MFCC参数提取MATLAB实例

close all

clear

clc

[x fs]=wavread('speech.wav');

bank=mel(24,256,fs,0,0.4,'m');%Mel滤波器的阶数为24，fft变换的长度为256，采样频率为8000Hz

% 归一化mel滤波器组系数

bank=full(bank);

bank=bank/max(bank(:));

% DCT系数,12*24

for k=1:12

n=0:23; dctcoef(k,:)=cos((2*n+1)*k*pi/(2*24));

end

% 归一化倒谱提升窗口

w = 1 + 6 * sin(pi * [1:12] ./ 12);

w = w/max(w);

% 预加重滤波器

xx=double(x);

xx=filter([1 -0.9375],1,xx);

% 语音信号分帧

xx=enframe(xx,256,80);%对x 256点分为一帧

% 计算每帧的MFCC参数

for i=1:size(xx,1)

y = xx(i,:);

s = y' .* hamming(256);

t = abs(fft(s));%fft快速傅立叶变换

t = t.^2;

c1=dctcoef * log(bank * t(1:129));

c2 = c1.*w';

m(i,:)=c2';

end

%求取差分系数

dtm = zeros(size(m));

for i=3:size(m,1)-2

dtm(i,:) = -2*m(i-2,:) - m(i-1,:) + m(i+1,:) + 2*m(i+2,:);

end

dtm = dtm / 3;

%合并mfcc参数和一阶差分mfcc参数

ccc = [m dtm];

%去除首尾两帧，因为这两帧的一阶差分参数为0

ccc = ccc(3:size(m,1)-2,:);

subplot(211)

ccc_1=ccc(:,1);

plot(ccc_1);title('MFCC');

ylabel('幅值');

[h,w]=size(ccc);

A=size(ccc);

subplot(212)

plot([1,w],A);

xlabel('维数');

ylabel('幅值');

title('维数于幅值的关系')