Hi Charles,
That is the current/next step - a colleague is writing a C module 
we'll wrap/include with weave. I was hoping there was a trick 
Numeric.where() methodology (which I'm just learning) to do it and 
push most all down to C anyway.

Thanks, Ray

At 12:07 AM 6/24/2006, you wrote:
> Why not wrap the C code for use as an C exstension?
> 
> Charles BUrnaford
> 
> 
> Ray Schumacher wrote:
> >I have been working with 24 bit ADC data returned from pyUSB as 
> >byte-tuples, which I need to convert to Float32 and save, I 
> >currently do it like this:
> ><code>
> >WRAP = 2.**23
> >BITS24 = 2.**24
> >data = []
> >for byteN in range(0, len(dataTuple), 3):
> >             try:
> >                 chValue = 
> > struct.unpack(">I", 
> > struct.pack(">4b", 0,*dataTuple[byteN:byteN+3])
> >                                 )[0]
> >             except:
> >                 chValue = 0
> >             if chValue>WRAP:                 chValue = 
> > ((BITS24-chValue) / WRAP)
> >             else:
> >                 chValue = (-chValue / WRAP)
> >             data[thisCh].append(chValue)
> >return data
> ></code>
> >
> >It is really slow...
> >I have not been able to come up with a trick way to do it in numpy, either.
> >What is really needed is a 24 bit type, or at least a type-cast 
> >ability to go to Float32, in core; all of the latest sound cards 
> >are now 24 bit, so the demand should be coming.
> >http://www.koders.com/c/fid2226C89ED85B3FF15286288F7CF31CD8647CDD79.aspx
> >for instance, is an LGPL C module for working with them.
> >
> >Cheers,
> >Ray
> >
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> >
> >
> >

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