UVCCamera does not work on specific device

Question

I am trying to connect a USB Camera with an OTG cable on my Android app and for this purpose I use the UVCCamera repo. All the samples and my app work fine on most devices I have tested, but not on a Motorola E4 (on which I specifically need to run the app).

What I have noticed is that the UsbDevice is detached right after I grant permission to use it, and then is reattached as a new device. If I don't check if this happens I get a NullPointerException as the connection to the device is null when trying to get raw descriptors.

Here are the error messages I get:

E/UsbManager: exception in UsbManager.openDevice
          java.lang.IllegalArgumentException: device /dev/bus/usb/001/008 does not exist or is restricted
              at android.os.Parcel.readException(Parcel.java:1688)
              at android.os.Parcel.readException(Parcel.java:1637)
              at android.hardware.usb.IUsbManager$Stub$Proxy.openDevice(IUsbManager.java:443)
              at android.hardware.usb.UsbManager.openDevice(UsbManager.java:353)
              at com.serenegiant.usb.USBMonitor$UsbControlBlock.<init>(USBMonitor.java:1011)
              at com.serenegiant.usb.USBMonitor$UsbControlBlock.clone(USBMonitor.java:1034)
              at com.serenegiant.usb.UVCCamera.open(UVCCamera.java:192)
              at com.serenegiant.usbcameracommon.AbstractUVCCameraHandler$CameraThread.handleOpen(AbstractUVCCameraHandler.java:444)
              at com.serenegiant.usbcameracommon.AbstractUVCCameraHandler.handleMessage(AbstractUVCCameraHandler.java:300)
              at com.serenegiant.usbcameracommon.UVCCameraHandler.handleMessage(UVCCameraHandler.java:31)
              at android.os.Handler.dispatchMessage(Handler.java:102)
              at android.os.Looper.loop(Looper.java:154)
              at com.serenegiant.usbcameracommon.AbstractUVCCameraHandler$CameraThread.run(AbstractUVCCameraHandler.java:747)


12-07 16:08:36.074 20866-20883/com.serenegiant.usbcameratest E/AndroidRuntime: FATAL EXCEPTION: USBMonitor Process: com.serenegiant.usbcameratest, PID: 20866 java.lang.NullPointerException: Attempt to invoke virtual method 'byte[] android.hardware.usb.UsbDeviceConnection.getRawDescriptors()' on a null object reference
at com.serenegiant.usb.USBMonitor.updateDeviceInfo(USBMonitor.java:900)
at com.serenegiant.usb.USBMonitor$UsbControlBlock.<init>(USBMonitor.java:974)
t com.serenegiant.usb.USBMonitor$UsbControlBlock.<init>(USBMonitor.java:0)
at com.serenegiant.usb.USBMonitor$3.run(USBMonitor.java:563)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.os.HandlerThread.run(HandlerThread.java:61)

Other applications on Google Play that use the same library to connect USB cameras work fine on the Motorola E4 too.

I have also posted the issue on github some time ago but have not got any answers.

UVCCamera does not work on specific device

0 Answers0