Problem USB Camera

[robert]

Hi,

I recently ordered a LitePlacer kit and assembled it the last few days. So far I was very satisfied with the detailed documention. Now I am in the setup and calibration phase and have some trouble to get the USB cameras to work in LitePlacer Software.
My OS is Windows 10 and when I plug in the cameras I am able to open the camera in the standard Windows camera app and receive images. However, in LitePacer software I get an error about "Problem Starting down camera" when I want to select one of the LitePlacer USB cameras. I am using the most recent version of LitPlacer Software. Below is an screenshot

liteplacer.png (338.01 KiB) Viewed 9418 times

The log specifies the problem to "Could not get resolution info". Here follows the last part of my og before the error:

Code: Select all

Refresh List
Device 0: HP HD Camera
Device 1: USB 2.0 PC Cam
Device 2: USB 2.0 PC Cam
DownCam_comboBox.SelectedIndex= 1
UpCamera start, moniker= @device:pnp:\\?\usb#vid_5149&pid_13d3&mi_00#6&228c6ece&0&0000#{65e8773d-8f56-11d0-a3b9-00a0c9223196}\global
Could not get resolution info
DownCamera start, moniker= @device:pnp:\\?\usb#vid_5149&pid_13d3&mi_00#7&2353ccfb&0&0000#{65e8773d-8f56-11d0-a3b9-00a0c9223196}\global
Could not get resolution info
DownCamera activated
Select
DownCam_comboBox.SelectedIndex= 1
DownCamera start, moniker= @device:pnp:\\?\usb#vid_5149&pid_13d3&mi_00#7&2353ccfb&0&0000#{65e8773d-8f56-11d0-a3b9-00a0c9223196}\global
Could not get resolution info
Select
DownCam_comboBox.SelectedIndex= 1
DownCamera start, moniker= @device:pnp:\\?\usb#vid_5149&pid_13d3&mi_00#7&2353ccfb&0&0000#{65e8773d-8f56-11d0-a3b9-00a0c9223196}\global
Could not get resolution info

Has anybody noticed this behaviour. Any idea how to solve it? I read though a couple of USB camera troubleshooting already a found nothing that solves my problem.
Thanks for any help!

[JuKu]

This is not a common problem. Let’s try to find out what is the issue. Please try:
- I see you have another camera in your system. Please disconnect both Liteplacer cameras. Can you get the software to show image from that camera? (This to check that the software and your system are not in conflict.)
- Connect the LitePlacer cameras one at a time. Can you get them to function? (Trying to find out if one of them is faulty.)
- In your other video application, can you change the camera resolution or read other camera properties? From both?
- What happens when after selecting the camera, you click stop and start?

I’m sorry I can’t help you right away. Hopefully we can find out what the problem is.

[robert]

The other camera on my system is a built-in webcam. The behaviour in Liteplacer Software is exactly the same with this camera:
1. When I click the "Select" button I get first an error message "Problem starting down camera" and directly afterwards "Problem starting this camera"
2. When I click on the "Start" button I get the error "Problem startig down camera".

In the Windows camera app I can use all cameras (built-in and Liteplacer) and change their resolution, as well.

I might have the wrong camera driver for Liteplacer Software, but so far I didn't do anything else then connecting the cameras and Windows took care of setting them up.

[JuKu]

Thank you for the information. Since the behavior is the same with your built in camera, this is a software problem. It is not a driver issue, I think, since the cameras are supposed to work with Windows standard driver. I’ll have a deeper look at the software. This might take some trial and error to solve, because it works on my Win 10 setup. Do you see any errors on device manager USB or cameras section?

[robert]

In the device manager both cameras are listed under the "Cameras" section as "USB 2.0 PC Cam" without any error or warning.

[JuKu]

Please check your email. (For others following: I have a feeling this might take several tests and reports. I'll post a solution when found, but emails are faster (I get notification on replies) and there is no point making forum posts on dead end debugging.)

[robert]

So I checked the camera setup with the PC of a colleague and it worked out of the box. I found out that there is an issue in case a PC has only one physical USB host controller. My PC unfortunately has only one controller, which I didn't know. I practically had the same issue with the cameras using OpenPnP and their current solution is to use a different computer instead. That is want I am going to do for the moment. I don't know if this issue is technically solvable at all, but it might be an idea to implement a better error message ("Use a PC with more than one USB host controller") to make debugging a bit easier for users.

[JuKu]

In most cases with only one controller, the “robust” switch method does work. This disconnects (or tries to) disconnect the unused camera, using only one at a time. It appears that your computer doesn’t actually do that, or keeps the existing camera on the bus(maybe?). I have no idea why the other application works; as far as I know, the LitePlacer and OpenPnP use the correct OS calls.