NQPTP(8)

NAME
nqptp - Not Quite PTP: PTP-based timing daemon for Apple AirPlay 2

SYNOPSIS
nqptp [-V] [-v|-vv|-vvv] [-h]

DESCRIPTION
nqptp is a daemon that monitors timing data from PTP (Precision Time Protocol) clocks. It is designed exclusively as a companion daemon to shairport-sync(1), which uses it to obtain the accurate timing information required for AirPlay 2 audio playback.

nqptp must be running before shairport-sync is started with AirPlay 2 support enabled. It communicates with shairport-sync via a shared memory interface and does not require any configuration file.

Under normal operation, nqptp runs silently in the background. It is typically started at boot time via a service manager such as systemd(1).

OPTIONS

-V  Print the version number and exit.

-v  Enable verbose logging. Basic informational messages about timing sources and state changes are written to the system log.

-vv Enable more verbose logging. Additional detail about PTP clock selection and timing computations is included.

-vvv
    Enable very verbose logging. Full diagnostic output, including low-level PTP message handling. Intended for debugging only.

-h  Print a brief help summary and exit.

SIGNALS

SIGTERM
    Cleanly shut down the daemon, releasing the shared memory interface before exiting.

SIGINT
    Cleanly shut down the daemon, equivalent to SIGTERM.

FILES

/dev/shm/nqptp
    Shared memory segment used to pass timing data to shairport-sync(1).

NOTES
nqptp listens on UDP port 319 and 320, the standard PTP event and general message ports. It therefore requires either CAP_NET_BIND_SERVICE or root privileges in order to bind these ports. When running under systemd(1), the provided unit file grants the necessary capability without requiring the daemon to run as root.

Only one instance of nqptp should be run at a time on a given host.

SEE ALSO
shairport-sync(1), ptp4l(8), systemd(1)

BUGS
Please report bugs at https://github.com/mikebrady/nqptp/issues.

AUTHORS
nqptp was written by Mike Brady.

This man page was originally written for the Debian package of nqptp by Chris Boot <bootc@debian.org>.