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1 ## Copyright (C) 2005 Michael Zeising |
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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} {} wavwrite(@var{filename}, @var{y}) |
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22 ## Write @var{y} to the canonical RIFF/WAVE sound file @var{filename}. A sample |
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23 ## rate of 8000 Hz and 16-bit samples are assumed. Each column of the data |
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24 ## represents a separate channel. |
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25 ## |
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26 ## @deftypefnx {Function File} {} wavwrite(@var{filename}, @var{y}, @var{fs}) |
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27 ## Set the sample rate to @var{fs} Hz. |
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28 ## |
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29 ## @deftypefnx {Function File} {} wavwrite(@var{filename}, @var{y}, @var{fs}, @var{bits}) |
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30 ## Set the sample rate to @var{fs} Hz and resolution to @var{bits} bits. |
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31 ## |
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32 ## @end deftypefn |
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33 ## |
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34 ## @seealso{wavread} |
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35 |
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36 ## Author: Michael Zeising <michael.zeising@stud.uni-erlangen.de> |
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37 ## Created: 06 December 2005 |
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38 |
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39 function wavwrite (filename, y, samplesPerSec, bitsPerSample) |
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40 BYTEORDER = "ieee-le"; |
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41 |
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42 # parse arguments |
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43 if (exist ("samplesPerSec","var") < 1) |
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44 warning ("wavwrite: sample rate set to 8000 Hz") |
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45 samplesPerSec = 8000; |
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46 endif |
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47 if (exist ("bitsPerSample","var") < 1) |
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48 warning ("wavwrite: sample resolution set to 16-bit") |
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49 bitsPerSample = 16; |
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50 endif |
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51 |
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52 # determine sample format |
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53 switch bitsPerSample |
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54 case 8 |
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55 format = "int8"; |
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56 case 16 |
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57 format = "int16"; |
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58 case 32 |
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59 format = "int32"; |
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60 otherwise |
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61 fclose (fid); |
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62 error ("wavread: sample resolution not supported"); |
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63 endswitch |
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64 |
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65 # calculate filesize |
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66 channels = size(y)(2); |
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67 n = size(y)(1); |
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68 |
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69 ckSize = n*channels*(bitsPerSample/8); # size of data chunk |
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70 |
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71 # open file for writing binary |
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72 [fid, msg] = fopen (filename, "wb"); |
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73 if (fid < 0) |
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74 error ("wavwrite: %s", msg) |
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75 endif |
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76 |
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77 # write RIFF/WAVE header |
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78 c = 0; |
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79 c += fwrite (fid, "RIFF", "uchar"); |
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80 c += fwrite (fid, ckSize + 36, "ulong", 0, BYTEORDER); # file size - 8 |
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81 c += fwrite (fid, "WAVEfmt ", "uchar"); |
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82 c += fwrite (fid, 16, "ulong", 0, BYTEORDER); # size of fmt chunk |
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83 c += fwrite (fid, 0x0001, "short", 0, BYTEORDER); # sample format code (PCM) |
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84 c += fwrite (fid, channels, "short", 0, BYTEORDER); # channels |
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85 c += fwrite (fid, samplesPerSec, "ulong", 0, BYTEORDER); # sample rate |
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86 c += fwrite (fid, samplesPerSec*channels*bitsPerSample/8, "ulong", 0, BYTEORDER); # bytes per second |
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87 c += fwrite (fid, channels*bitsPerSample/8, "short", 0, BYTEORDER); # block align |
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88 c += fwrite (fid, bitsPerSample, "short", 0, BYTEORDER); # bits/sample |
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89 c += fwrite (fid, "data", "uchar"); |
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90 c += fwrite (fid, ckSize, "ulong", 0, BYTEORDER); # size of data chunk |
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91 |
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92 if (c < 25) |
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93 fclose (fid); |
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94 error ("wavread: writing to file failed") |
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95 endif |
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96 |
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97 # scale samples |
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98 switch bitsPerSample |
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99 case 8 |
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100 y = floor (y*127 + 127); |
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101 case {16,32} |
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102 y = floor (y*((2 ** bitsPerSample) / 2 - 1)); |
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103 endswitch |
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104 |
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105 # interleave samples |
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106 l = n*channels; |
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107 for (i = 1:channels) |
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108 yi(i:channels:l) = y(:,i); |
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109 endfor |
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110 |
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111 # write to file |
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112 c = fwrite (fid, yi, format, 0, BYTEORDER); |
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113 |
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114 fclose (fid); |
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115 |
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116 endfunction |
