The problem is that the C922 does not advertise its H264 stream over UVC whereas the C920 does. This is because Logitech did not want to enable general use of the H264 for the C922, but instead wanted you to buy the camera with something like Skype which knows internally how to get hold of the data. The reason for this peculiar setup was to enable the camera ...
You may have to force the stream mode for your camera.
First chek if MPEG or H264 is really available :
Using v4l2-ctl --all you will see the current resolution and pixel Format for your camera.
To define another resolution and/or pixelFormat, use this command :
v4l2-ctl --device /dev/video0 --set-fmt-video=width=1280,height=960,...
I figured out what my problem was. I was using the wrong 'muxer'. When I switched to using the 'ogg' muxer, I was able to write to a file just fine. For the record, the command that is working for me is as follows:
cvlc –no-audio \
–v4l2-width 1920 \
–v4l2-height 1440 \
–v4l2-chroma MJPG \
fifos are not for saving or reading more than once. You may find tee better suited to your goals.
Untested guess at what you want(split a network stream):
mkfifo myfifo1 myfifo2 && curl -s http://192.168.1.27:8554 | tee myfifo1 > myfifo2;
Other guess at what you want(display and save on rpi):
raspistill --fullpreview --output - >> jpgs....