug in an external monitor. This allows PTB to pass the sync tests in my case. (It seems to work even if I just plug the monitor in and then unplug it again, as Mario suggests in that thread, even if Matlab and PTB are not running when I plug it in.)
It appears from the output I get that PTB is not even using the kernel extension with the Intel graphics that our MacBook Airs have, although I haven't bothered to disable the kernel extension again to check. So I think you could probably skip the kernel extension step and just try the external monitor trick to check it before going further.
If none of those solutions work, you might just have to skip the sync tests (as noted in your error output above and discussed in the GitHub thread) and deal with less-than-perfect timing, unless you are willing to commit to installing Linux or somesuch.
Good luck...

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Antworten (2)

Duru Ozkan
Duru Ozkan am 7 Apr. 2016
Hi,
I am having the same error in Windows 7 with Matlab 2016a:
WARNING: Couldn't compute a reliable estimate of monitor refresh interval! Trouble with VBL syncing?!?
----- ! PTB - ERROR: SYNCHRONIZATION FAILURE ! ----
And I am unable to even use demo scripts. I reinstalled a few times, no luck. Does this sound familiar to anyone?
Help would be much appreciated.
Duru

Han
Han am 11 Aug. 2016
Hi there! Sorry to hijack your question, but I'm also facing the same issue (see error message below). I'm using Psychtoolbox 3.0.13, on OS X 10.11.6 (El Captain). Thought I could have solved it by enabling the kernel extension, did not work. Either I did not enable it correctly, or the issue is of a different nature. Please advise....
PTB-INFO: This is Psychtoolbox-3 for Apple OS X, under Matlab 64-Bit (Version 3.0.13 - Build date: Jun 1 2016).
PTB-INFO: Support status on this operating system release: OSX 10.11 Supported and tested.
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: Installation of the PsychtoolboxKernelDriver is strongly recommended if you care about precise visual
PTB-INFO: onset timestamping or timing. See 'help PsychtoolboxKernelDriver' for installation instructions.
PTB-INFO: Fixed point precision integer framebuffer enabled.
PTB-INFO: OpenGL-Renderer is ATI Technologies Inc. :: AMD Radeon HD - FirePro D300 OpenGL Engine :: 2.1 ATI-1.42.15
PTB-INFO: Renderer has 2048 MB of VRAM and a maximum 1942 MB of texture memory.
PTB-INFO: VBL startline = 1080 , VBL Endline = -1
PTB-INFO: Beamposition queries unsupported or defective on this system. Using basic timestamping as fallback: Timestamps returned by Screen('Flip') will be less robust and accurate.
PTB-INFO: Measured monitor refresh interval from VBLsync = 8.333845 ms [119.992632 Hz]. (479 valid samples taken, stddev=0.508565 ms.)
PTB-INFO: Reported monitor refresh interval from operating system = 8.333333 ms [120.000000 Hz].
PTB-INFO: Small deviations between reported values are normal and no reason to worry.
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 BitsPlusPlus (line 1254)
[win, winRect] = Screen('OpenWindow', screenid, 0, winRect, pixelSize, numbuffers, stereomode, multiSample, imagingmode,
varargin{7:end});
Error in PsychImaging (line 1997)
[win, winRect] = BitsPlusPlus(bpcom, screenid, clearcolor, winRect, pixelSize, numbuffers, stereomode, multiSample, imagingMode,
specialFlags, clientRect);
Error in screenSetUp_DataPixx (line 22)
[w , scrRect] = PsychImaging('OpenWindow', scrNum, scrCol);

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