# v_fram2wav

## PURPOSE

V_FRAM2WAV converts frame values to a continuous waveform [W]=(X,TT,MODE)

## SYNOPSIS

function [w,s]=v_fram2wav(x,tt,mode)

## DESCRIPTION

```V_FRAM2WAV  converts frame values to a continuous waveform [W]=(X,TT,MODE)
Inputs:
x(nf,p)      is the input signal: one row per frame
tt(nf,3)     specifies the frames. Each row has the form [start_sample end_sample flag]
where flag = 1 for the start of a new spurt.
If tt(:,3) is omitted, a new spurt will be started whenever there is a gap
of more than one between the end of one frame and the beginning or the next.
A new spurt is automatically started if x() = NaN.
mode         consists of one or more of the following letters:
z for zero-order hold interpolation (i.e. constant within each frame)
l for linear interpolation within each spurt [default]

Outputs:
w(n,p)       contains the interpolated waveforms. Their length is n = tt(nf,2)
s(ns,2)      gives the starting and ending sample numbers of each spurt (excluding NaN spurts)

This routine converts frame-based values to continuous waveforms by performing
a chosen method of interpolation. Interpolation is restarted at the beginning of each spurt.```

## CROSS-REFERENCE INFORMATION

This function calls:
This function is called by:

## SOURCE CODE

```0001 function [w,s]=v_fram2wav(x,tt,mode)
0002 %V_FRAM2WAV  converts frame values to a continuous waveform [W]=(X,TT,MODE)
0003 %  Inputs:
0004 %          x(nf,p)      is the input signal: one row per frame
0005 %           tt(nf,3)     specifies the frames. Each row has the form [start_sample end_sample flag]
0006 %                       where flag = 1 for the start of a new spurt.
0007 %                       If tt(:,3) is omitted, a new spurt will be started whenever there is a gap
0008 %                       of more than one between the end of one frame and the beginning or the next.
0009 %                       A new spurt is automatically started if x() = NaN.
0010 %          mode         consists of one or more of the following letters:
0011 %                          z for zero-order hold interpolation (i.e. constant within each frame)
0012 %                          l for linear interpolation within each spurt [default]
0013 %
0014 % Outputs:
0015 %          w(n,p)       contains the interpolated waveforms. Their length is n = tt(nf,2)
0016 %          s(ns,2)      gives the starting and ending sample numbers of each spurt (excluding NaN spurts)
0017 %
0018 %    This routine converts frame-based values to continuous waveforms by performing
0019 %    a chosen method of interpolation. Interpolation is restarted at the beginning of each spurt.
0020
0021 %    Bugs/Suggestions
0022 %      (1)   Additional mode option for cubic interpolation
0023 %      (2)   Additional mode option for interpolation in log domain
0024 %      (3)   Additional mode option for x values being
0025 %            frame averages rather than mid-frame values.
0026
0027 %      Copyright (C) Mike Brookes 1997
0028 %      Version: \$Id: v_fram2wav.m 10865 2018-09-21 17:22:45Z dmb \$
0029 %
0030 %   VOICEBOX is a MATLAB toolbox for speech processing.
0031 %   Home page: http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/voicebox.html
0032 %
0033 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
0034 %   This program is free software; you can redistribute it and/or modify
0035 %   it under the terms of the GNU General Public License as published by
0036 %   the Free Software Foundation; either version 2 of the License, or
0037 %   (at your option) any later version.
0038 %
0039 %   This program is distributed in the hope that it will be useful,
0040 %   but WITHOUT ANY WARRANTY; without even the implied warranty of
0041 %   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
0042 %   GNU General Public License for more details.
0043 %
0044 %   You can obtain a copy of the GNU General Public License from
0045 %   http://www.gnu.org/copyleft/gpl.html or by writing to
0046 %   Free Software Foundation, Inc.,675 Mass Ave, Cambridge, MA 02139, USA.
0047 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
0048
0049 if nargin<3
0050     mode='l';
0051 end
0052 [nf,m]=size(x);
0053 n=round(tt(end,2));
0054 w=repmat(NaN,n,m);
0055 nt=size(tt,2);
0056 ix1=ceil(tt(:,1)); % start of frame sample
0057 ix2=floor(tt(:,2)); % end of frame sample
0058
0059 % determine the start and end of spurts
0060
0061 if nt>2
0062     ty=tt(:,3)>0;   % frame type set by user
0063 else
0064     ty=zeros(nf,1);
0065     ty(2:end)=ix1(2:end)>ix2(1:end-1)+1;    % new spurt whenever a gap
0066 end
0067 ty(1)=1;           % first frame always starts a spurt
0068 ty(isnan(x))=1;    % NaN always ends previous spurt
0069 ty(1+find(isnan(x(1:end-1))))=1; % NaN always forces a new spurt
0070 ty=double(ty);
0071 ty(1:end-1)=ty(1:end-1)+2*ty(2:end);
0072 ty(end)=ty(end)+2;   % last frame always ends a spurtw=repmat(NaN,n,m);  % initialize output to all NaN
0073 nx=ix2-ix1+1;
0074
0075 if any(mode=='z')   % zero-order hold
0076     for i=1:nf
0077         if nx(i)
0078             w(ix1(i):ix2(i),:)=repmat(x(i,:),nx(i),1);
0079         end
0080     end
0081 else   % linear interpolation is the default
0082     ttm=(tt(:,1)+tt(:,2))/2;    % mid point of frame
0083     ixm=floor(ttm); % end of first half of frame
0084     for i=1:nf
0085         if i==176
0086             i
0087         end
0088         if nx(i)
0089             tyi=ty(i);
0090             if tyi==3    % use a zero order hold
0091                 w(ix1(i):ix2(i),:)=repmat(x(i,:),nx(i),1);
0092             else
0093                 nxm=ixm(i)-ix1(i)+1;
0094                 if nxm
0095                     if tyi==1
0096                         grad=(x(i+1,:)-x(i,:))/(ttm(i+1)-ttm(i));
0097                     else
0098                         grad=(x(i,:)-x(i-1,:))/(ttm(i)-ttm(i-1));
0099                     end
0100                     w(ix1(i):ixm(i),:)=repmat(x(i,:),nxm,1)+((ix1(i):ixm(i))'-ttm(i))*grad;
0101                 end
0102                 if nx(i)>nxm
0103                     if tyi==2
0104                         grad=(x(i,:)-x(i-1,:))/(ttm(i)-ttm(i-1));
0105                     else
0106                         grad=(x(i+1,:)-x(i,:))/(ttm(i+1)-ttm(i));
0107                     end
0108                     w(ixm(i)+1:ix2(i),:)=repmat(x(i,:),ix2(i)-ixm(i),1)+((ixm(i)+1:ix2(i))'-ttm(i))*grad;
0109                 end
0110             end
0111         end
0112     end
0113 end
0114
0115 % now sort out the start and end spurt positions
0116
0117 ty(isnan(x))=0;    % Don't count NaN spurts
0118 s=repmat(ix1(bitand(ty,1)>0),1,2);
0119 s(:,2)=ix2(bitand(ty,2)>0);
0120 if ~nargout
0121     tw=(1:n)';
0122     for i=size(s,1):-1:2
0123         j=s(i,1);   % start of new spurt
0124         tw=[tw(1:j-1); tw(j); tw(j:end)];
0125         w=[w(1:j-1); NaN; w(j:end)];        % insert a NaN to force a plotting break
0126     end
0127     plot(tt(:,1:2)',repmat(x(:)',2,1),'r-+',tw,w,'b-');
0128 end
0129```

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