X-Git-Url: https://git.creatis.insa-lyon.fr/pubgit/?a=blobdiff_plain;f=octave_packages%2Fm%2Faudio%2Fwavread.m;fp=octave_packages%2Fm%2Faudio%2Fwavread.m;h=2a03c7e9354769ac62481741ed1affdee264cd0f;hb=1c0469ada9531828709108a4882a751d2816994a;hp=0000000000000000000000000000000000000000;hpb=63de9f36673d49121015e3695f2c336ea92bc278;p=CreaPhase.git
diff --git a/octave_packages/m/audio/wavread.m b/octave_packages/m/audio/wavread.m
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+## Copyright (C) 2005-2012 Michael Zeising
+##
+## This file is part of Octave.
+##
+## Octave is free software; you can redistribute it and/or modify it
+## under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 3 of the License, or (at
+## your option) any later version.
+##
+## Octave is distributed in the hope that it will be useful, but
+## WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+## General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with Octave; see the file COPYING. If not, see
+## .
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {@var{y} =} wavread (@var{filename})
+## Load the RIFF/WAVE sound file @var{filename}, and return the samples
+## in vector @var{y}. If the file contains multichannel data, then
+## @var{y} is a matrix with the channels represented as columns.
+##
+## @deftypefnx {Function File} {[@var{y}, @var{Fs}, @var{bps}] =} wavread (@var{filename})
+## Additionally return the sample rate (@var{fs}) in Hz and the number of bits
+## per sample (@var{bps}).
+##
+## @deftypefnx {Function File} {[@dots{}] =} wavread (@var{filename}, @var{n})
+## Read only the first @var{n} samples from each channel.
+##
+## @deftypefnx {Function File} {[@dots{}] =} wavread (@var{filename}, @var{n1} @var{n2})
+## Read only samples @var{n1} through @var{n2} from each channel.
+##
+## @deftypefnx {Function File} {[@var{samples}, @var{channels}] =} wavread (@var{filename}, "size")
+## Return the number of samples (@var{n}) and channels (@var{ch})
+## instead of the audio data.
+## @seealso{wavwrite}
+## @end deftypefn
+
+## Author: Michael Zeising
+## Created: 06 December 2005
+
+function [y, samples_per_sec, bits_per_sample] = wavread (filename, param)
+
+ FORMAT_PCM = 0x0001; # PCM (8/16/32 bit)
+ FORMAT_IEEE_FLOAT = 0x0003; # IEEE float (32/64 bit)
+ BYTEORDER = "ieee-le";
+
+ if (nargin < 1 || nargin > 2)
+ print_usage ();
+ endif
+
+ if (! ischar (filename))
+ error ("wavread: FILENAME must be a character string");
+ endif
+
+ fid = -1;
+
+ unwind_protect
+
+ [fid, msg] = fopen (filename, "rb");
+
+ if (fid < 0)
+ error ("wavread: %s", msg);
+ endif
+
+ ## Get file size.
+ fseek (fid, 0, "eof");
+ file_size = ftell (fid);
+ fseek (fid, 0, "bof");
+
+ ## Find RIFF chunk.
+ riff_size = find_chunk (fid, "RIFF", file_size);
+ riff_pos = ftell (fid);
+ if (riff_size == -1)
+ error ("wavread: file contains no RIFF chunk");
+ endif
+
+ riff_type = char (fread (fid, 4))';
+ if (! strcmp (riff_type, "WAVE"))
+ error ("wavread: file contains no WAVE signature");
+ endif
+ riff_pos = riff_pos + 4;
+ riff_size = riff_size - 4;
+
+ ## Find format chunk inside the RIFF chunk.
+ fseek (fid, riff_pos, "bof");
+ fmt_size = find_chunk (fid, "fmt ", riff_size);
+ fmt_pos = ftell(fid);
+ if (fmt_size == -1)
+ error ("wavread: file contains no format chunk");
+ endif
+
+ ## Find data chunk inside the RIFF chunk.
+ ## We don't assume that it comes after the format chunk.
+ fseek (fid, riff_pos, "bof");
+ data_size = find_chunk (fid, "data", riff_size);
+ data_pos = ftell (fid);
+ if (data_size == -1)
+ error ("wavread: file contains no data chunk");
+ endif
+
+ ### Read format chunk.
+ fseek (fid, fmt_pos, "bof");
+
+ ## Sample format code.
+ format_tag = fread (fid, 1, "uint16", 0, BYTEORDER);
+ if (format_tag != FORMAT_PCM && format_tag != FORMAT_IEEE_FLOAT)
+ error ("wavread: sample format %#x is not supported", format_tag);
+ endif
+
+ ## Number of interleaved channels.
+ channels = fread (fid, 1, "uint16", 0, BYTEORDER);
+
+ ## Sample rate.
+ samples_per_sec = fread (fid, 1, "uint32", 0, BYTEORDER);
+
+ ## Bits per sample.
+ fseek (fid, 6, "cof");
+ bits_per_sample = fread (fid, 1, "uint16", 0, BYTEORDER);
+
+ ### Read data chunk.
+ fseek (fid, data_pos, "bof");
+
+ ## Determine sample data type.
+ if (format_tag == FORMAT_PCM)
+ switch (bits_per_sample)
+ case 8
+ format = "uint8";
+ case 16
+ format = "int16";
+ case 24
+ format = "uint8";
+ case 32
+ format = "int32";
+ otherwise
+ error ("wavread: %d bits sample resolution is not supported with PCM",
+ bits_per_sample);
+ endswitch
+ else
+ switch (bits_per_sample)
+ case 32
+ format = "float32";
+ case 64
+ format = "float64";
+ otherwise
+ error ("wavread: %d bits sample resolution is not supported with IEEE float",
+ bits_per_sample);
+ endswitch
+ endif
+
+ ## Parse arguments.
+ if (nargin == 1)
+ length = idivide (8 * data_size, bits_per_sample);
+ else
+ nparams = numel (param);
+ if (nparams == 1)
+ ## Number of samples is given.
+ length = param * channels;
+ elseif (nparams == 2)
+ ## Sample range is given.
+ if (fseek (fid, (param(1)-1) * channels * (bits_per_sample/8), "cof") < 0)
+ warning ("wavread: seeking failed");
+ endif
+ length = (param(2)-param(1)+1) * channels;
+ elseif (nparams == 4 && char (param) == "size")
+ ## Size of the file is requested.
+ tmp = idivide (8 * data_size, channels * bits_per_sample);
+ y = [tmp, channels];
+ return;
+ else
+ error ("wavread: invalid PARAM argument");
+ endif
+ endif
+
+ ## Read samples and close file.
+ if (bits_per_sample == 24)
+ length *= 3;
+ endif
+
+ [yi, n] = fread (fid, length, format, 0, BYTEORDER);
+
+ unwind_protect_cleanup
+
+ if (fid >= 0)
+ fclose (fid);
+ endif
+
+ end_unwind_protect
+
+ ## Check data.
+ if (mod (numel (yi), channels) != 0)
+ error ("wavread: data in %s doesn't match the number of channels",
+ filename);
+ endif
+
+ if (bits_per_sample == 24)
+ yi = reshape (yi, 3, rows(yi)/3)';
+ yi(yi(:,3) >= 128, 3) -= 256;
+ yi = yi * [1; 256; 65536];
+ endif
+
+ if (format_tag == FORMAT_PCM)
+ ## Normalize samples.
+ switch (bits_per_sample)
+ case 8
+ yi = (yi - 128)/128;
+ case 16
+ yi /= 32768;
+ case 24
+ yi /= 8388608;
+ case 32
+ yi /= 2147483648;
+ endswitch
+ endif
+
+ ## Deinterleave.
+ nr = numel (yi) / channels;
+ y = reshape (yi, channels, nr)';
+
+endfunction
+
+## Given a chunk_id, scan through chunks from the current file position
+## though at most size bytes. Return the size of the found chunk, with
+## file position pointing to the start of the chunk data. Return -1 for
+## size if chunk is not found.
+
+function chunk_size = find_chunk (fid, chunk_id, size)
+ id = "";
+ offset = 8;
+ chunk_size = 0;
+
+ while (! strcmp (id, chunk_id) && (offset < size))
+ fseek (fid, chunk_size, "cof");
+ id = char (fread (fid, 4))';
+ chunk_size = fread (fid, 1, "uint32", 0, "ieee-le");
+ ## Chunk sizes must be word-aligned (2 byte)
+ chunk_size += rem (chunk_size, 2);
+ offset = offset + 8 + chunk_size;
+ endwhile
+ if (! strcmp (id, chunk_id))
+ chunk_size = -1;
+ endif
+endfunction
+
+## Mark file as being tested. Tests for wavread/wavwrite pair are in
+## wavwrite.m
+%!assert(1)