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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 ## @seealso{wavread} |
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32 ## @end deftypefn |
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33 |
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34 ## Author: Michael Zeising <michael.zeising@stud.uni-erlangen.de> |
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35 ## Created: 06 December 2005 |
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36 |
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37 function wavwrite (filename, y, samples_per_sec, bits_per_sample) |
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38 |
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39 BYTEORDER = "ieee-le"; |
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40 |
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41 if (nargin < 2 || nargin > 4) |
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42 usage ("wavwrite (filename, y, samples_per_sec, bits_per_sample)"); |
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43 endif |
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44 |
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45 ## parse arguments |
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46 if (nargin < 3) |
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47 warning ("wavwrite: sample rate set to 8000 Hz"); |
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48 samples_per_sec = 8000; |
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49 endif |
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50 |
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51 if (nargin < 4) |
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52 warning ("wavwrite: sample resolution set to 16-bit"); |
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53 bits_per_sample = 16; |
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54 endif |
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55 |
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56 ## determine sample format |
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57 switch (bits_per_sample) |
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58 case 8 |
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59 format = "uint8"; |
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60 case 16 |
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61 format = "int16"; |
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62 case 32 |
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63 format = "int32"; |
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64 otherwise |
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65 error ("wavread: sample resolution not supported"); |
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66 endswitch |
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67 |
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68 ## calculate filesize |
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69 channels = size(y)(2); |
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70 n = size(y)(1); |
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71 |
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72 ## size of data chunk |
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73 ck_size = n*channels*(bits_per_sample/8); |
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74 |
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75 ## open file for writing binary |
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76 |
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77 if (! ischar (filename)) |
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78 error ("wavwrite: expecting filename to be a character string"); |
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79 endif |
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80 |
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81 [fid, msg] = fopen (filename, "wb"); |
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82 if (fid < 0) |
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83 error ("wavwrite: %s", msg) |
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84 endif |
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85 |
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86 ## write RIFF/WAVE header |
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87 c = 0; |
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88 c += fwrite (fid, "RIFF", "uchar"); |
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89 |
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90 ## file size - 8 |
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91 c += fwrite (fid, ck_size + 36, "ulong", 0, BYTEORDER); |
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92 c += fwrite (fid, "WAVEfmt ", "uchar"); |
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93 |
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94 ## size of fmt chunk |
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95 c += fwrite (fid, 16, "ulong", 0, BYTEORDER); |
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96 |
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97 ## sample format code (PCM) |
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98 c += fwrite (fid, 0x0001, "short", 0, BYTEORDER); |
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99 |
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100 ## channels |
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101 c += fwrite (fid, channels, "short", 0, BYTEORDER); |
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102 |
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103 ## sample rate |
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104 c += fwrite (fid, samples_per_sec, "ulong", 0, BYTEORDER); |
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105 |
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106 ## bytes per second |
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107 bps = samples_per_sec*channels*bits_per_sample/8; |
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108 c += fwrite (fid, bps, "ulong", 0, BYTEORDER); |
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109 |
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110 ## block align |
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111 c += fwrite (fid, channels*bits_per_sample/8, "short", 0, BYTEORDER); |
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112 |
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113 c += fwrite (fid, bits_per_sample, "short", 0, BYTEORDER); |
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114 c += fwrite (fid, "data", "uchar"); |
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115 c += fwrite (fid, ck_size, "ulong", 0, BYTEORDER); |
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116 |
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117 if (c < 25) |
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118 fclose (fid); |
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119 error ("wavread: writing to file failed"); |
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120 endif |
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121 |
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122 ## interleave samples |
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123 yi = reshape (y', n*channels, 1); |
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124 |
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125 ## scale samples |
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126 switch (bits_per_sample) |
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127 case 8 |
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128 yi = round (yi*127.5 + 127.5); |
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129 case 16 |
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130 yi = floor (yi*32767.5); |
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131 case 32 |
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132 yi = floor (yi*2147483647.5); |
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133 endswitch |
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134 |
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135 ## write to file |
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136 c = fwrite (fid, yi, format, 0, BYTEORDER); |
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137 |
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138 fclose (fid); |
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139 |
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140 endfunction |
