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mechanism. Therefore, similarly to CLAM (Ama-
triain, 2005),
MARSYAS
makes a clear distinction
between data-flow which is synchronous, and
control flow which is asynchronous. Because
MarSystems
can be assembled hierarchically the
control mechanism utilizes a path notation similar
to OSC (Wright and Freed, 1997). For example
Series/playbacknet/Gain/g1/mrs_real/gain
is the
control name for accessing the
gain
control of a
Gain MarSystem
named
g1
in a
Series
composite
named
playbacknet
. A mechanism for linking
top-level controls (with shorter names that act
as aliases) to the longer full path control names
is provided. For example a single gain control at
the top-level can be linked to the gain controls
of 20 oscillators in a synthesis instrument. That
way, one-to-many mappings can be achieved in
a similar way to the use of regular expressions
in OSC (Wright & Freed, 1997).
Dataflow in Marsyas is synchronous which
means that at every “tick” a specific slice of data
is propagated across the entire dataflow network.
This eliminates the need for queues between
processing nodes and enables the use of shared
buffers which improves performance. This is
similar to the way Unix pipes are implemented
but with audio specific semantics (see section on
Implicit Patching).
One of the most useful characteristics of
MarSystems
is that they can be instantiated at
run-time. Because they are hierarchically compos-
able audio computation expressed as a dataflow,
the network can be instantiated at run-time. For
example, multiple instances of any complicated
network can be created as easily as the basic primi-
tive
MarSystems
. This is accomplished by using
a combination of the
Prototype
and
Composite
design patterns (Gamma et al., 1995).
examples. The list is by no means exhaustive.
An open source framework enables collabora-
tion possibilities. Two research publications that
resulted from such collaborations are Lippens et al
(2004) and Li and Tzanetakis (2003).
Musicream
is a new music playback interface for streaming,
sticking, sorting and recalling musical pieces that
uses
MARSYAS
for calculating features and con-
tent-based audio similarity (Goto & Goto, 2005).
The SndTools software also uses MARSYAS
under the graphical user interface (Misra, Wang
& Cook, 2005).
In industry MARSYAS has been used to
design and prototype the audio fingerprinting
software used by Moodlogic Inc. (http://mood-
logic.com). After the fingerprinting was designed
and evaluation experiments were conducted using
MARSYAS a new proprietary source code just
for the fingerprinting was written for the actual
working product. This method of using research
free software framework for prototyping and
then providing a full proprietary rewrite is one
possibility of how academic free software and
industry can co-exist. Another possibility is the
gender (male/female) voice detection scheme
developed for
Teligence Communications Inc
(http://www.teligence.net/) using
MARSYAS
. In
that case the developed software is part of the
free software distribution. However it is based
on machine learning and requires training data
that is not publicly available and belongs to
Teli-
gence Communications Inc.
As the company is
mainly concerned in using the tool internally
everything worked out ok for both parties. In both
of these industrial collaborations it would have
been possible for the company to just develop the
software on their own. However, by collaborat-
ing and paying the companies benefit from fast
turnaround and experienced knowledge and the
free software, authors benefit from consulting
payments. We hope that these strategies might
provide some information about how industrial
collaborations with academic free software proj-
ects can be established.
Projects
MARSYAS
has been used for a variety of projects
both in academia and industry. In this section
we briefly describe some specific representative
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