Provided by: shairport-sync_3.1.7-1build1_amd64 
NAME
shairport-sync - Synchronised Audio Player for iTunes / AirPlay
SYNOPSIS
shairport-sync [-djvw] [-a name] [-A latency] [-B command] [-c configurationfile] [-E
command] [--get-cover-art] [--logOutputLevel] [-L latency] [-m backend] [--meta-
dir=directory] [-o backend] [--password=secret] [-r threshold] [--statistics] [-S mode]
[-t timeout] [--tolerance=frames] [-- audio_backend_options]
shairport-sync -D
shairport-sync -k
shairport-sync -h
shairport-sync -R
shairport-sync -V
DESCRIPTION
shairport-sync plays audio streamed from iTunes or from an AirPlay device to an ALSA
compatible audio output device (available on Linux and FreeBSD) , to a "sndio" output
device (available on OpenBSD, FreeBSD and Linux) or to a PulseAudio output stream
(available on Linux).
A feature of shairport-sync is that the audio is played synchronously. This means that if
many devices are playing the same stream at the same time, all the outputs will stay in
step with one another. This allows multiple devices to play the same source without
getting out of phase with one another, enabling, for example, simultaneous multi-room
operation.
shairport-sync can be compiled to stream audio, without synchronisation, to a pipe, to
stdout or to a libao output device (an "AO" device). It can also be compiled to stream
metadata to a pipe or socket.
Settings can be made using the configuration file (recommended for all new installations)
or by using command-line options.
CONFIGURATION FILE SETTINGS
You should use the configuration file for setting up shairport-sync. This file is usually
shairport-sync.conf and is generally located in the System Configuration Directory, which
is normally the /etc directory in Linux or the /usr/local/etc directory in BSD unixes. You
may need to have root privileges to modify it.
(Note: Shairport Sync may have been compiled to use a different configuration directory.
You can determine which by performing the command $ shairport-sync -V. One of the items in
the output string is the value of the sysconfdir, i.e. the System Configuration
Directory.)
Within the configuration file, settings are organised into groups, for example, there is a
"general" group of standard settings, and there is an "alsa" group with settings that
pertain to the ALSA back end. Here is an example of a typical configuration file:
general = {
name = "Mike's Boombox";
interpolation = "soxr";
password = "secret";
output_backend = "alsa";
};
alsa = {
output_device = "hw:0";
mixer_control_name = "PCM";
};
Most settings have sensible default values, so -- as in the example above -- users
generally only need to set (1) the service name, (2) a password (if desired) and (3) the
output device. If the output device has a mixer that can be used for volume control, then
(4) the volume control's name should be specified. It is highly desirable to use the
output device's mixer for volume control, if available -- response time is reduced to zero
and the processor load is reduced. In the example above, "soxr" interpolation was also
enabled.
A sample configuration file with all possible settings, but with all of them commented
out, is installed at shairport-sync.conf.sample, within the System Configuration Directory
-- /etc in Linux, /usr/local/etc in BSD unixes.
To retain backwards compatibility with previous versions of shairport-sync you can use
still use command line options, but any new features, etc. will be available only via
configuration file settings.
The configuration file is processed using the libconfig library -- see
http://www.hyperrealm.com/libconfig/libconfig_manual.html.
"GENERAL" SETTINGS
These are the settings available within the general group:
name="service_name";
Use this service_name to identify this player in iTunes, etc.
The following substitutions are allowed: %h for the computer's hostname, %H for the
computer's hostname with the first letter capitalised (ASCII only), %v for the
shairport-sync version number, e.g. "3.0.1" and %V for the shairport-sync version
string, e.g. "3.0.1-OpenSSL-Avahi-ALSA-soxr-metadata-sysconfdir:/etc".
The default is "%H", which is replaced by the hostname with the first letter
capitalised.
password="password";
Require the password password to connect to the service. If you leave this setting
commented out, no password is needed.
interpolation="mode";
Interpolate, or "stuff", the audio stream using the mode. Interpolation here refers
to the process of adding or removing frames of audio to or from the stream sent to
the output device to keep it exactly in synchrony with the player. The default
mode, "basic", is normally almost completely inaudible. The alternative mode,
"soxr", is even less obtrusive but requires much more processing power. For this
mode, support for libsoxr, the SoX Resampler Library, must be selected when
shairport-sync is compiled.
statistics="setting";
Use this setting to enable ("yes") or disable ("no") the output of some statistical
information on the console or in the log. The default is to disable statistics.
mdns_backend="backend";
shairport-sync has a number of modules of code ("backends") for interacting with
the mDNS service to be used to advertise itself. Normally, the first mDNS backend
that works is selected. This setting forces the selection of the specific mDNS
backend. The default is "avahi". Perform the command shairport-sync -h to get a
list of available mDNS modules.
output_backend="backend";
shairport-sync has a number of modules of code ("backends") through which audio is
output. Normally, the first audio backend that works is selected. This setting
forces the selection of the specific audio backend. Perform the command shairport-
sync -h to get a list of available audio backends -- the default is the first on
this list. Only the "alsa", "sndio" and "pa" backends support synchronisation.
port=portnumber;
Use this to specify the portnumber shairport-sync uses to listen for service
requests from iTunes, etc. The default is port 5000.
udp_port_base=portnumber;
When shairport-sync starts to play audio, it establises three UDP connections to
the audio source. Use this setting to specify the starting portnumber for these
three ports. It will pick the first three unused ports starting from portnumber.
The default is port 6001.
udp_port_range=range;
Use this in conjunction with the previous setting to specify the range of ports
that can be checked for availability. Only three ports are needed. The default is
100, thus 100 ports will be checked from port 6001 upwards until three are found.
drift_tolerance_in_seconds=seconds;
Allow playback to drift up to seconds out of exact synchronization before
attempting to correct it. The default is 0.002 seconds, i.e. 2 milliseconds. The
smaller the tolerance, the more likely it is that overcorrection will occur.
Overcorrection is when more corrections (insertions and deletions) are made than
are strictly necessary to keep the stream in sync. Use the statistics setting to
monitor correction levels. Corrections should not greatly exceed net corrections.
This setting replaces the deprecated drift setting.
resync_threshold_in_seconds=threshold;
Resynchronise if timings differ by more than threshold seconds. If the output
timing differs from the source timing by more than the threshold, output will be
muted and a full resynchronisation will occur. The default threshold is 0.050
seconds, i.e. 50 milliseconds. Specify 0.0 to disable resynchronisation. This
setting replaces the deprecated resync_threshold setting.
log_verbosity=0;
Use this to specify how much debugging information should be output or logged. The
value 0 means no debug information, 3 means most debug information. The default is
0.
ignore_volume_control="choice";
Set this choice to "yes" if you want the volume to be at 100% no matter what the
source's volume control is set to. This might be useful if you want to set the
volume on the output device, independently of the setting at the source. The
default is "no".
volume_max_db=dBvalue;
Specify the maximum output level to be used with the hardware mixer, if used. If no
hardware mixed is used, this setting speciies the maximum setting permissible in
the software mixer, which has an attenuation of from 0.0 dB down to -96.3 dB.
volume_range_db=dBvalue;
Use this dBvalue to reduce or increase the attenuation range, in decibels, between
the minimum and maximum volume.
For example, if a mixer has a minimum volume of -80 dB and a maximum of +20 dB, you
might wish to use only 60 dB of the 100 dB available. This might be because the
sound becomes inaudible at the lowest setting and unbearably loud at the highest
setting -- indeed, many domestic HiFi systems have a volume control range of just
60 to 80dB.
Another potential use might be where the range specified by the mixer does not
match the capabilities of the device. For example, the Raspberry Pi's DAC that
feeds the built-in audio jack claims a range of 106 dB but has a useful range of
only about 30 dB. The setting allows you to specify the maximum range from highest
to lowest. The range suggested for the Raspberry Pi's built-in audio DAC, which
feeds the headphone jack, is 30. Using it in this case gives the volume control a
much more useful range of settings.
As a third example, you can actually extend the range provided by a mixer. Many
cheaper DACs have hardware mixers that offer a restricted attenuation range. If you
specify a volume range greater than the range of the mixer, software attenuation
and hardware attenuation will be combined to give the specified range.
If you omit this setting, the native range of the mixer is used.
regtype="regTypeString";
Use this advanced setting to set the service type and transport to be advertised by
Zeroconf/Bonjour. Default is "_raop._tcp".
playback_mode="mode";
The mode can be "stereo", "mono", "reverse stereo", "both left" or "both right".
Default is "stereo".
interface="name";
Use this advanced setting if you want to confine Shairport Sync to the named
interface. Leave it commented out to get the default bahaviour.
alac_decoder="decodername";
This can be "hammerton" or "apple". This advanced setting allows you to choose the
original Shairport decoder by David Hammerton or the Apple Lossless Audio Codec
(ALAC) decoder written by Apple. Shairport Sync must have been compiled with the
configuration setting "--with-apple-alac" and the Apple ALAC decoder library must
be present for this to work.
audio_backend_latency_offset_in_seconds=offset_in_seconds;
Set this offset_in_seconds to compensate for a fixed delay in the audio back end.
For example, if the output device delays by 100 ms, set this to -0.1.
audio_backend_buffer_desired_length_in_seconds=length_in_seconds;
Use this length_in_seconds to set the desired length of the queue of audio frames
in the backend's output buffer.
The default is 0.15 seconds for the ALSA backend, 0.35 seconds for the PA backend
and one second for all other backends.
If this value is set too small, underflow may occur on low-powered machines. If set
too large, the response times to the volume control may become excessive, or it may
exceed the backend's buffer size. It may need to be larger on low-powered machines
that are also performing other tasks, such as processing metadata.
audio_backend_silent_lead_in_time=lead_in_time_in_seconds;
This is an advanced setting. Use the lead_in_time_in_seconds to set the desired
length of the period of silence (a "silent lead-in") played before a play session
begins.
The purpose of this silent lead-in is to give the backend sufficient time to
prepare for operation and to make an estimate (and, importantly, to correct the
estimate) of the exact time at which to begin playing audio to achieve initial
synchronisation. The value can be from 0.0 up to a maximum of either 4.0 seconds.
The actual duration will be close to the setting but can not exceed the latency set
by the client, usually 2 seconds or a little more.
If the value chosen is too short for synchronised backends such as the ALSA, sndio
or PA backends, then audio will not be synchronised correctly at the start of play.
The default is to have a silent lead-in of approximately the same time as the
latency set by the client.
run_this_when_volume_is_set="/full/path/to/application/and/args";
Here you can specify a program and its arguments that will be run when the volume
is set or changed. Be careful to include the full path to the application. The
application must be marked as executable and, if it is a script, its first line
must begin with the standard #!/bin/... as appropriate.
The desired AirPlay volume is appended to the end of the command line – leave a
space if you want it treated as an extra argument. AirPlay volume goes from 0.0 to
-30.0 and -144.0 means "mute".
"ALSA" SETTINGS
These settings are for the ALSA back end, used to communicate with audio output
devices in the ALSA system. (By the way, you can use tools such as alsamixer or
aplay to discover what devices are available.) Use these settings to select the
output device and the mixer control to be used to control the output volume. You
can additionally set the desired size of the output buffer and you can adjust
overall latency. Here are the alsa group settings:
output_device="output_device";
Use the output device called output_device. The default is the device called
"default".
mixer_control_name="name";
Specify the name of the mixer control to be used by shairport-sync to control the
volume. The mixer control must be on the mixer device, which by default is the
output device. If you do not specify a mixer control name, shairport-sync will
adjust the volume in software.
mixer_device="mixer_device";
By default, the mixer is assumed to be output_device. Use this setting to specify a
device other than the output device.
output_rate=frame rate;
Use this setting to specify the frame rate to output to the ALSA device. Allowable
values are 44100 (default), 88200, 176400 and 352800. The device must have the
capability to accept the format you specify. There is no particular reason to use
anything other than 44100 if it is available.
output_format="format";
Use this setting to specify the format that should be used to send data to the ALSA
device. Allowable values are "U8", "S8", "S16", "S24", "S24_3LE", "S24_3BE" or
"S32". The device must have the capability to accept the format you specify.
"S" means signed; "U" means unsigned; BE means big-endian and LE means little-
endian. Except where stated (using *LE or *BE), endianness matches that of the
processor. The default is "S16".
If you are using a hardware mixer, the best setting is S16, as audio will pass
through Shairport Sync unmodifed except for interpolation. If you are using the
software mixer, use 32- or 24-bit, if your device is capable of it, to get the
lowest possible levels of dither.
disable_synchronization="no";
This is an advanced setting and is for debugging only. Set to "yes" to disable
synchronization. Default is "no". If you use it to disable synchronisation, then
sooner or later you'll experience audio glitches due to audio buffer overflow or
underflow.
period_size=number;
Use this optional advanced setting to set the alsa period size near to this value.
buffer_size=number;
Use this optional advanced setting to set the alsa buffer size near to this value.
use_mmap_if_available="yes";
Use this optional advanced setting to control whether MMAP-based output is used to
communicate with the DAC. Default is "yes".
mute_using_playback_switch="yes";
This is an advanced setting and the default is "yes", which means that hardware
mute will be implemented using a feature called a 'playback switch', where one is
available; set it to "no" to prevent the playback switch being used.
The motivation for this is to avoid using the alsa function call
"snd_mixer_selem_set_playback_switch_all", which is incorrectly implemented on
certain soundcards, including the emulated card in VMWare Fusion 8.5.
"SNDIO" SETTINGS
These settings are for the SNDIO back end, used to communicate with audio output
devices in the SNDIO system.
device="snd/0";
Use this optional setting to specify the name of the output device, e.g. "snd/0".
The default is to use the SNDIO system's default.
rate=44100;
Use this optional setting to specify the output rate in frames per second. Valid
rates are 44100, 88200, 176400 or 352800. The output device must have the
capability to accept data at the specified rate. The default is 44100.
format="S16";
Use this optional setting to specify the output format. Allowable values are "U8",
"S8", "S16", "S24", "S24_3LE", "S24_3BE" or "S32". The device must have the
capability to accept the format you specify.
"S" means signed; "U" means unsigned; BE means big-endian and LE means little-
endian. Except where stated (using *LE or *BE), endianness matches that of the
processor. The default is "S16".
Since the SNDIO backend does not use a hardware mixer for volume control, dither
will be introduced into the output if it is less than full volume. Thus, (unless
you are ignoring the volume control setting), consider using 32- or 24-bit output
if your device is capable of it, to get the lowest possible levels of dither.
Please note that 32- or 24-bit has not been extensively tested on SNDIO.
round=value;
Use this optional advanced setting to specify the period size of the SNDIO channel.
If omitted, a SNDIO system default value will be used.
bufsiz=value;
Use this optional advanced setting to specify the buffer size of the SNDIO channel.
If omitted, a SNDIO system default value will be used.
"PA" SETTINGS
These settings are for the new PulseAudio backend.
application_name="Shairport Sync";
Use this to set the name to appear in the Sounds "Applications" tab when Shairport
Sync is active. The default is the name "Shairport Sync".
"PIPE" SETTINGS
These settings are for the PIPE backend, used to route audio to a named unix pipe.
The audio is in raw CD audio format: PCM 16 bit little endian, 44,100 samples per
second, interleaved stereo.
name="/path/to/pipe";
Use this to specify the name and location of the pipe. The pipe will be created and
opened when shairport-sync starts up and will be closed upon shutdown. Frames of
audio will be sent to the pipe in packets of 352 frames and will be discarded if
the pipe has not have a reader attached. The sender will wait for up to five
seconds for a packet to be written before discarding it.
"STDOUT" SETTINGS
There are no settings for the STDOUT backend.
"AO" SETTINGS
There are no configuration file settings for the AO backend.
"METADATA" SETTINGS
shairport-sync can process metadata provided by the source, such as Track Number,
Album Name, cover art, etc. and can provide additional metadata such as volume
level, pause/resume, etc. It sends the metadata to a pipe, by default
/tmp/shairport-sync-metadata. To process metadata, shairport-sync must have been
compiled with metadata support included. You can check that this is so by running
the command $ shairport-sync -V; the identification string will contain the word
metadata.
Please note that different sources provide different levels of metadata. Some
provide a lot; some provide almost none.
The metadata group of settings allow you to enable metadata handling and to control
certain aspects of it:
enabled="choice";
Set the choice to "yes" to enable shairport-sync to look for metadata from the
audio source and to forward it, along with metadata generated by shairport-sync
itself, to the metadata pipe. The default is "no".
include_cover_art="choice";
Set the choice to "yes" to enable shairport-sync to look for cover art from the
audio source and to include it in the feed to the metadata pipe. You must also
enable metadata (see above). One reason for not including cover art is that the
images can sometimes be very large and may delay transmission of subsequent
metadata through the pipe. The default is "no".
pipe_name="filepathname";
Specify the absolute path name of the pipe through which metadata should be sent
The default is /tmp/shairport-sync-metadata.
socket_address="hostnameOrIP";
If hostnameOrIP is set to a host name or and IP address, UDP packets containing
metadata will be sent to this address. May be a multicast address. Additionally,
socket-port must be non-zero and enabled must be set to "yes".
socket_port=port;
If socket_address is set, use port to specify the port to send UDP packets to. Must
not be zero.
socket_msglength=65000;
The maximum packet size for any UDP metadata. This must be between 500 or 65000.
The default is 500.
"SESSIONCONTROL" SETTINGS
shairport-sync can run programs just before it starts to play an audio stream and
just after it finishes. You specify them using the sessioncontrol group settings
run_this_before_play_begins and run_this_after_play_ends.
run_this_before_play_begins="/path/to/application and args";
Here you can specify a program and its arguments that will be run just before a
play session begins. Be careful to include the full path to the application. The
application must be marked as executable and, if it is a script, its first line
must begin with the standard #!/bin/... as appropriate.
run_this_after_play_ends="/path/to/application and args";
Here you can specify a program and its arguments that will be run just after a play
session ends. Be careful to include the full path to the application. The
application must be marked as executable and, if it is a script, its first line
must begin with the standard #!/bin/... as appropriate.
wait_for_completion="choice";
Set choice to "yes" to make shairport-sync wait until the programs specified in the
run_this_before_play_begins, run_this_after_play_ends and
run_this_when_volume_is_set have completed execution before continuing. The default
is "no".
allow_session_interruption="choice";
If choice is set to "yes", then another source will be able to interrupt an
existing play session and start a new one. When set to "no" (the default), other
devices attempting to interrupt a session will fail, receiving a busy signal.
session_timeout=seconds;
If a play session has been established and the source disappears without warning
(such as a device going out of range of a network) then wait for seconds seconds
before ending the session. Once the session has terminated, other devices can use
it. The default is 120 seconds.
OPTIONS
This section is about the command-line options available in shairport-sync.
Note: if you are setting up shairport-sync for the first time or are updating an existing
installation, you are encouraged to use the configuration file settings described above.
Most of the command-line options described below simply replicate the configuration
settings and are retained to provide backward compatibility with older installations of
shairport-sync.
Many command-line options take sensible default values, so you can normally ignore most of
them. See the EXAMPLES section for typical usages.
There are two kinds of command-line options for shairport-sync: regular program options
and audio backend options. Program options are always listed first, followed by any audio
backend options, preceded by a -- symbol.
PROGRAM OPTIONS
These command-line options are used by shairport-sync itself.
-a service name | --name=service name
Use this service name to identify this player in iTunes, etc.
The following substitutions are allowed: %h for the computer's hostname, %H for the
computer's hostname with the first letter capitalised (ASCII only), %v for the
shairport-sync version number, e.g. "3.0.1" and %V for the shairport-sync version
string, e.g. "3.0.1-OpenSSL-Avahi-ALSA-soxr-metadata-sysconfdir:/etc".
The default is "%H", which is replaced by the hostname with the first letter
capitalised.
-B program | --on-start=program
Execute program when playback is about to begin. Specify the full path to the
program, e.g. /usr/bin/logger. Executable scripts can be used, but they must have
#!/bin/sh (or whatever is appropriate) in the headline.
If you want shairport-sync to wait until the command has completed before starting
to play, select the -w option as well.
-c filename | --configfile=filename
Read configuration settings from filename. The default is to read them from the
shairport-sync.conf in the System Configuration Directory -- /etc in Linux,
/usr/local/etc in BSD unixes. For information about configuration settings, see the
"Configuration File Settings" section above.
-D | --disconnectFromOutput
Disconnect the shairport-sync daemon from the output device and exit. (Requires
that the daemon has written its PID to an agreed file -- see the -d option).
Please note that this feature is deprecated and will be removed in a future version
of shairport-sync.
-d | --daemon
Instruct shairport-sync to demonise itself. It will write its Process ID (PID) to a
file, usually at /var/run/shairport-sync/shairport-sync.pid, which is used by the
-k, -D and -R options to locate the daemon at a later time. See also the -j option.
-E program | --on-stop=program
Execute program when playback has ended. Specify the full path to the program, e.g.
/usr/bin/logger. Executable scripts can be used, but they must have #!/bin/sh (or
whatever is appropriate) in the headline.
If you want shairport-sync to wait until the command has completed before
continuing, select the -w option as well.
--get-coverart
This option requires the --meta-dir option to be set, and enables shairport-sync to
request cover art from the source and to transmit it through the metadata pipe.
Please note that cover art data may be very large, and may place too great a burden
on your network.
-h | --help
Print brief help message and exit.
-j Instruct shairport-sync to demonise itself. Unlike the -d option, it will not write
a Process ID (PID) to a file -- it will just (hence the "j") demonise itself.
-k | --kill
Kill the shairport-sync daemon and exit. (Requires that the daemon has written its
PID to an agreed file -- see the -d option).
--logOutputLevel
Use this to log the volume level when the volume is changed. It may be useful if
you are trying to determine a suitable value for the maximum volume level. Not
available as a configuration file setting.
-L | --latency=latency
Use this to set the default latency, in frames, for audio coming from an
unidentified source or from an iTunes Version 9 or earlier source. The standard
value for the default latency is 88,200 frames, where there are 44,100 frames to
the second.
Please note that this feature is deprecated and will be removed in a future version
of shairport-sync.
--meta-dir=directory
Listen for metadata coming from the source and send it, along with metadata from
shairport-sync itself, to a pipe called shairport-sync-metadata in the directory
you specify. If you add the --get-cover-art then cover art will be sent through the
pipe too. See https://github.com/mikebrady/shairport-sync-metadata-reader for a
sample metadata reader.
-m mdnsbackend | --mdns=mdnsbackend
Force the use of the specified mDNS backend to advertise the player on the network.
The default is to try all mDNS backends until one works.
-o outputbackend | --output=outputbackend
Force the use of the specified output backend to play the audio. The default is to
try the first one.
-p port | --port=port
Listen for play requests on port. The default is to use port 5000.
--password=secret
Require the password secret to be able to connect and stream to the service.
-R | --reconnectToOutput
Reconnect the shairport-sync daemon to the output device and exit. It may take a
few seconds to synchronise. (Requires that the daemon has written its PID to an
agreed file -- see the -d option).
Please note that this feature is deprecated and will be removed in a future version
of shairport-sync.
-r threshold | --resync=threshold
Resynchronise if timings differ by more than threshold frames. If the output timing
differs from the source timing by more than the threshold, output will be muted and
a full resynchronisation will occur. The default threshold is 2,205 frames, i.e. 50
milliseconds. Specify 0 to disable resynchronisation. This setting is deprecated
and will be removed in a future version of shairport-sync.
--statistics
Print some statistics in the standard output, or in the logfile if in daemon mode.
-S mode | --stuffing=mode
Stuff the audio stream using the mode. "Stuffing" refers to the process of adding
or removing frames of audio to or from the stream sent to the output device to keep
it exactly in synchrony with the player. The default mode, basic, is normally
almost completely inaudible. The alternative mode, soxr, is even less obtrusive but
requires much more processing power. For this mode, support for libsoxr, the SoX
Resampler Library, must be selected when shairport-sync is compiled.
-t timeout | --timeout=timeout
Exit play mode if the stream disappears for more than timeout seconds.
When shairport-sync plays an audio stream, it starts a play session and will return
a busy signal to any other sources that attempt to use it. If the audio stream
disappears for longer than timeout seconds, the play session will be terminated. If
you specify a timeout time of 0, shairport-sync will never signal that it is busy
and will not prevent other sources from "barging in" on an existing play session.
The default value is 120 seconds.
--tolerance=frames
Allow playback to be up to frames out of exact synchronization before attempting to
correct it. The default is 88 frames, i.e. 2 ms. The smaller the tolerance, the
more likely it is that overcorrection will occur. Overcorrection is when more
corrections (insertions and deletions) are made than are strictly necessary to keep
the stream in sync. Use the --statistics option to monitor correction levels.
Corrections should not greatly exceed net corrections. This setting is deprecated
and will be removed in a future version of shairport-sync.
-V | --version
Print version information and exit.
-v | --verbose
Print debug information. Repeat up to three times to get more detail.
-w | --wait-cmd
Wait for commands specified using -B or -E to complete before continuing execution.
AUDIO BACKEND OPTIONS
These command-line options are passed to the chosen audio backend. The audio backend
options are preceded by a -- symbol to introduce them and to separate them from any
program options. In this way, option letters can be used as program options and also as
audio backend options without ambiguity.
In the ALSA backend, audio is sent to an output device which you can specify using the -d
option. The output level (the "volume") is controlled using a level control associated
with a mixer. By default, the mixer is implemented in shairport-sync itself in software.
To use a hardware level control on a mixer on the sound card, specify the name of the
mixer control with the -c option. If the mixer is not associated with the output device,
then you need to specify where the mixer is to be found with the -m option.
-c controlname
Use the level control called controlname on the hardware mixer for controlling
volume. This is needed if the mixer type is specified, using the -t option, to be
hardware. There is no default.
-d device
Use the specified output device. You may specify a card, e.g. hw:0, in which case
the default output device on the card will be chosen. Alternatively, you can
specify a specific device on a card, e.g. hw:0,0. The default is the device named
default.
-m mixer
Use the specified hardware mixer for volume control. Use this to specify where the
mixer is to be found. For example, if the mixer is associated with a card, as is
often the case, specify the card, e.g. hw:0. If (unusually) the mixer is associated
with a specific device on a card, specify the device, e.g. hw:0,1. The default is
the device named in the -d option, if given, or the device named default.
-t devicetype
This option is deprecated and is ignored. For your information, its functionality
has been automatically incorporated in the -c option -- if you specify a mixer name
with the -c option, it is assumed that the mixer is implemented in hardware.
EXAMPLES
Here is a slightly contrived example:
shairport-sync -d -a "Joe's Stereo" -S soxr -- -d hw:1,0 -m hw:1 -c PCM
The program will run in daemon mode ( -d ), will be visible as "Joe's Stereo" ( -a "Joe's
Stereo" ) and will use the SoX Resampler Library-based stuffing ( -S soxr ). The audio
backend options following the -- separator specify that the audio will be output on output
0 of soundcard 1 ( -d hw:1,0 ) and will take advantage of the same sound card's mixer ( -m
hw:1 ) using the level control named "PCM" ( -c "PCM" ).
The example above is slightly contrived in order to show the use of the -m option.
Typically, output 0 is the default output of a card, so the output device could be written
-d hw:1 and then the mixer option would be unnecessary, giving the following, simpler,
command:
shairport-sync -d -a "Joe's Stereo" -S soxr -- -d hw:1 -c PCM
CREDITS
Mike Brady developed shairport-sync from the original Shairport by James Laird.
shairport-sync can be found at https://github.com/mikebrady/shairport-sync.
Shairport can be found at https://github.com/abrasive/shairport.
COMMENTS
This man page was written using xml2man(1) by Oliver Kurth.