Capture Nikon D90 with `gphoto2` and stream from Raspberry Pi over RTP using GStreamer

Client code - receive and display stream

port=5000

gst-launch-1.0 -e -v udpsrc port=${port} ! \
  application/x-rtp, media=video, encoding-name=H264 ! \
  rtph264depay ! \
  queue ! \
  avdec_h264 ! \
  autovideosink sync=false

Server code - capture and transmit stream

# The D90 Live View is 640x426 at around 24fps
# The bottom 3 rows are magenta
# If we crop the 3 top and bottom rows we get 640x420

port=5000
host=192.168.1.127  # <- Set **client** IP here

gphoto2 --capture-movie --stdout | gst-launch-1.0 -v -e \
  fdsrc ! \
  image/jpeg,framerate='(fraction)'24/1,width=640,height=426 ! \
  jpegdec ! \
  videocrop top=3 bottom=3 ! \
  queue ! \
  x264enc pass=qual quantizer=35 tune=zerolatency ! \
  rtph264pay ! \
  udpsink host=${host} port=${port}