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JAMULUS(1) General Commands Manual JAMULUS(1)


Jamulusreal-time collaborative music session


Jamulus [-c | --connect address] [-d | --discononquit] [-e | --centralserver hostname] [-F | --fastupdate] [-f | --listfilter filter] [-h | -? | --help] [-i | --inifile file] [-j | --nojackconnect] [-L | --licence] [-l | --log file] [-M | --mutestream] [-m | --htmlstatus file] [-n | --nogui] [-o | --serverinfo info] [-p | --port number] [-R | --recording directory] [-s | --server] [-T | --multithreading] [-t | --notranslation] [-u | --numchannels] [-v | --version] [-w | --welcomemessage message] [-z | --startminimized] [--clientname name] [--ctrlmidich MIDISetup] [--mutemyown] [--norecord] [--serverpublicip ip] [--showallservers] [--showanalyzerconsole]


Jamulus, a low-latency audio client and server, enables musicians to perform real-time “jam” sessions over the internet. It is available across multiple platforms, so participants of any field can communicate without specialist setup requirements. This is not restricted to music, of course; other use (perhaps conferencing?) is also possible.

One participant starts Jamulus in server mode, ideally on a dedicated server (virtual) machine; all participants start the (graphical) client which transmits audio to the server, receiving back a mixed stream. Use of a metronome is recommended. Clients should be connected using ethernet, not wireless, and use proper headphone and microphone connections, not Bluetooth. The server should run on a low-latency system, ideally not a VM.

Running Jamulus without any extra options launches the full graphical client.

The options are as follows:

| address
(client mode only) connect to the given server address (hostname[:port]) at startup
(server mode only) disconnect all clients on quit
| hostname
(server mode only) make the server public and set its genre by setting the address of the central server to use to hostname; see also -o; to be a central server, use “localhost
(server mode only) use 64 samples frame size mode, which reduces latency if clients connect with “enable small network buffers” turned on; requires a faster CPU to avoid dropouts and uses more bandwidth to connected clients
| filter
(central server mode only) whitelist servers allowed to register on the server list; filter must consist of semicolon-separated IP addresses
| |
display a short help text and exit immediately
| file
(client and non-headless server mode only) override default initialisation file with file
(client mode only) do not automatically connect to JACK
(server mode only) require clients to accept the agreement shown in the welcome message (use -w to set the text) before they are allowed joining
| file
(server mode only) enable logging to file
(client mode only) start in muted state
| file
(server mode only) write server status and list of connected clients, in HTML format, to file periodically
disable the GUI
| info
(public servers only) set server location details, formatted as name;city;locale where locale is the numeric value of a QLocale; see for a list
| number
set the local UDP port to use to number (default: 22124)
| directory
(server mode only) enable recording (but see --norecord) storing tracks in directory
start in server mode
(server mode only) use multithreading to make better use of multi-core CPUs and support more clients
disable translations, use built-in English strings
(server mode only) set maximum number of channels (and, therefore, users); default is 10, maximum is 150
display version information and exit immediately
| message
(server mode only) show message (may contain HTML and inline CSS) to users on connect
(server mode only) start with minimised window
(client mode only) set window title and JACK client name
(client mode only) set MIDI controller channel to listen on, control number offset and consecutive CC numbers (channels); format: channel[;foff*nchans][;poff*nchans][;soff*nchans][;moff*nchans]

The first semicolon-separated element sets the MIDI channel Jamulus listens on for control messages. The other elements specify the items to control by their first literal letter (f = volume fader, p = pan, m = mute, s = solo) directly followed by the offset (CC number) to start from, a literal asterisk, and the amount of consecutive CC numbers to assign. Fader strips in the mixer window are controlled in ascending order from left to right. Jamulus does not provide feedback as to the current state of the Solo and Mute buttons so the controller must track and signal their state locally.

(headless client only) mute my channel in my personal mix
(server mode only) do not automatically start recording even if configured with -R
(server mode only) configure public Legacy IP address when both the central server and the actual server are situated behind the same NAT, so that clients can connect
(client mode only) show all registered servers in the serverlist regardless whether a ping to the server is possible or not (debugging command)
(client mode only) show analyser console to debug network buffer properties (debugging command)

Note that the debugging commands are not intended for general use.

Jamulus knows four modes of operation: client mode and three kinds of server (private, public, central). A private server is unlisted, clients can only connect if given the address (IP address and port). A public server will contact a central server (whose address must be given at server startup) and show up in that server's list; clients can retrieve a list of public servers from the central server. Several central servers are operated by the Jamulus project; there is a central server for each genre, which is how public servers are categorised into genres.


online handbook
more details on the individual server types
documentation on server configuration
current list of central servers operated by the Jamulus project, controlling the “genre”
verbose --ctrlmidich documentation and other more or less useful information


mirabilos ⟨⟩ wrote this manual page for the Debian project, but it may be used elsewhere as well.


This manual page was derived from the source code and summarises some of the information from the website, but it could be more helpful.

Some of the networking code seems to assume Legacy IP (IPv4).

April 11, 2021 Debian