diff --git a/man/shairport-sync.7 b/man/shairport-sync.7 index 0da7ba01..35fa5a5b 100644 --- a/man/shairport-sync.7 +++ b/man/shairport-sync.7 @@ -17,9 +17,11 @@ shairport-sync -V\fB .SH 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. +A feature of shairport-sync is that it offers full audio synchronisation. Full audio synchronisation means that audio is played on the output device at exactly the time specified by the audio source. 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. +shairport-sync can be compiled to stream audio synchronised audio output to a unix pipe or to standard output, or to audio systems that do not provide timing information. This could perhaps be described as partial audio synchronisation, where synchronised audio is provided by shairport-sync, but what happens to it in the subsequent processing chain, before it reaches the listener's ear, is outside the control of shairport-sync. + +shairport-sync can 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. .SH CONFIGURATION FILE SETTINGS @@ -151,7 +153,7 @@ If the value chosen is too short for synchronised backends such as the ALSA, snd \fBrun_this_when_volume_is_set=\f1\fI"/full/path/to/application/and/args"\f1\fB;\f1 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 \fI#!/bin/...\f1 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". +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". .TP \fB"ALSA" SETTINGS\f1 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 \fBalsamixer\f1 or \fBaplay\f1 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 \fBalsa\f1 group settings: @@ -187,10 +189,12 @@ Use this optional advanced setting to set the alsa buffer size near to this valu \fBuse_mmap_if_available=\f1\fI"yes"\f1\fB;\f1 Use this optional advanced setting to control whether MMAP-based output is used to communicate with the DAC. Default is \fI"yes"\f1. .TP -\fBmute_using_playback_switch=\f1\fI"yes"\f1\fB;\f1 -This is an advanced setting and the default is \fI"yes"\f1, which means that hardware mute will be implemented using a feature called a 'playback switch', where one is available; set it to \fI"no"\f1 to prevent the playback switch being used. +\fBmute_using_playback_switch=\f1\fI"no"\f1\fB;\f1 +This is an advanced setting and the default is \fI"no"\f1. If it is set to \fI"yes"\f1, hardware mute will be implemented using a feature called a 'playback switch', where one is available. Set it to \fI"no"\f1 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. +If Shairport Sync is sharing the output device with other applications, it is best to leave this set to \fI"no"\f1 for compatibility with those applications. + +Another motivation for this is to allow the alsa function call "snd_mixer_selem_set_playback_switch_all" to be avoided. It is incorrectly implemented on certain soundcards, including the emulated card in VMWare Fusion 8.5. .TP \fB"SNDIO" SETTINGS\f1 These settings are for the SNDIO back end, used to communicate with audio output devices in the SNDIO system. diff --git a/man/shairport-sync.7.xml b/man/shairport-sync.7.xml index c59d8988..6d79a7f7 100644 --- a/man/shairport-sync.7.xml +++ b/man/shairport-sync.7.xml @@ -4,7 +4,7 @@