[PD-dev] sms pd external - design choices

[Rich E]

Hi all,

As I may have mentioned in a few other places, I have been working
with a c library for analysis/synthesis known as SMS.  The library,
although in flux still, is now capable for performing synthesis in
real-time; I wrote a prototype external that does this by reading a
streaming file from disk.

Now, I want to turn write a set of externals using a buffered
analysis.  Originally, I thought that all operations to the buffer
would happen using one external, but this now seems like it will get
too messy once anything more than basic operations are attempted
(something like cross-synthesis would take enough code to constitude
its own external).  So, I have decided that, like the process of SMS,
the different modes of operation should be seperated into analysis,
synthesis, and editing.  However, they would all still need access to
the same buffer (which could also be its own external, or possibly be
inside the analysis external).

So now I am looking for a way to make it where various externals have
access to the same buffer - a data structure containing a header and
sequential frames of analysis.

I originally thought that outputting a pointer would be the easiest,
but then realized that pd can output 'gpointers', which are not the
same as a void pointer.  So it does not look possible to pass a
regular c pointer around in pd land.

I see that [pool] has the ability to share a data space among
different buffers by taking a name as its first argument.  I am
digging through its code right now, but am not familiar with the flext
API. I don't yet see how it manages to allow different [pool]'s to
share the same data.

Any suggestions from this list is appreciated..

cheers,
rich

On Jan 27, 2008 6:01 PM,  <geiger at xdv.org> wrote:
> Quoting Rich E <reakinator at gmail.com>:
>
> > Hi Gunter Geiger, pd devs,
> >
> > I have recently begun to write an external for SMS synthesis, by basically
> > porting the command line tool Xavier Serra wrote within the original SMS
> > code (found at http://www.iua.upf.es/~sms/software/Old-SMS-for-NextStep.zip).
> > I was talking to Xavier about this and he mentioned that you almost got an
> > external working with sms.. Before I did too much work, I figured I would
> > ask to see what types of problems you ran into, or if you have any
> > suggestions.
>
> Hi,
>
> I have part of the SMS process implemented, but not as a single external
> but as a collection of externals for generation of windows, peak
> detection, interpolation, FFT resynthesis. These are glued together
> with standard
> pd objects.
> I sort of got stuck trying to figure out how to use the extracted data in
> a meaningful way inside pd.
>
> So, after all,it might be a better approach to do it as a single external and
> program your transformations in C/C++. So maybe the best bet would be
> to have a
> base SMS analysis/synthesis engine and do an external for each effect that
> you want to implement with it.
>
> Gunter
>
>
>
>
>
> >
> > I'm also sending this to the pd-dev list to see if others have suggestions.
> > I figure that I will start by doing just a port of the command line tool,
> > and then later add in features for seeking through frames at any speed and
> > direction, visually manipulating the data, and other fun things.  But I
> > would like to know what others think.
> >
> > regards,
> > rich
> >
>
>
>
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