Currently there is some AirPlay functionality supported in
pyatv, but it is
very limited. These features are currently supported:
- Device authentication (“pairing”)
- Playing media via URL
- Streaming of local files
In the external interface, AirPlay support is implemented via the interface.Stream API.
Additional features will be added as needed.
In tvOS 10.2, Apple started to enforce a feature called “device authentication”. This requires every device that streams content via AirPlay to enter a PIN code the first time before playback is started. Once done, the user will never have to do this again. The actual feature has been available for a while but as opt-in, so it would have to be explicitly enabled. Now it is enabled by default and cannot be disabled. Devices not running tvOS (e.g. Apple TV 2nd and 3rd generation) are not affected, even though device authentication can be enabled on these devices as well.
The device authentication process is based on the Secure Remote Password protocol (SRP), with slight modifications. All the reverse engineering required for this process was made by funtax (GitHub username) and has merely been ported to python for usage in this library. Please see references at bottom of page for reference implementation.
Device Authentication (“Pairing”)
When performing device authentication, a device identifier and a private key is required. Once authenticated, they can be used to authenticate without using a PIN code. So they must be saved and re-used whenever something is to be played.
In this library, the device identifier and private key is called AirPlay credentials and are concatenated into a string, using : as separator. An example might look like this:
D9B75D737BE2F0F1:6A26D8EB6F4AE2408757D5CA5FF9C37E96BEBB22C632426C4A02AD4FA895A85B ^ ^ Identifier Private key
The device authentication is performed via the pairing API, just like with any other protocol. New random credentials are generated by default, as long as no existing credentials are provided. So there is nothing special here.
Playing a URL is as simple as passing the URL to interface.Stream.play_url:
url = "http://commondatastorage.googleapis.com/gtv-videos-bucket/sample/BigBuckBunny.mp4" await atv.stream.play_url(url)
If the device requires device authentication, credentials must be present for the AirPlay service. Otherwise an error message will be shown on the screen.
To play a local file, just pass a local file to interface.Stream.play_url instead:
url = "/home/user/BigBuckBunny.mp4" await atv.stream.play_url(url)
When doing this,
pyatv will internally start web server on a random port, serving this
file only and start streaming from there. When streaming is done, the web server is shut
Unofficial AirPlay Protocol Specification
AirPlay 2 Internals