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loadaudio.m
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1998-11-10
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## Copyright (C) 1996, 1997 John W. Eaton
##
## 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 2, 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, write to the Free
## Software Foundation, 59 Temple Place - Suite 330, Boston, MA
## 02111-1307, USA.
## usage: X = loadaudio (name [, ext [, bit]])
##
## Loads audio data from the file "name.ext" into the data vector X.
## Default value for the "ext" argument, which has to be written
## without the initial ".", is "lin".
## Currently, the following audio formats are supported:
## *) mu-law encoding with extension "mu", "au", or "snd"
## *) linear encoding with extension "lin", "pcm", or "raw"
##
## The `bit' argument can be either 8 (default) or 16.
## Depending on the value of bit, linearly encoded files are
## interpreted as being in 8 and 16 bit format, respectively, and
## mu-law encoded files are transformed to 8 and 16-bit linear
## format, respectively.
## Author: AW <Andreas.Weingessel@ci.tuwien.ac.at>
## Created: 10 April 1994
## Adapted-By: jwe
function X = loadaudio (name, ext, bit)
if (nargin == 0 || nargin > 3)
usage ("loadaudio (name [, ext [, bit]])");
endif
if (nargin == 1)
ext = "lin";
endif
if (nargin < 3)
bit = 8;
elseif (bit != 8 && bit != 16)
error ("loadaudio: bit must be either 8 or 16");
endif
name = [name, ".", ext];
num = fopen (name, "rb");
if (strcmp (ext, "lin") || strcmp (ext, "raw") || strcmp (ext, "pcm"))
if (bit == 8)
[Y, c] = fread (num, inf, "uchar");
X = Y - 127;
else
[X, c] = fread (num, inf, "short");
endif
elseif (strcmp (ext, "mu") || strcmp (ext, "au") || strcmp (ext, "snd"))
[Y, c] = fread (num, inf, "uchar");
## remove file header
m = max (find (Y(1:64) == 0));
if (! isempty (m))
Y(1:m) = [];
endif
X = mu2lin (Y, bit);
else
fclose (num);
error ("loadaudio does not support given extension");
endif
fclose (num);
endfunction