Re: Core Audio Spectrum Analyzer
Re: Core Audio Spectrum Analyzer
- Subject: Re: Core Audio Spectrum Analyzer
- From: Heinrich Fink <email@hidden>
- Date: Fri, 10 Jun 2011 10:25:03 -0700
Hey,
we have recently implemented extraction of Mel-Frequency-Cepstral-Coefficients on top of the Accelerate-framework. It also grabs and optionally returns the power spectrum and mel-frequency spectrum, that you could use for visualization purposes
https://github.com/hfink/matchbox/blob/master/Xcode/WordMatch/MFCCProcessor.hpp
https://github.com/hfink/matchbox/blob/master/Xcode/WordMatch/MFCCProcessor.cpp
I have made a few additional improvements in terms of flexibility and performance which I haven't pushed yet (but I'll do so pretty soon)
cheers,
h
On Jun 9, 2011, at 6:56 PM, Rohan Jyoti wrote:
> Hello, I am in need for some assistance in how to go about making a spectrum analyzer using Core Audio and vDSP (part of Apple's Accelerate Library).
> I know C/C++ and just recently learned Objective-C for Cocoa Development. However, I am somewhat lost as to how to use Core Audio to accomplish aforementioned task. Note that I am new to Mac OS X development.
> My task is along the lines of:
> -Say a song is playing on iTunes
> -Use Core Audio to get array of floats from currently playing sound on default sound device
> -Use Apple's vDSP to apply a window function and then perform a Fourier Transformation
> -Convert to logarithmic scale and build max values (peak)
> -Create bar spectrum analyzer
>
> An example is the spectrum analyzer found in iTunes (in the currently playing song info). Only difference is that I want my spectrum analyzer to be stand-alone based on the default sound out.
>
> I have done extensive research (Base library, PortAudio, RTAudio, FFTW...); however, I would like to accomplish this using Apple's native Core Audio and Accelerate Library. I would really appreciate any guidance as to how to get started. My main concern is with using Core Audio to extract floats (so they can be processed by fft) from default out sound device. Thanks in advance. _______________________________________________
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