AirConnect: AirPlay → Chromecast bridge

This repository builds aircast, the Chromecast/Google Home target for AirPlay audio. It is intended for a Raspberry Pi or other Linux host that receives audio from an iOS device and forwards it to Chromecast devices on the same local network.

It will detect Chromecast players (e.g. Google Home Speakers), create as many virtual AirPlay devices as needed, and act as a bridge/proxy between AirPlay clients (iPhone, iPad, iTunes, MacOS, AirFoil ...) and the real Chromecast players.

This project is a fork from Philippe44/AirConnect, hardened with CodeQL and dependency scanning results, and minimized to focus on the iOS → Google Home use case, thus removing all unnecessary features and dependencies. For the full-featured functionality, including Sonos and UPnP compatibility and different platform build options, see the original repo (or the master branch of this one: see below). The original README file also includes a much more in-depth explanation of the inner workings of the software.

The default branch is hardened. The master branch mirrors the original upstream repo, and is used to pull changes which are then imported into hardened. See sync-upstream.sh.

• aircast/ — the component that bridges AirPlay input to Chromecast output
• shared libraries under common/ needed by aircast
• build scripts for native or cross-platform compilation

1. Clone the repository and initialize submodules:

git clone https://github.com/GiuliaLo/AirConnect.git
cd AirConnect
git submodule update --init --recursive

2. Build only the aircast component.

For a 64-bit Raspberry Pi OS:

cd aircast
make CC=gcc HOST=linux PLATFORM=aarch64 -j$(nproc)

For a 32-bit Raspberry Pi OS:

cd aircast
make CC=gcc HOST=linux PLATFORM=arm -j$(nproc)

3. The executable is written to bin/aircast-<host>-<platform>. For example:

ls -l bin/aircast-linux-aarch64

Run the built aircast binary from the repository root.

./bin/aircast-linux-aarch64 -Z

Useful runtime options:

• -Z : disable interactive mode
• -z : disable interactive mode and self-daemonize
• -h : show help and available command-line options
• -c mp3|aac|flac : choose the audio codec used for Chromecast output
• -v <scale> : set Chromecast volume factor
• -b <ip|iface> : bind to a specific network interface or address
• -N "<name>" : set the AirPlay device name

If you want the process to run in the background, use -z or create a systemd unit that starts the aircast binary with -Z/-z.

• Your Raspberry Pi and Chromecast devices must be on the same local network.
• UDP port 5353 must be reachable for mDNS discovery.
• Each device uses 1 port permanently (RTSP) and when playing adds 1 port for HTTP and 3 ports for RTP (use -gor <ports> parameter, default is random)
• If running inside Docker, use host networking so Chromecast discovery works.