voc-poc is a proof of concept for video put from the DJI FPV Goggles over USB.
Connect your DJI FPV goggles to your PC, power on your quad, make sure the stream is connected and run:
node index.js -f outfile.bin
If all goes well voc-poc will find your DJI Goggles, obtain the USB interface and write the raw video stream to outfile.bin.
If you want to preview the stream live install ffplay (part of the ffmpeg package) and use the -o option.
node index.js -o | ffplay -i - -analyzeduration 1 -probesize 32 -sync ext
If you want to produce a nice outfile.mp4, pipe the output through ffmpeg:
node index.js -o | ffmpeg -vcodec copy outfile.mp4 -i -
If needed -o and -f may be combined.
node index.js --help for more options.
If you get USB errors on Windows make sure the Goggles Bulk Transfer Endpoint is using WinUSB drivers using Zadiq.
How does this work
It sends the magic
0x524d5654 packet to the USB Bulk Transfer Out Endpoint on the Goggles and starts dumping data from the USB Bulk Transfer Out Endpoint to file or stdout.
The Goggles have a Bulk Transfer Endpoint. To initiate the video stream one has to simply send
0x524d5654 to the Out Bulk Endpoint and then Listen on the In Bulk Endpoint for data.
The data format is currently largely unknown:
0x00010910seems to indicate the beginning of some sort of h264 frame according to this.
- Followed by a 6 byte (frame?) counter
- Which is always followed by
In any case, ffmpeg and other an make sense of it.
Get data out over USB Figure out the packet structure
- It sort of just works
Mux together an mp4 stream for output
- ffmpeg is good enough for the time being
Nice to have
Set the output file path via cli
- More error handling
- Wait for Goggles to appear if not connected
- Reconnect (and re send magic packet) when connection lost
- Support multiple Goggles
- Rewrite to C
Support the effort
If you’d like, you can send some ETH to
0xbAB1fec80922328F27De6E2F1CDBC2F322397637 or BTC to
3L7dE5EHtyd2b1tXBwdnWC2MADkV2VTbrq or buy me a coffe.