function spec=cps_to_specgram(filename_or_cepstr,cmap)
% spec=cps_to_specgram(filename_or_cepstr,cmap)
%
% makes FFT out of cps coeffs read from an HTK file - can process either
% cepstral matrix or HTK file if out arg is specified, does not draw the spec. 
%
% if colormap not supplied, uses the default one. 

if (isstr(filename_or_cepstr))
  h = readhtk(filename_or_cepstr); 
else
  h =filename_or_cepstr;
end

if nargin==1,
  cmap = colormap;
end

[P,vecs] = size(h);

spec = zeros(129,vecs);
for ii=1:vecs,
  c = h(:,ii);
  ospec = abs(fft([c ; zeros(256-P-(P-1),1) ; c(P:-1:2)]));
  spec(:,ii) = ospec(1:129);   % for fft 
end
%imagesc(spec); axis xy 
if (nargout == 0)
%  image(spec/max(max(spec))*64); colormap(cmap); axis xy 
  imagesc(spec); axis xy; colormap (cmap); 
  colorbar;
end