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File Date Author Commit
 doc 2009-01-09 Sean Bolton Sean Bolton [800e9d] * 1.0.0 release
 dssi 2009-01-09 Sean Bolton Sean Bolton [800e9d] * 1.0.0 release
 examples 2010-06-01 Sean Bolton Sean Bolton [fff9f6] Update example GUIs from Qt3 to Qt4
 jack-dssi-host 2009-01-09 Sean Bolton Sean Bolton [800e9d] * 1.0.0 release
 message_buffer 2004-10-01 Chris Cannam Chris Cannam [092325]
 scripts 2004-10-28 Chris Cannam Chris Cannam [c91f7e]
 tests 2005-05-25 Sean Bolton Sean Bolton [d4435e] * Version bump to 0.9.1
 COPYING 2009-01-09 Sean Bolton Sean Bolton [800e9d] * 1.0.0 release
 ChangeLog 2010-05-31 Sean Bolton Sean Bolton [03ebcd] Fixed an uninitialized variable bug in less_tri...
 INSTALL 2005-05-25 Sean Bolton Sean Bolton [d4435e] * Version bump to 0.9.1 2009-01-09 Sean Bolton Sean Bolton [800e9d] * 1.0.0 release
 README 2009-01-09 Sean Bolton Sean Bolton [800e9d] * 1.0.0 release 2005-10-07 Sean Bolton Sean Bolton [b247d2] * Added '-a' no-auto-connect option to jack-dss... 2010-06-01 Sean Bolton Sean Bolton [fff9f6] Update example GUIs from Qt3 to Qt4 2005-05-25 Sean Bolton Sean Bolton [d4435e] * Version bump to 0.9.1

Read Me


This is the DSSI Soft Synth Interface specification & example
code repository.

You'll find here:

  doc/RFC.txt -- proposed DSSI specification -- read this first

  dssi/dssi.h -- DSSI header file -- the comments define those parts
  of the spec dealing with host/plugin interaction (not covered in RFC)

  jack-dssi-host/jack-dssi-host.c -- a simple JACK/ALSA-sequencer plugin host

  examples/dssi_osc_update.c -- simple DSSI OSC test programs

  examples/trivial_synth.c -- a quite useless but fairly clear
  illustrative synth plugin

  examples/less_trivial_synth.c -- a synth that actually does some
  basic synthesis

  examples/less_trivial_synth_qt_gui.cpp -- a very simple Qt GUI
  for the above

  examples/karplong.cpp -- a simple Karplus+Strong plucked string synth

  examples/trivial_sampler.c -- a simple one-sample polyphonic
  mono sampler (that doesn't do proper pitch scaling)

  examples/trivial_sampler_qt_gui.cpp -- a very simple Qt GUI for
  the above


In order to install the development files (dssi.h and dssi.pc)
needed to compile DSSI applications, you only need the following:

  pkgconfig with PKG_CONFIG_PATH set appropriately
  ALSA 0.9/1.0.x (or libdssialsacompat: see

To build the included host and plugins, you will also need:

  liblo-0.12 or above:

To build the less_trivial_synth and trivial_sampler Qt GUIs, you
will need:

  Qt 3

Note that because DSSI itself is just an API, it is possible to use
DSSI applications (say, Rosegarden with Xsynth-DSSI) without any of
the hosts or plugins contained in this DSSI distribution.
Furthermore, to compile DSSI applications, only the DSSI development
files (dssi.h and dssi.pc) are needed. OS distribution maintainers
are urged to keep these dependencies in mind when packaging DSSI,
and not make their `dssi-devel' package dependent on JACK or Qt, for


DSSI can be installed using the usual autoconf/automake `./configure
&& make && make install' procedure.  See the included file INSTALL
for generic installation instructions.

You will need to ensure PKG_CONFIG_PATH is set correctly to locate
the pkgconfig files for ALSA or libdssialsacompat, liblo, JACK,
sndfile, and samplerate.  You may also need to set the QTDIR and/or
QTINCDIR variables to point to your Qt installation.  If you do not
have any of these, any DSSI programs or plugins dependent on them
will not be built.

For example, to build on Debian I use:

  $ QTDIR=/usr
  $ QTINCDIR=/usr/include/qt3
  $ PKG_CONFIG_PATH=/usr/lib/pkgconfig
  $ ./configure
  $ make && make check

After compiling, optionally test the host and example plugins (see
below) and then run `make install' from the top-level directory to
install the dssi header, dssi.pc pkgconfig file, and the host and
examples.  The default install prefix is /usr/local.


The quickest test (provided your system has all the required
software, you've done `make install', and JACK is running) is just
to run `less_trivial_synth' or `trivial_sampler', which should have
been installed in your $PREFIX/bin.  These should simply start up a
standalone sampler/synth with a GUI window.  If these both work,
pretty much everything else should.

Here's a more descriptive test:

Assuming you've built the host and plugins, installed them to
/usr/local, and JACK is running, you may run:

  $ export DSSI_PATH=/usr/local/lib/dssi
  $ /usr/local/bin/jack-dssi-host

A synth GUI should pop up, with an ALSA sequencer input and JACK
output (connected by default to the first alsa_pcm out).  If you
connect a MIDI keyboard (or vkeybd) to its ALSA MIDI input, you should
be able to play it and use MIDI controllers to adjust its parameters:
MIDI CC1 (the modulation wheel) controls timbre, and controllers 72,
73, 75 and 79 control release, attack, decay and sustain respectively
(some keyboards already have controls set up for these values).

What has actually happened (if it worked) is that the host has
been started, has loaded the first synth plugin (labelled LTS) found
in the given .so file, has located the GUI executable that the make
procedure installed into examples/less_trivial_synth/LTS_qt,
instantiated the plugin, started the GUI and is now managing the MIDI
input from ALSA, control changes from the GUI and audio out to JACK.

You may also run multiple synth instances simultaneously with this

  $ export DSSI_PATH=/usr/local/lib/dssi
  $ export PATH=$PATH:/usr/local/bin     # if it's not there already
  $ jack-dssi-host -2 -3

This will create two less_trivial_synth instances and three
trivial_sampler instances.  Note that the instances are assigned
consecutive MIDI channels, and their outputs are spread across all
of the available JACK physical outputs.


The DSSI API itself (dssi.h) is licensed under the GNU Lesser General
Public License.  See COPYING for details.

The jack-dssi-host is provided under a BSD-style license.  This means
you can do anything you want with it so long as you retain the
copyright attribution and license information.  See the source files
for details.

Licensing for the files in the examples directory may vary: please
check the individual files for details.  Most of them are in the
public domain, which means you can use them for anything you want.

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