Add a useful package (from Source forge) for octave

[CreaPhase.git] / octave_packages / audio-1.1.4 / soundsc.m

diff --git a/octave_packages/audio-1.1.4/soundsc.m b/octave_packages/audio-1.1.4/soundsc.m
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+## Copyright (C) 2000 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: soundsc(x, fs, limit) or soundsc(x, fs, [ lo, hi ])
+##
+## soundsc(x)
+##    Scale the signal so that [min(x), max(x)] -> [-1, 1], then 
+##    play it through the speakers at 8000 Hz sampling rate.  The
+##    signal has one column per channel.  
+##
+## soundsc(x,fs)
+##    Scale the signal and play it at sampling rate fs.
+##
+## soundsc(x, fs, limit)
+##    Scale the signal so that [-|limit|, |limit|] -> [-1, 1], then
+##    play it at sampling rate fs.  If fs is empty, then the default
+##    8000 Hz sampling rate is used.
+##
+## soundsc(x, fs, [ lo, hi ])
+##    Scale the signal so that [lo, hi] -> [-1, 1], then play it
+##    at sampling rate fs.  If fs is empty, then the default 8000 Hz
+##    sampling rate is used.
+##
+## y=soundsc(...)
+##    return the scaled waveform rather than play it.
+##
+## See sound for more information.
+
+function data_r = soundsc(data, rate, range)
+
+  if nargin < 1 || nargin > 3, usage("soundsc(x, fs, [lo, hi])") endif
+  if nargin < 2, rate = []; endif
+  if nargin < 3, range = [min(data(:)), max(data(:))]; endif
+  if isscalar(range), range = [-abs(range), abs(range)]; endif
+  
+  data=(data - mean(range))/((range(2)-range(1))/2);
+  if nargout > 0
+    data_r = data;
+  else
+    sound(data, rate);
+  endif
+endfunction
+
+
+%!demo
+%! [x, fs] = auload(file_in_loadpath("sample.wav"));
+%! soundsc(x,fs);
+
+%!shared y
+%! [x, fs] = auload(file_in_loadpath("sample.wav"));
+%! y=soundsc(x);
+%!assert (min(y(:)), -1, eps)
+%!assert (max(y(:)), 1, eps)