--- /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/>.
+
+## usage: ausave('filename.ext', x, fs, format)
+##
+## Writes an audio file with the appropriate header. The extension on
+## the filename determines the layout of the header. Currently supports
+## .wav and .au layouts. Data is a matrix of audio samples in the
+## range [-1,1] (inclusive), one row per time step, one column per
+## channel. Fs defaults to 8000 Hz. Format is one of ulaw, alaw, char,
+## short, long, float, double
+##
+## Note that translating the symmetric range [-1,1] into the asymmetric
+## range [-2^n,2^n-1] requires a DC offset of -2/2^n. The inverse
+## process used by auload 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.
+
+
+## 2001-10-23 Paul Kienzle
+## * force lin2mu to use [-1:1] regardless of its default
+## 2001-12-11 Paul Kienzle <pkienzle@users.sf.net>
+## * use closed interval [-1,1] rather than open interval [-1,1) internally
+## * rescale data if it exceeds the range
+
+function ausave(path, data, rate, sampleformat)
+
+ if nargin < 2 || nargin>4
+ usage("ausave('filename.ext', x [, fs, sampleformat])");
+ end
+ if nargin < 3, rate = 8000; end
+ if nargin < 4, sampleformat = 'short'; end
+
+ ext = rindex(path, '.');
+ if (ext == 0)
+ usage("ausave('filename.ext', x [, fs, sampleformat])");
+ end
+ ext = tolower(substr(path, ext+1, length(path)-ext));
+
+ # determine data size and orientation
+ [samples, channels] = size(data);
+ if (samples < channels)
+ data = data.';
+ [samples, channels] = size(data);
+ endif
+
+ ## 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.
+
+ if (strcmp(sampleformat,'uchar'))
+ formatid = 1;
+ samplesize = 1;
+ elseif (strcmp(sampleformat,'short'))
+ formatid = 1;
+ samplesize = 2;
+ elseif (strcmp(sampleformat, 'long'))
+ formatid = 1;
+ samplesize = 4;
+ elseif (strcmp(sampleformat, 'float'))
+ formatid = 3;
+ samplesize = 4;
+ elseif (strcmp(sampleformat, 'double'))
+ formatid = 3;
+ samplesize = 8;
+ elseif (strcmp(sampleformat, 'alaw'))
+ formatid = 6;
+ samplesize = 1;
+ elseif (strcmp(sampleformat, 'ulaw'))
+ formatid = 7;
+ samplesize = 1;
+ else
+ error("%s is invalid format for .wav file\n", sampleformat);
+ end
+ datasize = channels*samplesize*samples;
+
+ [file, msg] = fopen(path, 'wb');
+ if (file == -1)
+ error("%s: %s", msg, path);
+ end
+
+ ## write the magic header
+ arch = 'ieee-le';
+ fwrite(file, toascii('RIFF'), 'char');
+ fwrite(file, datasize+36, 'long', 0, arch);
+ fwrite(file, toascii('WAVE'), 'char');
+
+ ## write the "fmt " section
+ fwrite(file, toascii('fmt '), 'char');
+ fwrite(file, 16, 'long', 0, arch);
+ fwrite(file, formatid, 'short', 0, arch);
+ fwrite(file, channels, 'short', 0, arch);
+ fwrite(file, rate, 'long', 0, arch);
+ fwrite(file, rate*channels*samplesize, 'long', 0, arch);
+ fwrite(file, channels*samplesize, 'short', 0, arch);
+ fwrite(file, samplesize*8, 'short', 0, arch);
+
+ ## write the "data" section
+ fwrite(file, toascii('data'), 'char');
+ fwrite(file, datasize, 'long', 0, arch);
+
+ ## 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.
+
+ if (strcmp(sampleformat, 'ulaw'))
+ formatid = 1;
+ samplesize = 1;
+ elseif (strcmp(sampleformat,'uchar'))
+ formatid = 2;
+ samplesize = 1;
+ elseif (strcmp(sampleformat,'short'))
+ formatid = 3;
+ samplesize = 2;
+ elseif (strcmp(sampleformat, 'long'))
+ formatid = 5;
+ samplesize = 4;
+ elseif (strcmp(sampleformat, 'float'))
+ formatid = 6;
+ samplesize = 4;
+ elseif (strcmp(sampleformat, 'double'))
+ formatid = 7;
+ samplesize = 8;
+ else
+ error("%s is invalid format for .au file\n", sampleformat);
+ end
+ datasize = channels*samplesize*samples;
+
+ [file, msg] = fopen(path, 'wb');
+ if (file == -1)
+ error("%s: %s", msg, path);
+ end
+
+ arch = 'ieee-be';
+ fwrite(file, toascii('.snd'), 'char');
+ fwrite(file, 24, 'long', 0, arch);
+ fwrite(file, datasize, 'long', 0, arch);
+ fwrite(file, formatid, 'long', 0, arch);
+ fwrite(file, rate, 'long', 0, arch);
+ fwrite(file, channels, 'long', 0, arch);
+
+ ## 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
+
+ if (strcmp(sampleformat,'uchar'))
+ samplesize = 1;
+ elseif (strcmp(sampleformat,'short'))
+ samplesize = 2;
+ elseif (strcmp(sampleformat, 'long'))
+ samplesize = 4;
+ else
+ error("%s is invalid format for .aiff file\n", sampleformat);
+ end
+ datasize = channels*samplesize*samples;
+
+ [file, msg] = fopen(path, 'wb');
+ if (file == -1)
+ error("%s: %s", msg, path);
+ end
+
+ ## write the magic header
+ arch = 'ieee-be';
+ fwrite(file, toascii('FORM'), 'char');
+ fwrite(file, datasize+46, 'long', 0, arch);
+ fwrite(file, toascii('AIFF'), 'char');
+
+ ## write the "COMM" section
+ fwrite(file, toascii('COMM'), 'char');
+ fwrite(file, 18, 'long', 0, arch);
+ fwrite(file, channels, 'short', 0, arch);
+ fwrite(file, samples, 'long', 0, arch);
+ fwrite(file, 8*samplesize, 'short', 0, arch);
+ fwrite(file, 16414, 'ushort', 0, arch); % sample rate exponent
+ fwrite(file, [rate, 0], 'ulong', 0, arch); % sample rate mantissa
+
+ ## write the "SSND" section
+ fwrite(file, toascii('SSND'), 'char');
+ fwrite(file, datasize+8, 'long', 0, arch); # section length
+ fwrite(file, 0, 'long', 0, arch); # block size
+ fwrite(file, 0, 'long', 0, arch); # offset
+
+ ## file extension unknown
+ else
+ error('ausave(filename.ext,...) understands .wav .au and .aiff only');
+ end
+
+ ## Make sure the data fits into the sample range
+ scale = max(abs(data(:)));
+ if (scale > 1.0)
+ warning("ausave: audio data exceeds range [-1,1] --- rescaling");
+ data = data / scale;
+ endif
+
+ ## convert samples from range [-1, 1]
+ if strcmp(sampleformat, 'alaw')
+ error("FIXME: ausave needs linear to alaw conversion\n");
+ precision = 'uchar';
+ elseif strcmp(sampleformat, 'ulaw')
+ data = lin2mu(data, 0);
+ precision = 'uchar'
+ elseif strcmp(sampleformat, 'uchar')
+ data = round((data+1)*127.5);
+ precision = 'uchar';
+ elseif strcmp(sampleformat, 'short')
+ data = round(data*32767.5 - 0.5);
+ precision = 'short';
+ elseif strcmp(sampleformat, 'long')
+ data = round(data*(2^31-0.5) - 0.5);
+ precision = 'long';
+ else
+ precision = sampleformat;
+ end
+ fwrite(file, data', precision, 0, arch);
+ fclose(file);
+
+endfunction
git://git.creatis.insa-lyon.fr / CreaPhase.git / blobdiff