1 | <?php |
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2 | // +----------------------------------------------------------------------+ |
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3 | // | PHP version 5 | |
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4 | // +----------------------------------------------------------------------+ |
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5 | // | Copyright (c) 2002-2006 James Heinrich, Allan Hansen | |
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6 | // +----------------------------------------------------------------------+ |
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7 | // | This source file is subject to version 2 of the GPL license, | |
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8 | // | that is bundled with this package in the file license.txt and is | |
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9 | // | available through the world-wide-web at the following url: | |
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10 | // | http://www.gnu.org/copyleft/gpl.html | |
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11 | // +----------------------------------------------------------------------+ |
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12 | // | getID3() - http://getid3.sourceforge.net or http://www.getid3.org | |
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13 | // +----------------------------------------------------------------------+ |
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14 | // | Authors: James Heinrich <infoØgetid3*org> | |
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15 | // | Allan Hansen <ahØartemis*dk> | |
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16 | // +----------------------------------------------------------------------+ |
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17 | // | module.audio.aac_adts.php | |
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18 | // | Module for analyzing AAC files with ADTS header. | |
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19 | // | dependencies: NONE | |
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20 | // +----------------------------------------------------------------------+ |
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21 | // |
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22 | // $Id: module.audio.aac_adts.php 3318 2009-05-20 21:54:10Z vdigital $ |
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23 | |
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24 | |
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25 | |
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26 | class getid3_aac_adts extends getid3_handler |
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27 | { |
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28 | |
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29 | public $option_max_frames_to_scan = 1000000; |
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30 | public $option_return_extended_info = false; |
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31 | |
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32 | |
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33 | private $decbin_cache; |
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34 | private $bitrate_cache; |
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35 | |
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36 | |
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37 | |
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38 | public function __construct(getID3 $getid3) { |
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39 | |
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40 | parent::__construct($getid3); |
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41 | |
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42 | // Populate bindec_cache |
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43 | for ($i = 0; $i < 256; $i++) { |
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44 | $this->decbin_cache[chr($i)] = str_pad(decbin($i), 8, '0', STR_PAD_LEFT); |
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45 | } |
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46 | |
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47 | // Init cache |
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48 | $this->bitrate_cache = array (); |
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49 | |
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50 | // Fast scanning? |
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51 | if (!$getid3->option_accurate_results) { |
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52 | $this->option_max_frames_to_scan = 200; |
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53 | $getid3->warning('option_accurate_results set to false - bitrate and playing time are not accurate.'); |
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54 | } |
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55 | } |
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56 | |
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57 | |
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58 | |
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59 | public function Analyze() { |
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60 | |
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61 | $getid3 = $this->getid3; |
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62 | |
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63 | // based loosely on code from AACfile by Jurgen Faul <jfaulØgmx.de> |
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64 | // http://jfaul.de/atl or http://j-faul.virtualave.net/atl/atl.html |
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65 | |
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66 | |
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67 | // http://faac.sourceforge.net/wiki/index.php?page=ADTS |
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68 | |
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69 | // * ADTS Fixed Header: these don't change from frame to frame |
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70 | // syncword 12 always: '111111111111' |
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71 | // ID 1 0: MPEG-4, 1: MPEG-2 |
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72 | // layer 2 always: '00' |
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73 | // protection_absent 1 |
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74 | // profile 2 |
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75 | // sampling_frequency_index 4 |
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76 | // private_bit 1 |
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77 | // channel_configuration 3 |
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78 | // original/copy 1 |
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79 | // home 1 |
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80 | // emphasis 2 only if ID == 0 (ie MPEG-4) |
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81 | |
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82 | // * ADTS Variable Header: these can change from frame to frame |
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83 | // copyright_identification_bit 1 |
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84 | // copyright_identification_start 1 |
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85 | // aac_frame_length 13 length of the frame including header (in bytes) |
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86 | // adts_buffer_fullness 11 0x7FF indicates VBR |
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87 | // no_raw_data_blocks_in_frame 2 |
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88 | |
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89 | // * ADTS Error check |
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90 | // crc_check 16 only if protection_absent == 0 |
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91 | |
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92 | $getid3->info['aac']['header'] = array () ; |
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93 | $info_aac = &$getid3->info['aac']; |
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94 | $info_aac_header = & $info_aac['header']; |
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95 | |
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96 | $byte_offset = $frame_number = 0; |
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97 | |
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98 | while (true) { |
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99 | |
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100 | // Breaks out when end-of-file encountered, or invalid data found, |
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101 | // or MaxFramesToScan frames have been scanned |
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102 | |
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103 | fseek($getid3->fp, $byte_offset, SEEK_SET); |
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104 | |
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105 | // First get substring |
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106 | $sub_string = fread($getid3->fp, 10); |
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107 | $sub_string_length = strlen($sub_string); |
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108 | if ($sub_string_length != 10) { |
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109 | throw new getid3_exception('Failed to read 10 bytes at offset '.(ftell($getid3->fp) - $sub_string_length).' (only read '.$sub_string_length.' bytes)'); |
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110 | } |
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111 | |
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112 | // Initialise $aac_header_bitstream |
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113 | $aac_header_bitstream = ''; |
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114 | |
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115 | // Loop thru substring chars |
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116 | for ($i = 0; $i < 10; $i++) { |
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117 | $aac_header_bitstream .= $this->decbin_cache[$sub_string[$i]]; |
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118 | } |
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119 | |
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120 | $sync_test = bindec(substr($aac_header_bitstream, 0, 12)); |
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121 | $bit_offset = 12; |
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122 | |
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123 | if ($sync_test != 0x0FFF) { |
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124 | throw new getid3_exception('Synch pattern (0x0FFF) not found at offset '.(ftell($getid3->fp) - 10).' (found 0x0'.strtoupper(dechex($sync_test)).' instead)'); |
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125 | } |
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126 | |
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127 | // Only gather info once - this takes time to do 1000 times! |
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128 | if ($frame_number > 0) { |
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129 | |
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130 | // MPEG-4: 20, // MPEG-2: 18 |
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131 | $bit_offset += $aac_header_bitstream[$bit_offset] ? 18 : 20; |
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132 | } |
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133 | |
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134 | // Gather info for first frame only - this takes time to do 1000 times! |
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135 | else { |
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136 | |
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137 | $info_aac['header_type'] = 'ADTS'; |
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138 | $info_aac_header['synch'] = $sync_test; |
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139 | $getid3->info['fileformat'] = 'aac'; |
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140 | $getid3->info['audio']['dataformat'] = 'aac'; |
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141 | |
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142 | $info_aac_header['mpeg_version'] = $aac_header_bitstream{$bit_offset++} == '0' ? 4 : 2; |
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143 | $info_aac_header['layer'] = bindec(substr($aac_header_bitstream, $bit_offset, 2)); |
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144 | $bit_offset += 2; |
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145 | |
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146 | if ($info_aac_header['layer'] != 0) { |
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147 | throw new getid3_exception('Layer error - expected 0x00, found 0x'.dechex($info_aac_header['layer']).' instead'); |
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148 | } |
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149 | |
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150 | $info_aac_header['crc_present'] = $aac_header_bitstream{$bit_offset++} == '0' ? true : false; |
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151 | |
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152 | $info_aac_header['profile_id'] = bindec(substr($aac_header_bitstream, $bit_offset, 2)); |
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153 | $bit_offset += 2; |
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154 | |
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155 | $info_aac_header['profile_text'] = getid3_aac_adts::AACprofileLookup($info_aac_header['profile_id'], $info_aac_header['mpeg_version']); |
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156 | |
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157 | $info_aac_header['sample_frequency_index'] = bindec(substr($aac_header_bitstream, $bit_offset, 4)); |
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158 | $bit_offset += 4; |
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159 | |
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160 | $info_aac_header['sample_frequency'] = getid3_aac_adts::AACsampleRateLookup($info_aac_header['sample_frequency_index']); |
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161 | |
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162 | $getid3->info['audio']['sample_rate'] = $info_aac_header['sample_frequency']; |
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163 | |
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164 | $info_aac_header['private'] = $aac_header_bitstream{$bit_offset++} == 1; |
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165 | |
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166 | $info_aac_header['channel_configuration'] = $getid3->info['audio']['channels'] = bindec(substr($aac_header_bitstream, $bit_offset, 3)); |
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167 | $bit_offset += 3; |
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168 | |
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169 | $info_aac_header['original'] = $aac_header_bitstream{$bit_offset++} == 1; |
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170 | $info_aac_header['home'] = $aac_header_bitstream{$bit_offset++} == 1; |
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171 | |
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172 | if ($info_aac_header['mpeg_version'] == 4) { |
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173 | $info_aac_header['emphasis'] = bindec(substr($aac_header_bitstream, $bit_offset, 2)); |
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174 | $bit_offset += 2; |
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175 | } |
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176 | |
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177 | if ($this->option_return_extended_info) { |
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178 | |
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179 | $info_aac[$frame_number]['copyright_id_bit'] = $aac_header_bitstream{$bit_offset++} == 1; |
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180 | $info_aac[$frame_number]['copyright_id_start'] = $aac_header_bitstream{$bit_offset++} == 1; |
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181 | |
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182 | } else { |
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183 | $bit_offset += 2; |
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184 | } |
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185 | } |
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186 | |
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187 | $frame_length = bindec(substr($aac_header_bitstream, $bit_offset, 13)); |
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188 | |
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189 | if (!isset($this->bitrate_cache[$frame_length])) { |
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190 | $this->bitrate_cache[$frame_length] = ($info_aac_header['sample_frequency'] / 1024) * $frame_length * 8; |
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191 | } |
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192 | @$info_aac['bitrate_distribution'][$this->bitrate_cache[$frame_length]]++; |
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193 | |
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194 | $info_aac[$frame_number]['aac_frame_length'] = $frame_length; |
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195 | $bit_offset += 13; |
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196 | |
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197 | $info_aac[$frame_number]['adts_buffer_fullness'] = bindec(substr($aac_header_bitstream, $bit_offset, 11)); |
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198 | $bit_offset += 11; |
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199 | |
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200 | $getid3->info['audio']['bitrate_mode'] = ($info_aac[$frame_number]['adts_buffer_fullness'] == 0x07FF) ? 'vbr' : 'cbr'; |
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201 | |
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202 | $info_aac[$frame_number]['num_raw_data_blocks'] = bindec(substr($aac_header_bitstream, $bit_offset, 2)); |
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203 | $bit_offset += 2; |
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204 | |
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205 | if ($info_aac_header['crc_present']) { |
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206 | $bit_offset += 16; |
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207 | } |
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208 | |
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209 | if (!$this->option_return_extended_info) { |
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210 | unset($info_aac[$frame_number]); |
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211 | } |
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212 | |
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213 | $byte_offset += $frame_length; |
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214 | if ((++$frame_number < $this->option_max_frames_to_scan) && (($byte_offset + 10) < $getid3->info['avdataend'])) { |
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215 | |
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216 | // keep scanning |
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217 | |
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218 | } else { |
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219 | |
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220 | $info_aac['frames'] = $frame_number; |
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221 | $getid3->info['playtime_seconds'] = ($getid3->info['avdataend'] / $byte_offset) * (($frame_number * 1024) / $info_aac_header['sample_frequency']); // (1 / % of file scanned) * (samples / (samples/sec)) = seconds |
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222 | $getid3->info['audio']['bitrate'] = (($getid3->info['avdataend'] - $getid3->info['avdataoffset']) * 8) / $getid3->info['playtime_seconds']; |
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223 | ksort($info_aac['bitrate_distribution']); |
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224 | |
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225 | $getid3->info['audio']['encoder_options'] = $info_aac['header_type'].' '.$info_aac_header['profile_text']; |
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226 | |
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227 | return true; |
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228 | } |
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229 | } |
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230 | } |
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231 | |
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232 | |
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233 | |
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234 | public static function AACsampleRateLookup($samplerate_id) { |
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235 | |
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236 | static $lookup = array ( |
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237 | 0 => 96000, |
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238 | 1 => 88200, |
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239 | 2 => 64000, |
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240 | 3 => 48000, |
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241 | 4 => 44100, |
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242 | 5 => 32000, |
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243 | 6 => 24000, |
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244 | 7 => 22050, |
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245 | 8 => 16000, |
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246 | 9 => 12000, |
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247 | 10 => 11025, |
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248 | 11 => 8000, |
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249 | 12 => 0, |
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250 | 13 => 0, |
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251 | 14 => 0, |
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252 | 15 => 0 |
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253 | ); |
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254 | return (isset($lookup[$samplerate_id]) ? $lookup[$samplerate_id] : 'invalid'); |
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255 | } |
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256 | |
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257 | |
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258 | |
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259 | public static function AACprofileLookup($profile_id, $mpeg_version) { |
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260 | |
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261 | static $lookup = array ( |
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262 | 2 => array ( |
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263 | 0 => 'Main profile', |
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264 | 1 => 'Low Complexity profile (LC)', |
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265 | 2 => 'Scalable Sample Rate profile (SSR)', |
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266 | 3 => '(reserved)' |
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267 | ), |
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268 | 4 => array ( |
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269 | 0 => 'AAC_MAIN', |
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270 | 1 => 'AAC_LC', |
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271 | 2 => 'AAC_SSR', |
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272 | 3 => 'AAC_LTP' |
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273 | ) |
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274 | ); |
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275 | return (isset($lookup[$mpeg_version][$profile_id]) ? $lookup[$mpeg_version][$profile_id] : 'invalid'); |
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276 | } |
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277 | |
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278 | |
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279 | } |
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280 | |
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281 | |
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282 | ?> |
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