# MFCC feature extraction

I have a block of audio and I have performed an FFT on it. Now what I want to do is convert this FFT into a set of MFCCs, however while I know I need to do something with weighting the FFT samples based upon a set f triangular filters I haven't really got a clue what this involves.

Can anyone go into some good detail on it? If you are going to give me a matlab example please explain each step well as matlab allows you to cut quite a few corners and I'm trying to implement MFCC extraction on iPhone.

2. weigh the bins using triangular windows; usually the windows are chosen such that the centers of the triangles are equidistant on a mel-frequency scale, and such that each triangle begins and ends at the centers of the two adjacent triangles. The mel-frequency scale is defined by $$m=2595\log_{10}(1+f/700)$$ where $f$ is the frequency in Hz. Look at the figure to see how it works: Note that the kernels are normalized such that the sum of the weights per triangle equals 1. Usually around 20 such triangular windows are used.