function [snd, srate, nbits] = wavin(infile,nframes);
% [snd, srate, nbits] = wavin(infile,[nframes])
%
% Read .wav file into snd (size  (nchans,nsamples)).
% srate = sampling rate in Hz.
% nbits = bits per sample.
% optional nframes = no. samples to read (all channels)
%   (default = all samples in file).

% XXX FIXME XXX merge with auload
% This program is public domain
% Author: Julius O. Smith III


% kpl replaced this line with following line: 10/24/05 
% according to maintainers this fix should already be in the next octave-forge release
% fpi = fopen(infile,'r');
fpi = fopen(infile,'rb','ieee-le');

riffId = 1179011410;  % 'RIFF'
waveId	= 1163280727; % 'WAVE'
fmtId	= 544501094;  % 'fmt '
dataId  = 1635017060;  % 'data'


% read the file id - it must be 'RIFF' for this to be a .wav file
id =  fread(fpi, 1,'int32');	
if id != riffId
  error(strcat(infile, ' is not a RIFF file'));
end

disp(strcat( infile,  "is in RIFF format:"));

nbytes = fread(fpi, 1,'int32');
disp(sprintf('\tTotal length = %d bytes',nbytes));

% read the 'WAVE' id
subfmt = fread(fpi, 1,'int32');
if subfmt != waveId
  error(strcat('*** Cannot handle subformat %s',subfmt));
end

% read the 'fmt ' id
fmt = fread(fpi, 1,'int32');  
%if (strcmp(fmt,'fmt ')!=0)
if fmt != fmtId
  error(strcat("*** Expected 'fmt ' in header, but got '",fmt));
end

cl = fread(fpi, 1,'int32');
if (cl ~= 16) 
  error(sprintf('*** Expected format chunk length = 16 in soundfile header, but got %d',cl));
end

% read the sample data format id
tmps = fread(fpi,1,'int16');	
if (tmps != 1) 
  error(sprintf('*** Expected 01 in format chunk, but got %d',tmps));
end

% read the number of audio channels
nchans = fread(fpi,1,'int16');	% channels
disp(sprintf('\tNumber of channels = %d',nchans));

srate = fread(fpi,1,'int32');	% sample rate
disp(sprintf('\tSampling rate = %d Hz',srate));
tmpi = fread(fpi,1,'int32');	% bytes per sec

% kpl: if (tmpi != 2*srate) 
if (tmpi != 2*srate*nchans) 
  error(sprintf('*** %d bytes per second looks wrong. Expect %d',
  tmpi,2*srate));
end

bps = fread(fpi,1,'int16');		% bytes per sample
nbits = fread(fpi,1,'int16');	% bits per sample

nbytes = 0;

% seek to the 'data' chunk
do
	id = fread(fpi,1,'int32');		% 'data'?
	nbytes = fread(fpi,1,'int32');		% chunk byte cnt
	
	if( id != dataId )
		if( fseek(fpi,nbytes,'cof') == -1 )
			error(strcat(infile," has no audio data."));
		endif
	endif
	
until( (id == dataId) || feof(fpi)  );

%id = fread(fpi,1,'int32');		% 'data'
%%if (strcmp(id,'data')!=0) 
%if id != dataId
%  error(sprintf("Did not find 'data' ID where expected"));
%end

% nbytes = fread(fpi,1,'int32');	% data chunk byte count
if (mod(nbytes,2)==1) 
  error(sprintf('*** Number of data bytes (%d) is ODD!',nbytes));
end
nsamps = nbytes/2;
disp(sprintf('\tData length = %d samples', nsamps));

if (mod(nsamps,nchans)~=0) 
  error(sprintf(['*** Number of channels (%d) does not divide nsamps ' ...
                 '(%d)!'],nchans,nsamps));
end

if nargin < 2
  nframes = nsamps/nchans;
elseif (nframes=='size') && (nargout = 1)
  nspc = (nbytes/2)/nchannels; % no. samples per channel
  snd=[nspc nchannels]; % should first arg = total samples instead?
  return; 
end

datafmt = sprintf('int%d',nbits');
snd = fread(fpi,[nchans,nframes],datafmt);
snd = snd' / (2^(nbits-1)-1); % Transpose for Matlab compatibility