-
Notifications
You must be signed in to change notification settings - Fork 0
/
Copy pathenframe.m
135 lines (130 loc) · 5.69 KB
/
enframe.m
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
function [f,t,w]=enframe(x,win,inc,m)
%ENFRAME split signal up into (overlapping) frames: one per row. [F,T]=(X,WIN,INC)
%
% Usage: (1) f=enframe(x,n) % split into frames of length n
% (2) f=enframe(x,hamming(n,'periodic'),n/4) % use a 75% overlapped Hamming window of length n
% (3) calculate spectrogram in units of power per Hz
%
% W=hamming(NW); % analysis window (NW = fft length)
% W=W/sqrt(FS*sum(W.^2)); % normalize to give power per Hz (FS = sample freq)
% P=rfft(enframe(S,W,INC);,nfft,2); % computer first half of fft (INC = frame increment in samples)
% P(:,2:end-1)=2*P(:,2:end-1); % double to account for -ve frequencies (except DC and Nyquist)
%
% (3) frequency domain frame-based processing:
%
% S=...; % input signal
% OV=2; % overlap factor of 2 (4 is also often used)
% INC=20; % set frame increment in samples
% NW=INC*OV; % DFT window length
% W=sqrt(hamming(NW,'periodic')); % omit sqrt if OV=4
% W=W/sqrt(sum(W(1:INC:NW).^2)); % normalize window
% F=rfft(enframe(S,W,INC),NW,2); % do STFT: one row per time frame, +ve frequencies only
% ... process frames ...
% X=overlapadd(irfft(F,NW,2),W,INC); % reconstitute the time waveform (omit "X=" to plot waveform)
%
% Inputs: x input signal
% win window or window length in samples
% inc frame increment in samples
% m mode input:
% 'z' zero pad to fill up final frame
% 'r' reflect last few samples for final frame
% 'A' calculate the t output as the centre of mass
% 'E' calculate the t output as the centre of energy
%
% Outputs: f enframed data - one frame per row
% t fractional time in samples at the centre of each frame
% with the first sample being 1.
% w window function used
%
% By default, the number of frames will be rounded down to the nearest
% integer and the last few samples of x() will be ignored unless its length
% is lw more than a multiple of inc. If the 'z' or 'r' options are given,
% the number of frame will instead be rounded up and no samples will be ignored.
%
% Example of frame-based processing:
% INC=20 % set frame increment in samples
% NW=INC*2 % oversample by a factor of 2 (4 is also often used)
% S=cos((0:NW*7)*6*pi/NW); % example input signal
% W=sqrt(hamming(NW),'periodic')); % sqrt hamming window of period NW
% F=enframe(S,W,INC); % split into frames
% ... process frames ...
% X=overlapadd(F,W,INC); % reconstitute the time waveform (omit "X=" to plot waveform)
% Bugs/Suggestions:
% (1) Possible additional mode options:
% 'u' modify window for first and last few frames to ensure WOLA
% 'a' normalize window to give a mean of unity after overlaps
% 'e' normalize window to give an energy of unity after overlaps
% 'wm' use Hamming window
% 'wn' use Hanning window
% 'x' include all frames that include any of the x samples
% Copyright (C) Mike Brookes 1997-2014
% Version: $Id: enframe.m 6490 2015-08-05 12:47:13Z 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.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
nx=length(x(:));
if nargin<2 || isempty(win)
win=nx;
end
if nargin<4 || isempty(m)
m='';
end
nwin=length(win);
if nwin == 1
lw = win;
w = ones(1,lw);
else
lw = nwin;
w = win(:).';
end
if (nargin < 3) || isempty(inc)
inc = lw;
end
nli=nx-lw+inc;
nf = max(fix(nli/inc),0); % number of full frames
na=nli-inc*nf+(nf==0)*(lw-inc); % number of samples left over
fx=nargin>3 && (any(m=='z') || any(m=='r')) && na>0; % need an extra row
f=zeros(nf+fx,lw);
indf= inc*(0:(nf-1)).';
inds = (1:lw);
if fx
f(1:nf,:) = x(indf(:,ones(1,lw))+inds(ones(nf,1),:));
if any(m=='r')
ix=1+mod(nf*inc:nf*inc+lw-1,2*nx);
f(nf+1,:)=x(ix+(ix>nx).*(2*nx+1-2*ix));
else
f(nf+1,1:nx-nf*inc)=x(1+nf*inc:nx);
end
nf=size(f,1);
else
f(:) = x(indf(:,ones(1,lw))+inds(ones(nf,1),:));
end
if (nwin > 1) % if we have a non-unity window
f = f .* w(ones(nf,1),:);
end
if nargout>1
if any(m=='E')
t0=sum((1:lw).*w.^2)/sum(w.^2);
elseif any(m=='A')
t0=sum((1:lw).*w)/sum(w);
else
t0=(1+lw)/2;
end
t=t0+inc*(0:(nf-1)).';
end