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1 ### Copyright (C) 1996 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, 59 Temple Place - Suite 330, Boston, MA |
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18 ### 02111-1307, USA. |
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19 |
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20 ## usage: X = loadaudio (name [, ext [, bit]]) |
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21 ## |
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22 ## Loads audio data from the file "name.ext" into the data vector X. |
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23 ## Default value for the "ext" argument, which has to be written |
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24 ## without the initial ".", is "lin". |
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25 ## Currently, the following audio formats are supported: |
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26 ## *) mu-law encoding with extension "mu", "au" or "snd" |
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27 ## *) linear encoding with extension "lin" or "raw" |
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28 ## |
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29 ## The `bit' argument can be either 8 (default) or 16. |
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30 ## Depending on the value of bit, linearly encoded files are |
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31 ## interpreted as being in 8 and 16 bit format, respectively, and |
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32 ## mu-law encoded files are transformed to 8 and 16-bit linear |
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33 ## format, respectively. |
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34 |
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35 function X = loadaudio (name, ext, bit) |
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36 |
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37 ## Written by AW (Andreas.Weingessel@ci.tuwien.ac.at) on Apr 10, 1994 |
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38 ## Last modified by AW on Oct 29, 1994 |
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39 |
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40 if (nargin == 0 || nargin > 3) |
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41 usage ("loadaudio (name [, ext [, bit]])"); |
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42 endif |
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43 |
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44 if (nargin == 1) |
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45 ext = "lin"; |
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46 endif |
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47 |
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48 if (nargin < 3) |
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49 bit = 8; |
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50 elseif (bit != 8 && bit != 16) |
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51 error ("loadaudio: bit must be either 8 or 16"); |
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52 endif |
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53 |
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54 name = [name, ".", ext]; |
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55 num = fopen (name, "r"); |
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56 |
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57 if (strcmp (ext, "lin") || strcmp (ext, "raw")) |
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58 if (bit == 8) |
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59 [Y, c] = fread (num, inf, "uchar"); |
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60 X = Y - 127; |
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61 else |
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62 [X, c] = fread (num, inf, "short"); |
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63 endif |
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64 elseif (strcmp (ext, "mu") || strcmp (ext, "au") || strcmp (ext, "snd")) |
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65 [Y, c] = fread (num, inf, "uchar"); |
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66 ## remove file header |
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67 m = max (find (Y(1:64) == 0)); |
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68 if (! isempty (m)) |
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69 Y(1:m) = []; |
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70 endif |
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71 X = mu2lin (Y, bit); |
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72 else |
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73 fclose (num); |
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74 error ("loadaudio does not support given extension"); |
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75 endif |
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76 |
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77 fclose (num); |
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78 |
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79 endfunction |
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80 |
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81 |
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82 |
