phase_alignment2.m

%% Progetto 2016 - Elaborazione del Audio Digitale
% version 2.0

% Load audio files
[ref, Fs] = audioread('reference2.wav');
[test, FsT] = audioread('test2.wav');

% Time vectors
tr=0:1/Fs:(length(ref)-1)/Fs;
tt=0:1/Fs:(length(test)-1)/Fs;

%% track segmentation
fd=2;       %frame duration
fs=fd*Fs;   %frame size
ws=1;      %window size parameter <--ws*fs--| fs |--ws*fs-->

% Segmentation
[refF, refN]=segment(ref,fs,fs);
[testF, testN]=segment(test,fs,fs);

%initialize vectors
lagVector=zeros(testN,1);
M=zeros(refN,1);
aligned=zeros(length(test),1);
xc=cell(1,testN);
refw=cell(1,2*ws+1);
%resT=cell(1,testN);


%% XCorrelation calc


%coef=(i-ws):(i+ws);
for i=1:testN
    
    %search segment under the window construction
    %for j=1:2*ws+1
     %   refw{j}=refF{i+coef(j)};
    %end
    if ((i-ws)<=0)
       refw={cat(1,refF{1:(i+ws)})};
    elseif (i+ws)>refN
        refw={cat(1,refF{(i-ws):refN})};
    else
        refw={cat(1,refF{(i-ws):(i+ws)})};
    end
    
    searchwindow=cell2mat(refw);
    % Xcorrelation
    [xc{i}, lag]=xcorr(testF{i},searchwindow);
    [M(i),I]=max(abs(xc{i}));
    lagVector(i)=lag(I);
end

lagVector=optlags2(lagVector,40);

%% Plot Xcorr segment graphs
for i=1:refN
figure
subplot(3,1,1), plot(refF{i}), ylabel('Ref')
string=sprintf('Segment number %d',i);
title(string)
subplot(3,1,2), plot(testF{i}), ylabel('Test')
subplot(3,1,3), plot(lag,abs(xc{i})), ylabel('XCorr')
end

%% Alignment solution 1
for i=1:refN
% if lagVector(i)>0
%     
%     resT{i}=padarray(testF{i}(lagVector(i)+1:end),[lagVector(i) 0],'post');
%     
%     %resR=padarray(refF{1},[lag(I) 0],'pre');
% else
%     resT{i}=padarray(testF{i}(1:end-lagVector(i)-1),[lagVector(i) 0],'pre');
%     %resR=padarray(refF{1},[lag(I) 0],'post');
% end

%% Alignment solution 2

if i==1
    if sign(lagVector(i)) == 1
        resT=padarray(testF{i}(lagVector(i)+1:end),[lagVector(i) 0],'post');
        aligned(1:fs)=resT;
        %Problem: Information loses at the beginin of the segment
    elseif sign(lagVector(i)) == -1
        resT=padarray(testF{i},[lagVector(i) 0],'pre');
        aligned(1:fs+abs(lagVector(i)))=resT;
        %Problem: Information loses at the end of the segment when Segment
        %i=2 overlaps
    else
        aligned(1:fs)=testF{i};
    end
else
    start=((i-1)*fs)-lagVector(i);
    stop=(start+fs)-1;
    aligned(start:stop)=testF{i};

end


end


%% XCorrelation between entire tracks

[xcT, lagT]=xcorr(test,ref);
[xcA, lagA]=xcorr(aligned,ref);
%audiowrite('aligned.wav',aligned,Fs);

% plots
figure
title('Cross correlation beteen reference and test (blue) and aligned (red) tracks)')
subplot(2,1,1), plot(lagT,xcT,'b'), ylabel('XCorr')
subplot(2,1,2), plot(lagA,xcA,'r'), ylabel('XCorr')


%% Plots

% Graph: Ref & Test Signals
figure
subplot(3,1,1), plot(tr,ref,'g'), ylabel('Ref')
string=sprintf('Reference & Test (.wav) Signals, with %d seconds segmentation',fd);
title(string)
subplot(3,1,2), plot(tt,test,'g'), ylabel('Test')
%Plot lags found in each segment
seg_lags=repelem(lagVector,fd);
seg_lags=seg_lags ./ Fs;
subplot(3,1,3), plot(1:(i*fd),seg_lags,'g'), xlabel('Time (s)'), ylabel('Lag time')

%plot aligned signal
ta=0:1/Fs:(length(aligned)-1)/Fs;
figure
subplot(2,1,1), plot(tr,ref,'r'), ylabel('Ref')
string=sprintf('Reference & Test (.wav) Signals, with %d seconds segmentation',fd);
title(string)
subplot(2,1,2), plot(ta,aligned,'r'), ylabel('Test')