Implemented a very simple server to pipe the DJI USB to WiFi.

README.md

@@ -43,6 +43,9 @@ To this:
 
 If there is any issue, please check on our [Discord server](https://discord.gg/uGYMNByeTH), some people might help you there. You can also consult the [DigiView Wiki.](https://github.com/fpvout/fpvout.com/wiki)
 
+## Experimental
+- The WiFi module can be used to pipe the USB from the goggles to a WiFi client. This can allow devices that are unsupported by libUSB (iOS) to act as a screen. There is currently no service setup up for this. See fpvout-stream-listen.py for more details.
+
 ## Known Issues
 - Do not plug into the Pi until after video is showing in your goggles.
 - If you need to power cycle the air unit, you may need to replug the USB cable in order to re-establish the stream.

Scripts/fpvout-start.sh

@@ -4,4 +4,22 @@ export DISPLAY=:0;
 
 cd /home/fpvout/Scripts/fpv-c/ 
 
-./fpv-video-out | /opt/vc/src/hello_pi/hello_video/hello_video.bin
+# If there is no display connected don't start streaming with fpv-video-out.
+# At best it's a waste of resources, at worst it will prevent the WiFi 
+# stream from obtaining the USB connection.
+#
+# NOTE This is pretty poorly tested (and understood by me). I don't even
+#      have an HDMI cable for this PI right now, so I can't test the case
+#      where the display is available. I also suspect that this wouldn't 
+#      work with composite video out, which is a pretty valid use case
+#      for using an old analog monitor (like the one sitting in my garage).
+#      I could probably embed a PI zero inside of that display and get a
+#      high quality but low res stream for passengers.
+displayStatus=$(/usr/bin/tvservice -s)
+displayDetect="[TV is off]"
+if [[ "$displayStatus" ==  *"$displayStatus"* ]]; then
+    echo "No HDMI display connected, not streaming to screen. $displayStatus"
+else
+    echo "HDMI display detected, streaming to screen. $displayStatus"
+    ./fpv-video-out | /opt/vc/src/hello_pi/hello_video/hello_video.bin
+fi

Scripts/fpvout-stream-listen.py

@@ -0,0 +1,43 @@
+#!/usr/bin/python3
+# 
+# A server that waits for connections and pipes the output of fpv-c to the 
+# remote client. The client will be an h264 stream (without an MP4 wrapper)
+# so clients will need to act accordingly. To view the stream in VLC open
+# a url: tcp/h264://fpvout.local:8081
+# 
+# This service can be used to create a simple device that will clients such
+# as iOS to connect to DJI FPV goggles. I haven't tested yet, but I suspect
+# even a Pi Zero could handle it since it's just redirecting USB to Wifi and
+# not even decoding the video. That said my Pi 4 has horrible latency, so this
+# may not work.
+
+import socket
+import subprocess
+import sys
+
+# Create a TCP/IP socket
+sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+
+# Bind the socket to the port
+server_address = ('', 8081)
+print('starting up on %s port %s' % server_address, file=sys.stderr)
+sock.bind(server_address)
+
+# Listen for incoming connections
+sock.listen(1)
+
+while True:
+    # Wait for a connection
+    print('waiting for a connection', file=sys.stderr)
+    connection, client_address = sock.accept()
+
+    try:
+        print('connection from %s port %s' % client_address, file=sys.stderr)
+
+        socket_input = connection.makefile('wb',0)
+        proc = subprocess.run(['/home/fpvout/Scripts/fpv-c/fpv-video-out'], stdout=socket_input)
+    finally:
+        # Clean up the connection
+        print('closed connection from %s port %s' % client_address, file=sys.stderr)
+        connection.close()
+