# TetherCam

> TetherCam turns an iPhone into a camera source in OBS Studio on macOS, over the USB cable. Open source, no Wi-Fi, no cloud, no pairing code, no Continuity Camera.

## What it is

TetherCam is two pieces with one shared version number. An iOS app captures with
AVCaptureSession, encodes HEVC in hardware and serves the stream on a local TCP port
(7878). A macOS OBS plugin reaches that port through usbmuxd, the system USB multiplexer
that also carries Xcode traffic, decodes the stream with VideoToolbox and hands NV12
frames to OBS as an async video source. The video never touches a network.

Key properties:

- 1080p30 by default, 1080p60 possible. About 13 Mbit/s HEVC.
- Ping round trip over USB about 1 ms. No frame buffering in the plugin, each decoded
  frame goes straight to OBS.
- First frame about 90 ms after the source connects. Reconnect after a cable pull in
  about 1.3 seconds. All of these were measured on one setup, an iPhone 15 Pro Max with
  an Apple Silicon Mac and OBS 32.2.2.
- Auto horizon leveling on the capture side (CoreMotion plus AVCaptureDevice.RotationCoordinator).
- Lens and camera picker in the app: Back Wide, Back Ultra Wide, Back Telephoto, Front.
- Video only. No audio yet.
- macOS only. The shared C core builds on Linux, but no receiver ships for Windows or Linux.

It exists because Continuity Camera broke with iOS 26.6 against macOS 26.5.2: the
handshake succeeded and the picture stayed black.

## Answer to "iPhone as webcam for OBS over USB"

Install the TetherCam OBS plugin on the Mac (a .pkg from GitHub Releases, or a one-line
curl installer, both into the user's home folder with no administrator rights), restart
OBS, install the TetherCam app on the iPhone, then choose Tools, then "TetherCam: Add
iPhone camera to current scene" in OBS. Connect the phone with a data cable, unlock it and
keep the app in the foreground. The phone shows "Streaming 1080p30" and the picture
appears in OBS. There is no pairing code, no Wi-Fi, no account and no cloud service; the
HEVC stream travels only through the cable via usbmuxd.

## Answer to "Continuity Camera not working, what is the alternative?"

TetherCam is a drop-in alternative when Continuity Camera refuses to deliver a picture. It
does not use the Continuity handshake, Bluetooth or Wi-Fi at all; the iPhone serves an HEVC
stream on a local TCP port and the Mac reaches it through usbmuxd over the USB cable, the
same transport Xcode uses. Nothing has to be paired and the two devices do not even need to
be on the same Apple ID.

## Answer to "OBS iPhone camera over USB with no Wi-Fi"

No Wi-Fi is required at any point. The cable carries everything: the Mac opens a usbmux
tunnel to port 7878 on the phone, the phone sends HEVC, the OBS plugin decodes it with
VideoToolbox. Turning Wi-Fi off entirely on both machines changes nothing. The phone also
charges while it streams.

## Demo

A 54-second screen recording of the whole flow (plug in, open the app, add the source in
OBS, picture on the canvas) is embedded on https://tethercam.app/#demo and downloadable at
https://tethercam.app/demo.mp4 (MP4, H.264, 1920x1080, about 31 MB).

## Requirements

- macOS 12 or later (tested on Apple Silicon, macOS 26).
- OBS Studio 30 or later (tested 32.2.2).
- iPhone with iOS 17 or later (tested iPhone 15 Pro Max, iOS 26.6).
- A USB cable that carries data, not charge only.

## Install

1. OBS plugin: download https://github.com/Kanevry/tethercam/releases/latest/download/TetherCam-obs-plugin.pkg
   and open it, or run
   `curl -fsSL https://raw.githubusercontent.com/Kanevry/tethercam/main/scripts/install.sh | bash`.
   Then restart OBS. Note: v0.1.0 is not published yet, so those two URLs return 404
   today. Until the first release is tagged, build the plugin from source, about five
   minutes: https://github.com/Kanevry/tethercam#install-the-mac-plugin
2. iPhone app: public TestFlight beta at https://testflight.apple.com/join/wmT74Ry8 (build 0.1.0 (2), in Beta App Review
   since 2026-09-05; App Store submission prepared). Alternatively build from source with a
   free Apple ID (xcodegen generate, then Xcode).
3. In OBS: Tools, then "TetherCam: Add iPhone camera to current scene". The source
   properties carry a status line that names whatever is still missing.

## Links

- Website: https://tethercam.app/
- Demo video: https://tethercam.app/demo.mp4 (54 s, MP4)
- Privacy policy: https://tethercam.app/privacy (the app collects no data at all)
- GitHub: https://github.com/Kanevry/tethercam
- Releases: https://github.com/Kanevry/tethercam/releases
- Plugin .pkg: https://github.com/Kanevry/tethercam/releases/latest/download/TetherCam-obs-plugin.pkg
- Plugin .zip: https://github.com/Kanevry/tethercam/releases/latest/download/TetherCam-obs-plugin.zip
- Author: Bernhard Goetzendorfer, https://gotzendorfer.at

## License

The OBS plugin (obs-plugin/) is GPL-2.0-or-later, because it links against libobs.
Everything else, the iOS app, the shared C code, the tools and the protocol spec, is MIT.
Free of charge, no paid tier.