[Clam-devel] SMSSynthesis

[Greg Kellum]

Hi,

I made the aforementioned changes in the SMSSynthesis class, or I made some
of the aforementioned changes...  I agree that it would be possible to both
check to see whether all ports were connected and to make it configurable to
remove the out ports for the residual and sinusoidal audio, but it struck me
as both easier and more important to do the first rather than the second.

My reasons for thinking so are:
One, I think one should program with the users in mind that don't know very
much about how the application works, and such users won't know to look into
the configuration dialog to disable two unused ports.  And these two ports
can make a significant difference in an application's performance.  My own
application runs 10% with those two unneeded IFFTs disabled.
Two, we have to keep in mind that CLAM is first and foremost a C++ library
for audio and music, and it's unlikely that a programmer looking at the API
for SMSSynthesis would know to navigate through SMSSynthesis's nested
configuration elements to set the right flags to disable those two out
ports.

Anyway, while I was working on this, I compared my profiling results with a
pure SinusoidalSynthesis.  One would think that the CPU usage of the
SinusoidalSynthesis and the SMSSynthesis with one IFFT would be nearly
identical, but they're not.  The SinusoidalSynthesis is 30% faster.  I spent
some time thinking about why this might be, and all I could come up with is
that the residual spectrum objects are very large and copying around their
data must eating up a lot of CPU cycles.  So, I wanted to ask whether there
is any code in CLAM for analyzing and resynthesizing residuals stored as
envelopes rather than as the complete FFT bin values.  Using envelopes would
take much less memory...

Best,
Greg
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