# Latest **URL:** https://psychtoolbox.discourse.group/latest.md?page=1 [Latest](https://psychtoolbox.discourse.group/latest.md) · [Categories](https://psychtoolbox.discourse.group/categories.md) · [Tags](https://psychtoolbox.discourse.group/tags.md) **Page:** 2 --- ## [Problems installing PTB on Linux](https://psychtoolbox.discourse.group/t/problems-installing-ptb-on-linux/5759)
**Author:** [@theprof07](https://psychtoolbox.discourse.group/u/theprof07)\ **Replies:** 19\ **Last updated:** [November 13, 2025, 1:35am UTC](https://psychtoolbox.discourse.group/t/problems-installing-ptb-on-linux/5759 "2025-11-13T01:35:15Z")
The NeuroDebian site is not working so I cannot install PsychToolbox. The line “After selecting a release the setup code will be shown here.” is not being replaced with the needed commands after selecting the OS release… --- ## [Frame sequential stereo with Volfoni glasses and VPIXX](https://psychtoolbox.discourse.group/t/frame-sequential-stereo-with-volfoni-glasses-and-vpixx/5768)
**Author:** [@kevdent](https://psychtoolbox.discourse.group/u/kevdent)\ **Replies:** 2\ **Last updated:** [November 5, 2025, 5:06am UTC](https://psychtoolbox.discourse.group/t/frame-sequential-stereo-with-volfoni-glasses-and-vpixx/5768 "2025-11-05T05:06:45Z")
I am trying to use a VIEWPIXX 3D lite connected to a DataPixx3 to present 3-D stimuli using MatLab and the Psychophysics toolbox. I am using Volfoni glasses and a Volfoni emitter. The operating system is Windows 10 and t… --- ## [Modern OLED displays for vision science](https://psychtoolbox.discourse.group/t/modern-oled-displays-for-vision-science/4400)
**Author:** [@tomwallis](https://psychtoolbox.discourse.group/u/tomwallis)\ **Replies:** 10\ **Last updated:** [November 4, 2025, 10:32pm UTC](https://psychtoolbox.discourse.group/t/modern-oled-displays-for-vision-science/4400 "2025-11-04T22:32:40Z")
Hello PTB forum users, I know this topic comes up every so often in different lists, but to my surprise there doesn’t seem to be a recent post on the topic on here. I am looking to purchase a commercial monitor as a “b… --- ## [Joystick driver](https://psychtoolbox.discourse.group/t/joystick-driver/5237)
**Author:** [@gopie](https://psychtoolbox.discourse.group/u/gopie)\ **Replies:** 3\ **Last updated:** [October 27, 2025, 5:30am UTC](https://psychtoolbox.discourse.group/t/joystick-driver/5237 "2025-10-27T05:30:15Z")
Hi All, I’m attempting to install the joystick driver on a 22.04 version of linux that has the hwe installed. However, running the command provided in the instructions (sudo apt install xserver-xorg-input-joystick-hwe-2… --- ## [ASIO now dual licensed under GPLv3](https://psychtoolbox.discourse.group/t/asio-now-dual-licensed-under-gplv3/5764)
**Author:** [@aforren1](https://psychtoolbox.discourse.group/u/aforren1)\ **Replies:** 0\ **Last updated:** [October 22, 2025, 1:53pm UTC](https://psychtoolbox.discourse.group/t/asio-now-dual-licensed-under-gplv3/5764 "2025-10-22T13:53:05Z")
Maybe relevant to some? Press release, SDK page --- ## [Visual Stimuli Off by Factor of Refresh Rate](https://psychtoolbox.discourse.group/t/visual-stimuli-off-by-factor-of-refresh-rate/5763)
**Author:** [@123](https://psychtoolbox.discourse.group/u/123)\ **Replies:** 1\ **Last updated:** [October 21, 2025, 5:53pm UTC](https://psychtoolbox.discourse.group/t/visual-stimuli-off-by-factor-of-refresh-rate/5763 "2025-10-21T17:53:22Z")
Linux - Ubuntu 24.04.3 Kernel Version: 6.8.0-85-generic System: OptiPlex 7090 (0A52) Processor: Intel Core i9-10900 GPU: Advanced Micro Devices, Inc. \[AMD/ATI\] Lexa \[Radeon 540X/550X/630 / RX 640 / E9171 MCM\] GNU Oc… --- ## [Faint frame surrounding Gabor](https://psychtoolbox.discourse.group/t/faint-frame-surrounding-gabor/5762)
**Author:** [@Ghu](https://psychtoolbox.discourse.group/u/Ghu)\ **Replies:** 2\ **Last updated:** [October 3, 2025, 7:04am UTC](https://psychtoolbox.discourse.group/t/faint-frame-surrounding-gabor/5762 "2025-10-03T07:04:22Z")
Hello! Our lab is working on an experiment that involves the presentation of Gabors, but we are noticing a frame-like structure around all four sides of the Gabor that doesn’t fully blend in with the background. It is fa… --- ## [Specify a movie fps different from what is in .mov file](https://psychtoolbox.discourse.group/t/specify-a-movie-fps-different-from-what-is-in-mov-file/5761)
**Author:** [@saumil](https://psychtoolbox.discourse.group/u/saumil)\ **Replies:** 1\ **Last updated:** [September 29, 2025, 11:45pm UTC](https://psychtoolbox.discourse.group/t/specify-a-movie-fps-different-from-what-is-in-mov-file/5761 "2025-09-29T23:45:16Z")
Hi, We are trying to play a series of movies with different fps (e.g. about 24, 25, 30, 60; fps are not exact and have decimal digits, e.g. 29.037) continuously. We are using Psychtoolbox-3 on Linux machine with a Nvidia… --- ## [Intermittent synchronization failure](https://psychtoolbox.discourse.group/t/intermittent-synchronization-failure/5760)
**Author:** [@rdkirkden](https://psychtoolbox.discourse.group/u/rdkirkden)\ **Replies:** 4\ **Last updated:** [September 15, 2025, 8:53am UTC](https://psychtoolbox.discourse.group/t/intermittent-synchronization-failure/5760 "2025-09-15T08:53:53Z")
I’ve been trying to set up a new PC in one of our labs and am quite frequently, but not always, getting a ‘synchronization failure’ error when using Psychtoolbox to run MATLAB demos, or when typing the command ‘VBLSyncTe… --- ## [PsychPortAudio('Start', ...) returns timestamp with large offset](https://psychtoolbox.discourse.group/t/psychportaudio-start-returns-timestamp-with-large-offset/5756)
**Author:** [@skjerns](https://psychtoolbox.discourse.group/u/skjerns)\ **Replies:** 1\ **Last updated:** [August 28, 2025, 6:45pm UTC](https://psychtoolbox.discourse.group/t/psychportaudio-start-returns-timestamp-with-large-offset/5756 "2025-08-28T18:45:42Z")
We’re using a loop to play several audio stimuli withlastStim = PsychPortAudio('Start', handle, 1, 0, 1);. However, the first value returned by the function is offset by a very large number, e.g. it has an offset of last… --- ## [Playing a given sound from a given speaker](https://psychtoolbox.discourse.group/t/playing-a-given-sound-from-a-given-speaker/1323)
**Author:** [@lenarell](https://psychtoolbox.discourse.group/u/lenarell)\ **Replies:** 13\ **Last updated:** [August 14, 2025, 3:07pm UTC](https://psychtoolbox.discourse.group/t/playing-a-given-sound-from-a-given-speaker/1323 "2025-08-14T15:07:14Z")
Hello, I'm using Asio SoundCard with Motu driver and have 3 Speaker. I want to specify at a given time whether the sound will be played on Speaker 1 / 2 / 3 . How could I specify which Speaker should be used (n… --- ## [License management on air-gapped devices](https://psychtoolbox.discourse.group/t/license-management-on-air-gapped-devices/5750)
**Author:** [@hakam.nkassis](https://psychtoolbox.discourse.group/u/hakam.nkassis)\ **Replies:** 2\ **Last updated:** [August 7, 2025, 7:00am UTC](https://psychtoolbox.discourse.group/t/license-management-on-air-gapped-devices/5750 "2025-08-07T07:00:58Z")
3.0.22 - Flavor: Manual Install ———- Windows 11 Hi all, I have a PTB license for multiple devices, one of which is an air-gapped lab PC. The PC has to stay offline for data security reasons. Is there anyway to activate… --- ## [Trigger generation issue](https://psychtoolbox.discourse.group/t/trigger-generation-issue/5491)
**Author:** [@bono.kat](https://psychtoolbox.discourse.group/u/bono.kat)\ **Replies:** 2\ **Last updated:** [August 6, 2025, 2:04am UTC](https://psychtoolbox.discourse.group/t/trigger-generation-issue/5491 "2025-08-06T02:04:49Z")
Dear Community, Info: Psychtoolbox-3 (3.0.19) MATLAB platform (2021b) ubuntu (22.04) I have a very broad question. I am running my experiment and pass the triggers on EEG. However, sometimes random triggers are miss… --- ## [First time using eyelink and psycho toolbox](https://psychtoolbox.discourse.group/t/first-time-using-eyelink-and-psycho-toolbox/5743)
**Author:** [@scientist](https://psychtoolbox.discourse.group/u/scientist)\ **Replies:** 2\ **Last updated:** [July 31, 2025, 10:07pm UTC](https://psychtoolbox.discourse.group/t/first-time-using-eyelink-and-psycho-toolbox/5743 "2025-07-31T22:07:28Z")
Hi, A newbie to eyelink here. I’m trying to do pupillometry simultaneously with a resting-state scan. I’m attaching my Matlab script that I’m trying to use to start eyelink to record below. But it’s unclear to me what … --- ## [iSCAN and PsychToolBox Communication](https://psychtoolbox.discourse.group/t/iscan-and-psychtoolbox-communication/5741)
**Author:** [@chauano](https://psychtoolbox.discourse.group/u/chauano)\ **Replies:** 0\ **Last updated:** [July 29, 2025, 7:18pm UTC](https://psychtoolbox.discourse.group/t/iscan-and-psychtoolbox-communication/5741 "2025-07-29T19:18:50Z")
I am currently using an iSCAN ETL 200 to track eye movements with a task in Psychtoolbox-3. There is a signal shown in the Psychtoolbox control screen, as well as a signal shown in the iSCAN program. However, I am confus… --- ## [Keystrokes generate short beeps](https://psychtoolbox.discourse.group/t/keystrokes-generate-short-beeps/5728)
**Author:** [@mjwenger](https://psychtoolbox.discourse.group/u/mjwenger)\ **Replies:** 3\ **Last updated:** [July 11, 2025, 6:38pm UTC](https://psychtoolbox.discourse.group/t/keystrokes-generate-short-beeps/5728 "2025-07-11T18:38:45Z")
Hardware and software: Mac OS 15.3.1 (24D70) Mac Mini 2024, Apple M4 chip Matlab 2025a Psychtoolbox 3.0.22.0 Paid license I’ve configured this new Mac Mini as above, and tried to run some scripts that run fine on o… --- ## [Psychtoolbox 3.0.22.1 "Little Miss Sunshine!" 💃](https://psychtoolbox.discourse.group/t/psychtoolbox-3-0-22-1-little-miss-sunshine/5732)
**Author:** [@mariokleiner](https://psychtoolbox.discourse.group/u/mariokleiner)\ **Replies:** 0\ **Last updated:** [July 11, 2025, 8:50pm UTC](https://psychtoolbox.discourse.group/t/psychtoolbox-3-0-22-1-little-miss-sunshine/5732 "2025-07-11T20:50:54Z")
Psychtoolbox 3.0.22.1 :sun\_with\_face:“Little Miss Sunshine!”:woman\_dancing: was released at 11th July 2025. You can download it as a zip file from the following link: https://github.com/Psychtoolbox-3/Psychtoolbox-3/re… --- ## [Serial port interface code -- a performance comparison](https://psychtoolbox.discourse.group/t/serial-port-interface-code-a-performance-comparison/3781)
**Author:** [@Ian-Max-Andolina](https://psychtoolbox.discourse.group/u/Ian-Max-Andolina)\ **Replies:** 20\ **Last updated:** [July 1, 2025, 6:59pm UTC](https://psychtoolbox.discourse.group/t/serial-port-interface-code-a-performance-comparison/3781 "2025-07-01T18:59:43Z")
MATLAB has a fairly new (R2019B+) serial port interface, Serialport. Some of my arduino control code had previously used the serial command that MATLAB has now deprecated. So I was curious to compare the old and new inte… --- ## [Sending triggers through parallel port to EEG amplifier](https://psychtoolbox.discourse.group/t/sending-triggers-through-parallel-port-to-eeg-amplifier/4909)
**Author:** [@Maria\_Coelho](https://psychtoolbox.discourse.group/u/Maria_Coelho)\ **Replies:** 7\ **Last updated:** [June 20, 2025, 12:06am UTC](https://psychtoolbox.discourse.group/t/sending-triggers-through-parallel-port-to-eeg-amplifier/4909 "2025-06-20T00:06:12Z")
Hi! I am running my experiment in PTB, while EEG is recording in brain vision recorder. I am having some difficulties in sending triggers through a parallel port. In previous topics I found this possible code: ioObj =… --- ## [Gabor generation](https://psychtoolbox.discourse.group/t/gabor-generation/5724)
**Author:** [@blob](https://psychtoolbox.discourse.group/u/blob)\ **Replies:** 1\ **Last updated:** [June 18, 2025, 2:22pm UTC](https://psychtoolbox.discourse.group/t/gabor-generation/5724 "2025-06-18T14:22:47Z")
what did he mean when he says in the commentars that it could be written in a nicer way? what is wrong with this actual verison? if 1 % Definition of a Gabor patch as Matlab grayscale matrix 'm' with % proper si… --- ## ["Invalid movie handle provided" error message](https://psychtoolbox.discourse.group/t/invalid-movie-handle-provided-error-message/5719)
**Author:** [@inichoson](https://psychtoolbox.discourse.group/u/inichoson)\ **Replies:** 2\ **Last updated:** [June 12, 2025, 11:55pm UTC](https://psychtoolbox.discourse.group/t/invalid-movie-handle-provided-error-message/5719 "2025-06-12T23:55:05Z")
I have a script that just plays videos back to back based off of the “Play Movies Without Gaps” script in PTB’s Movie Demos. I am having a weird issue though where the script consistently picks one movie iteration to qui… --- ## [How to use OBS to screen record a third monitor in a multi-display setup on Linux/Ubuntu?](https://psychtoolbox.discourse.group/t/how-to-use-obs-to-screen-record-a-third-monitor-in-a-multi-display-setup-on-linux-ubuntu/5721)
**Author:** [@autopoiesis](https://psychtoolbox.discourse.group/u/autopoiesis)\ **Replies:** 2\ **Last updated:** [June 8, 2025, 11:35am UTC](https://psychtoolbox.discourse.group/t/how-to-use-obs-to-screen-record-a-third-monitor-in-a-multi-display-setup-on-linux-ubuntu/5721 "2025-06-08T11:35:29Z")
I need to run OBS to screen record one of three monitors (the primary stimulus presentation monitor). However, after configuring the screens via XOrgConf in Matlab, the two additional monitors are now blacked out (with a… --- ## [Absolute scaling of texture values for HDR (BT2100) videos](https://psychtoolbox.discourse.group/t/absolute-scaling-of-texture-values-for-hdr-bt2100-videos/5722)
**Author:** [@mantiuk](https://psychtoolbox.discourse.group/u/mantiuk)\ **Replies:** 2\ **Last updated:** [June 6, 2025, 2:17pm UTC](https://psychtoolbox.discourse.group/t/absolute-scaling-of-texture-values-for-hdr-bt2100-videos/5722 "2025-06-06T14:17:56Z")
When reading frames from HDR video files (BT2100), the values in the textures seem to be in linear RGB BT.2020 colorspace, but absolute scaling of those values differs depending on how the corresponding Psychtoolbox wind… --- ## [Failed to choose the 12-bit precision window on AMD graphics card](https://psychtoolbox.discourse.group/t/failed-to-choose-the-12-bit-precision-window-on-amd-graphics-card/5699)
**Author:** [@ziyuan](https://psychtoolbox.discourse.group/u/ziyuan)\ **Replies:** 20\ **Last updated:** [May 28, 2025, 3:57pm UTC](https://psychtoolbox.discourse.group/t/failed-to-choose-the-12-bit-precision-window-on-amd-graphics-card/5699 "2025-05-28T15:57:13Z")
hi community and team, I encountered problems while setting up Psychtoolbox to achieve a precision of 12 bits. My configuration is as follows: OS: Ubuntu 22.04.5 LTS; GPU: AMD® Radeon pro w7600; Matlab: R2024b; I in… --- ## [Problem with EEG trigger from photodetector recording when importing on Eeglab](https://psychtoolbox.discourse.group/t/problem-with-eeg-trigger-from-photodetector-recording-when-importing-on-eeglab/5716)
**Author:** [@lpeintur](https://psychtoolbox.discourse.group/u/lpeintur)\ **Replies:** 1\ **Last updated:** [May 28, 2025, 9:39am UTC](https://psychtoolbox.discourse.group/t/problem-with-eeg-trigger-from-photodetector-recording-when-importing-on-eeglab/5716 "2025-05-28T09:39:00Z")
Hi, I am preparing my experiment that uses an EEG equipement with dry electorde (wearable sensing) and a photodetector linked to triggerbox to setup trigger. On the EEG software I can see that the trigger is well detec… --- ## [Psychtoolbox 3.0.22.0 release "Oh wie schoen ist Panama!" 🦥](https://psychtoolbox.discourse.group/t/psychtoolbox-3-0-22-0-release-oh-wie-schoen-ist-panama/5715)
**Author:** [@mariokleiner](https://psychtoolbox.discourse.group/u/mariokleiner)\ **Replies:** 0\ **Last updated:** [May 27, 2025, 11:56pm UTC](https://psychtoolbox.discourse.group/t/psychtoolbox-3-0-22-0-release-oh-wie-schoen-ist-panama/5715 "2025-05-27T23:56:38Z")
Psychtoolbox 3.0.22.0 :sloth: “Oh wie schoen ist Panama!” :tropical\_fish: was released at 28th May 2025. :panama: :palm\_tree: You can download it as a zip file from the following link: https://github.com/Psychtoolbox-3… --- ## [Specify start and end time during multiple movie playback](https://psychtoolbox.discourse.group/t/specify-start-and-end-time-during-multiple-movie-playback/5687)
**Author:** [@saumil](https://psychtoolbox.discourse.group/u/saumil)\ **Replies:** 3\ **Last updated:** [May 25, 2025, 7:47pm UTC](https://psychtoolbox.discourse.group/t/specify-start-and-end-time-during-multiple-movie-playback/5687 "2025-05-25T19:47:16Z")
Hi, We have been playing multiple movies sequentially without a break by using async flag 4 for first movie and then 6 for all subsequent movies. And this is working very well. Now we want to specify a start and end fra… --- ## [Paid support membership support suspended until at least mid July 2025. 🌞](https://psychtoolbox.discourse.group/t/paid-support-membership-support-suspended-until-at-least-mid-july-2025/5713)
**Author:** [@mariokleiner](https://psychtoolbox.discourse.group/u/mariokleiner)\ **Replies:** 0\ **Last updated:** [May 25, 2025, 7:41pm UTC](https://psychtoolbox.discourse.group/t/paid-support-membership-support-suspended-until-at-least-mid-july-2025/5713 "2025-05-25T19:41:27Z")
It’s that time of the year. I’m exhausted like never before, and will go on a long vacation throughout June and bits of July, starting in a few days, using up all the carried over remaining vacation days from 2023 and 20… --- ## [Anyone used RTX 4060 with movie playback?](https://psychtoolbox.discourse.group/t/anyone-used-rtx-4060-with-movie-playback/5709)
**Author:** [@saumil](https://psychtoolbox.discourse.group/u/saumil)\ **Replies:** 1\ **Last updated:** [May 16, 2025, 9:57pm UTC](https://psychtoolbox.discourse.group/t/anyone-used-rtx-4060-with-movie-playback/5709 "2025-05-16T21:57:17Z")
Hi, Was wondering if RTX4060 works well with 4K movie playback using latest version of psychtoolbox ? Thanks, Best, Saumil --- ## [About multiple keyboards](https://psychtoolbox.discourse.group/t/about-multiple-keyboards/5704)
**Author:** [@wjl511061](https://psychtoolbox.discourse.group/u/wjl511061)\ **Replies:** 1\ **Last updated:** [May 14, 2025, 2:25am UTC](https://psychtoolbox.discourse.group/t/about-multiple-keyboards/5704 "2025-05-14T02:25:42Z")
Hey everyone! I’ve tried to use PTB in our experiments. In our experiment design, we’ve prepared 2 extra diy-keyboards, one contains numbers from 0-4 and the other contains 5-9. The code is as follows: ---------------… [Previous page](https://psychtoolbox.discourse.group/latest.md) [Next page](https://psychtoolbox.discourse.group/latest.md?page=2)