# Video frame rate in Ubuntu **URL:** \ **Category:** Uncategorized\ **Created:** [November 24, 2017, 4:40am UTC](https://psychtoolbox.discourse.group/t/video-frame-rate-in-ubuntu/69 "2017-11-24T04:40:23Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![Allen\_Ingling](https://avatars.discourse-cdn.com/v4/letter/a/a183cd/32.png) [@Allen\_Ingling](https://psychtoolbox.discourse.group/u/Allen_Ingling)\ **Post date:** [November 24, 2017, 4:40am UTC](https://psychtoolbox.discourse.group/t/video-frame-rate-in-ubuntu/69/1 "2017-11-24T04:40:23Z")
Psychtoolbox aficionados:   I’m converting from Mac OSX to Linux, and cannot obtain the required video frame rate.   My system is dual-boot with Mac OSX on one side and Ubuntu on the other.   I can obtain 800 pixels x 600 pixels x 120 Hz on the Mac side, and I’ve confirmed the frame rate with a photometer. So I know that the hardware can support 120 Hz.   But when I run     Matlab \> SetResolution(1, 800, 600, 120)   on Linux the result is     Error using SetResolution (line 105)   Can't find a resolution of 800 x 600 x 120 Hz. Resolution remains unchanged.   See below for system details.   Any ideas?   Regards,   Alan Freeman.     SYSTEM SETTINGS   Processor: Intel Xeon Operating system: Ubuntu 16.04 LTS   TERMINAL   alan@alan-MacPro:~$ sudo lshw [sudo] password for alan: alan-macpro                   description: Tower Computer     product: MacPro5,1 (System SKU#)     vendor: Apple Inc.     version: 0.0     serial: YM142008EUG     width: 64 bits     capabilities: smbios-2.4 dmi-2.4 vsyscall32     configuration: boot=normal chassis=tower family=MacPro sku=System SKU# uuid=84F78D82-FB6A-AC5F-BE13-3CF105E5DC37   \*-core        description: Motherboard        product: Mac-F221BEC8        vendor: Apple Inc.        physical id: 0        serial: J5138018SCZJC        slot: Part Component ... alan@alan-MacPro:~$ xrandr Screen 0: minimum 320 x 200, current 1280 x 1024, maximum 8192 x 8192 DisplayPort-0 connected primary 1280x1024+0+0 (normal left inverted right x axis y axis) 338mm x 270mm    1280x1024     60.02\*+  75.02     1280x960      75.04    70.03    60.00     1152x864      75.00    69.97    59.97     1024x768      75.03    70.07    60.00     832x624       74.55     800x600       72.19    75.00    60.32    56.25     640x480       75.00    72.81    66.67    59.94     720x400       70.08    MATLAB   > \>\> version   ans =   9.1.0.441655 (R2016b)   > \>\> Screen('version')   ans =     struct with fields:        version: '3.0.14.464087083'        major: 3        minor: 0        point: 14        build: 464087083         date: 'Jun  8 2017'         time: '09:04:43'       module: 'Screen'      project: 'OpenGL Psychtoolbox'           os: 'GNU/Linux X11'     language: 'Matlab 64-Bit'      authors: [1×7 struct]   > \>\> Screen('screens')   ans =        0     1   > \>\> ResolutionTest(1)   SCREEN 1: CURRENT COMBINED RESOLUTION:         width: 1920        height: 1440     pixelSize: 24            hz: 60     SCREEN 1 - Output 0: CURRENT RESOLUTION:               width: 1920              height: 1440           pixelSize: 24                  hz: 60              xStart: 0              yStart: 0                name: 'DVI-0'      displayWidthMM: 360     displayHeightMM: 270       SCREEN 1: AVAILABLE COMBINED RESOLUTIONS: 1920 x 1440 1600 x 1200 1280 x 1024 1152 x 864 1024 x 768 832 x 624 800 x 600 640 x 480 720 x 400   SCREEN 1: AVAILABLE COMBINED DETAILED RESOLUTIONS: 1920 x 1440    60 Hz 24 bits 1600 x 1200    70 Hz 24 bits 1280 x 1024    85 Hz 24 bits 1280 x 1024    75 Hz 24 bits 1152 x  864    75 Hz 24 bits 1024 x  768    85 Hz 24 bits 1024 x  768    75 Hz 24 bits 1024 x  768    70 Hz 24 bits 1024 x  768    60 Hz 24 bits 832 x  624    75 Hz 24 bits 800 x  600    85 Hz 24 bits 800 x  600    72 Hz 24 bits 800 x  600    75 Hz 24 bits 800 x  600    60 Hz 24 bits 640 x  480    85 Hz 24 bits 640 x  480    75 Hz 24 bits 640 x  480    73 Hz 24 bits 640 x  480    60 Hz 24 bits 720 x  400    70 Hz 24 bits     SCREEN 1 - OUTPUT 0: AVAILABLE PER OUTPUT DETAILED RESOLUTIONS: 1920 x 1440    60 Hz 32 bits 1600 x 1200    70 Hz 32 bits 1280 x 1024    85 Hz 32 bits 1280 x 1024    75 Hz 32 bits 1152 x  864    75 Hz 32 bits 1024 x  768    85 Hz 32 bits 1024 x  768    75 Hz 32 bits 1024 x  768    70 Hz 32 bits 1024 x  768    60 Hz 32 bits 832 x  624    75 Hz 32 bits 800 x  600    85 Hz 32 bits 800 x  600    72 Hz 32 bits 800 x  600    75 Hz 32 bits 800 x  600    60 Hz 32 bits 640 x  480    85 Hz 32 bits 640 x  480    75 Hz 32 bits 640 x  480    73 Hz 32 bits 640 x  480    60 Hz 32 bits 720 x  400    70 Hz 32 bits     > \>\>   ---
**Author:** ![mariokleiner](https://avatars.discourse-cdn.com/v4/letter/m/13edae/32.png) [@mariokleiner](https://psychtoolbox.discourse.group/u/mariokleiner)\ **Post date:** [November 28, 2017, 7:02pm UTC](https://psychtoolbox.discourse.group/t/video-frame-rate-in-ubuntu/69/2 "2017-11-28T19:02:23Z")
Alan, has this been resolved via Uli's pointers? I wonder if it might make sense to add a little helper function to PTB to automate this process. -mario ---
**Author:** ![Allen\_Ingling](https://avatars.discourse-cdn.com/v4/letter/a/a183cd/32.png) [@Allen\_Ingling](https://psychtoolbox.discourse.group/u/Allen_Ingling)\ **Post date:** [November 28, 2017, 11:02pm UTC](https://psychtoolbox.discourse.group/t/video-frame-rate-in-ubuntu/69/3 "2017-11-28T23:02:41Z")
Mario, Uli: > \> has this been resolved via Uli's pointers? I have two monitors attached to a single video card, with one monitor for command and the other for stimulation. The stimulus monitor is dark until I use Screen to open a window on it. Xrandr reports only on the command monitor, presumably because the stimulus monitor is inactive. I am therefore having trouble running   xrandr --addmode name “800x600\_120” because I can’t find the name of the stimulus monitor. How do I activate a second monitor? > \> I wonder if it might make sense to add a little helper function to PTB to automate this process. I speak Linux poorly, so any help is welcome! Regards, Alan.   ---
**Author:** ![mariokleiner](https://avatars.discourse-cdn.com/v4/letter/m/13edae/32.png) [@mariokleiner](https://psychtoolbox.discourse.group/u/mariokleiner)\ **Post date:** [November 28, 2017, 11:53pm UTC](https://psychtoolbox.discourse.group/t/video-frame-rate-in-ubuntu/69/4 "2017-11-28T23:53:39Z")
---In PSYCHTOOLBOX@yahoogroups.com, \ wrote : Mario, Uli: > > \> has this been resolved via Uli's pointers? > > I have two monitors attached to a single video card, with one monitor for command and the other for stimulation. > > The stimulus monitor is dark until I use Screen to open a window on it. Xrandr reports only on the command monitor, presumably because the stimulus monitor is inactive. I am therefore having trouble running > >   xrandr --addmode name “800x600\_120” > > because I can’t find the name of the stimulus monitor. > > How do I activate a second monitor? > > -\> So xrandr only shows X-Screen 0 (=your desktop GUI display) by default in multi-x-screen mode: Prefixing --screen 1 selects X-Screen 1, the stimulation screen, instead: > > In your case: > > \> xrandr --screen 1 > > would show the output named DVI-0 as assigned to that screen, and its parameters. > > % Generate video timing modeline for 800x600 at 120 Hz: > > \> gtf 800 600 120 > > Gives as output: > >   # 800x600 @ 120.00 Hz (GTF) hsync: 77.16 kHz; pclk: 83.95 MHz >   Modeline "800x600\_120.00"  83.95  800 856 944 1088  600 601 604 643  -HSync +Vsync > > % Add to database of supported modes: > > \> xrandr --screen 1 --newmode "800x600\_120.00"  83.95  800 856 944 1088  600 601 604 643  -HSync +Vsync > > % Add to list of supported modes for video output "DVI-0" on X-Screen 1: > > xrandr --screen 1 --addmode DVI-0 "800x600\_120.00" > > From now on you can either use SetResolution(1, 800, 600, 120) in PTB, or do it also from a terminal: > > xrandr --screen 1 --output DVI-0 --mode 800x600\_120.00 > > You could put these commands into a shell script to execute, or you could also put it into a little Matlab script, which executes them via the system() command. > > One could also put such additional mode definitions into the xorg.conf files generated by XOrgConfCreator, that might be a worthwhile new feature for XOrgConfCreator() for a future PTB beta. > > -mario > > > \> I wonder if it might make sense to add a little helper function to PTB to automate this process. > > I speak Linux poorly, so any help is welcome! > > Regards, > > Alan. > >   ---
**Author:** ![Allen\_Ingling](https://avatars.discourse-cdn.com/v4/letter/a/a183cd/32.png) [@Allen\_Ingling](https://psychtoolbox.discourse.group/u/Allen_Ingling)\ **Post date:** [November 30, 2017, 6:09am UTC](https://psychtoolbox.discourse.group/t/video-frame-rate-in-ubuntu/69/5 "2017-11-30T06:09:58Z")
Mario, Uli: xrandr --screen 1 --addmode DVI-0 "800x600\_120.00" Wow, it works! One could also put such additional mode definitions into the xorg.conf files generated by XOrgConfCreator, that might be a worthwhile new feature for XOrgConfCreator() for a future PTB beta. Good idea. Thanks for your help, Alan.