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I have an old Creative NX Pro webcam. In short, guvcview and v4l2ucp work perfectly; cheese can't find the webcam; and Skype can find the webcam but shows a black screen.

Diagnostics:

$ cat /etc/lsb-release 

DISTRIB_ID=Ubuntu

DISTRIB_RELEASE=18.04

DISTRIB_CODENAME=bionic

DISTRIB_DESCRIPTION="Ubuntu 18.04.1 LTS"



$ dmesg

[   36.781826] Linux video capture interface: v2.00

[   36.807977] gspca_main: v2.14.0 registered

[   36.812809] gspca_main: gspca_zc3xx-2.14.0 probing 041e:401e

[   36.885023] input: gspca_zc3xx as /devices/pci0000:00/0000:00:1d.7/usb1/1-6/1-6.4/input/input12

[   36.885186] usbcore: registered new interface driver gspca_zc3xx



$ lsusb

Bus 001 Device 007: ID 041e:401e Creative Technology, Ltd Webcam NX Pro



$ lsmod

Module                  Size  Used by

v4l2_common            16384  1 gspca_main

videodev              184320  3 v4l2_common,gspca_zc3xx,gspca_main

gspca_zc3xx            57344  0

gspca_main             36864  1 gspca_zc3xx



$ find /usr/lib -iname '*v4l*'

/usr/lib/x86_64-linux-gnu/libgviewv4l2core-2.0.so.2

/usr/lib/x86_64-linux-gnu/directfb-1.7-7/interfaces/IDirectFBVideoProvider/libidirectfbvideoprovider_v4l.so

/usr/lib/x86_64-linux-gnu/libv4l

/usr/lib/x86_64-linux-gnu/libv4l/v4l2convert.so

/usr/lib/x86_64-linux-gnu/libv4l/v4l1compat.so

/usr/lib/x86_64-linux-gnu/libv4l/plugins/libv4l-mplane.so

/usr/lib/x86_64-linux-gnu/libv4l2.so.0

/usr/lib/x86_64-linux-gnu/libv4l1.so.0.0.0

/usr/lib/x86_64-linux-gnu/libv4l1.so.0

/usr/lib/x86_64-linux-gnu/libv4lconvert.so.0

/usr/lib/x86_64-linux-gnu/libgviewv4l2core-2.0.so.2.0.0

/usr/lib/x86_64-linux-gnu/libv4lconvert0

/usr/lib/x86_64-linux-gnu/libv4lconvert.so.0.0.0

/usr/lib/x86_64-linux-gnu/libv4l2.so.0.0.0



$ sudo apt install v4l2ucp

$ v4l2ucp

# Works perfectly, including preview



$ guvcview 

GUVCVIEW: version 2.0.5

V4L2_CORE: (UVCIOC_CTRL_MAP) Error: Inappropriate ioctl for device

V4L2_CORE: (UVCIOC_CTRL_MAP) Error: Inappropriate ioctl for device

V4L2_CORE: (UVCIOC_CTRL_MAP) Error: Inappropriate ioctl for device

V4L2_CORE: (UVCIOC_CTRL_MAP) Error: Inappropriate ioctl for device

V4L2_CORE: (UVCIOC_CTRL_MAP) Error: Inappropriate ioctl for device

V4L2_CORE: (UVCIOC_CTRL_MAP) Error: Inappropriate ioctl for device

V4L2_CORE: (UVCIOC_CTRL_MAP) Error: Inappropriate ioctl for device

V4L2_CORE: (UVCIOC_CTRL_MAP) Error: Inappropriate ioctl for device

V4L2_CORE: (UVCIOC_CTRL_MAP) Error: Inappropriate ioctl for device

V4L2_CORE: V4L2_CAP_TIMEPERFRAME not supported

control[0]:(unknown - 0x6) 0x980001 'User Controls'

control[7]:(unknown - 0x6) 0x9d0001 'JPEG Compression Controls'

V4L2_CORE: V4L2_CAP_TIMEPERFRAME not supported

# Works perfectly



$ cheese

** Message: 12:16:47.766: cheese-application.vala:211: Error during camera setup: No device found

(cheese:9944): cheese-CRITICAL **: 12:16:47.779: cheese_camera_device_get_name: assertion 'CHEESE_IS_CAMERA_DEVICE (device)' failed

# No devices found



$ cat /usr/share/skypeforlinux/version 

v2.0.10



$ /usr/share/skypeforlinux/skypeforlinux

# Audio and Video Settings sees USB Camera (041e:401e), but black screen

# Video-calling produces "We could not connect to your selected camera. Please select a different camera or try restarting Skype."



$ LD_PRELOAD=/usr/lib/x86_64-linux-gnu/libv4l/v4l1compat.so /usr/share/skypeforlinux/skypeforlinux

does not help.



$ cat ~/.config/skypeforlinux/logs/skype-startup.log

Empty.

What should I do to fix Skype?

Had a similar(?) problem with a gspca_ov519 camera that worked perfectly when opened with vlc but was not recognized as webcam by android-emulator. Another uvcvideo camera was recognized as webcam but failed to show a valid picture in any program. I ended using a uvcvideo Microsoft webcam that was available and everything worked fine.

I guess switching the webcam would be an easy to try solution.