--- /dev/null
+## Copyright (C) 1999 Paul Kienzle
+##
+## This program 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 2 of the License, or
+## (at your option) any later version.
+##
+## This program 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 this program; If not, see <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {[@var{x},@var{fs},@var{sampleformat}] =} auload (@var{filename})
+##
+## Reads an audio waveform from a file given by the string @var{filename}.
+## Returns the audio samples in data, one column per channel, one row per
+## time slice. Also returns the sample rate and stored format (one of ulaw,
+## alaw, char, int16, int24, int32, float, double). The sample value will be
+## normalized to the range [-1,1] regardless of the stored format.
+##
+## @example
+## [x, fs] = auload(file_in_loadpath("sample.wav"));
+## auplot(x,fs);
+## @end example
+##
+## Note that translating the asymmetric range [-2^n,2^n-1] into the
+## symmetric range [-1,1] requires a DC offset of 2/2^n. The inverse
+## process used by ausave requires a DC offset of -2/2^n, so loading and
+## saving a file will not change the contents. Other applications may
+## compensate for the asymmetry in a different way (including previous
+## versions of auload/ausave) so you may find small differences in
+## calculated DC offsets for the same file.
+## @end deftypefn
+
+## 2001-09-04 Paul Kienzle <pkienzle@users.sf.net>
+## * skip unknown blocks in WAVE format.
+## 2001-09-05 Paul Kienzle <pkienzle@users.sf.net>
+## * remove debugging stuff from AIFF format.
+## * use data length if it is given rather than reading to the end of file.
+## 2001-12-11 Paul Kienzle <pkienzle@users.sf.net>
+## * use closed interval [-1,1] rather than open interval [-1,1) internally
+
+function [data, rate, sampleformat] = auload(path)
+
+ if (nargin != 1)
+ usage("[x, fs, sampleformat] = auload('filename.ext')");
+ end
+ data = []; # if error then read nothing
+ rate = 8000;
+ sampleformat = 'ulaw';
+ ext = rindex(path, '.');
+ if (ext == 0)
+ usage('x = auload(filename.ext)');
+ end
+ ext = tolower(substr(path, ext+1, length(path)-ext));
+
+ [file, msg] = fopen(path, 'rb');
+ if (file == -1)
+ error([ msg, ": ", path]);
+ end
+
+ msg = sprintf('Invalid audio header: %s', path);
+ ## Microsoft .wav format
+ if strcmp(ext,'wav')
+
+ ## Header format obtained from sox/wav.c
+ ## April 15, 1992
+ ## Copyright 1992 Rick Richardson
+ ## Copyright 1991 Lance Norskog And Sundry Contributors
+ ## This source code is freely redistributable and may be used for
+ ## any purpose. This copyright notice must be maintained.
+ ## Lance Norskog And Sundry Contributors are not responsible for
+ ## the consequences of using this software.
+
+ ## check the file magic header bytes
+ arch = 'ieee-le';
+ str = char(fread(file, 4, 'char')');
+ if !strcmp(str, 'RIFF')
+ error(msg);
+ end
+ len = fread(file, 1, 'int32', 0, arch);
+ str = char(fread(file, 4, 'char')');
+ if !strcmp(str, 'WAVE')
+ error(msg);
+ end
+
+ ## skip to the "fmt " section, ignoring everything else
+ while (1)
+ if feof(file)
+ error(msg);
+ end
+ str = char(fread(file, 4, 'char')');
+ len = fread(file, 1, 'int32', 0, arch);
+ if strcmp(str, 'fmt ')
+ break;
+ end
+ fseek(file, len, SEEK_CUR);
+ end
+
+ ## read the "fmt " section
+ formatid = fread(file, 1, 'int16', 0, arch);
+ channels = fread(file, 1, 'int16', 0, arch);
+ rate = fread(file, 1, 'int32', 0, arch);
+ fread(file, 1, 'int32', 0, arch);
+ fread(file, 1, 'int16', 0, arch);
+ bits = fread(file, 1, 'int16', 0, arch);
+ fseek(file, len-16, SEEK_CUR);
+
+ ## skip to the "data" section, ignoring everything else
+ while (1)
+ if feof(file)
+ error(msg);
+ end
+ str = char(fread(file, 4, 'char')');
+ len = fread(file, 1, 'int32', 0, arch);
+ if strcmp(str, 'data')
+ break;
+ end
+ fseek(file, len, SEEK_CUR);
+ end
+
+ if (formatid == 1)
+ if bits == 8
+ sampleformat = 'uchar';
+ precision = 'uchar';
+ samples = len;
+ elseif bits == 16
+ sampleformat = 'int16';
+ precision = 'int16';
+ samples = len/2;
+ elseif bits == 24
+ sampleformat = 'int24';
+ precision = 'int24';
+ samples = len/3;
+ elseif bits == 32
+ sampleformat = 'int32';
+ precision = 'int32';
+ samples = len/4;
+ else
+ error(msg);
+ endif
+ elseif (formatid == 3)
+ if bits == 32
+ sampleformat = 'float';
+ precision = 'float';
+ samples = len/4;
+ elseif bits == 64
+ sampleformat = 'double';
+ precision = 'double';
+ samples = len/8;
+ else
+ error(msg);
+ endif
+ elseif (formatid == 6 && bits == 8)
+ sampleformat = 'alaw';
+ precision = 'uchar';
+ samples = len;
+ elseif (formatid == 7 && bits == 8)
+ sampleformat = 'ulaw';
+ precision = 'uchar';
+ samples = len;
+ else
+ error(msg);
+ return;
+ endif
+
+ ## Sun .au format
+ elseif strcmp(ext, 'au')
+
+ ## Header format obtained from sox/au.c
+ ## September 25, 1991
+ ## Copyright 1991 Guido van Rossum And Sundry Contributors
+ ## This source code is freely redistributable and may be used for
+ ## any purpose. This copyright notice must be maintained.
+ ## Guido van Rossum And Sundry Contributors are not responsible for
+ ## the consequences of using this software.
+
+ str = char(fread(file, 4, 'char')');
+ magic=' ds.';
+ invmagic='ds. ';
+ magic(1) = char(0);
+ invmagic(1) = char(0);
+ if strcmp(str, 'dns.') || strcmp(str, magic)
+ arch = 'ieee-le';
+ elseif strcmp(str, '.snd') || strcmp(str, invmagic)
+ arch = 'ieee-be';
+ else
+ error(msg);
+ end
+ header = fread(file, 1, 'int32', 0, 'ieee-be');
+ len = fread(file, 1, 'int32', 0, 'ieee-be');
+ formatid = fread(file, 1, 'int32', 0, 'ieee-be');
+ rate = fread(file, 1, 'int32', 0, 'ieee-be');
+ channels = fread(file, 1, 'int32', 0, 'ieee-be');
+ fseek(file, header-24, SEEK_CUR); % skip file comment
+
+ ## interpret the sample format
+ if formatid == 1
+ sampleformat = 'ulaw';
+ precision = 'uchar';
+ bits = 12;
+ samples = len;
+ elseif formatid == 2
+ sampleformat = 'uchar';
+ precision = 'uchar';
+ bits = 8;
+ samples = len;
+ elseif formatid == 3
+ sampleformat = 'int16';
+ precision = 'int16';
+ bits = 16;
+ samples = len/2;
+ elseif formatid == 5
+ sampleformat = 'int32';
+ precision = 'int32';
+ bits = 32;
+ samples = len/4;
+ elseif formatid == 6
+ sampleformat = 'float';
+ precision = 'float';
+ bits = 32;
+ samples = len/4;
+ elseif formatid == 7
+ sampleformat = 'double';
+ precision = 'double';
+ bits = 64;
+ samples = len/8;
+ else
+ error(msg);
+ end
+
+ ## Apple/SGI .aiff format
+ elseif strcmp(ext,'aiff') || strcmp(ext,'aif')
+
+ ## Header format obtained from sox/aiff.c
+ ## September 25, 1991
+ ## Copyright 1991 Guido van Rossum And Sundry Contributors
+ ## This source code is freely redistributable and may be used for
+ ## any purpose. This copyright notice must be maintained.
+ ## Guido van Rossum And Sundry Contributors are not responsible for
+ ## the consequences of using this software.
+ ##
+ ## IEEE 80-bit float I/O taken from
+ ## ftp://ftp.mathworks.com/pub/contrib/signal/osprey.tar
+ ## David K. Mellinger
+ ## dave@mbari.org
+ ## +1-831-775-1805
+ ## fax -1620
+ ## Monterey Bay Aquarium Research Institute
+ ## 7700 Sandholdt Road
+
+ ## check the file magic header bytes
+ arch = 'ieee-be';
+ str = char(fread(file, 4, 'char')');
+ if !strcmp(str, 'FORM')
+ error(msg);
+ end
+ len = fread(file, 1, 'int32', 0, arch);
+ str = char(fread(file, 4, 'char')');
+ if !strcmp(str, 'AIFF')
+ error(msg);
+ end
+
+ ## skip to the "COMM" section, ignoring everything else
+ while (1)
+ if feof(file)
+ error(msg);
+ end
+ str = char(fread(file, 4, 'char')');
+ len = fread(file, 1, 'int32', 0, arch);
+ if strcmp(str, 'COMM')
+ break;
+ end
+ fseek(file, len, SEEK_CUR);
+ end
+
+ ## read the "COMM" section
+ channels = fread(file, 1, 'int16', 0, arch);
+ frames = fread(file, 1, 'int32', 0, arch);
+ bits = fread(file, 1, 'int16', 0, arch);
+ exp = fread(file, 1, 'uint16', 0, arch); % read a 10-byte float
+ mant = fread(file, 2, 'uint32', 0, arch);
+ mant = mant(1) / 2^31 + mant(2) / 2^63;
+ if (exp >= 32768), mant = -mant; exp = exp - 32768; end
+ exp = exp - 16383;
+ rate = mant * 2^exp;
+ fseek(file, len-18, SEEK_CUR);
+
+ ## skip to the "SSND" section, ignoring everything else
+ while (1)
+ if feof(file)
+ error(msg);
+ end
+ str = char(fread(file, 4, 'char')');
+ len = fread(file, 1, 'int32', 0, arch);
+ if strcmp(str, 'SSND')
+ break;
+ end
+ fseek(file, len, SEEK_CUR);
+ end
+ offset = fread(file, 1, 'int32', 0, arch);
+ fread(file, 1, 'int32', 0, arch);
+ fseek(file, offset, SEEK_CUR);
+
+ if bits == 8
+ precision = 'uchar';
+ sampleformat = 'uchar';
+ samples = len - 8;
+ elseif bits == 16
+ precision = 'int16';
+ sampleformat = 'int16';
+ samples = (len - 8)/2;
+ elseif bits == 32
+ precision = 'int32';
+ sampleformat = 'int32';
+ samples = (len - 8)/4;
+ else
+ error(msg);
+ endif
+
+ ## file extension unknown
+ else
+ error('auload(filename.ext) understands .wav .au and .aiff only');
+ end
+
+ ## suck in all the samples
+ if (samples <= 0) samples = Inf; end
+ if (precision == 'int24')
+ data = fread(file, 3*samples, 'uint8', 0, arch);
+ if (arch == 'ieee-le')
+ data = data(1:3:end) + data(2:3:end) * 2^8 + cast(typecast(cast(data(3:3:end), 'uint8'), 'int8'), 'double') * 2^16;
+ else
+ data = data(3:3:end) + data(2:3:end) * 2^8 + cast(typecast(cast(data(1:3:end), 'uint8'), 'int8'), 'double') * 2^16;
+ endif
+ else
+ data = fread(file, samples, precision, 0, arch);
+ endif
+ fclose(file);
+
+ ## convert samples into range [-1, 1)
+ if strcmp(sampleformat, 'alaw')
+ alaw = [ \
+ -5504, -5248, -6016, -5760, -4480, -4224, -4992, -4736, \
+ -7552, -7296, -8064, -7808, -6528, -6272, -7040, -6784, \
+ -2752, -2624, -3008, -2880, -2240, -2112, -2496, -2368, \
+ -3776, -3648, -4032, -3904, -3264, -3136, -3520, -3392, \
+ -22016, -20992, -24064, -23040, -17920, -16896, -19968, -18944, \
+ -30208, -29184, -32256, -31232, -26112, -25088, -28160, -27136, \
+ -11008, -10496, -12032, -11520, -8960, -8448, -9984, -9472, \
+ -15104, -14592, -16128, -15616, -13056, -12544, -14080, -13568, \
+ -344, -328, -376, -360, -280, -264, -312, -296, \
+ -472, -456, -504, -488, -408, -392, -440, -424, \
+ -88, -72, -120, -104, -24, -8, -56, -40, \
+ -216, -200, -248, -232, -152, -136, -184, -168, \
+ -1376, -1312, -1504, -1440, -1120, -1056, -1248, -1184, \
+ -1888, -1824, -2016, -1952, -1632, -1568, -1760, -1696, \
+ -688, -656, -752, -720, -560, -528, -624, -592, \
+ -944, -912, -1008, -976, -816, -784, -880, -848 ];
+ alaw = ([ alaw,-alaw]+0.5)/32767.5;
+ data = alaw(data+1);
+ elseif strcmp(sampleformat, 'ulaw')
+ data = mu2lin(data, 0);
+ elseif strcmp(sampleformat, 'uchar')
+ ## [ 0, 255 ] -> [ -1, 1 ]
+ data = data/127.5 - 1;
+ elseif strcmp(sampleformat, 'int16')
+ ## [ -32768, 32767 ] -> [ -1, 1 ]
+ data = (data+0.5)/32767.5;
+ elseif strcmp(sampleformat, 'int32')
+ ## [ -2^31, 2^31-1 ] -> [ -1, 1 ]
+ data = (data+0.5)/(2^31-0.5);
+ end
+ data = reshape(data, channels, length(data)/channels)';
+
+endfunction
+
+%!demo
+%! [x, fs] = auload(file_in_loadpath("sample.wav"));
+%! auplot(x,fs);
git://git.creatis.insa-lyon.fr / CreaPhase.git / blobdiff