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LPC Error Synthesis

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LPC Error Synthesis

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13 Feb 2014 (Updated )

This MATLAB exercise performs LPC analysis and synthesis on a speech file.

Callbacks_lpc_error_syn_GUI25(f,C,start_path)
function Callbacks_lpc_error_syn_GUI25(f,C,start_path)
%SENSE COMPUTER AND SET FILE DELIMITER
switch(computer)				
    case 'MACI64',		char= '/';
    case 'GLNX86',  char='/';
    case 'PCWIN',	char= '\';
    case 'PCWIN64', char='\';
    case 'GLNXA64', char='/';
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
x=C{1,1};
y=C{1,2};
a=C{1,3};
b=C{1,4};
u=C{1,5};
v=C{1,6};
m=C{1,7};
n=C{1,8};
lengthbutton=C{1,9};
widthbutton=C{1,10};
enterType=C{1,11};
enterString=C{1,12};
enterLabel=C{1,13};
noPanels=C{1,14};
noGraphicPanels=C{1,15};
noButtons=C{1,16};
labelDist=C{1,17};%distance that the label is below the button
noTitles=C{1,18};
buttonTextSize=C{1,19};
labelTextSize=C{1,20};
textboxFont=C{1,21};
textboxString=C{1,22};
textboxWeight=C{1,23};
textboxAngle=C{1,24};
labelHeight=C{1,25};
fileName=C{1,26};
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%PANELS
for j=0:noPanels-1
uipanel('Parent',f,...
'Units','Normalized',...
'Position',[x(1+4*j) y(1+4*j) x(2+4*j)-x(1+4*j) y(3+4*j)-y(2+4*j)]);
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%GRAPHIC PANELS
for i=0:noGraphicPanels-1
switch (i+1)
case 1
graphicPanel1 = axes('parent',f,...
'Units','Normalized',...
'Position',[a(1+4*i) b(1+4*i) a(2+4*i)-a(1+4*i) b(3+4*i)-b(2+4*i)],...
'GridLineStyle','--');
case 2
graphicPanel2 = axes('parent',f,...
'Units','Normalized',...
'Position',[a(1+4*i) b(1+4*i) a(2+4*i)-a(1+4*i) b(3+4*i)-b(2+4*i)],...
'GridLineStyle','--');
case 3
graphicPanel3 = axes('parent',f,...
'Units','Normalized',...
'Position',[a(1+4*i) b(1+4*i) a(2+4*i)-a(1+4*i) b(3+4*i)-b(2+4*i)],...
'GridLineStyle','--');
end
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%TITLE BOXES
for k=0:noTitles-1
switch (k+1)
case 1
titleBox1 = uicontrol('parent',f,...
'Units','Normalized',...
'Position',[u(1+4*k) v(1+4*k) u(2+4*k)-u(1+4*k) v(3+4*k)-v(2+4*k)],...
'Style','text',...
'FontSize',textboxFont{k+1},...
'String',textboxString(k+1),...
'FontWeight',textboxWeight{k+1},...
'FontAngle',textboxAngle{k+1});
end
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%BUTTONS
for i=0:(noButtons-1)
enterColor='w';
if strcmp(enterType{i+1},'pushbutton')==1 ||strcmp(enterType{i+1},'text')==1
enterColor='default';
end
if (strcmp(enterLabel{1,(i+1)},'')==0 &&...
        strcmp(enterLabel{1,(i+1)},'...')==0) %i.e. there is a label
%creating a label for some buttons
uicontrol('Parent',f,...
'Units','Normalized',...
'Position',[m(1+2*i) n(1+2*i)-labelDist-labelHeight(i+1) ...
(m(2+2*i)-m(1+2*i)) labelHeight(i+1)],...
'Style','text',...
'String',enterLabel{i+1},...
'FontSize', labelTextSize(i+1),...
'HorizontalAlignment','center');
end
switch (i+1)
case 1
button1=uicontrol('Parent',f,...
'Units','Normalized',...
'Position',[m(1+2*i) n(1+2*i) (m(2+2*i)-m(1+2*i)) (n(2+2*i)-n(1+2*i))],...
'Style',enterType{i+1},...
'String',enterString{i+1},...
'FontSize', buttonTextSize(1+i),...
'BackgroundColor',enterColor,...
'HorizontalAlignment','center',...
'Callback',@button1Callback);
case 2
button2=uicontrol('Parent',f,...
'Units','Normalized',...
'Position',[m(1+2*i) n(1+2*i) (m(2+2*i)-m(1+2*i)) (n(2+2*i)-n(1+2*i))],...
'Style',enterType{i+1},...
'String',enterString{i+1},...
'FontSize', buttonTextSize(1+i),...
'BackgroundColor',enterColor,...
'HorizontalAlignment','center',...
'Callback',@button2Callback);
case 3
button3=uicontrol('Parent',f,...
'Units','Normalized',...
'Position',[m(1+2*i) n(1+2*i) (m(2+2*i)-m(1+2*i)) (n(2+2*i)-n(1+2*i))],...
'Style',enterType{i+1},...
'String',enterString{i+1},...
'FontSize', buttonTextSize(1+i),...
'BackgroundColor',enterColor,...
'HorizontalAlignment','center',...
'Callback',@button3Callback);
case 4
button4=uicontrol('Parent',f,...
'Units','Normalized',...
'Position',[m(1+2*i) n(1+2*i) (m(2+2*i)-m(1+2*i)) (n(2+2*i)-n(1+2*i))],...
'Style',enterType{i+1},...
'String',enterString{i+1},...
'FontSize', buttonTextSize(1+i),...
'BackgroundColor',enterColor,...
'HorizontalAlignment','center',...
'Callback',@button4Callback);
case 5
button5=uicontrol('Parent',f,...
'Units','Normalized',...
'Position',[m(1+2*i) n(1+2*i) (m(2+2*i)-m(1+2*i)) (n(2+2*i)-n(1+2*i))],...
'Style',enterType{i+1},...
'String',enterString{i+1},...
'FontSize', buttonTextSize(1+i),...
'BackgroundColor',enterColor,...
'HorizontalAlignment','center',...
'Callback',@button5Callback);
case 6
button6=uicontrol('Parent',f,...
'Units','Normalized',...
'Position',[m(1+2*i) n(1+2*i) (m(2+2*i)-m(1+2*i)) (n(2+2*i)-n(1+2*i))],...
'Style',enterType{i+1},...
'String',enterString{i+1},...
'FontSize', buttonTextSize(1+i),...
'BackgroundColor',enterColor,...
'HorizontalAlignment','center',...
'Callback',@button6Callback);
case 7
button7=uicontrol('Parent',f,...
'Units','Normalized',...
'Position',[m(1+2*i) n(1+2*i) (m(2+2*i)-m(1+2*i)) (n(2+2*i)-n(1+2*i))],...
'Style',enterType{i+1},...
'String',enterString{i+1},...
'FontSize', buttonTextSize(1+i),...
'BackgroundColor',enterColor,...
'HorizontalAlignment','center',...
'Callback',@button7Callback);
case 8
button8=uicontrol('Parent',f,...
'Units','Normalized',...
'Position',[m(1+2*i) n(1+2*i) (m(2+2*i)-m(1+2*i)) (n(2+2*i)-n(1+2*i))],...
'Style',enterType{i+1},...
'String',enterString{i+1},...
'FontSize', buttonTextSize(1+i),...
'BackgroundColor',enterColor,...
'HorizontalAlignment','center',...
'Callback',@button8Callback);
case 9
button9=uicontrol('Parent',f,...
'Units','Normalized',...
'Position',[m(1+2*i) n(1+2*i) (m(2+2*i)-m(1+2*i)) (n(2+2*i)-n(1+2*i))],...
'Style',enterType{i+1},...
'String',enterString{i+1},...
'FontSize', buttonTextSize(1+i),...
'BackgroundColor',enterColor,...
'HorizontalAlignment','center',...
'Callback',@button9Callback);
case 10
button10=uicontrol('Parent',f,...
'Units','Normalized',...
'Position',[m(1+2*i) n(1+2*i) (m(2+2*i)-m(1+2*i)) (n(2+2*i)-n(1+2*i))],...
'Style',enterType{i+1},...
'String',enterString{i+1},...
'FontSize', buttonTextSize(1+i),...
'BackgroundColor',enterColor,...
'HorizontalAlignment','center',...
'Callback',@button10Callback);
case 11
button11=uicontrol('Parent',f,...
'Units','Normalized',...
'Position',[m(1+2*i) n(1+2*i) (m(2+2*i)-m(1+2*i)) (n(2+2*i)-n(1+2*i))],...
'Style',enterType{i+1},...
'String',enterString{i+1},...
'FontSize', buttonTextSize(1+i),...
'BackgroundColor',enterColor,...
'HorizontalAlignment','center',...
'Callback',@button11Callback);
case 12
button12=uicontrol('Parent',f,...
'Units','Normalized',...
'Position',[m(1+2*i) n(1+2*i) (m(2+2*i)-m(1+2*i)) (n(2+2*i)-n(1+2*i))],...
'Style',enterType{i+1},...
'String',enterString{i+1},...
'FontSize', buttonTextSize(1+i),...
'BackgroundColor',enterColor,...
'HorizontalAlignment','center',...
'Callback',@button12Callback);
case 13
button13=uicontrol('Parent',f,...
'Units','Normalized',...
'Position',[m(1+2*i) n(1+2*i) (m(2+2*i)-m(1+2*i)) (n(2+2*i)-n(1+2*i))],...
'Style',enterType{i+1},...
'String',enterString{i+1},...
'FontSize', buttonTextSize(1+i),...
'BackgroundColor',enterColor,...
'HorizontalAlignment','center',...
'Callback',@button13Callback);
case 14
button14=uicontrol('Parent',f,...
'Units','Normalized',...
'Position',[m(1+2*i) n(1+2*i) (m(2+2*i)-m(1+2*i)) (n(2+2*i)-n(1+2*i))],...
'Style',enterType{i+1},...
'String',enterString{i+1},...
'FontSize', buttonTextSize(1+i),...
'BackgroundColor',enterColor,...
'HorizontalAlignment','center',...
'Callback',@button14Callback);
end
end

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%USER CODE FOR THE VARIABLES AND CALLBACKS
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Initialize Variables
    curr_file=1;
    fs=8000;
    fsd=10000;
    directory_name='abcd';
    wav_file_names='abce';
    fin_path='filename';
    fname='output';
    nsamp=1;
    xin=[];
    ss=0;
    es=0;
    Lm=40;
    Rm=10;
    p=12;
    iwin=1;
    spct=[];
    exct=[];
    
% Name the GUI
    set(f,'Name','lpc_error_synthesis');

% CALLBACKS
% Callback for button1 -- Get Speech Files Directory
 function button1Callback(h,eventdata)
     directory_name=uigetdir(start_path,'dialog_title');
%       if isempty(getpref('SpeechApps'))
%          url = sprintf('%s%s%s',...
%              'http://www.mathworks.com/matlabcentral/fileexchange/',...
%              '42911-speech-and-audio-files-for-speech-processing-excercises',...
%              '?download=true');
%          [saveloc,~,~] = fileparts(pwd); %save to one level up from current folder
%          % Create a waitbar during download
%          h = waitbar(0.35,'This may take several minutes...',...
%              'Name','Downloading Speech Files...');
%          % Download the zipped file
%          [filestr,status] = urlwrite(url,[saveloc filesep 'speech_files.zip'],...
%              'Timeout',10);
%          if status
%              delete(h);
%              hh1= helpdlg('Downloaded. Select a location to UNZIP the speech files.');
%              uiwait(hh1);
%              unziploc = uigetdir(saveloc,'Select a location to unzip the speech files');
%              h2 = waitbar(0.2,'This may take a minute...',...
%                  'Name','Unzipping the Speech Files to Location Selected...');
%              unzip(filestr,unziploc);
%              delete(h2)
%              addpref('SpeechApps','path',unziploc);
%              hh2= helpdlg('Ready. Select the speech_files folder in the next window');
%              uiwait(hh2);
%          else
%              warndlg('No Internet Connection to MATLAB Central!');
%          end
%          
%      else
%      end
%      directory_name=uigetdir(getpref('SpeechApps','path'));
     A=strvcat(strcat((directory_name),[char,'*.wav']));
     struct_filenames=dir(A);
     wav_file_names={struct_filenames.name};
     set(button2,'String',wav_file_names);
     
% once the popupmenu/drop down menu is created, by default, the first
% selection from the popupmenu/drop down menu id not called
    indexOfDrpDwnMenu=1;
    
% by default first option from the popupmenu/dropdown menu will be loaded
    [curr_file,fs]=loadSelection(directory_name,wav_file_names,indexOfDrpDwnMenu);
 end

% Callback for button2 -- Choose speech file for play and plot
 function button2Callback(h,eventdata)
     indexOfDrpDwnMenu=get(button2,'val');
     [curr_file,fs]=loadSelection(directory_name,wav_file_names,indexOfDrpDwnMenu);
 end

%*************************************************************************
% function -- load selection from designated directory and file
%
function [curr_file,fs]=loadSelection(directory_name,wav_file_names,...
    indexOfDrpDwnMenu);
%
% read in speech/audio file
% fin_path is the complete path of the .wav file that is selected
    fin_path=strcat(directory_name,char,strvcat(wav_file_names(indexOfDrpDwnMenu)));
    
% clear speech/audio file
    clear curr_file;
    
% read in speech/audio signal into curr_file; sampling rate is fs 
    [curr_file,fs]=wavread(fin_path);
    xin=curr_file*32768;
    
% create title information with file, sampling rate, number of samples
    fname=wav_file_names(indexOfDrpDwnMenu);
    FS=num2str(fs);
    nsamp=num2str(length(curr_file));
    file_info_string=strcat('  file: ',fname,', fs: ',FS,' Hz, nsamp:',nsamp);
    
% read in filename (fname) from cell array
    fname=wav_file_names{indexOfDrpDwnMenu};
    
% replace each '_' character in fname with ' '
    fname(find(fname(:) == '_')) = ' ';
    
% determine ss and es from file
    ss=1;
    es=length(xin);
    set(button13,'string',num2str(ss));
    set(button14,'string',num2str(es));
end

% Callback for button3 -- Lm: analysis frame length in msec
 function button3Callback(h,eventdata)
     Lm=str2num(get(button3,'string'));
     if ~((Lm >= 1 && Lm <= 100))
        waitfor(errordlg('Lm must be a positive number between 1 and 100'))
        return;
     end
 end

% Callback for button4 -- Rm: analysis frame shift in msec
 function button4Callback(h,eventdata)
     Rm=str2num(get(button4,'string'));
     if ~((Rm >= 1 && Rm <= 100))
        waitfor(errordlg('Rm must be a positive number between 1 and 100'))
        return;
     end
 end

% Callback for button5 -- p: lpc system order
 function button5Callback(h,eventdata)
     p=str2num(get(button5,'string'));
     if ~((p >= 4 && p <= 32))
        waitfor(errordlg('p must be a positive integer between 4 and 32'))
        return;
     end
     p=round(p);
     set(button5,'string',num2str(p));
 end

% Callback for button6 -- iwin: window switch (1:Hamming, 2:Rectangular)
 function button6Callback(h,eventdata)
     iwin=get(button6,'val');
 end

% Callback for button7 -- Run LPC Error Synthesis
 function button7Callback(h,eventdata)
     
% reset ss and es for full file analysis
    ss=1;
    es=length(curr_file);
    set(button13,'string',num2str(ss));
    set(button14,'string',num2str(es));
    
% check editable buttons for changes
    button3Callback(h,eventdata);
    button4Callback(h,eventdata);
    button5Callback(h,eventdata);
    button6Callback(h,eventdata);
    
% setup lpc error synthesis
    xin=curr_file(ss:es);
    es=es-ss+1;
    ss=1;
    [spct,exct]=setup_lpc_error_synthesis(xin,fs,ss,es,Lm,Rm,p,iwin,fname);
 end

%*********************************************************************
    function [spct,exct]=setup_lpc_error_synthesis(xin,fs,ss,es,Lm,Rm,...
            p,iwin,filename)
%
% Program to filter speech by the LPC polynomial to give the error signal, 
% on a frame-by-frame basis, and then to filter the error signal, again on
% a frame-by-frame basis to give back the original speech

% convert Lm from msec to samples, Rm from msec to samples
    L=round(Lm*fs/1000);
    R=round(Rm*fs/1000);

% normalize speech file to range [-1 1]
    xinm=max(-min(xin),max(xin));
    xinn=xin/xinm;
    
% if ss =0 search for first non-zero sample
    if (ss == 0)
        begin=find(xinn ~= 0);
        ss=begin(1);
    end
    
% if es = 0 search for last non-zero sample as es
    if (es == 0)
        begin=find(xinn ~= 0);
        es=begin(length(begin));
    end
    
% set up specified window for lpc analysis
    if (iwin == 1)
        win=hamming(L);
    else
        win=ones(1,L)';
    end
    
% overlap-add gain term: R/W(e^{j0})
    gain=R/sum(win);
    
% process file in frames and overlap add the results using a Hamming window
% on the synthesis addition
    flen=min(length(xinn),es+4*L);
    exct=zeros(flen-ss+1,1);
    spct=zeros(flen-ss+1,1);
    n=ss;
    while (n+L-1 <= es)
        x=xinn(n:n+L-1);
        xw=x.*win;
        [A,G,a,r]=autolpc(xw,p);
        excx=filter(A,G,x);
        exct(n-ss+1:n-ss+L)=exct(n-ss+1:n-ss+L)+excx(1:L).*win(1:L)*gain;
        spcx=filter(G,A,excx);
        spct(n-ss+1:n-ss+L)=spct(n-ss+1:n-ss+L)+spcx(1:L).*win(1:L)*gain;
        n=n+R;
    end
       
% plot original signal, error signal, synthesized signal (from error)
    l1=length(spct);
    nt=0:l1-1;
    stitle=sprintf(' filename: %s, ss/es: %d %d, lpc parameters, L: %d, R: %d, p:%d',...
        filename,ss,es,L,R,p);

% clear graphics Panel 3
        reset(graphicPanel3);
        axes(graphicPanel3);
        cla;
    
% plot original speech signal in graphics Panel 3
    plot(nt,xinn(ss:ss+l1-1),'r','LineWidth',2);
    xpp=['Time in Samples; fs=',num2str(fs),' samples/second'];
        axis ([0 l1-1 -1 1]),xlabel(xpp),grid on;...
        ylabel('Value'),legend('original speech signal');
    
% clear graphics Panel 2
        reset(graphicPanel2);
        axes(graphicPanel2);
        cla;
    
% plot resynthesized signal (from error signal excitation) on graphics
% Panel 2
    plot(nt,spct,'b','LineWidth',2),axis ([0 l1-1 -1 1]),grid on;...
        xlabel(xpp),ylabel('Value'),legend('resynthesized signal');
    
% clear grpahics Panel 1
        reset(graphicPanel1);
        axes(graphicPanel1);
        cla;
    
% plot lpc error signal (excitation) on graphics Panel 1
    plot(nt,exct,'g','LineWidth',2),axis ([0 l1-1 -1 1]),grid on;...
        xlabel(xpp),ylabel('Value'),legend('lpc error signal');
    
% display fname, signal processing parameters in titleBox1
        stitle1=strcat('LPC Error Synthesis -- ',stitle);
        set(titleBox1,'string',stitle1);
        set(titleBox1,'FontSize',18);
    
% close text file
    fclose('all');        
    end

% Callback for button8 -- play original speech file
 function button8Callback(h,eventdata)
     soundsc(xin,fs);
 end

% Callback for button9 -- play synthesized signal
 function button9Callback(h,eventdata)
     soundsc(spct,fs);
 end

% Callback for button10 -- play lpc excitation signal
 function button10Callback(h,eventdata)
     soundsc(exct,fs);
 end

% Callback for button12 -- Expand Speech Segment
    function button12Callback(h,eventdata)
	xin=curr_file*32768;
        
% use cursor to find region of speech to expand
    [X,Y]=ginput(2);
    X=round(X);
    if (X(1) < 1) X(1)=1; end
    if (X(2) > length(curr_file)) X(2)=length(curr_file); end
    ss=X(1);
    es=X(2);
    set(button13,'string',num2str(ss));
    set(button14,'string',num2str(es));
    xpp=['Time in Samples; fs=',num2str(fs),' samples/second'];

% plot expanded region of each waveform
    reset(graphicPanel3);
    axes(graphicPanel3);
    cla;
    plot(ss:es,xin(ss:es),'b','LineWidth',2);
    xlabel(xpp);ylabel('Value');axis tight,grid on;
    legend('original speech signal - expanded');

% plot expanded region of each waveform
    reset(graphicPanel2);
    axes(graphicPanel2);
    cla;
    plot(ss:es,spct(ss:es),'r','LineWidth',2);
    xlabel(xpp);ylabel('Value');axis tight,grid on;
    legend('resynthesized speech signal - expanded');
    
% plot expanded region of each waveform
    reset(graphicPanel1);
    axes(graphicPanel1);
    cla;
    plot(ss:es,exct(ss:es),'g','LineWidth',2);
    xlabel(xpp);ylabel('Value');axis tight,grid on;
    legend('lpc error signal - expanded');
    end

% Callback for button13 -- ss: starting sample
    function button13Callback(h,eventdata)
    end

% Callback for button14 -- es: ending sample
    function button14Callback(h,eventdata)
    end

% Callback for button11 -- Close GUI
 function button11Callback(h,eventdata)
     fclose('all');
     close(gcf);
 end
end

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