endp.m

matlab book matlab book2

function cropped = endp(grabname,Srate)
% takes waveform matrix and detects endpoints, then crops it
% adapted version of 'endpoint.m', part of COLEA speech program (original version within == points)
% freeware, copyright of P.C. Loizou, formerly of UALR, http://www.ualr.edu/www/index.htmlx 

x = grabname; 
n_samples = length(x);
if (n_samples < 30000)
    tryagain; uiwait(tryagain); cropped = 0; return;
end;

% =====================================
% beginning of 'endpoint.m' fragment

n_Secs = n_samples/Srate;
Dur = 10.0;
fSize= Dur*Srate/1000;

nFrames=floor(n_samples/fSize);
k=1;
engy=zeros(1,nFrames);
for i=1:nFrames
	y=x(k:k+fSize-1);
	engy(i)=10*log10(norm(y));
	k=k+fSize;
end;

mx=max(engy); mn=min(engy);
ind=find(engy>(mx-5));
lind=length(ind);

% =====================================
% adapted here
if (lind < 3)
    tryagain; cropped = 0; return;
else
    onSample=(ind(1)-1)*fSize;
end;
% ======================================

if (ind(lind)-ind(lind-1) > 1)
  offSample=(ind(lind-1)-1)*fSize;
else
  offSample=(ind(lind)-1)*fSize;
end;
% =====================================
% end of 'endpoint.m' fragment

if (onSample == 0)
    onSample = 1;
end;
cropdur = offSample-onSample;

for count = 1:1:cropdur
    cropped(count) = x(count+onSample-1);
end;

return;