High Refresh Rate Rendering with VPixx Devices

Starting from version 1.10, you may choose to render at a high refresh rate in LabMaestro. This process is automated and will adjust your stimuli to the selected mode. Depending on the VPixx device used, the total refresh available will vary according to your device type.

Changing to a High Refresh Rate Mode in LabMaestro

Setting up your Hardware Refresh Rate

To set up your refresh rate, refer to this page: Using the PROPixx within LabMaestro | Setting-up-the-PROPixx-Desired-Resolution-(EDID). Please note that the method for setting up the resolution differs depending on whether you are using a PROPixx with DATAPixx3 or a PROPixx Controller.

Setting up the LabMaestro Mode via Hardware Properties

By clicking on your VPixx hardware in the Project window, under the Environment tab, you can access the device properties. In the Video section, you can select the required video mode for your experiment.

Through Timeline Properties (Preferred Way)

Another option is to specify a rendering mode for the experiment timeline. The rendering mode defined for a specific timeline overrides the one described in device properties, making it useful if you need to change rendering modes between timelines during the experiment. To do so, you must first check the Overriding Rendering Mode box in your timeline’s properties (double-click on the timeline to access its properties). In the properties, select the preferred rendering mode.

Rendering Modes

480Hz (QUAD4X)

In 480Hz mode, video is passed from the software to the display with a required resolution of 1920 x 1080 at 120Hz. Our custom sequencer divides the 1920 x 1080 image into four full-color 960 x 540 quadrants and shows them sequentially. All quadrants are displayed full-screen. As such, this allows the frame rate to be four times higher, sacrificing half the horizontal and vertical resolution.

For more information on the inner workings of 480Hz rendering, please visit the vocal guide on this mode.

1440Hz Grayscale (QUAD12X)

Download the LM project demo here: M16RenderingDemo.lm

In 1440Hz grayscale mode, video is passed from the software to the display with a required resolution of 1920 x 1080 at 120Hz. Our custom sequencer divides the 1920 x 1080 image into 12 grayscale quadrants of 960 x 540 each, from each color channel, and displays them sequentially. All quadrants are displayed full-screen. As such, this allows the frame rate to be twelve times higher, sacrificing half the horizontal and vertical resolution.

High Refresh Rate Demo

Download the demo here: HighRefreshRateDemo.lm

When building an experiment in LabMaestro, it is essential to note that the application automatically handles the splitting of the screen into quadrants and adjusts the resolution accordingly. As such, what you build for your experiment and what you see in the timeline preview reflect what will be shown to the participant.

The above demo is an experiment rendering the counterclockwise rotation of three spirals, updating at 120Hz, 480Hz, and 1440Hz from left to right. The Wait command waits for 1/1440^th of a second, the length of one frame in 1440Hz grayscale rendering. Running this experiment in 1440Hz grayscale will show the three wheels spinning at the same speed, with much smoother movement for the higher refresh rates.

If you have access to a second monitor, or if no PROPixx is connected, you can observe what video is actually sent to the PROPixx. In the Default rendering mode, the second monitor and PROPixx will display the same image. In 480Hz mode, the second monitor will display four quadrants with full color. In 1440Hz mode, the second monitor will display four quadrants with partially overlapping red, white, and blue regions, representing the different frames encoded in each color channel.