AudioProcessing

An toolbox for audio processing in Matlab,the verison of Matlab is R2016a.
The audio sample in this toobox is 8000Hz, 16 bits.

extractAudioFingerpriner

extract audio fingerprinter by calcuating the difference of the energy of each frequency sub-band

divide audio into frames, the overlap length is alterable
do fft for each frame
divide frequency spectrum into 32 frequency sub bands
calcuate the energy of each sub band
calcuate audio fingerprinter as follow

The result is shown below

getZCR

calcuate the zero-crossing which can be used to predict the frequency roughly

divide audio into frames
calcuate zcr of each frame using the following equation

where sgn(x) is given by

The result is shown below.

getLocalMaximum

This function is to get few maximuns in local matrix in a given matrix

getLandmarks

calcuate the enegry max points(also called landmark) in frequency spectrum

divide audio into frames, the overlap length is alterable
do fft for each frame
calcuate the energy of frequency
calcuate the local maximum as landmark The result is shown below

getEnergy

calcuate the short-time energy
1.divide audio into frames, the overlap length is alterable
2.calcuate the energy using the following equation:

The result is shown below

getSpecgram

Implementation of matlab function Specgram()

divide signal into frames in time domain
do fft of each frame

getLMSPredictor

where a = b = 0.953125
r0 = r1 = 0
COR0 = COR1 =0
VAR0 = VAR1 = 1
The update procedure is shown below:
K1(n) = bCOR0(n-1)/VAR0(n-1);
K2(n) = bCOR1(n-1)/VAR1(n-1);
Xest(n) = K1(n)r0(n-1) + K2(n)r1(n-1);
e0(n) = Xrec(n);
e1(n) = e0(n) - K1(n)r0(n-1);
VAR0(n) = uVAR0(n-1) + 0.5[r0(n-1)^2+e0(n)^2];
COR0(n) = uCOR0(n-1) + r0(n-1)e0(n);
VAR1(n) = uVAR1(n-1) + 0.5*[r1(n-1)^2+e1(n)^2];
COR1(n) = u*COR1(n-1) + r1(n-1)e1(n);
r1(n) = a(r0(n-1)-K1(n)e0(n));
r0(n) = ae0(n);
Xerr(n) = Xrec(n) - Xest(n);
The function returns the estimate value Xest and the setimate error Xerr

jingpeng / AudioProcessing-toolbox