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1 ## Copyright (C) 1996, 1997 John W. Eaton |
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2 ## |
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3 ## This file is part of Octave. |
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4 ## |
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5 ## Octave is free software; you can redistribute it and/or modify it |
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6 ## under the terms of the GNU General Public License as published by |
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7 ## the Free Software Foundation; either version 2, or (at your option) |
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8 ## any later version. |
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9 ## |
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10 ## Octave is distributed in the hope that it will be useful, but |
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11 ## WITHOUT ANY WARRANTY; without even the implied warranty of |
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12 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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13 ## General Public License for more details. |
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14 ## |
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15 ## You should have received a copy of the GNU General Public License |
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16 ## along with Octave; see the file COPYING. If not, write to the Free |
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17 ## Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
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18 ## 02110-1301, USA. |
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19 |
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20 ## -*- texinfo -*- |
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21 ## @deftypefn {Function File} {} loadaudio (@var{name}, @var{ext}, @var{bps}) |
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22 ## Loads audio data from the file @file{@var{name}.@var{ext}} into the |
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23 ## vector @var{x}. |
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24 ## |
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25 ## The extension @var{ext} determines how the data in the audio file is |
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26 ## interpreted; the extensions @file{lin} (default) and @file{raw} |
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27 ## correspond to linear, the extensions @file{au}, @file{mu}, or @file{snd} |
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28 ## to mu-law encoding. |
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29 ## |
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30 ## The argument @var{bps} can be either 8 (default) or 16, and specifies |
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31 ## the number of bits per sample used in the audio file. |
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32 ## @end deftypefn |
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33 ## |
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34 ## @seealso{lin2mu, mu2lin, saveaudio, playaudio, setaudio, and record} |
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35 |
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36 ## Author: AW <Andreas.Weingessel@ci.tuwien.ac.at> |
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37 ## Created: 10 April 1994 |
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38 ## Adapted-By: jwe |
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39 |
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40 function X = loadaudio (name, ext, bit) |
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41 |
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42 if (nargin == 0 || nargin > 3) |
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43 usage ("loadaudio (name, ext, bit)"); |
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44 endif |
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45 |
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46 if (nargin == 1) |
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47 ext = "lin"; |
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48 endif |
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49 |
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50 if (nargin < 3) |
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51 bit = 8; |
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52 elseif (bit != 8 && bit != 16) |
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53 error ("loadaudio: bit must be either 8 or 16"); |
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54 endif |
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55 |
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56 name = [name, ".", ext]; |
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57 num = fopen (name, "rb"); |
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58 |
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59 if (strcmp (ext, "lin") || strcmp (ext, "raw") || strcmp (ext, "pcm")) |
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60 if (bit == 8) |
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61 [Y, c] = fread (num, inf, "uchar"); |
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62 X = Y - 127; |
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63 else |
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64 [X, c] = fread (num, inf, "short"); |
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65 endif |
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66 elseif (strcmp (ext, "mu") || strcmp (ext, "au") |
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67 || strcmp (ext, "snd") || strcmp(ext, "ul")) |
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68 [Y, c] = fread (num, inf, "uchar"); |
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69 ## remove file header |
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70 m = max (find (Y(1:64) == 0)); |
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71 if (! isempty (m)) |
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72 Y(1:m) = []; |
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73 endif |
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74 X = mu2lin (Y, bit); |
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75 else |
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76 fclose (num); |
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77 error ("loadaudio does not support given extension"); |
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78 endif |
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79 |
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80 fclose (num); |
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81 |
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82 endfunction |
