FPV Ground Recorder and Spectator Screen with a Raspberry Pi
Capture the analog video from your goggles or a receiver, record every flight and show it live on a TV for friends.
Many analog goggles and 5.8 GHz receivers have an AV output. A cheap USB capture adapter turns that signal into a webcam-like device, and ffmpeg on a Pi 4 records it with the hardware video encoder.
Ground equipment never replaces a spotter. In the U.S., recreational pilots must pass the free FAA TRUST test, register drones over 250 g (0.55 lb), comply with Remote ID and keep the aircraft within visual line of sight (FPV pilots need a visual observer). Rules change — check faa.gov before you fly. LiPo batteries can catch fire if punctured, overcharged or shorted. Charge in a LiPo bag, never unattended, and always remove propellers while working on the bench.
Mission steps
Connect the video
Run a cable from the goggles' or receiver's AV-out to the capture adapter's composite input and plug the adapter into the Pi.
Find the device
Run v4l2-ctl --list-devices (from the v4l-utils package) to see which /dev/video number the adapter got.
Record
Run the ffmpeg command; it saves a timestamped file using the Pi 4's hardware H.264 encoder.
Show it live
Open the same device in a player such as mpv on the Pi's desktop and send it to a TV over HDMI for spectators.
Automate
Wrap the command in a systemd service so recording starts when the Pi boots at the field.
Code
sudo apt install -y ffmpeg v4l-utils mpv
v4l2-ctl --list-devices
# record (NTSC capture, hardware H.264 on Pi 4)
ffmpeg -f v4l2 -video_size 720x480 -i /dev/video0 \
-c:v h264_v4l2m2m -b:v 4M -pix_fmt yuv420p \
~/fpv_$(date +%Y%m%d_%H%M%S).mkv
# live view for spectators (in another terminal)
mpv av://v4l2:/dev/video0 --profile=low-latencyTip: test every script on the bench before installing it in a moving machine.
Questions
Does this work with digital FPV systems?
Digital systems such as DJI, Walksnail and HDZero record inside the goggles; some have HDMI out, which needs an HDMI capture device instead.
Why use a Pi 4 and not a Pi 5?
The Pi 4 has a hardware H.264 encoder; the Pi 5 does not, though it can encode standard-definition video in software.