pulseaudio(1) | General Commands Manual | pulseaudio(1) |
pulseaudio - The PulseAudio Sound System
pulseaudio [options]
pulseaudio --help
pulseaudio --version
pulseaudio --dump-conf
pulseaudio --dump-modules
pulseaudio --dump-resample-methods
pulseaudio --cleanup-shm
pulseaudio --start
pulseaudio --kill
pulseaudio --check
PulseAudio is a networked low-latency sound server for Linux, POSIX and Windows systems.
Note that a non-zero return value doesn't necessarily mean that PulseAudio is not usable. Even if the server is not running, it may get automatically started via PulseAudio's autospawning mechanism or systemd's socket activation, or the environment might be such that checking for processes doesn't work (for example, the running server might not show up in a container, even if the server is accessible via a socket). Also disabling PID files with --use-pid-file=no prevents --check from detecting running servers.
A more robust check in most situations would be to try establishing a client connection to the server. Unfortunately there's currently no --check-connection option to replace --check, but running "pactl info" could be a pretty good substitute.
When PulseAudio runs in the per-user mode and detects a login session, then any positive value will be reset to 0 so that PulseAudio will terminate immediately on logout. A positive value therefore has effect only in environments where there's no support for login session tracking (or if the user is logged in without a session spawned, a.k.a. lingering). A negative value can still be used to disable any automatic exit.
When PulseAudio runs in the system mode, automatic exit is always disabled, so this option does nothing.
~/.config/pulse/daemon.conf, /etc/pulse/daemon.conf: configuration settings for the PulseAudio daemon. If the version in the user's home directory does not exist the global configuration file is loaded. See pulse-daemon.conf(5) for more information.
~/.config/pulse/default.pa, /etc/pulse/default.pa: the default configuration script to execute when the PulseAudio daemon is started. If the version in the user's home directory does not exist the global configuration script is loaded. See default.pa(5) for more information.
~/.config/pulse/client.conf, /etc/pulse/client.conf: configuration settings for PulseAudio client applications. If the version in the user's home directory does not exist the global configuration file is loaded. See pulse-client.conf(5) for more information.
SIGINT, SIGTERM: the PulseAudio daemon will shut down (Same as --kill).
SIGHUP: dump a long status report to STDOUT or syslog, depending on the configuration.
SIGUSR1: load module-cli, allowing runtime reconfiguration via STDIN/STDOUT.
SIGUSR2: load module-cli-protocol-unix, allowing runtime reconfiguration via a AF_UNIX socket. See pacmd(1) for more information.
Group pulse-access: if PulseAudio is running as a system daemon (see --system above) access is granted to members of this group when they connect via AF_UNIX sockets. If PulseAudio is running as a user daemon this group has no meaning.
User pulse, group pulse: if PulseAudio is running as a system daemon (see --system above) and is started as root the daemon will drop privileges and become a normal user process using this user and group. If PulseAudio is running as a user daemon this user and group has no meaning.
To minimize the risk of drop-outs during playback it is recommended to run PulseAudio with real-time scheduling if the underlying platform supports it. This decouples the scheduling latency of the PulseAudio daemon from the system load and is thus the best way to make sure that PulseAudio always gets CPU time when it needs it to refill the hardware playback buffers. Unfortunately this can be a security risk on some systems, since PulseAudio runs as user process, and giving realtime scheduling privileges to a user always comes with the risk that the user misuses it to lock up the system -- which is possible since making a process real-time effectively disables preemption. To solve this problem, PulseAudio uses rtkit to safely acquire real-time scheduling when available.
If the risk of locking up the machine is considered too big to enable real-time scheduling, high-priority scheduling can be enabled instead (i.e. negative nice level). This can be enabled by passing --high-priority (see above) when starting PulseAudio and may also be enabled with the appropriate option in daemon.conf. Negative nice levels can only be enabled when the appropriate resource limit RLIMIT_NICE is set (see setrlimit(2) for more information), possibly configured in /etc/security/limits.conf. A resource limit of 31 (corresponding with nice level -11) is recommended.
The PulseAudio client libraries check for the existence of the following environment variables and change their local configuration accordingly:
$PULSE_SERVER: the server string specifying the server to connect to when a client asks for a sound server connection and doesn't explicitly ask for a specific server. The server string is a list of server addresses separated by whitespace which are tried in turn. A server address consists of an optional address type specifier (unix:, tcp:, tcp4:, tcp6:), followed by a path or host address. A host address may include an optional port number. A server address may be prefixed by a string enclosed in {}. In this case the following server address is ignored unless the prefix string equals the local hostname or the machine id (/etc/machine-id).
$PULSE_SINK: the symbolic name of the sink to connect to when a client creates a playback stream and doesn't explicitly ask for a specific sink.
$PULSE_SOURCE: the symbolic name of the source to connect to when a client creates a record stream and doesn't explicitly ask for a specific source.
$PULSE_BINARY: path of PulseAudio executable to run when server auto-spawning is used.
$PULSE_CLIENTCONFIG: path of file that shall be read instead of client.conf (see above) for client configuration.
$PULSE_COOKIE: path of file that contains the PulseAudio authentication cookie. Defaults to ~/.config/pulse/cookie.
These environment settings take precedence -- if set -- over the configuration settings from client.conf (see above).
The PulseAudio Developers <pulseaudio-discuss (at) lists (dot) freedesktop (dot) org>; PulseAudio is available from http://pulseaudio.org/
pulse-daemon.conf(5), default.pa(5), pulse-client.conf(5), pacmd(1)
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