Psychtoolbox interfaces between Matlab or Octave and the computer hardware. The PTB core routines provide access to the display frame buffer and color lookup table, reliably synchronize with the vertical screen retrace, support sub-millisecond timing, expose raw OpenGL commands, support video playback and capture as well as low-latency audio, and facilitate the collection of observer responses. Ancillary routines support common needs like color space transformations and the QUEST threshold seeking algorithm.

Psychtoolbox has many active users, an active forum, and is widely cited. PTB-3 is based on the deprecated Psychophysics Toolbox Version 2 with its Matlab C extensions rewritten to be more modular and to use OpenGL on the back end. The current version supports Matlab R2012a+ and Octave 3.8 and later on Linux, and Octave 4.4.1 on MacOSX, and Windows.

Psychtoolbox News

Psychtoolbox beta updated

kleinerm

Psychtoolbox 3.0.16 Beta update “Toiletpaperhamsteridiots” was released at 26th March 2020. As usual, the complete development history can be found in our GitHub repository. The release tag is “PTB_Beta-2020-03-26_V3.0.16”, with the full tree and commit logs under the URL:

https://github.com/Psychtoolbox-3/Psychtoolbox-3/tree/PTB_Beta-2020-03-26_V3.0.16

If you choose to use Psychtoolbox with Matlab then the most well tested Matlab versions on Linux are now R2014b and R2019a. The most well tested Matlab version on MS-Windows and macOS is now R2019a. For best results and support, use R2019a.

This release brings minor bug fixes and improvements.

New features and improvements:

All operating systems:

  • PlayMoviesDemo: Add alpha-blending support for transparent movies.

  • Improve help text for Screen Screens?

  • PsychPortAudio: Fix start of capture ‘capturetime’ timestamps in certain exotic conditions.

Linux:

  • Fix default audio input/capture device selection for certain exotic audio input devices which expose separate logical audio devices for playback vs. capture.

  • Cut down on chatter if running on latest generations of AMD gpu’s with DCN display engine, e.g., AMD Ryzen integrated processor graphics (Raven Ridge / Picasso / Renoir / …) and AMD Navi family discrete graphics cards. These latest generation DCN display engines are not supported by our bag of low-level tricks, as there is neither need nor benefit. Spare the user from pointing this out with extra debug clutter.

  • Fix detection code for VRR capable displays (HDMI VRR and DisplayPort Adaptive Sync / FreeSync). The detection code only probed the first connected display output, regardless into which output the display is plugged in, therefore falsely disabling VRR capable displays from using VRR.

macOS:

  • Fix crash on Screen() reload if GStreamer isn’t installed, but libglib is installed by 3rd party, e.g., from HomeBrew.

  • SetMouse: Deal better with Retina displays on macOS: At least if a window handle is provided, this should deal with position scaling on Retina displays if not using native Retina resolution on the trainwreck. Not great, but better than nothing.

Enjoy!

Psychtoolbox beta updated

kleinerm

Psychtoolbox 3.0.16 Beta update “English breakfast” was released at 30th January 2020. As usual, the complete development history can be found in our GitHub repository. The release tag is “PTB_Beta-2020-01-30_V3.0.16”, with the full tree and commit logs under the URL:

https://github.com/Psychtoolbox-3/Psychtoolbox-3/tree/PTB_Beta-2020-01-30_V3.0.16

If you choose to use Psychtoolbox with Matlab then the most well tested Matlab versions on Linux are now R2014b and R2019a. The most well tested Matlab version on MS-Windows and macOS is now R2019a. For best results and support, use R2019a.

This release brings minor bug fixes and improvements to high precision color support on Linux. Especially the 12 bpc 12 bit per color channel output mode (PsychImaging(…‘EnableNative16BitFramebuffer’…) has been improved and now verified to truly provide 12 bpc precision.

New features and improvements:

All operating systems:

  • Fix movie playback with pixelformat = 10, ie. deep color playback of more than 8 bpc content.

Linux:

  • Various high precision color improvements for Linux: Enable 10 bpc framebuffer support on Mesa by default. Make sure video outputs operate at maximum output precision in > 8 bpc modes. Improvements to 16 bpc native framebuffer support on AMD DCE-8+ gpu’s. I have now verified with a ColorCal2 to be able to produce 12 bpc output precision on at least one display with at least one AMD Polaris gpu. This should work with all AMD gpu’s except for ones with the new DCN display engines, ie. it should work starting with “Sea Island” gpu’s, going on to “Volcanic Island”, “Polaris” and ending with “Vega”. AMD Ryzen integrated processor graphics “Raven Ridge” and later, and the latest AMD “Navi” gpu’s are not supported for 11 bpc and 12 bpc mode for the time being.

  • Improve default KbQueue selection to ignore more mice which pretend to be also keyboards.

Windows:

  • More hand-holding for people who are challenged with reading and install the wrong GStreamer variant. Our PsychStartup script tries to detect wrong GStreamer and gives warning and troubleshooting tips.

Enjoy!

Psychtoolbox forum back again on Discourse!

kleinerm

Happy new year!

Our user forum has been resurrected at its new home at Discourse:

Link to new forum at Discourse

This is a way more polished and featureful discussion group system, so it should also provide improved usability. We have to figure out all the new bells and whistles ourselves over time, but all the basics should be ready.

People signed up to the old forum may have to (re-)sign up for the new Discourse forum. Much of the old content from the old YahooGroups forum has been imported into the new forum.

Yahoo has by now deleted all forum content from the old forum, so that one is as dead as it can be - you can delete your bookmarks to it, and R.I.P.

As some stats: The old Yahoo Groups forum had 2,810 subscribers at the time of its shutdown by Yahoo at the end of October 2019, and received 24136 messages during its lifetime from 17th January 2000 to 28th October 2019. We hope the new forum will show as much user engagement, now that it is reestablished!

For bug reports and feature requests, go to our Issue tracker by clicking this link

Hip hip hurray, and post away!

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