and with a decent CD-quality Digital to Analog Converter (DAC).
## CPU Power and Memory
-Computer power and memory requirements are modest -- a Raspberry Pi 2 or better, including the Pi Zero 2 W, is fine.
+Computer power and memory requirements are modest – a Raspberry Pi 2 or better, including the Pi Zero 2 W, is fine.
Unfortunately, while the original Raspberry Pi and the Pi Zero are powerful enough for AirPlay operation,
they are not really suitable for AirPlay 2 operation.
## CPU Clock
For best performance, Shairport Sync requires a stable and accurate system clock.
-This is because the output DAC's output rate is normally determined by the system clock (some high-end USB streamers use their own built-in clocks).
+This is because the output DAC's output rate is normally determined by the system clock (exceptionally, some high-end USB streamers use their own built-in clocks).
If the clock drifts, or if its actual frequency is far from its nominal frequency, Shairport Sync will have to do more interpolation,
which inevitably must degrade the audio fidelity, even if it is very hard to hear.
Some very old laptops are known to have inaccurate clocks and and some embedded systems can suffer from temperature-related clock drift.
A good Digital to Analog Converter (DAC) will have a huge influence on the quality of the audio.
Shairport Sync runs at 44,100 frames per second (FPS), each frame consisting of a pair of signed 16 bit linear samples, one for left and one for right.
-Actually, Shairport Sync will take advantage to 24- or 32-bit DACs if available, and will run at 44,100 or 88,200, 176,400 or 352,800 FPS if necessary,
+Shairport Sync will take advantage to 24- or 32-bit DACs if available, and will run at 44,100 or 88,200, 176,400 or 352,800 FPS if necessary,
though there is no advantage to the higher rates. The 44,100 FPS rate was chosen to match the rate of AirPlay.
Good DACs are available at a very wide range of prices, from low-cost USB "Sound Cards" to very high-end HiFi streaming DACs.
-In the Raspberry Pi world, many very good low-cost I2S DACs, some with integrated amplifiers, are available. Staying with the Raspberry Pi, the DAC powering the built-in audio jack is not great. It may be good enough for trying out Shairport Sync, but it has a very limited frequency response and can generate very large transients when it starts up. A separate DAC will transform the output quality.
+In the Raspberry Pi world, many very good low-cost I2S DACs, some with integrated amplifiers, are available. The DAC powering the Pi's built-in audio jack is not great, however. While it may be good enough for trying out Shairport Sync or for casual listening, it has a very limited frequency response and can generate very large transients when it starts up. A separate DAC will transform the output quality.
**Note**
-Make sure that the DAC is capable of 44,100 FPS operation -- this is really mandatory.
+Make sure that the DAC is capable of 44,100 FPS operation – this is really mandatory.
Most recent DACs are okay, but some older DACs will only run at 48,000 FPS or multiples of it, and Shairport Sync can not use them.
## Maximum Output Level
The `volume_max_db` setting allows you to reduce the maximum level of DAC output to prevent possible overloading of the amplifier or premplifier it feeds.
## Volume Range
-The volume range is the difference (technically the ratio, expressed in dB) between the highest and lowest level of the volume control. Ideally, this should give the highest volume at the high end and a barely audible sound at the lowest level. Typical volume ranges are 60 dB to 75dB. If the range is much less than this, the difference between high and low volume won't seem large enough to the listener. If the range is much more, much of the low end of the volume control range will be inaudible. (The built-in DAC of the Raspberry Pi has this problem.) Use the `volume_range_db` setting to set the volume range. The built-in attenuator will be used to augment the volume range if necessary.
+The volume range is the difference (technically the ratio, expressed in dB) between the highest and lowest level of the volume control. Ideally, this should give the highest volume at the high end and a barely audible sound at the lowest level. Typical volume ranges are 60 dB to 75dB. If the range is much less than this, the difference between high and low volume won't seem large enough to the listener. If the range is much more, much of the low end of the volume control range will be inaudible. (The built-in DAC of the Raspberry Pi has this problem.) Use the `volume_range_db` setting to set the volume range. If the range you request is greater than the range available in the hardware mixer, the built-in attenuator will be used to make up the difference.
## Volume Control
-Audio is sent at full volume in AirPlay and AirPlay 2 with separate information being sent to set the actual volume. This volume information can be used in three ways:
+Audio is sent at full volume in AirPlay and AirPlay 2 with separate information being sent to set the actual volume. This volume information can be used in four ways:
* It can be used to control a built-in attenuator. This is the default.
* It can be used to control a mixer built in to the DAC. To use a mixer, set the `mixer_control_name` in the configuration file to the name of the mixer you wish to use.
* It can be ignored by Shairport Sync. This may be appropriate when you want the volume to be controlled by just one control, typically an audio system's volume control knob or the volume control of a car radio. To make Shairport Sync ignore the volume information, set `ignore_volume_control` to `"yes"`.
-* AirPlay volume changes cause events when an executable -- a program or executable script -- can be called. So, you could get Shairport Sync to ignore volume control information but call an executable to control an external volume control.
+* AirPlay volume changes cause events when an executable – a program or executable script – can be called. So, you could get Shairport Sync to ignore volume control information but call an executable to control an external volume control.
## Other Settings
* The `disable_standby_mode` setting can be used to prevent the DAC from transitioning between active and standby states, which can sometimes cause a faint popping noise. If activated, Shairport Sync sends frames of silence to keep the DAC busy, preventing it from entering standby mode.
* The `disable_synchronisation` setting can be used to prevent Shairport Sync from doing any interpolation whatever. Normally, this would lead to a problem when the DAC's buffer either overflowed or underflowed, but some very high-end streamers adjust the rate at which their DACs run to match the exact rate at which audio arrives, thus preventing underflow or overflow.
# Finish Setting Up
-When you complete the instructions in [BUILD.md](../BUILD.md), you have a basic functioning Shairport Sync installation. If you want more control -- for example, if you want to use a specific DAC, or if you want AirPlay to control the DAC's volume control -- you can use settings in the configuration file (recommended) or you can use command-line options.
+When you complete the instructions in [BUILD.md](../BUILD.md), you have a basic functioning Shairport Sync installation. If you want more control – for example, if you want to use a specific DAC, or if you want AirPlay to control the DAC's volume control – you can use settings in the configuration file (recommended) or you can use command-line options.
## The Configuration File
Shairport Sync reads settings from a configuration file at `/etc/shairport-sync.conf` (note that in FreeBSD it will be at `/usr/local/etc/shairport-sync.conf`). When you run `$sudo make install`, a sample configuration file called `shairport-sync.conf.sample` is always installed or updated. This contains all the setting groups and all the settings available, but they all are commented out (comments begin with `//`) so that default values are used. The file contains explanations of the settings, useful hints and suggestions.
```
Make sure to uncomment entries you wish to make active, and restart Shairport Sync after you have made changes.
-If you make a syntax error, Shairport Sync will not start and will leave a message in the log. More details below and also in the comments in the configuration file.
+If you make a syntax error, Shairport Sync will not start and will leave a message in the log. See more details below and in the comments in the configuration file.
Please note that if your system has a sound server such as PulseAudio or PipeWire (most desktop linuxes have one of these), you may not be able to access the sound hardware directly, so you may only be able to use the `default` output.
(Remember, anything preceded by `//` is a comment and will have no effect on the setting of Shairport Sync.)
-**Important:** You should *never* use an important password as the AirPlay password for a Shairport Sync player -- the password is stored in Shairport Sync's configuration file in plain text and is thus completely vulnerable.
+**Important:** You should *never* use an important password as the AirPlay password for a Shairport Sync player – the password is stored in Shairport Sync's configuration file in plain text and is thus completely vulnerable.
No backend is specified here, so it will default to the `alsa` backend if more than one back end has been compiled. To route the output to PulseAudio, set:
```
The `pa` group is used to specify settings relevant to the PulseAudio backend. You can set the "Application Name" that will appear in the "Sound" control panel.
-Note: Shairport Sync can take configuration settings from command line options. This is mainly for backward compatibility, but sometimes still useful. For normal use, it is strongly recommended that you use the configuration file method.
+Note: Shairport Sync can take configuration settings from command line options. This is mainly for backward compatibility, but sometimes still useful. For normal use, it is recommended that you use the configuration file method.
### Raspberry Pi
mixer_control_name = "Headphone"; // the name of the mixer to use to adjust output volume. If not specified, volume in adjusted in software.
// ... other alsa settings
```
-(Remember to uncomment the lines by removing the `//` at the start of each.) When these changes have been made, reboot the machine.
+(Remember to uncomment the lines by removing the `//` at the start of each.) When these changes have been made, restart Shairport Sync or simply reboot the system.
-A problem with the built-in DAC that it declares itself to have a very large mixer volume control range – all the way from -102.38dB up to +4dB, a range of 106.38 dB. In reality, only the top 60 dB of it is in any way usable. To help get the most from it, consider using the `volume_range_db` setting in the `general` group to instruct Shairport Sync to use the top of the DAC mixer's declared range. For example, if you set the `volume_range_db` figure to 60, the top 60 dB of the range will the used. With this setting on the Raspberry Pi, maximum volume will be +4dB and minimum volume will be -56dB, below which muting will occur.
+A problem with the built-in DAC that it declares itself to have a very large mixer volume control range – all the way from -102.38dB up to +4dB, a range of 106.38 dB. In reality, only the top 60 dB or so is in any way usable. To help get the most from it, consider using the `volume_range_db` setting in the `general` group to instruct Shairport Sync to use the top of the DAC mixer's declared range. For example, if you set the `volume_range_db` figure to 60, the top 60 dB of the range will the used. With this setting on the Raspberry Pi, maximum volume will be +4dB and minimum volume will be -56dB, below which muting will occur.
From a user's point of view, the effect of using this setting is to move the minimum usable volume all the way down to the bottom of the user's volume control, rather than have the minimum usable volume concentrated very close to the maximum volume.
};
```
-This gives the service a particular name — "Joe's Stereo" and specifies that audio device `hw:0` be used.
+This gives the service the name "Joe's Stereo" and specifies that audio device `hw:0` be used.
For best results with the `alsa` backend — including getting true mute and instant response to volume control and pause commands — you should access the hardware volume controls. Use `amixer` or `alsamixer` or similar to discover the name of the mixer control to be used as the `mixer_control_name`.
Sources that supply metadata include iTunes and the Music app in macOS and iOS.
-## Metadata over UDP**
+## Metadata over UDP
As an alternative to sending metadata to a pipe, the `socket_address` and `socket_port` tags may be set in the metadata group to cause Shairport Sync
to broadcast UDP packets containing the track metadata.
# Advanced Topics
Here you will find links to some advanced features and things you can do with Shairport Sync.
-* [Finish setting up](InitialConfiguration.md).
-* [Get the best](GetTheBest.md) from your system.
+* [Finish Setting Up](InitialConfiguration.md).
+* [Get The Best](GetTheBest.md) from your system.
* [Metadata](Metadata.md).
* [Events](Events.md).
* [Statistics](Statistics.md).
* [Car Installation](../CAR%20INSTALL.md)
– build an isolated WiFi network containing a Shairport Sync player on a Raspberry Pi. Suitable for a car radio with an `aux` input or for the stereo in that broadband-free holiday cottage.
-The configuration file -- which contains lots of documentation -- is on your system. By default, the sample configuration file is
+The configuration file – which contains lots of documentation – is on your system. By default, the sample configuration file is
placed at `/etc/shairport-sync.conf.sample` (`/usr/local/etc/shairport-sync.conf.sample` on FreeBSD).
-You can also view an online version [here](https://github.com/mikebrady/shairport-sync/blob/master/scripts/shairport-sync.conf).
+You can also view an online version [here](../scripts/shairport-sync.conf).
Build configuration flags are discussed [here](CONFIGURATION%20FLAGS.md).
# Statistics
-If you set the `statistics` setting in the `diagnostics` section of the configuration file to `"YES"`, some statistics will be logged at regular intervals. The items logged will depend on the type of stream being processed: AirPlay 1, AirPlay 2 Buffered Audio or AirPlay 2 Realtime Audio. If the `log_verbosity` is set to 1, 2 or 3, additional items will be logged.
+If you set the `statistics` setting in the `diagnostics` section of the configuration file to `"YES"`, some statistics will be logged at regular intervals. The items logged will depend on the type of stream being processed: classic AirPlay, AirPlay 2 Buffered Audio or AirPlay 2 Realtime Audio. If the `log_verbosity` is set to 1, 2 or 3, additional items will be logged.
From an audio enthusiast's point of view, the most important figure is possibly the `All Sync PPM` figure. This is the total amount of interpolation needed by Shairport Sync to keep the audio stream in sync. The number represents is the ratio of frames added and removed from the audio stream relative to all the frames output in the last interval, expressed in parts per million (PPM). For reference, adding or removing one frame per second into a 44,100 frames per second stream is ± 22.68 PPM. The lower this number number is, the higher the fidelity of the audio signal passed to the output device. On a well sorted system, this figure can be 0.0 for considerable periods, but it can't really be zero forever unless the output device is adapting to the true data rate (some very high-end streamers seem to do so). You may also find that the number might be higher at the start while the system settles down.
The second most important figure is possibly the `Sync Error ms`. This is the average synchronisation error in milliseconds in the last interval. Ideally it should be 0.0. By default, Shairport Sync has a tolerance of a sync error of ± 2.0 milliseconds without triggering interpolation.
-Two other interesting measurements of the output rate may be available -- `Output FPS (r)` and `Output FPS (c)`, where `(r)` means "raw" and the `(c)` means "corrected".
+Two other interesting measurements of the output rate may be available – `Output FPS (r)` and `Output FPS (c)`, where `(r)` means "raw" and the `(c)` means "corrected".
The "raw" figure is the rate at which the output device (typically a DAC) accepts data measured relative to the computer's own system clock (specifically the `CLOCK_MONOTONIC_RAW` clock). The accuracy of the number depends on the accuracy of the clock, which will typically be accurate to within anything from 20 to 100 ppm.
-The "corrected" figure is the rate at which the output device accepts data relative to the computer's network-time-disciplined clock (specifically the `CLOCK_MONOTONIC` clock). This clock is normally adjusted ("disciplined") to keep time with network time and should be accurate to with a few tens of milliseconds over a _long_ period. So (1) if you could run a play session for a long period -- say a day -- and (2) if network time synchronisation is enabled and (3) if the network connection to the network time service is fast and stable, then you should get an accurate absolute measure of exact frame rate of the output device. If your internet connection is not good, the corrected figure will be very inaccurate indeed.
+The "corrected" figure is the rate at which the output device accepts data relative to the computer's network-time-disciplined clock (specifically the `CLOCK_MONOTONIC` clock). This clock is normally adjusted ("disciplined") to keep time with network time and should be accurate to with a few tens of milliseconds over a _long_ period. So (1) if you could run a play session for a long period – say a day – and (2) if network time synchronisation is enabled and (3) if the network connection to the network time service is fast and stable, then you should get an accurate absolute measure of exact frame rate of the output device. If your internet connection is not good, the corrected figure will be very inaccurate indeed.
Here is a brief description of the figures that might be provided.
##### Sync Error ms
##### Net Sync PPM
This is the total amount of interpolation done by Shairport Sync to keep the audio stream in sync. The number represents is the total number of frames added and removed from the audio stream, expressed in parts per million (PPM) in the last interval. For reference, adding or removing one frame per second into a 44,100 frames per second stream is 22.68 ppm.
##### All Sync PPM
-This is the net amount of interpolation done by Shairport Sync to keep the audio stream in sync. The number represents is the number of frames added plus the number removed from the audio stream, expressed in parts per million (PPM) in the last interval. The magnitude of this should be the same as the `net sync ppm'. If it is much larger it means that Shairport Sync is overcorrecting for sync errors -- try increasing the drift tolerance to reduce it.
+This is the net amount of interpolation done by Shairport Sync to keep the audio stream in sync. The number represents is the number of frames added plus the number removed from the audio stream, expressed in parts per million (PPM) in the last interval. The magnitude of this should be the same as the `net sync ppm`. If it is much larger it means that Shairport Sync is overcorrecting for sync errors – try increasing the drift tolerance to reduce it.
##### Packets
This is the number of packets of audio frames received since the start of the session. A packet normally contains 352 ± 1 audio frames.
##### Missing
-This is the number of packets of audio frames that were expected but not received in the last interval. It should be zero, and if not it usually indicates a significant problem with the network. AirPlay 1 and AirPlay 2 Realtime Streams only.
+This is the number of packets of audio frames that were expected but not received in the last interval. It should be zero, and if not it usually indicates a significant problem with the network. classic AirPlay and AirPlay 2 Realtime Streams only.
##### Late
-This is the number of packets of audio frames that were received late -- but still in time to be used -- in the last interval. AirPlay 1 and AirPlay 2 Realtime Streams only.
+This is the number of packets of audio frames that were received late – but still in time to be used – in the last interval. Classic AirPlay and AirPlay 2 Realtime Streams only.
##### Too Late
-This is the number of packets of audio frames that were received too late to be used in the last interval. It is possible that these packets were already received, so those frames might not actually be missing when the time comes to play them. AirPlay 1 and AirPlay 2 Realtime Streams only.
+This is the number of packets of audio frames that were received too late to be used in the last interval. It is possible that these packets were already received, so those frames might not actually be missing when the time comes to play them. Classic AirPlay and AirPlay 2 Realtime Streams only.
##### Resend Reqs
-This is the number of times Shairport Sync requests the resending of missing frames. Requests can be for one or more frames. AirPlay 1 and AirPlay 2 Realtime Streams only.
+This is the number of times Shairport Sync requests the resending of missing frames. Requests can be for one or more frames. Classic AirPlay and AirPlay 2 Realtime Streams only.
##### Min DAC Queue
The is the smallest number of frames of audio in the DAC's hardware queue. If it goes too low, the DAC may begin to underrun.
##### Min Buffers
-The is the smallest number of packets of audio in the queue to be processed in the last interval. It is related to the overall latency in AirPlay 1 and AirPlay 2 Realtime Streams. If it comes close to zero it's often a sign that the network is poor.
+The is the smallest number of packets of audio in the queue to be processed in the last interval. It is related to the overall latency in Classic AirPlay and AirPlay 2 Realtime Streams. If it comes close to zero it's often a sign that the network is poor.
##### Max Buffers
The is the largest number of packets of audio in the queue to be processed in the last interval.
##### Min Buffer Size
The is smallest remaining number of bytes in the Buffered Audio buffer in the last interval. It can legitimately be zero when a track ends or begins. If it reaches zero while a track is playing, it means that audio data is not arriving at Shairport Sync quickly enough and may indicate network problems. AirPlay 2 Buffered Audio streams only.
##### Nominal FPS
-This is the rate specified in the AirPlay stream itself. AirPlay 1 only.
+This is the rate specified in the AirPlay stream itself. Classic AirPlay only.
##### Received FPS
-This is the rate at which frames are received from the network averaged since the start of the play session. AirPlay 1 only.
+This is the rate at which frames are received from the network averaged since the start of the play session. Classic AirPlay only.
##### Output FPS (r)
Output rate measured relative to the computer system's clock since the start of the play session. See above for a discussion.
##### Output FPS (c)
Output rate measured relative to the network-clock-disciplined computer system's clock since the start of the play session. See above for a discussion.
##### Source Drift PPM
-This is a measure of the difference between the source clock and Shairport Sync's clock expressed in parts per million. Only valid when 10 or more drift samples have been received. AirPlay 1 only.
+This is a measure of the difference between the source clock and Shairport Sync's clock expressed in parts per million. Only valid when 10 or more drift samples have been received. Classic AirPlay only.
##### Drift Samples
-This is the number drift samples have been accepted for calculating the source drift. AirPlay 1 only.
+This is the number drift samples have been accepted for calculating the source drift. Classic AirPlay only.
#### Example
The following example is of an AirPlay 2 Buffered Audio Stream from a HomePod mini to a WiFi-connected Raspberry Pi 3 equipped with a Pimoroni "Audio DAC SHIM (Line-Out)" with `log_verbosity` set to `1` after 3 hours and 37 minutes of operation. The audio is from a radio station accessed through Apple Music:
In this example, a Raspberry Pi Zero 2 W and a Pimoroni PHAT DAC are used. Shairport Sync will be built for AirPlay 2 operation, but you can build it for "classic" AirPlay (aka AirPlay 1) operation if you prefer. A Pi Zero W is powerful enough for classic AirPlay.
-Please note that some of the details of setting up networks are specific to the version of Linux used -- Rasberry Pi OS (Bullseye) Lite or later.
+Please note that some of the details of setting up networks are specific to the version of Linux used – Rasberry Pi OS (Bullseye) Lite or later.
### Prepare the initial SD Image
-* Download the latest version of Raspberry Pi OS (Lite) -- Bullseye (Lite) of 2022-04-04 at the time of writing -- and install it onto an SD Card using `Raspberry Pi Imager`. The Lite version is preferable to the Desktop version as it doesn't include a sound server like PulseAudio or PipeWire that can prevent direct access to the audio output device.
-* Before writing the image to the card, use the Settings control on `Raspberry Pi Imager` to set hostname, enable SSH and provide a username and password to use while building the system. Similarly, you can specify a wireless network the Pi will connect to while building the system. Later on the Pi will be configured to start its own isolated network.
+* Download the latest version of Raspberry Pi OS (Lite) – Bullseye (Lite) of 2022-04-04 at the time of writing – and install it onto an SD Card using `Raspberry Pi Imager`. The Lite version is preferable to the Desktop version as it doesn't include a sound server like PulseAudio or PipeWire that can prevent direct access to the audio output device.
+* Before writing the image to the card, use the Settings control on `Raspberry Pi Imager` to set hostname, enable SSH and provide a username and password to use while building the system. Similarly, you can specify a wireless network the Pi will connect to while building the system. Later on, the Pi will be configured to start its own isolated network.
* The next few steps are to add the overlay needed for the sound card. This may not be necessary in your case, but in this example a Pimoroni PHAT is being used. If you do not need to add an overlay, skip these steps.
- * Mount the card on a Linux machine. Two drives should appear -- a `boot` drive and a `rootfs` drive.
+ * Mount the card on a Linux machine. Two drives should appear – a `boot` drive and a `rootfs` drive.
* `cd` to the `boot` drive (since my username is `mike`, it will be `$ cd /media/mike/boot`).
* Edit the `config.txt` file to add the overlay needed for the sound card. This may not be necessary in your case, but in this example a Pimoroni PHAT is being used and it needs the following entry to be added:
```
* Close the file and carefully dismount and eject the two drives. *Be sure to dismount and eject the drives properly; otherwise they may be corrupted.*
* Remove the SD card from the Linux machine, insert it into the Pi and reboot.
-After a short time, the Pi should appear on your network -- it may take a minute or so. To check, try to `ping` it at the `<hostname>.local`, e.g. if the hostname is `bmw` then use `$ ping bmw.local`. Once it has appeared, you can SSH into it and configure it.
+After a short time, the Pi should appear on your network – it may take a minute or so. To check, try to `ping` it at the `<hostname>.local`, e.g. if the hostname is `bmw` then use `$ ping bmw.local`. Once it has appeared, you can SSH into it and configure it.
### Boot, Configure, Update
The first thing to do on a Pi would be to use the `raspi-config` tool to expand the file system to use the entire card. Next, do the usual update and upgrade:
```
# apt install --no-install-recommends build-essential git xmltoman autoconf automake libtool \
libpopt-dev libconfig-dev libasound2-dev avahi-daemon libavahi-client-dev libssl-dev libsoxr-dev \
- libplist-dev libsodium-dev libavutil-dev libavcodec-dev libavformat-dev uuid-dev libgcrypt-dev xxd
+ libplist-dev libsodium-dev libavutil-dev libavcodec-dev libavformat-dev uuid-dev xxd
```
If you are building classic Shairport Sync, the list of packages is shorter:
```
```
$ git clone https://github.com/mikebrady/shairport-sync.git
$ cd shairport-sync
-$ git checkout development
$ autoreconf -fi
$ ./configure --sysconfdir=/etc --with-alsa \
--with-soxr --with-avahi --with-ssl=openssl --with-systemd --with-airplay-2
```
The `autoreconf` step may take quite a while – please be patient!
-**Note:** *Do not* enable Shairport Sync to start automatically at boot time -- later on in this installation, we will arrange for it to start after the network has been set up.
+**Note:** *Do not* enable Shairport Sync to start automatically at boot time – later on in this installation, we will arrange for it to start after the network has been set up.
### Configure Shairport Sync
Here are the important options for the Shairport Sync configuration file at `/etc/shairport-sync.conf`:
};
```
-Two `general` settings are worth noting. First, the option to ignore the sending device's volume control is enabled -- this means that the car audio's volume control is the only one that affects the audio volume. Of course this is a matter of personal preference.
+Two `general` settings are worth noting. First, the option to ignore the sending device's volume control is enabled. This means that the car audio's volume control is the only one that affects the audio volume. Of course this is a matter of personal preference.
Second, the maximum output offered by the DAC to the AUX port of the car audio can be reduced if it is overloading the input circuits. Again, that's a matter for personal selection and adjustment.
-The `alsa` settings are for the Pimoroni PHAT -- it does not have a hardware mixer, so no `mixer_control_name` is given.
+The `alsa` settings are for the Pimoroni PHAT – it does not have a hardware mixer, so no `mixer_control_name` is given.
Note that the DAC's 32-bit capability is automatically selected if available, so there is no need to set it here. Similarly, since `soxr` support is included in the build, `soxr` interpolation will be automatically enabled if the device is fast enough.
wmm_enabled=1
```
-Note that, since car network is isolated from the Internet, you don't really need to secure it with a password.
+Note that, since the car network is isolated from the Internet, you don't really need to secure it with a password.
#### Configure DHCP server
-First, replace the contents of `/etc/dhcp/dhcpd.conf` with this:
+First, replace the contents of `/etc/dhcp/dhcpd.conf` with this:
```
subnet 10.0.10.0 netmask 255.255.255.0 {
range 10.0.10.5 10.0.10.150;
#option broadcast-address <the-broadcast-IP-address-for-your-network>;
}
```
-Second, modify the INTERFACESv4 entry at the end of the file `/etc/default/isc-dhcp-server` to look as follows:
+Second, modify the `INTERFACESv4` entry at the end of the file `/etc/default/isc-dhcp-server` to look as follows:
```
INTERFACESv4="wlan0"
INTERFACESv6=""
```
denyinterfaces wlan0
```
-From this point on, at least on the Raspberry Pi, if you reboot the machine, it will not reconnect to your network – instead, it will act as the WiFi base station you have configured with `hostapd` and `isc-dhcp-server`.
+From this point on, at least on the Raspberry Pi, if you reboot the machine, it will not reconnect to your network. Instead, it will act as the WiFi base station you have configured with `hostapd` and `isc-dhcp-server`.
-### Optimise startup time -- Raspberry Pi Specific
+### Optimise startup time – Raspberry Pi Specific
-This is applicable to a Raspberry Pi only. Some of it may be applicable to other systems, but it has not been tested on them. There are quite a few services that are not necessary for this setup. Disabling them can improve startup time. Running these commands disables them:
+This is applicable to a Raspberry Pi only. Some of it may be applicable to other systems, but it has not been tested on them.
-````
+There are quite a few services that are not necessary for this setup. Disabling them can improve startup time. Running these commands disables them:
+
+```
sudo systemctl disable systemd-timesyncd.service
sudo systemctl disable keyboard-setup.service
sudo systemctl disable triggerhappy.service
sudo systemctl disable wpa_supplicant.service
sudo systemctl disable dphys-swapfile.service
sudo systemctl disable networking.service
-````
-
-### Read-only mode -- Raspberry Pi Specific
+```
+### Read-only mode – Raspberry Pi Specific
Run `sudo raspi-config` and then choose `Performance Options` > `Overlay Filesystem` and choose to enable the overlay filesystem, and to set the boot partition to be write-protected.
### Ready
Install the Raspberry Pi in your car. It should be powered from a source that is switched off when you leave the car, otherwise the slight current drain will eventually flatten the car's battery.
When the power source is switched on, typically when you start the car, it will take maybe a minute for the system to boot up.
+
### Enjoy!
# Features
* Outputs AirPlay audio to [ALSA](https://www.alsa-project.org/wiki/Main_Page), [sndio](http://www.sndio.org), [PulseAudio](https://www.freedesktop.org/wiki/Software/PulseAudio/), [Jack Audio](http://jackaudio.org), to a unix pipe or to `STDOUT`. It also has experimental support for [PipeWire](https://pipewire.org) and limited support for [libao](https://xiph.org/ao/) and for [libsoundio](http://libsound.io).
* Metadata — Shairport Sync can deliver metadata supplied by the source, such as Album Name, Artist Name, Cover Art, etc. through a pipe or UDP socket to a recipient application program — see https://github.com/mikebrady/shairport-sync-metadata-reader for a sample recipient. Sources that supply metadata include iTunes and the Music app in macOS and iOS.
-* An interface to [MQTT](https://en.wikipedia.org/wiki/MQTT), a popular protocol for Inter Process Communication, Machine-to-Machine, Internet of Things and Home Automation projects. The interface including access to metadata and artwork, and limited remote control.
+* An interface to [MQTT](https://en.wikipedia.org/wiki/MQTT), a popular protocol for Inter Process Communication, Machine-to-Machine, Internet of Things and Home Automation projects. The interface provides access to metadata and artwork, and has limited remote control.
* Digital Signal Processing facilities – please see the [DSP Wiki Page Guide](https://github.com/mikebrady/shairport-sync/wiki/Digital-Signal-Processing-with-Shairport-Sync). (Thanks to [Yann Pomarède](https://github.com/yannpom) for the code and to [Paul Wieland](https://github.com/PaulWieland) for the guide.)
* An [MPRIS](https://specifications.freedesktop.org/mpris-spec/2.2/)-like interface, partially complete and very functional, including access to metadata and artwork, and limited remote control.
* A native D-Bus interface, including access to metadata and artwork, limited remote control and system settings.
projects / thirdparty / shairport-sync.git / commitdiff
