Inquiry about using multiple USB cameras (winvideo) instead of the default gentl, and setting 60 FPS

[Sicheng-package]

I am currently working with your EyeTracker toolbox and have a setup involving three standard USB cameras. While the toolbox defaults to using the 'gentl' adapter for GenICam/industrial cameras, my cameras appear only under 'winvideo'. I am also running into an issue with frame rate detection. Specifically:

Q1:USB Cameras
I can see USB cameras via 'winvideo', but the toolbox code seems to be hard-coded to use the 'gentl' adapter. As a result, it does not detect my cameras properly.

Q2:Frame Rate Error
Since the camera initialisation never succeeds with 'gentl', the variable sET.dblRealFrameRate is never assigned. Consequently, the code throws an error when it tries to set objVidWriter.FrameRate = sET.dblRealFrameRate;.

Q3:Desired Setup (60 FPS)
All my cameras support 60 FPS, and I would like to use the second USB camera (device 2). However, I am not sure where in the code I should modify both the adapter selection (to 'winvideo') and the frame rate assignment (to 60 FPS). I have searched through the documentation and the codebase, but I am still uncertain which files or lines need updating to accommodate a standard USB camera at 60 FPS.

Could you please advise on:

• Which files/functions should be edited to change the adapter from 'gentl' to 'winvideo'?
• How to properly assign sET.dblRealFrameRate (or otherwise configure the toolbox) for a 60 FPS USB camera?
• Whether any other hidden dependencies or parameters must be adjusted for 'winvideo'?

My MATLAB experience is somewhat limited, and the manual does not provide a clear example of using multiple USB cameras. Any guidance or clarification on these points would be greatly appreciated.

Thank you for your time and for creating such a useful toolkit. I look forward to your suggestions.

[JorritMontijn]

Hi Sicheng,

The toolbox can certainly work with winvideo. If you look at the landing page and user manual, it even has a screenshot using my USB webcam using the winvideo driver: https://user-images.githubusercontent.com/15422591/200864719-8d84b70c-d05e-4845-bc62-85f4b2909a76.jpg

I think the two most likely culprits are:

1. You're using a different version of matlab, and this somehow broke the toolbox. Can you test whether it works in R2019b? Or if you don't have that one, some other version between R2016b and R2022b?
2. You have multiple cameras connected, some using gentl, and some using winvideo. I've never tested this type of configuration, so it's possible there's a bug somewhere. Could you test the toolbox with only 1 camera connected to see if you can get it to work that way?

Best wishes & good luck,
Jorrit