Psychtoolbox 3.0.19.15 release "Last free lunch"

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Psychtoolbox 3.0.19 update “Last free lunch” was released at 3rd November 2024.
The complete development history can be found in our GitHub repository.
The release tag is “3.0.19.15”, with the full tree and commit logs under the URL:

https://github.com/Psychtoolbox-3/Psychtoolbox-3/tree/3.0.19.15

This is almost certainly the last release of the free 3.0.19 series.

Compatibility changes wrt. Psychtoolbox 3.0.19.14:

  • None.

Highlights:

  • None. Only bug fixes for various 3rd party components, and small improvements.

All:

  • Change enumeration order of video capture devices. This should avoid
    selection of suboptimal capture devices by preferring more optimal ones,
    especially on modern Ubuntu 22.04-LTS and later Linux distributions, which
    often choose the new but immature pipewiresrc as video source plugin for a
    camera instead of the old and proven/mature more optimal v4l2src as video
    source. Specifically we hope to avoid VideoRecordingDemo.m problems like
    the ones encountered in the following thread:

    Codecs in VideoRecordingDemo not working on Linux

  • PsychImaging: Fix HDR mode with types of PsychColorCorrection() that involve
    lookup tables and only use one color correction operation in total. E.g,
    standard LUT based correction, 3D LUT based correction or application of
    per-pixel gain matrices. See:

    Best approach for gamma correction in HDR10?

  • CI release scripts: Disable building of .mltbx files for releases for now.

    The current approach contributed by Mathworks team is broken. It includes the
    whole Psychtoolbox-3 tree for some utterly unclear reason, although the project
    file only specified the Psychtoolbox/ subfolder. Worse, it adds toolbox folders
    to the Matlab path in randomized (!?!) order, so our carefully selected ordering
    of MatlabWindowsFilesR2007a/ folder wrt. PsychBasic folder gets screwed up and mex
    files can’t be found on MS-Windows anymore. Even worse, if SetupPsychtoolbox() fixes
    it, then the Matlab Add-On Manager undos the fix every single time Matlab restarts!
    This leads to issues like the following linked one:

    Problem with 'Screen' function - PTB just installed - #9 by gtrumpy

    Apart from that, the Add On manager doesn’t allow toolbox updates, and doesn’t
    set things like the Matlab Java path, doesn’t deal with GStreamer etc. It has
    zero benefit for our users, but is a source of hazarads and extra support overhead.
    Drop it.

  • Add Psychtoolbox/PsychBasic/PsychPlugins/ to the search path for dynamic shared
    libraries for all operating systems, so PTB specific plugin libraries can be found
    during mex file load time.

Linux:

  • Psychtoolbox was built and tested against Matlab R2024a and Octave 5.2 and later.

  • PsychImaging: Update ‘EnableNative16BitFramebuffer’ help text for year 2024.

  • Screen: Fix Vulkan display backend support with Mesa versions 23.3 and later
    and thereby for Ubuntu 24.04-LTS and later. The same problem that affected the
    Broadcom VideoCore 6 of the RaspberryPi 4 and later under Mesa 23.3 now affects
    at least Intel and AMD under Mesa 24.0 with Ubuntu 24.04.0-LTS.

    It appears a slightly broken GL_EXT_direct_state_access implementation
    in Mesa was introduced in Mesa 23.3 and later. Work around this in an effective
    and safe way.

  • PsychVulkan: Add workaround against an AMDVLK bug that causes crash if the used
    Vulkan display monitor has more than 64 video modes. A proper fix, especially
    for multi-display setups, can only be done in a future AMDVLK driver from AMD’s
    Vulkan team, but for single display stimulation this workaround should prevent
    crashes and problems, and on some multi-display setups things may still work
    with a sprinkle of dumb luck - no guarantees for multi-display though!
    Note that the AMDVLK driver is only used on AMD gpu’s if a color depth of more
    than standard 8 bpc (aka “deep color”) or HDR-10 display mode is requested. For
    other Vulkan use cases, the high quality Mesa radv Vulkan driver is used, which
    does not suffer such a problem. For context see:

    Vulkan breaks with *** stack smashing detected ***: terminated

  • XOrgConfCreator: Adapt to Ubuntu 24.04-LTS changes in /dev/dri/card enumeration.
    This broke hybrid graphics laptop detection, at least on three single gpu
    laptops with AMD gpu’s. It reported a dual-gpu config when there was not any.
    Since Ubuntu 24.04-LTS, or more likely with a recent Linux 6.8 kernel shipping
    in both Ubuntu 24.04-LTS and in Ubuntu 22.04.5-LTS with HWE stack, the first
    (and only) gpu on a single gpu machine now has a /dev/dri/card1 device file,
    instead of a /dev/dri/card0 device file, ie. device file indexing now starts
    at 1 instead of 0. On multi-gpu machines, the second gpu is now associated
    with /dev/dri/card2 and so on. This broke some hard-coded assumptions about
    0-based device numbering. We now use a more robust detection logic for hybrid
    gpu detection. The fix was successfully tested on single-gpu AMD and Intel
    graphics machines, and on a dual-gpu Intel + AMD laptop for each gpu and in
    prime render offload mode.

  • Add braces for NetWM reporting to make compiler happier. It caused a weird
    problem in the Screen mex build for Matlab, in which the “PTB-INFO: …” lines
    about the used flip timestamping mechanism are not printed! No clue why, looks
    like some compiler bug, but adding the - technically not needed - braces fixes
    it.

Windows:

  • Psychtoolbox was built and lightly tested against Matlab R2024a and Octave 7.3.

  • VideoRecordingDemo.m: Remove special case MS-Windows path. It does not seem to
    be as necessary anymore with the future default MediaFoundation path for capture
    and recording. Also added some cleanups and ability to specify video capture
    device as argument.

macOS:

  • Psychtoolbox was built and tested against Matlab R2024a and against Octave 9.2
    from HomeBrew.

Enjoy!