function [pitch,voicing] = pitch_extract(signal,fshift,sample_freq)
% function [pitch,voicing] = pitch_extract(signal,fshift,sample_freq)
%
% GOAL:   Extract the pitch frequency and the voicing evidence of a given
%         speech signal. Both values are calculated each <fshift> seconds.
%
% INPUT:  signal         residusignaal
%         fshift         frame shift (in sec), tijd tussen 2 pitchwaarden
%         sample_freq    sampling frequentie van 'signal' (in Hz)
% OUTPUT: pitch          array met pitchwaarden van 'signal'
%         voicing        array met overeenkomstige voicing evidence

if(nargin < 3)
  sample_freq = [];
  if(nargin < 2)
    fshift = [];
    if(nargin < 1)
      help pitch_extract;
      return;
    end
  end
end
if(isempty(sample_freq));	sample_freq=16000;	end;
if(isempty(fshift));		fshift=0.01;		end;

n1 = floor(fshift*sample_freq+0.5);
n2 = floor(fshift*4000+0.5);
while(n2/gcd(n1,n2) > 3)
  n2 = n2+1;
end
sample_freq2 = sample_freq*n2/n1;

% write the data in a known format
nsamples = prod(size(signal));
if(nsamples ~= max(size(signal)))
  error('can only handle mono signals');
end
if(max(abs(signal(:))) <= 1)
  signal(:) = signal(:).*2^15;
end
tmp_ifname = tempname;
tmp_ofname = tempname;
tmp_sfname = tempname;
fd = fopen(tmp_ifname,'w');
if(fd == -1)
  cleanup(tmp_ifname,tmp_ofname,tmp_sfname);
  error(sprintf('can''t open %s',tmp_ifname));
end
fprintf(fd,'.key\nDATATYPE SAMPLE\nDATAFORMAT A-FLOAT\nNCHAN 1\nCHANLEN %i\nSAMPLEFREQ %i\n#\n',nsamples,sample_freq);
fprintf(fd,'%i\n',signal(:));
fclose(fd);

% write the pre-processing script
fd = fopen(tmp_sfname,'w');
if(fd == -1)
  cleanup(tmp_ifname,tmp_ofname,tmp_sfname);  
  error(sprintf('can''t open %s',tmp_sfname));
end

fprintf(fd,'.fshift %g\n.convert to FLOAT\n\n',fshift);
fprintf(fd,'[time_filter]\n  set samplefreq to %.4f\n',sample_freq2);
fprintf(fd,'[fun_eval]\n  eval ovec=ivec^3\n');
fprintf(fd,'[sam2trk]\n  flength %g\n  preemp  0.00\n',3*fshift);
fprintf(fd,'[scale]\n  window HAMMING no_norm\n');
fprintf(fd,'[fun_eval]\n  eval ovec=[ivec,0:0:3*vlen]\n');
fprintf(fd,'[anafft]\n  type POWER\n');
fprintf(fd,'[envelope]\n  norm\n');
fprintf(fd,'[pitch]\n  freq_band 2000\n  window    HAMMING\n  voicing   evidence\n  track\n');
fprintf(fd,'.convert to A-FLOAT\n');
fclose(fd);

% process the data
[rv,e] = unix(sprintf('/users/spraak/spch/soft/ssp23/binlinux-i386/sigp -ssp %s -i %s -o %s -Fo NOHEADER',tmp_sfname,tmp_ifname,tmp_ofname));
if(rv | ~isempty(e))
  cleanup(tmp_ifname,tmp_ofname,tmp_sfname);
  error(e);
end

% read the result
x = load(tmp_ofname);
pitch   = x(:,1);
voicing = x(:,2);

% that's all folks
cleanup(tmp_ifname,tmp_ofname,tmp_sfname);
return;

function cleanup(tmp_ifname,tmp_ofname,tmp_sfname)
unix(sprintf('/bin/rm -f %s %s %s',tmp_ifname,tmp_ofname,tmp_sfname));
return;