RAOP

import { connect, discover, toTarget } from '@corewire/airplay/raop';

RAOP is the older AirPlay audio protocol, over RTSP and RTP. Use it for receivers that do not speak AirPlay 2, such as an AirPort Express. For an Apple TV or HomePod, AirPlay audio streams are the better choice.

Streaming

import { TimingServer } from '@corewire/airplay';
import { connect, discover, pctToDbfs, toTarget } from '@corewire/airplay/raop';
import { FileSource } from '@corewire/audio-source';

const timing = new TimingServer();
await timing.listen();

const [receiver] = await discover();
const session = await connect(toTarget(receiver), {timing});

session.on('closed', reason => console.log('closed', reason));

const playback = await session.stream(await FileSource.fromPath('song.mp3'), {
    volumeDb: pctToDbfs(40),
    metadata: {title: 'Song', artist: 'Artist', album: 'Album', duration: 215}
});

await playback.ended;

await session.close();
timing.close();

connect(target, options) follows the session pattern of the other protocols. It opens the RTSP connection and the control channel, reads GET /info, runs /auth-setup for an AirPort and sends ANNOUNCE and SETUP. The session it returns is ready. It ends once, with the closed event and its signal, when you call close() or when the RTSP connection drops.

Member	Meaning
stream(source, options?)	Resolves once audio flows and returns a RaopPlayback. volumeDb is in dBFS. metadata shows title, artist, album, duration and artwork on the receiver. One stream runs at a time
playback.ended	Settles when the source ran out
playback.stop()	Stops the stream
setVolumeDb(volumeDb)	The volume in dBFS, -144 to 0
close()	Stops the stream and closes every connection
target, info, context, volumeDb	About the receiver and the session

pctToDbfs(percentage) converts a percentage to dBFS.

The RAOP target needs the port of the _raop._tcp service. toTarget() takes it from a discovery result. The encryption, metadata and audio properties come from its txt.

Options

connect() requires a TimingServer in timing, whose port goes into SETUP. The other options are optional:

Option	Meaning
context	A Context for the logger and the client identity
metadata	Title, artist and album to show while a stream has no metadata of its own. Defaults to Streaming with CoreWire, CoreWire and AirPlay
password	Answers a digest challenge on ANNOUNCE for a receiver with a password
signal	Aborts the handshake

Reading a TXT record

getEncryptionTypes(), getMetadataTypes() and getAudioProperties() read the properties of a receiver from its TXT record. See the reference.