Python probably isn't too slow for this. You don't need the host IO calls 
either. Just get the samples from the spout buffer and stream them to your 
own soundfile. That means calling csoundPerformKsmps do compute one spout 
buffer at a time. There is a Python wrapper for libsndfile in the CsoundAC 
module you can use to write your output. If the Python access to spout 
doesn't work, let me know and I will make it work.

Perhaps more to the point, Csound can recompile the orchestra and re-create 
the soundfile plenty fast -- usually in a few seconds or less. Loading 
soundfonts, samples, or VST plugins slows it down somewhat but it is still 
tolerable (to me, anyway).

Regards,
Mike

----- Original Message ----- 
From: "Lilith Bryant" 
To: 
Sent: Wednesday, April 02, 2008 11:10 PM
Subject: [Csnd] CSound (Python) API & Output Buffers


>I wonder if I could tap the list here for some advice.
>
> I'm writing a score writer front-end in python using the csound API.
>
> The big idea with this project, is to be able to quickly change the score 
> and
> re-render with having csound reload the whole orchestra/csd file for every
> simple score change.  So i'm simply calling the csoundCompile and all the
> prequisites once at the beginning of my application (or whenever the user
> asks to reload the orchestra/csd)
>
> Then for each renderering, I call csoundScoreRewind and then 
> csoundScoreEvent
> for each note.
>
> Which works as expected, except the output wav file simply grows with easy
> pass.  i.e. it  csoundScoreRewind doesn't clear it, like would be useful 
> for
> this case.
>
> Now I can alternatively not use wav file output at all, and use
> csoundSetHostImplementedAudioIO and manually fish out the samples, and 
> write
> them to a wav file myself.  But this is python and that hideously slow.
>
> So the questions are:
> 1) Is there a way to restart the wav file output without reloading the
> orchestra/csd?
>
> OR
>
> 2) Is there a quick way to fish out the output buffer samples into a 
> python
> string or array, for writing out to file using the python wav module?
>
> The best i have so far is something like:
>
> ob=csnd.csoundGetOutputBuffer(self.cs)
> fa=csnd.floatArray.frompointer(ob)
> sa=array.Array('h',[0]*buffersize*2)
> for n in range(buffersize*2):
> sa[n]=fa[n]*32767
> wavdata=sa.tostring()
>
> which really SUCKS performance-wise (not surprisingly).
>
> I don't want to write a C/SWIG function to do just this, since i want to 
> be
> able to give this to people who aren't up to running compilers.
>
>
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> csound"