fftw

Let us say that I have a WAV file. In this file, is a series of sine tones at precise 1 second intervals. I want to use the FFTW library to extract these tones in sequence. Is this particularly hard to do? How would I go about this? Also, what is the best way to write tones of this kind into a WAV file? I assume I would only need a simple audio library for the output. My language of choice is C To get the power spectrum of a section of your file: collect N samples, where N is a power of 2 - if your sample rate is 44.1 kHz for example and you want to sample approx every second then go for say N

I'm trying to link third party libraries like fftw3 and sndfile to my iPhone project in Xcode3.2. I got it working in a regular Mac project by setting the "Header Search Path" to "/usr/local/include" and the "Other Linker Flags" to "-lfftw3 -lsndfile" under the project build configuration. However, it gave me "library not found for -lfftw3" with exit code 1 error message when I tried to build it in the iPhone project using the same settings. Does apple not allow this on the iPhone? Is there a way to get around this? You need to build your libraries as universal static libraries. The process

I want to make a program that would record audio data using PortAudio (I have this part done) and then display the frequency information of that recorded audio (for now, I'd like to display the average frequency of each of the group of samples as they come in). From some research I've done, I know that I need to do an FFT. So I googled for a library to do that, in C, and found FFTW. However, now I am a little lost. What exactly am I supposed to do with the samples I recorded to extract some frequency information from them? What kind of FFT should I use (I assume I'd need a real data 1D?)? And

What is the fastest FFT implementation in Python? It seems numpy.fft and scipy.fftpack both are based on fftpack, and not FFTW. Is fftpack as fast as FFTW? What about using multithreaded FFT, or using distributed (MPI) FFT? JoshAdel You could certainly wrap whatever FFT implementation that you wanted to test using Cython or other like-minded tools that allow you to access external libraries. GPU-based If you're going to test FFT implementations, you might also take a look at GPU-based codes (if you have access to the proper hardware). There are several: reikna.fft , scikits.cuda . CPU-based