mfcc.zip_MFCC_kids198_mfcc.m函数_mfcc函数_语音

function [c,tc]=melcepst(s,fs,w,nc,p,n,inc,fl,fh) %MELCEPST Calculate the mel cepstrum of a signal C=(S,FS,W,NC,P,N,INC,FL,FH) % % % Simple use: (1) c=melcepst(s,fs) % calculate mel cepstrum with 12 coefs, 256 sample frames % (2) c=melcepst(s,fs,'E0dD') % include log energy, 0th cepstral coef, delta and delta-delta coefs % % Inputs: % s speech signal % fs sample rate in Hz (default 11025) % w mode string (see below) % nc number of cepstral coefficients excluding 0'th coefficient [default 12] % p number of filters in filterbank [default: floor(3*log(fs)) = approx 2.1 per ocatave] % n length of frame in samples [default power of 2 < (0.03*fs)] % inc frame increment [default n/2] % fl low end of the lowest filter as a fraction of fs [default = 0] % fh high end of highest filter as a fraction of fs [default = 0.5] % % w any sensible combination of the following: % % 'R' rectangular window in time domain % 'N' Hanning window in time domain % 'M' Hamming window in time domain (default) % % 't' triangular shaped filters in mel domain (default) % 'n' hanning shaped filters in mel domain % 'm' hamming shaped filters in mel domain % % 'p' filters act in the power domain % 'a' filters act in the absolute magnitude domain (default) % % '0' include 0'th order cepstral coefficient % 'E' include log energy % 'd' include delta coefficients (dc/dt) % 'D' include delta-delta coefficients (d^2c/dt^2) % % 'z' highest and lowest filters taper down to zero (default) % 'y' lowest filter remains at 1 down to 0 frequency and % highest filter remains at 1 up to nyquist freqency % % If 'ty' or 'ny' is specified, the total power in the fft is preserved. % % Outputs: c mel cepstrum output: one frame per row. Log energy, if requested, is the % first element of each row followed by the delta and then the delta-delta % coefficients. % tc fractional time in samples at the centre of each frame % with the first sample being 1. % % BUGS: (1) should have power limit as 1e-16 rather than 1e-6 (or possibly a better way of choosing this) % and put into VOICEBOX % (2) get rdct to change the data length (properly) instead of doing it explicitly (wrongly) % Copyright (C) Mike Brookes 1997 % Version: $Id: melcepst.m 10185 2017-10-04 08:20:32Z dmb $ % % VOICEBOX is a MATLAB toolbox for speech processing. % Home page: http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/voicebox.html % %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % This program is free software; you can redistribute it and/or modify % it under the terms of the GNU General Public License as published by % the Free Software Foundation; either version 2 of the License, or % (at your option) any later version. % % This program is distributed in the hope that it will be useful, % but WITHOUT ANY WARRANTY; without even the implied warranty of % MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the % GNU General Public License for more details. % % You can obtain a copy of the GNU General Public License from % http://www.gnu.org/copyleft/gpl.html or by writing to % Free Software Foundation, Inc.,675 Mass Ave, Cambridge, MA 02139, USA. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% if nargin<2 fs=11025; end if nargin<3 w='M'; end if nargin<4 nc=12; end if nargin<5 p=floor(3*log(fs)); end if nargin<6 n=pow2(floor(log2(0.03*fs))); end if nargin<9 fh=0.5; if nargin<8 fl=0; if nargin<7 inc=floor(n/2); end end end if isempty(w) w='M'; end if any(w=='R') [z,tc]=enframe(s,n,inc); elseif any (w=='N') % [z,tc]=enframe(s,hanning(n),inc); [z,tc]=enframe(s,0.5-0.5*cos(2*pi*(1:n)'/(n+1)),inc); % Hanning window else % [z,tc]=enframe(s,hamming(n),inc); [z,tc]=enframe(s,0.54-0.46*cos(2*pi*(0:n-1)'/(n-1)),inc); % Hamming window end f=rfft(z.'); [m,a,b]=melbankm(p,n,fs,fl,fh,w); pw=f(a:b,:).*conj(f(a:b,:)); pth=max(pw(:))*1E-20; if any(w=='p') y=log(max(m*pw,pth)); else ath=sqrt(pth); y=log(max(m*abs(f(a:b,:)),ath)); end c=rdct(y).'; nf=size(c,1); nc=nc+1; if p>nc c(:,nc+1:end)=[]; elseif p<nc c=[c zeros(nf,nc-p)]; end if ~any(w=='0') c(:,1)=[]; nc=nc-1; end if any(w=='E') c=[log(max(sum(pw),pth)).' c]; nc=nc+1; end % calculate derivative if any(w=='D') vf=(4:-1:-4)/60; af=(1:-1:-1)/2; ww=ones(5,1); cx=[c(ww,:); c; c(nf*ww,:)]; vx=reshape(filter(vf,1,cx(:)),nf+10,nc); vx(1:8,:)=[]; ax=reshape(filter(af,1,vx(:)),nf+2,nc); ax(1:2,:)=[]; vx([1 nf+2],:)=[]; if any(w=='d') c=[c vx ax]; else c=[c ax]; end elseif any(w=='d') vf=(4:-1:-4)/60; ww=ones(4,1); cx=[c(ww,:); c; c(nf*ww,:)]; vx=reshape(filter(vf,1,cx(:)),nf+8,nc); vx(1:8,:)=[]; c=[c vx]; end if nargout<1 [nf,nc]=size(c); % t=((0:nf-1)*inc+(n-1)/2)/fs; ci=(1:nc)-any(w=='0')-any(w=='E'); imh = imagesc(tc/fs,ci,c.'); axis('xy'); xlabel('Time (s)'); ylabel('Mel-cepstrum coefficient'); map = (0:63)'/63; colormap([map map map]); colorbar; end