use combobox to select v4l2loopback video device

[yetist]

Please review and test.

[yetist]

Before:

After:

[colemickens]

Is it possible that this doesn't work with devices that have exclusive_caps=1 ?

[colemickens]

I can confirm, if I remove these lines, then I still get a dropdown, and I get all v4l2 devices in the dropdown:

        if (video_cap.capabilities & V4L2_CAP_DEVICE_CAPS) {
            caps = video_cap.device_caps;
        } else {
            caps = video_cap.capabilities;
        }

        if (!(caps & V4L2_CAP_VIDEO_CAPTURE)) {
            ::close(fd);
            continue;
        }

        if (strcmp((char*) video_cap.driver, "v4l2 loopback") != 0) {
            ::close(fd);
            continue;
        }

One of those checks doesn't hold when exclusive_caps=1 is used.