Documentation updates

AIRPLAY2.md

@@ -1,9 +1,9 @@
 AirPlay 2
 ===
 
-Shairport Sync offers limited AirPlay 2 support for audio sources on iOS devices and Macs. In addition, it partly works if the audio source is a HomePod mini or an Apple TV. It does not work for iTunes on Windows. Unfortunately, it does not integrate with the Home app or with Siri.
+Shairport Sync offers limited AirPlay 2 support for audio sources on iOS devices and Macs. In addition, it partly works if the audio source is a HomePod mini or an Apple TV. It does not work for iTunes on Windows. It has limited integration with the Home app and Siri.
 
-The focus of the development effort has been on getting good audio performance for iOS and Mac. Features outside this focus may be missing or broken. So, for example, integration with Apple's Home app is missing; remote control doesn't work.
+The focus of the development effort has been on getting good audio performance for iOS and Mac. Features outside this focus may be missing or broken. So, for example, remote control doesn't work.
 
 For AirPlay 2, Shairport Sync uses another application called [`nqptp`](https://github.com/mikebrady/nqptp) ("Not Quite PTP") for timing and synchronisation. `nqptp` must run as `root` and must have exclusive access to ports `319` and `320`.
 
@@ -17,13 +17,13 @@ The AirPlay 2 build requires a good deal of extra library support and may not fi
 - AirPlay 2 for iOS and Mac players.
 
 ### What Does Not Work
-- No integration with Siri or HomeKit
 - Lossless or High Definition Lossless material is transcoded to AAC before transmission over AirPlay 2. 
 - No Remote Control
 - No Artwork in the Metadata
 - No AirPlay 2 for Windows iTunes
 
 ### What Partly Works
+- Incomplete functionality with Siri and HomeKit
 - Incomplete functionality using AppleTV or HomePod as player.
    A Shairport Sync player will work -- i.e. it will play -- but the selection button won't persist and the volume can't be set.
 
@@ -51,15 +51,16 @@ Guides
 AirPlay 2 -- More About What Works
 ---
 * Two types of audio are received by Shairport Sync -- "Realtime" streams of CD quality ALAC (like AirPlay 1) and "Buffered Audio" streams of AAC stereo at 44,100 frames per second. The selection of stream type is made by the player.
-* Audio is synchronised with other AirPlay 2 devices, including AirPlay 2 devices that have their own master clocks. (Note: This has not been tested with multiple nearly-identical master clock devices such as with two HomePod minis -- Shairport Sync will get confused about which is the current master.)
+* Audio is synchronised with other AirPlay 2 devices, including AirPlay 2 devices that have their own master clocks.
 * Shairport Sync continues to support AirPlay 1, and offers an AirPlay 1 compatibility mode for situations where iTunes on macOS or macOS Music plays to multiple speakers and one of more of them is compatible with AirPlay 1 only.
 
 Acknowledgements
 ----
-Huge thanks are due to number of individuals made direct and valuable contributions to Shairport Sync:
+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.
 3. [Charles Omer](https://github.com/charlesomer) contributed ideas, comments, bug fixes, documentation and Docker automation (forthcoming).
+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.
 

BUILDFORAP2.md

@@ -5,9 +5,8 @@ Building Shairport Sync for AirPlay 2
 * Be especially careful with audio systems capable of very high volume output -- the volume control in this software may not be reliable!
 * For now, leave the settings in the configuration file at default except as noted below.
 * At the time of writing, May 2, 2021, everything is on the latest version of the software -- macOS 11.3, iOS 14.5, Raspberry Pi OS 5.10.17-v7l+ (Buster), Ubuntu 20.04 -- fully updated.
-* Shairport Sync relies on a program called [`nqptp`](https://github.com/mikebrady/nqptp) to monitor timing signals. This program uses ports 319 and 320 and replaces any PTP service you have on the computer.  
- (FYI, most computers do not have a PTP clock running. They often use a (totally different) [Network Timing Protocol (NTP)](http://www.ntp.org) service to keep the system clock synchronised with world time.)
-* Shairport Sync has a build dependency on `nqptp`, so you should build or update `nqptp` *before* building or updating Shairport Sync.
+* Shairport Sync relies on a program called [`nqptp`](https://github.com/mikebrady/nqptp) to monitor timing signals. This program uses ports 319 and 320 and replaces any PTP service you have on the computer. 
+ (FYI, most computers do not have a PTP clock running. They often use a (totally different) [Network Timing Protocol (NTP)](http://www.ntp.org) service to keep the system clock synchronised with world time.) 
 * The POSIX Shared Memory Interface (SMI) Version numbers of `nqptp` and Shairport Sync must match. If they don't, you'll get a message in the logs. It means that one of the programs is out of date with respect to the other.
 * Build instructions are likely to change.
 
@@ -59,17 +58,14 @@ First, install the packages needed by Shairport Sync:
     libpopt-dev libconfig-dev libasound2-dev avahi-daemon libavahi-client-dev libssl-dev libsoxr-dev libglib2.0-dev \
     libplist-dev libsodium-dev libavutil-dev libavcodec-dev libavformat-dev uuid-dev libgcrypt-dev
 ```
-(Note: if you don't want the `D-Bus` interface, you may omit `libglib2.0-dev`.)
 
 ### nqptp ###
 Download, install, enable and start `nqptp` from [here](https://github.com/mikebrady/nqptp).
 
-***Note:*** Shairport Sync expects the `nqptp` repository folder to be in the same directory as the `shairport-sync` repository folder, as it will look for a header file at `../nqptp/nqptp-shm-structures.h`.
-
 ### Shairport Sync
 
 #### Please use `git` to clone the repository!
-As you probably know, you can download the repository in two ways: (1) using `git` to clone it  -- recommended -- or (2) downloading the repository as a ZIP archive. Please us the `git` method. The reason it that when you use `git`, the build process can incorporate the `git` build information in the version string you get when you execute the command `$ shairport-sync -V`. This will be very useful for identifying the exact build if you are making comments or bug reports. Here is an example:
+As you probably know, you can download the repository in two ways: (1) using `git` to clone it  -- recommended -- or (2) downloading the repository as a ZIP archive. Please use the `git` method. The reason it that when you use `git`, the build process can incorporate the `git` build information in the version string you get when you execute the command `$ shairport-sync -V`. This will be very useful for identifying the exact build if you are making comments or bug reports. Here is an example:
 ```
 Version with git information:
 4.0-dev-138-g2789572-AirPlay2-OpenSSL-Avahi-ALSA-soxr-metadata-dbus-sysconfdir:/etc

README.md

@@ -26,6 +26,6 @@ For the development of AirPlay 2 support, special thanks are due to:
 * [ejurgensen](https://github.com/ejurgensen) for advice and [code to deal with pairing and encryption](https://github.com/ejurgensen/pair_ap).
 * [ckdo](https://github.com/ckdo) for pointing the way, particularly with pairing and encryption protocols, with a [functional Python implementation](https://github.com/ckdo/airplay2-receiver) of AirPlay 2.
 * [invano](https://github.com/invano) for showing what might be possible and for initial Python development.
-* [Charles Omer](https://github.com/charlesomer) for Docker automation (forthcoming), testing, encouragement, enthusiasm.
+* [Charles Omer](https://github.com/charlesomer) for Docker automation, repository management automation, testing, encouragement, enthusiasm.
 
 And of course, thanks to everyone who has supported and improved Shairport Sync over the years.