Problems installing Psychtoolbox with Octave

Hi, I’m trying to install Psychtoolbox on a Windows 10 computer. I have MATLAB installed but I can no longer use it because I no longer have a license. So I am trying to use Octave instead (the version I have installed is GNU Octave 7.3.0).

I followed the instructions carefully here: Psychtoolbox-3 - Download, Installation, and Update

On step 5, when trying to download it from Octave, I got the following error:

Sorry, this updater doesn’t support your operating system: x86_64-w64-mingw32.
DownloadPsychtoolbox can only install the new (OSX, Linux and Windows)
OpenGL-based versions of the Psychtoolbox-3. To install the older (OS9 and Windows)
versions (not based on OpenGL, aka PTB-2) please go to the legacy Psychtoolbox website:
error: Your operating system is not supported by DownloadPsychtoolbox.
error: called from
DownloadPsychtoolbox at line 335 column 5

I went to the legacy website suggested and got a 404 error. I also tried looking for PTB-2 on the versions page, but couldn’t find it.

Is the version of Octave I’m using too new? Is there a way to get Psychtoolbox-3 working with Octave, or do I need to use PTB-2? (if so, where can I find that?)

I’m happy to provide more information if needed. Please help!

  • Kevin

Use Octave 6.4.0, and make sure it is the 64bit version

Mario has recompiled PTB’s mex files for Octave 7, which will be available whenever PTB V3.0.19 is released. If you don’t want to wait for the official release you can try his development git version (you will need to manually git clone and set this up yourself as this is a development version, do not rely on this for final experiment code etc).

I uninstalled my current version of Octave, and downloaded the 64-bit version of 6.4.0 as you suggested, and get the same exact error code.

Any other idea about what might be going wrong?

Your downloader is over 2 years old and totally outdated, not sure how you got that one if you followed the instructions. But it is weird, because even the old one should have recognized that as a supported platform.

What’s the output of:
strfind(computer, '-w64-mingw32')
~isempty(strfind(computer, '-w64-mingw32'))
IsWin = ~isempty(strfind(computer, 'PCWIN')) || ~isempty(strfind(computer, '-w64-mingw32'))
One of these must fail although it shouldn’t.

Anyhow, the PTB 3.0.19 release is imminent, hopefully today, which on MS-Windows will only support and therefore require Octave 7.3 64-Bit, and GStreamer 1.20.5 or later. The 3.0.18 release can be considered dead and unsupported as of this moment.


My Psychtoolbox downloader is old? I got it from here very recently: Psychtoolbox-3 - Download, Installation, and Update

Outputs are:

>> strfind(computer, ‘-w64-mingw32’)
ans = 7

>> ~isempty(strfind(computer, ‘-w64-mingw32’))
ans = 1

>> IsWin = ~isempty(strfind(computer, ‘PCWIN’)) || ~isempty(strfind(computer, ‘-w64-mingw32’))
IsWin = 1

Given your last paragraph, should I reinstall the latest version of Octave and GStreamer? Will 3.0.19 be on the webpage I linked above, or elsewhere?

That link points to the latest version, which is not what you used. Maybe you have some old verson somewhere in your path, i.d.k.

According to that output, that error message should not have ever showed. Something’s weird on your machine.

It will show there after the announcement.

Yep, I just checked my path and it had an old PTB downloader in my old MATLAB folder. I assumed this wouldn’t be in the path since I just deleted and reinstalled a different version of Octave and didn’t add it manually, so I’m guessing it does that automatically?..

So it installed but gave me the sync error:

Trying to trigger an update of the fontconfig cache if that should prove neccessary.
This may take a couple of seconds, or sometimes even minutes. Please be patient…
PTB-ERROR: Mismatch between requested display swap interval 1 and actual swap interval 0! Synchronization of Screen(‘Flip’)
to display refresh will likely malfunction!
PTB-ERROR: This is either a bug in your graphics driver or system setup, or some misconfiguration in the display setting con
trol panel of your system. See ‘help SyncTrouble’ for more info.

I’m working through the steps in ‘help SyncTrouble’, but am not seeing some of the settings mentioned such as the “Synchronize bufferswaps to the vertical retrace” (or any similarly named settings)
Other settings like “Triple buffering” are already off. My drivers are up-to-date.

Given some of the sync problems I’m reading others have had, I’m afraid it might be a problem of the design of my laptop graphics hardware and drivers, as you have mentioned in other related threads. :confused:

To be clear, this install was with Octave 6.4.0, would you still recommend upgrading to the latest version of Octave, for the impending update?

I’ll look out for that update on the homepage!

Thank you for your super fast response btw :slight_smile:

I think it is better to use whatever is the most current PTB (now 3.0.19) which means a newer Octave and GStreamer would be best…

You can ignore those errors during update, a side effect / false positive of the fontconfig update. If they happen during normal use, that’s a different story.

As of an hour ago, 3.0.19 is out, and 3.0.18 is dead and unsupported. Make sure to get GStreamer 1.20.5 at least, maybe better 1.22.0, as this is the new minimum requirement for proper text rendering on Windows, going forward. Also for Octave, which didn’t need that for text rendering so far, but since now does, as we always use dll’s from GStreamer. This all to reduce maintenance costs, given the piss-poor financial support by our dear users.

As a little remark:

The amount of money in form of researchers work time this alone will waste in a medium size lab, assuming typical salaries, would have made it a sweet deal for almost any MS-Windows using lab to just support us with a 150 Euros/year ptb membership, but what can you do. Penny wise, pound foolish they are…


Hello all,

I am facing a problem when installing the package on Octave 8.3 using the command:

pkg install
error: package is missing file: COPYING
error: called from
install>verify_directory at line 363 column 7
install at line 127 column 9
pkg at line 619 column 9"

tried multiple versions and still no go.
I installed the Gstreamer msvc and SVN

any help will be appreciated,

PTB is not an octave package (well not the last time I checked), so you can’t use pkg install – you either need to follow the instructions on the PTB website to use the installer file, or if you want to install from a github zip, then you need to unzip, then run octave in a terminal (no GUI), cd to the Psychtoolbox folder and run SetupPsychToolbox

What Ian says. Also only for Octave 7.3 on Windows. Latest Octave has compatibility problems with PTB on Windows and thanks to the lack of financial support by our users we don’t have the funding to waste on fixing this. So Octave 7.3 it is for the foreseeable future.