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Re: Basic sample code for FFT audio frequency spectrum?
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Re: Basic sample code for FFT audio frequency spectrum?


  • Subject: Re: Basic sample code for FFT audio frequency spectrum?
  • From: Martin Gasser <email@hidden>
  • Date: Thu, 12 Jul 2007 18:45:45 +0200

Hi,

I have built a small example AU that visualizes the waveform of a stereo signal in real time (http://www.ofai.at/~martin.gasser/ CocoaPlugin.zip). It's far from perfect, and it's only meant to be a starting point for more other visualizations like a spectrum display, but it demonstrates how to use AU properties to communicate between the AU and a Cocoa view.

If you want to know how to do an offline spectrum analysis and plot the result in a NSView, you definitely need some basics:
1) Learn how to setup a simple Cocoa Application and how to draw in a NSView/NSOpenGLView. Have a look at the OpenGL examples in /Developer/ Examples (I strongly recommend using OpenGL, it' easy to learn and use, portable, and fast).
2) Use libsndfile to load audio data (http://www.mega-nerd.com/ libsndfile/)
3) Use fftw (http://www.fftw.org/) or vDSP to perform the spectral analysis


HTH,
Martin


On Jul 4, 2007, at 4:04 AM, IgnisFatuus wrote:

Hello all,

I am looking and am still looking for some basic foundation sample
code to where I can load an audio file, press the button, and have the
frequency spectrum of the audio in a window in an NSView. Just the basics so
I can understand the process involved.


Then once I have a foundation understanding, i'll add multiple tracks, to view
for mixing purposes layered in an NSView of how the frequency spectrum of
individual tracks relate to each other.


Thanks for any feedback.
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 >Basic sample code for FFT audio frequency spectrum? (From: IgnisFatuus <email@hidden>)

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