nils/shairport-sync
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Update AIRPLAY2.md

Browse Source
This commit is contained in:
Mike Brady
2022-06-30 15:48:07 +01:00
committed by GitHub
parent 994edf81c3
commit c21ca295a8
1 changed files with 16 additions and 28 deletions
Download Patch File Download Diff File Expand all files Collapse all files
AIRPLAY2.md
+16 -28
View File
@@ -1,49 +1,41 @@
AirPlay 2
===
# AirPlay 2
Shairport Sync offers AirPlay 2 support for audio sources on iOS devices, Macs, HomePod minis and Apple TVs.
### Features and Limitations
#### What Works
## What Works
- AirPlay 2 audio for iOS, HomePod mini, AppleTV and Mac players.
- Devices running Shairport Sync in AirPlay 2 mode can be [added as speakers](https://github.com/mikebrady/shairport-sync/blob/development/ADDINGTOHOME.md) to the Home app.
* Two types of audio are received by Shairport Sync – "Realtime" streams of CD quality ALAC (like "classic" AirPlay) and "Buffered Audio" streams of AAC stereo at 44,100 frames per second. The selection of stream type is made by the player. Realtime streams generally have a latency of about two seconds. Buffered Audio streams typically have a latency of half a second or less.
* Audio is synchronised with other AirPlay 2 devices.
* Shairport Sync offers "classic" AirPlay compatibility for situations where iTunes on macOS or macOS Music plays to multiple speakers and where one of more of them is compatible with AirPlay only.
#### What Does Not Work
- No Remote Control
- No AirPlay 2 for Windows iTunes
- Devices running Shairport Sync in AirPlay 2 mode can be [added](https://github.com/mikebrady/shairport-sync/blob/development/ADDINGTOHOME.md) to the Home app.
### General
## What Does Not Work
- No AirPlay 2 for Windows iTunes.
- Remote control facilities are not implemented.
## General
Shairport Sync uses a companion application called [`nqptp`](https://github.com/mikebrady/nqptp) ("Not Quite PTP") for timing and synchronisation in AirPlay 2. `nqptp` must run as `root` and must have exclusive access to ports `319` and `320`.
Lossless and High Definition Lossless material is transcoded to AAC before it reaches Shairport Sync.
AirPlay 2 -- What You Need
---
## What You Need
AirPlay 2 support needs a slightly more powerful CPU for decoding and synchronisation and more memory for bigger buffers and larger libraries. A Raspberry Pi 2 or Raspberry Pi Zero 2 W or better is recommended.
Here are some guidelines:
* Full access, including `root` privileges, to a system at least as powerful as a Raspberry Pi 2 or a Raspberry Pi Zero 2 W.
* A fully up-to-date Linux or FreeBSD. This is important, as some of the libraries must be the latest available.
* An up-to-date Linux or FreeBSD. This is important, as some of the libraries must be the latest available.
* Shairport Sync will not run on a Mac because NQPTP, on which it relies, needs ports 319 and 320, which are already used by macOS.
* A version of the [ffmpeg](https://www.ffmpeg.org) library with an AAC decoder capable of decoding Floating Planar -- `fltp` -- material. There is a guide [here](https://github.com/mikebrady/shairport-sync/blob/development/TROUBLESHOOTING.md#aac-decoder-issues-airplay-2-only) to help you find out if your system has it. (At the time of writing, Debian, Ubuntu, Raspberry Pi OS and FreeBSD all include this decoder. Fedora 36 does not.)
* An audio output, for example an `alsa` device (or `sndio` in FreeBSD). You can use an application called [`sps-alsa-explore`](https://github.com/mikebrady/sps-alsa-explore) to test the suitability of hardware `alsa` audio devices on your device. Other backends continue to work as with "classic" Shairport Sync.
Guides
---
## Guides
* To build Shairport Sync for AirPlay 2 on Linux, please follow the guide at [BUILDFORAP2.md](https://github.com/mikebrady/shairport-sync/blob/development/BUILDFORAP2.md).
* A guide for building on FreeBSD is available [here](https://github.com/mikebrady/shairport-sync/blob/development/FREEBSD.md).
AirPlay 2 -- More About What Works
---
* Two types of audio are received by Shairport Sync -- "Realtime" streams of CD quality ALAC (like "classic" AirPlay) and "Buffered Audio" streams of AAC stereo at 44,100 frames per second. The selection of stream type is made by the player. Realtime streams generally have a latency of about two seconds. Buffered Audio streams typically have a latency of half a second or less.
* Audio is synchronised with other AirPlay 2 devices, including AirPlay 2 devices that have their own master clocks.
* Shairport Sync offers "classic" AirPlay compatibility for situations where iTunes on macOS or macOS Music plays to multiple speakers and where one of more of them is compatible with AirPlay only.
Note
----
## Note
The functionality offered by Shairport Sync is the result of study and analysis of the AirPlay and AirPlay 2 protocols by many people over the years. These protocols have not been officially published, and there is no assurance that Shairport Sync will continue to work with AirPlay in future.
Acknowledgements
----
## Acknowledgements
Huge thanks are due to a number of individuals who made direct and valuable contributions to Shairport Sync:
1. [ejurgensen](https://github.com/ejurgensen) contributed ideas and code. The `pair_ap` submodule and related code in `rtsp.c` is theirs.
2. [JD Smith](https://github.com/jdtsmith) contributed ideas, comments and suggestions along with extensive and thorough testing.
@@ -51,7 +43,3 @@ Huge thanks are due to a number of individuals who made direct and valuable cont
4. [ckdo](https://github.com/ckdo) for their pathfinding work on AirPlay 2, especially the HomeKit pairing.
Much of Shairport Sync's AirPlay 2 functionality is based on ideas developed at the [openairplay airplay2-receiver]( https://github.com/openairplay/airplay2-receiver) repository. It is a pleasure to acknowledge the work of the contributors there.
Finally
----
AirPlay 2 support is experimental.