# v_ccwarpf

## PURPOSE

V_CCWARPF Warp cepstral coefficients M=(F,N,S)

## SYNOPSIS

function m=v_ccwarpf(f,n,s)

## DESCRIPTION

    V_CCWARPF  Warp cepstral coefficients M=(F,N,S)
     f(1) is the original sample freq, f(2) is the new sample freq
     n(1) is the original number of coefficients, n(2) is the new number
     s is a string: s(1),s(2) =l for linear, m for mel frequency, use capitals if c0 included

## CROSS-REFERENCE INFORMATION

This function calls:

This function is called by:

## SOURCE CODE

    0001 function m=v_ccwarpf(f,n,s)
    0002 %V_CCWARPF  Warp cepstral coefficients M=(F,N,S)
    0003 % f(1) is the original sample freq, f(2) is the new sample freq
    0004 % n(1) is the original number of coefficients, n(2) is the new number
    0005 % s is a string: s(1),s(2) =l for linear, m for mel frequency, use capitals if c0 included
    0006
    0007
    0008 %      Copyright (C) Mike Brookes 1998
    0009 %      Version: $Id: v_ccwarpf.m 10865 2018-09-21 17:22:45Z dmb $
    0010 %
    0011 %   VOICEBOX is a MATLAB toolbox for speech processing.
    0012 %   Home page: http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/voicebox.html
    0013 %
    0014 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    0015 %   This program is free software; you can redistribute it and/or modify
    0016 %   it under the terms of the GNU Lesser General Public License as published by
    0017 %   the Free Software Foundation; either version 3 of the License, or
    0018 %   (at your option) any later version.
    0019 %
    0020 %   This program is distributed in the hope that it will be useful,
    0021 %   but WITHOUT ANY WARRANTY; without even the implied warranty of
    0022 %   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    0023 %   GNU Lesser General Public License for more details.
    0024 %
    0025 %   You can obtain a copy of the GNU Lesser General Public License from
    0026 %   https://www.gnu.org/licenses/ .
    0027 %
    0028 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    0029
    0030 if nargin<3
    0031    s='ll';
    0032 end
    0033 if length(f)<2
    0034    f(2)=1;
    0035 end
    0036 if length(n)<2
    0037    n(2)=n(1);
    0038 end
    0039 z=s<'a';
    0040 s=s+32*z;
    0041 if all(s=='l')
    0042    k=1:n(2)-z(2);
    0043    ff=((1:n(1)).'-z(1))*f(2)/f(1);
    0044    fa=2*sin(ff*pi).*ff/pi;
    0045    fb=ff.^2;
    0046    ka=1-2*rem(k,2);
    0047    kb=k.^2;
    0048    r1=ones(n(1),1);
    0049    c1=ones(1,n(2)-z(2));
    0050    a=fa(:,c1).*ka(r1,:);
    0051    b=fb(:,c1)-kb(r1,:);
    0052    f0=find(fix(ff)==ff);
    0053    if length(f0)
    0054       a(f0,:)=ff(f0,c1)==k(ones(length(f0),1),:);
    0055       b(f0,:)=1;
    0056    end
    0057    m=a./b;
    0058    if z(2)
    0059       m=[[1; 0.5*fa(2:n(1))./fb(2:n(1))] m];
    0060    end
    0061 end
    0062
    0063
    0064