Using the iPhone camera as a Linux webcam with v4l2loopback (2020) - Michael Stapelberg

For my programming stream at twitch.tv/stapelberg, I wanted to add an additional camera to show test devices, electronics projects, etc. I couldn’t find my old webcam, and new ones are hard to come by currently, so I figured I would try to include a phone camera somehow.

Disclaimer: I was only interested in a video stream! I don’t think this setup would be helpful for video conferencing, due to lacking audio/video synchronization.

As hinted at in the blog posts, the way the app works is by streaming MPEG1 video from the iPhone (presumably via ffmpeg?) to the jsmpeg JavaScript library via WebSockets.

After some git archeology, I figured out that jsmpeg was rewritten in commit 7bf420fd just after v0.2. You can browse the old version on GitHub.

Notably, the Instant Webcam app seems to still use the older v0.2 version, which starts WebSocket streams with a custom 8-byte header that we need to strip.

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