Chromecast

Google Cast support over WAV-over-HTTP plus the Cast control channel.

Rockbox streams audio to any Google Cast-compatible device — Google Home, Chromecast Audio, Chromecast with Google TV, Nest Hub, or third-party receivers — using two channels at once:

Channel	Port	Purpose
Cast protocol	TCP 8009	TLS + Protobuf — playback control, queue, metadata
WAV over HTTP	TCP 7881	Live audio/wav stream with finite Content-Length

The finite content length is what lets the Chromecast show a progress bar and auto-advance at track boundaries.

Configuration

music_dir            = "/path/to/Music"
audio_output         = "chromecast"
chromecast_host      = "192.168.1.60"  # LAN IP of the target device
chromecast_port      = 8009            # optional, default 8009 (Cast protocol)
chromecast_http_port = 7881            # optional, default 7881 (WAV stream)

Auto-discovery

Devices on the LAN are discovered via mDNS (_googlecast._tcp.local.) and appear in the web UI and desktop app device picker — clicking starts a Cast session on demand without audio_output = "chromecast" in the config.

Track metadata

Title, artist, album, duration, and album art are pushed to the device on every track change so the “Now playing” card stays accurate.

Network requirement: the Chromecast must be able to reach port 7881 on the host running rockboxd. If rockboxd is in a VM or container, forward that port to the host (or run with --network host).

Picking a device from the API

query DiscoveredCastDevices {
  devices {
    id
    name
    ip
    port
    isCastDevice
  }
}

mutation Cast {
  connectDevice(id: "chromecast-living-room")
}

…or with the TypeScript SDK:

const devices = await client.devices.list();
const cast = devices.find((d) => d.isCastDevice);
if (cast) await client.devices.connect(cast.id);

Architecture

Implementation lives in crates/chromecast/. See crates/chromecast/README.md for the protocol-level details.