OpenFaceOffline.exe crashes when trying to open webcam

[SilentSin]

I just downloaded the latest executables (OpenFace_2.0.3_win_x64.zip) from https://github.com/TadasBaltrusaitis/OpenFace/releases and it works fine with a video file but I can't get it to work with a webcam. When I go to File/Open Webcam it opens another window that says "Loading Webcams" then crashes after a few seconds.

Compiling it from source and running inside VS in Debug mode gives the following exception:

System.ArgumentException: 'Value does not fall within the expected range.'

In OpenCVWrappers.h at line 230

The line is return gcnew WriteableBitmap(Width, Height, 72, 72, Format, nullptr);

Width and Height are 0 and Format is Gray8

I'm using Windows 10 with an Intel RealSense D435 camera in case it matters.

[SilentSin]

If I try File/Open Webcam without the webcam plugged in, it shows a "No cameras detected" dialog box.

Then if I do it again, it shows the same dialog ... then crashes (It shows the Windows dialog "OpenFaceOffline has stopped working") with the following exception:

System.InvalidOperationException: 'Cannot set Visibility or call Show, ShowDialog, or WindowInteropHelper.EnsureHandle after a Window has closed.'

In MainWindow.xaml.cs as line 875.

The line is cam_sec.Visibility = System.Windows.Visibility.Visible;

[TadasBaltrusaitis]

For the first part of the issue:

• Is the RealSense camera a depth camera or does it also have an RGB module? OpenFace works with visible light (RGB) cameras only, I haven't tested it with a RealSense camera before.
• The second issue sounds like a bug, I will try reproducing it and fixing it, thanks for reporting it

[SilentSin]

The RealSense camera has both depth and RGB. When I list the webcam devices in Unity they each show up as a separate device.

I seem to have fixed it by going to CameraSelection.xaml.cs line 63 and adding:

if (s.Item4.Width == 0 || s.Item4.Height == 0)
    continue;

to the start of the foreach loop so it skips over the depth camera which I'm assuming was failing to give its width and height for whatever reason.

Should I still be incrementing the i variable to match the device index? I can't tell if this would screw up when there are more webcams after the skipped one.

[TadasBaltrusaitis]

Thanks for the update, I will investigate this further with a multi-camera setup.

[PhilGauthier]

Hi,
I got the same issue off the demos program crashing when searching for webcams. From a video file it works. At first i had several built-in, I disabled them to have a single one, and tryed several webcams models (Logitech, Microsoft). I tried deleting the generated camera_list.xml also to make sure he was searching one and it looks suspicious :
<?xml version="1.0"?> <opencv_storage> <cameras> <_><name>"NewTek NDI Video"</name> <resolutions> <_><res>"320x240"</res></_> <_><res>"640x480"</res></_> <_><res>"-1x-1"</res></_></resolutions></_> <_><name>"Microsoft LifeCam VX-5000"</name> <resolutions> <_><res>"1920x1080"</res></_> <_><res>"-1x-1"</res></_></resolutions></_></cameras> </opencv_storage>
I'm on windows 10 and OpenFace_2.2.0_win_x64.

[TadasBaltrusaitis]

Thanks, interestingly it seems to be listing negative values for resolutions. Annoyingly, I can't seem to reproduce the issue my end, but the negative values might provide a hint of what's going wrong.

[PhilGauthier]

If I do gui/OpenFaceOffline/UI_items/CameraSelection.xaml.cs:43

// Finding the cameras here
if (cams == null)
{
	String root = AppDomain.CurrentDomain.BaseDirectory;
	//cams = CameraInterop.Capture.GetCameras(root);
	List<Tuple<int, String, List<Tuple<int, int>>, OpenCVWrappers.RawImage>> camsTmp;
	camsTmp = UtilitiesOF.SequenceReader.GetCameras(root);
	cams = new List<Tuple<int, String, List<Tuple<int, int>>, OpenCVWrappers.RawImage>>();
	foreach (var s in camsTmp)
	{                   
		if ( s.Item4.Width > 0 && s.Item4.Height > 0)
			cams.Add(s);
	}
} 

It works

[TadasBaltrusaitis]

Thanks for the fix, I'll include it in the next version