Qt6 MediaDevices Class Does not Recognize Custom Camera Devices

jellyfish

Hello, we cross-compile a Qt app from a Ubuntu Desktop VM to a commercial embedded device running Ubuntu 22.04. The embedded device has some custom camera devices that use a custom V4L driver and enumerate as /dev/video*. When the app was running in Qt5, we used the Camera QML component to display live camera footage. We assigned the device node "/dev/video*" to deviceId of the Camera component and it recognized the device. Here's a snippet of the code.

VideoOutput {
    id: cameraVideo
    visible: false
    flushMode: VideoOutput.LastFrame
    source: Camera {
        id: camera
    }
...
}
...
camera.deviceId = "/dev/video3"
camera.start()

As we moved to Qt6, we're using the new MediaDevices component to enumerate camera devices. Our problem is that the MediaDevices component enumerates off-the-shelf web cams, but not our custom devices.

MediaDevices {
    id: mediaDevices
}
Camera {
    id: camera
    cameraDevice: mediaDevices.videoInputs[0] // this list is empty with our camera devices connected
}

Can you please let me know what it takes to be recognized by MediaDevices?

Here's some more property information about our device for your reference.

bsci@611f7feec5ff:~$ v4l2-ctl --get-fmt-video -d /dev/video4
Format Video Capture:
        Width/Height      : 560/480
        Pixel Format      : 'RGB3' (24-bit RGB 8-8-8)
        Field             : None
        Bytes per Line    : 1680
        Size Image        : 806912
        Colorspace        : sRGB
        Transfer Function : Default (maps to sRGB)
        YCbCr/HSV Encoding: Default (maps to ITU-R 601)
        Quantization      : Default (maps to Full Range)
        Flags             :