Psychtoolbox update "Experimental Taylor expansion " SP2

Psychtoolbox 3.0.18 Beta update "Experimental Taylor expansion " SP2 was released at 20th April 2022. As usual, the complete development history can be found in our GitHub repository. The release tag is “”, with the full tree and commit logs under the URL:

This release contains minor improvements and fixes. Also hopefully basic Ubuntu 22.04-LTS support for the upcoming Ubuntu 22.04.0-LTS “Jammy Jellifish” release.


  • GetClicks(): Add timeout for 1st click, and click time reporting.
  • Setup/Download/UpdatePsychtoolbox(): Add highly experimental optional support for non-interactive operation. May help sysadmins to setup multiple machines faster without too much user interaction. Experimental, unsupported in case of trouble, will not work easily on Linux - would need more work to update PsychLinuxConfiguration.
  • PsychPaidSupportAndServices(): Update language a bit for new support conditions.
  • Fixes by Diederick for DrawFormattedText2() cached text drawing while geometric transformations are applied.
  • DKLDemo.m: Some comment fixes by David Brainard.


  • PsychPortAudio(): Change realtime priority setup for ALSA and Pulseaudio: Instead of assigning static FIFO RT priority 1, use priority of main thread (aka Priority()) + 4, so audio processing stays at higher RT priority than main thread or other PTB threads. May help some special edge cases, e.g., Microsoft Surface Pro 6 audio glitches in some scnearios that I could not reproduce, but a user could. See Audio and Surface Pen questions
  • Add a GitHub actions CI setup to allow to build our mex files for 64-Bit Linux on Intel in the GitHub cloud, both for Octave 5.2 and Matlab under Ubuntu 20.04-LTS.
  • Make Screen() mex files hopefully compatible with Ubuntu 22.04.0-LTS, by changing link dependency to libdc1394-25. Only lightly tested.


  • Require use of GStreamer 1.18.x series, 1.18.5 as latest tested release. GStreamer 1.20 contains multiple potential compatibility bugs wrt. fontconfig / high quality text rendering under Matlab + Windows. Octave 6.4 + Windows should be unaffected, as are other operating systems.