=head1 NAME

read_wav

=head1 SYNOPSYS

perl read_wav chimes.wav > chimes.dat

=head1 DESCRIPTION

This routine reads a .wav file and prints out the waveform so that
it can be graphed with gnuplot or processed by some other program.

This program only works on 8 bit sound files.

=cut

$/ = "";
$_ = <>;

@val= unpack("C*", $_);

$file_type= pack("C*", splice(@val,0,4));
# print "File type: $file_type\n";

$garbage= pack("C*", splice(@val,0,4));
# print "garbage: $garbage\n";

$wave_chunk= pack("C*", splice(@val,0,4));
# print "wave chunk: $wave_chunk\n";

while ($#val > 0)
{
  $chunk_type= pack("C*", splice(@val,0,4));
# print "chunk type: $chunk_type\n";
  $chunk_size= &my_pack_dword(splice(@val,0,4));
# print "chunk size: $chunk_size\n";
  @chunk= splice(@val,0,$chunk_size);
  if ($chunk_type eq "data")
  {
    if ($fmt_cat != 1 and $channels != 1) {die "Unsupported format";}
    for ($i=0; $i< $#chunk; $i++)
    {
      print $i/$samp_per_sec." ".($chunk[$i]-128)."\n";
    }
  }
  elsif ($chunk_type eq "fmt ")
  {
    $fmt_cat= &my_pack_word(splice(@chunk, 0, 2));
    $channels= &my_pack_word(splice(@chunk, 0, 2));
    $samp_per_sec= &my_pack_dword(splice(@chunk, 0, 4));
    $bytes_per_sec= &my_pack_dword(splice(@chunk, 0, 4));
    $block_size= &my_pack_word(splice(@chunk, 0, 2));
    # print "format section:\n";
    # print "format: $fmt_cat\n";
    # print "channels: $channels\n";
    # print "samp_per_sec: $samp_per_sec\n";
    # print "bytes_per_sec: $bytes_per_sec\n";
    # print "block_size: $block_size\n";
  }
}

sub my_pack_dword
{
  $b0= shift;
  $b1= shift;
  $b2= shift;
  $b3= shift;
  $b0+256*$b1+65536*$b2+16777216*$b3;
}

sub my_pack_word
{
  $b0= shift;
  $b1= shift;
  $b0+256*$b1;
}