Beat extraction in MATLAB

I have no experience in MATLAB and unfortunately my project is in MATLAB.

Basically the objective is to read a music source (preferably in mp3 format but .wav is also OK) into MATLAB and then apply a low pass filter in such a way that it filters everything except the beats. Then it should get the time 开发者_开发知识库at which each beat occurs and write the results to a text file.

It's quite a bit easier to work with .wav files I think, although Matlab way well have utilities for such things, in fact it does: Reading .wav

The easiest way to implement a low pass filter is a moving average filter.

The simplest way to do this would be be to loop over the data and take an average of each group of n values. I'm not sure exactly how the cutoff frequency would depend on n, but you could experiment a bit.

Otherwise, I know that there is a signal processing toolkit for Octave and I think that Matlab has a built-in filter function: https://ccrma.stanford.edu/~jos/fp/Matlab_Filter_Implementation.html

A third way which is over the top, would be to perform an FFT and do the filtering in the frequency domain.

Once you have the low-frequency part of the signal you can check for samples that are above an amplitude threshold and output where in the data these were found.

30 seconds on google with the keywords "beat extraction matlab" yield the following two code sources:

1. Music Audio Tempo Estimation and Beat Tracking
2. Beat This A Beat Synchronization Project

In Matlab you can use and state of the art Multi Feature beat tracker algorithm, the information of the algorithm is publish here: J.R. Zapata, M. Davies and E. Gómez, "Multi-feature beat tracker," IEEE/ACM Transactions on Audio, Speech and Language Processing. 22(4), pp. 816-825, 2014. http://dx.doi.org/10.1109/TASLP.2014.2305252

The Matlab implementation of the multifeature beat tracker is: https://github.com/JoseRZapata/MultiFeatureBeatTracking