Psychtoolbox release "Bitty Bits" released

Psychtoolbox 3.0.19 Beta update “Bitty Bits” was released at 26th March 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:

Compatibility changes wrt. Psychtoolbox

  • None.


  • None, just bug fixes and minor improvements, and Octave 9.1 on macOS support.


  • PropixxImageUndistortionThrowaway.m: Fix stupid bug. Don’t close the onscreen
    window and then try use it again afterwards!

  • Fix wrong definition of glPathGlyphIndexRangeNV().

  • Sound input demos: Allow specification of number of input channels.
    For BasicSoundInputDemo and DelayedSoundFeedbackDemo, allow to specify the
    number of inputs, to also deal with sound cards which only provide one mono
    input channel. Continue to default to 2 stereo channels.

  • Various internal cleanups with no immediate user facing benefit.


  • Psychtoolbox was built and lightly tested against Matlab R2023b.

  • Screen: Fix idiotic bug in Screen('GetFlipInfo') there since day 1!
    If a query for a flip info struct was made, but no new struct was available,
    the function errored out, instead of returning an empty return argument!

    This was not ever noticed due to the way our only test scripts for this
    PerceptualVBLSyncTestFlipInfo2 had try-catch-end statement placed just so
    that the error was swallowed and never showed up!

    Fix this properly by returning an empty return argument in this case,
    as expected.


  • Psychtoolbox was built and lightly tested against Matlab R2023b.


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

  • Enable use with the brand-new Octave 9.1.0 from HomeBrew.