Discovery

AppleTvControlLibrary.Discovery is a separate package that implements mDNS/DNS-SD discovery for the Companion Link, MRP, and AirPlay services used by this library. It has no dependency on the protocol libraries and can be used independently, for example to build a device picker without also depending on AppleTvControlLibrary or AppleTvControlLibrary.Mrp.

API documentation is published at oznetmaster.github.io/AppleTVControlLibrary, covering the Companion Link, MRP, and Discovery libraries.

Install

dotnet add package AppleTvControlLibrary.Discovery

Service types

Service	mDNS service type	Discovery type
Companion Link	_companion-link._tcp.local	ICompanionDiscovery
AirPlay (used to tunnel MRP)	_airplay._tcp.local	IAirPlayDiscovery
MRP	_mediaremotetv._tcp.local	IMrpDiscovery

Each service is isolated behind its own interface so a host can swap in a different discovery implementation per service without affecting the others.

Multicast discovery

Multicast discovery sends a DNS-SD PTR query to the mDNS multicast group (224.0.0.251:5353) and collects responses until the requested timeout elapses, or until a specific device name has been fully resolved.

using AppleTvControlLibrary.Discovery.Companion;

var discovery = new MulticastCompanionDiscovery ();
var devices = await discovery.ScanAsync (TimeSpan.FromSeconds (5));

The same pattern applies to MulticastAirPlayDiscovery and MulticastMrpDiscovery.

To resolve a single, known device by its mDNS service instance name and stop scanning as soon as it is found, use each discovery type's static DiscoveryAsync method, for example DiscoveryAsync.

Unicast discovery

When a host already knows an Apple TV's IPv4 address but not its current Companion TCP port, query that device directly instead of joining the multicast group:

using AppleTvControlLibrary.Discovery.Companion;

var discovery = new UnicastCompanionDiscovery (IPAddress.Parse ("192.0.2.10"));
var devices = await discovery.ScanAsync (TimeSpan.FromSeconds (5));

Static discovery

When a host supplies its own discovery mechanism, or multicast is unavailable or unreliable (for example on some Mono or embedded hosts), StaticCompanionDiscovery returns a single, pre-configured device without performing any network scan.

TXT record stability

Some Companion Link TXT record fields (rpHA, rpHN, rpAD, rpHI, rpBA) rotate periodically as a privacy measure. Do not use them as a stable device identifier; prefer the discovery result's unique identifier, or a value persisted from the pairing flow instead.

See the Discovery API reference.