Finding cameras

There are three locations with camera devices:

• /dev/video* - these are randomly assigned

• /dev/v4l/by-id/ - by the name of the camera (which is typically the manufacturer and model number)

• /dev/v4l/by-path/ - by the USB port

You can use ls -l /dev/v4l/by-id/ and ls -l /dev/v4l/by-path/ to correlate the two; they are symlinks to /dev/video*.

Most cameras have two devices, typically only the first one works.

Testing cameras

start a stream from v4l2 device with m-jpeg transcoded into h264 rtp/udp

gst-launch-1.0 v4l2src device=/dev/video0 ! image/jpeg ! decodebin ! videoconvert ! x264enc tune=zerolatency bitrate=8000 speed-preset=medium ! rtph264pay ! udpsink host=127.0.0.1 port=8081

test the stream (requires graphical environment)

gst-launch-1.0 udpsrc port=8081 caps="application/x-rtp, media=(string)video, clock-rate=(int)90000, encoding-name=(string)H264, payload=(int)96" ! rtph264depay ! decodebin ! videoconvert ! autovideosink

If the graphical environment and the device with the camera are different, use udpsink host=<IP address of graphical environment> instead of udpsink host=127.0.0.1.