Capture a signal through sound card

[dacoolest]

Is it possible to capture a signal through the sound card (headphone/line in) jack using C++ ?

If possible, can you please suggest a method to do? Thanks.

[dacoolest]

well, I did some research and I found that its possible and I have to use FFT algorithm to get frequency and amplitude relation information out of recorded signal.

I thought of using FFTW with C++. Still confused about the FFT algorithm though. Can someone please explain to me what should be the input and what should be the output for the FFTW? That would help me to understand how to use it in my program. Thanks.

[cnoeval]

You can find a library for Windows OS here: http://msdn.microsoft.com/en-us/library/ms713225
It will return a wavefile that is most likely some header info and an array of data points.

I don't know why you would need an FFT. Unless you mean you need to analyze the frequency content, if that's the case then FFTW looks like a good choice.