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Newsgroups: comp.lang.python
Date: Mon, 10 Sep 2012 13:14:18 -0700 (PDT)
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Subject: Re: Numpy combine channels
From: Wanderer <wanderer@dialup4less.com>
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On Monday, September 10, 2012 4:12:40 PM UTC-4, MRAB wrote:
> On 10/09/2012 20:39, Wanderer wrote:
> 
> > I have an array generated by audiolab of left and right stereo
> 
> > channels. It looks like [[1,1],[1,2],[2,3]]. I would like to combine
> 
> > the left and right channels to get an array [2,3,5]. Is there a numpy
> 
> > command to do that?
> 
> >
> 
> >>> import numpy
> 
> >>> numpy.array([[1,1],[1,2],[2,3]], dtype="i")
> 
> array([[1, 1],
> 
>         [1, 2],
> 
>         [2, 3]])
> 
> >>> a[:, 0]
> 
> array([1, 1, 2])
> 
> >>> a[:, 1]
> 
> array([1, 2, 3])
> 
> >>> a[:, 0] + a[:, 1]
> 
> array([2, 3, 5])
> 
> 
> 
> But should they be added together to make mono?
> 
> 
> 
> Suppose, for example, that both channels have a maximum value. Their
> 
> sum would be _twice_ the maximum.
> 
> 
> 
> Therefore, I think that it should probably be the average.
> 
> 
> 
>  >>> (a[:, 0] + a[:, 1]) / 2
> 
> array([1, 1, 2])

I'm decoding morse code. So it's CV dots and dashes.