jackwsmeter - jack meter over websockets
========================================

jackwsmeter get the signal values of the audio signals that flow through
JACK ports and make the peak levels available over a websocket link,
it's a clean and efficient way to get an overview of levels from a serie
of jack servers.


Installation
------------

JACK <http://jackaudio.org> and libwebsockets <http://libwebsockets.org>
development files are required.

Building and installing is done via the autotools:

  ./autogen.sh
  make
  make install


Usage
-----

Run the following command, then open your browser at http://localhost:7681.

  jackwsmeter system:capture_1 system:capture_2

It's also possible to specify invalid ports, in that case the corresponding
number of jack input ports will be created but unconnected; the following
command creates four input ports:

  jackwsmeter x x x x

(the limit is set at 20 input ports)


Protocol
--------

jackwsmeter comes with a minimalistic HTML page but can be used in much better
integration when using its WebSocket interface.

The WebSocket protocol string is jack-wsmeter-protocol, it will periodically
emit a message consisting of a string containing a space separated list of
level values.

  var ws = new WebSocket('ws://localhost:7681', 'jack-wsmeter-protocol');
  ws.onmessage = function(event) {
      var peaks = event.data.split(" ");
      console.log('got ', peaks.length, ' measures:', event.data);
  }


Real world usage
----------------

jackwsmeter was developed to be used in Radio Panik, a free community radio in
Brussels, Belgium. <http://www.radiopanik.org>


Feedback
--------

You can send bug reports or any kind of comment to the author.

  mailto:Frederic Peters <fpeters@0d.be>