Psychtoolbox release “Scraps” released

Psychtoolbox 3.0.19 update “Scraps” was released at 5th June 2024.
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:

Some of this Psychtoolbox release was sponsored by Mathworks under the year
2023/2024 contract.

Compatibility changes wrt. Psychtoolbox

  • None.


  • None. Just some small fixups for improved Ubuntu 24.04-LTS and Matlab R2024a



  • Psychtoolbox was built and tested against Matlab R2024a.

  • PsychLinuxConfiguration: Quote paths, to improve MLTBX compatibility.

  • PsychLinuxConfiguration(): Add users also to ‘gamemode’ group.
    This provides additional permissions to the gamemoded running on behalf
    of the user, to execute additional performance optimizations as part
    of Priority(n) with n > 0. Needed on at least Ubuntu 24.04-LTS and later.

  • Screen('OpenMovie'): On Linux, use pipewiresink as audio sink if
    available. Should fix the following issue on Ubuntu 24.04-LTS and later,
    and other distributions that use Pipewire as desktop sound server and
    have an outdated buggy Pulseaudio 16 installation, instead of the more
    recent Pulseaudio 17. The bug can’t be fixed on Ubuntu 22.04-LTS without
    manual user workarounds. See following issue for this bug, which is
    likely not encountered often:

    On unfixed affected systems (mostly Ubuntu 22.04-LTS), if there is
    a notable time delay between Screen('OpenMovie') and start of
    video+audio playback via Screen('PlayMovie'), then the movie
    playback will freeze after displaying the 1st video frame for the
    duration of that delay between OpenMovie and PlayMovie, then
    continue. Problem didn’t exist in earler Linux distributions like
    Ubuntu 20.04-LTS and is fixed by this bug fix for later distros like
    Ubuntu 24.04-LTS from April 2024.


  • Psychtoolbox was built and lightly tested against Matlab R2023b.


  • Psychtoolbox was built against Matlab R2023b and tested against
    Matlab R2024a and Octave 8.4 from HomeBrew. It also works on the
    new Octave 9.1 from HomeBrew

  • SetupPsychtoolbox: Quote paths, to improve MLTBX compatibility.

  • TextInOffscreenWindowTest.m: Fix it for Retina displays on macOS. Also cleanup.

  • BitsPlusPlus: Handle Apple macOS Retina displays properly for imaging pipeline validation runs.

  • ImagingStereoDemo: Handle Apple Retina displays properly during movie writing.

  • TwoStateQuery(): Add workaround for broken Matlab R2024a on Apple macOS.


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