module.audio.ac3.php 38 KB

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  1. <?php
  2. /////////////////////////////////////////////////////////////////
  3. /// getID3() by James Heinrich <info@getid3.org> //
  4. // available at https://github.com/JamesHeinrich/getID3 //
  5. // or https://www.getid3.org //
  6. // or http://getid3.sourceforge.net //
  7. // see readme.txt for more details //
  8. /////////////////////////////////////////////////////////////////
  9. // //
  10. // module.audio.ac3.php //
  11. // module for analyzing AC-3 (aka Dolby Digital) audio files //
  12. // dependencies: NONE //
  13. // ///
  14. /////////////////////////////////////////////////////////////////
  15. class getid3_ac3 extends getid3_handler
  16. {
  17. /**
  18. * @var array
  19. */
  20. private $AC3header = array();
  21. /**
  22. * @var int
  23. */
  24. private $BSIoffset = 0;
  25. const syncword = 0x0B77;
  26. /**
  27. * @return bool
  28. */
  29. public function Analyze() {
  30. $info = &$this->getid3->info;
  31. ///AH
  32. $info['ac3']['raw']['bsi'] = array();
  33. $thisfile_ac3 = &$info['ac3'];
  34. $thisfile_ac3_raw = &$thisfile_ac3['raw'];
  35. $thisfile_ac3_raw_bsi = &$thisfile_ac3_raw['bsi'];
  36. // http://www.atsc.org/standards/a_52a.pdf
  37. $info['fileformat'] = 'ac3';
  38. // An AC-3 serial coded audio bit stream is made up of a sequence of synchronization frames
  39. // Each synchronization frame contains 6 coded audio blocks (AB), each of which represent 256
  40. // new audio samples per channel. A synchronization information (SI) header at the beginning
  41. // of each frame contains information needed to acquire and maintain synchronization. A
  42. // bit stream information (BSI) header follows SI, and contains parameters describing the coded
  43. // audio service. The coded audio blocks may be followed by an auxiliary data (Aux) field. At the
  44. // end of each frame is an error check field that includes a CRC word for error detection. An
  45. // additional CRC word is located in the SI header, the use of which, by a decoder, is optional.
  46. //
  47. // syncinfo() | bsi() | AB0 | AB1 | AB2 | AB3 | AB4 | AB5 | Aux | CRC
  48. // syncinfo() {
  49. // syncword 16
  50. // crc1 16
  51. // fscod 2
  52. // frmsizecod 6
  53. // } /* end of syncinfo */
  54. $this->fseek($info['avdataoffset']);
  55. $tempAC3header = $this->fread(100); // should be enough to cover all data, there are some variable-length fields...?
  56. $this->AC3header['syncinfo'] = getid3_lib::BigEndian2Int(substr($tempAC3header, 0, 2));
  57. $this->AC3header['bsi'] = getid3_lib::BigEndian2Bin(substr($tempAC3header, 2));
  58. $thisfile_ac3_raw_bsi['bsid'] = (getid3_lib::LittleEndian2Int(substr($tempAC3header, 5, 1)) & 0xF8) >> 3; // AC3 and E-AC3 put the "bsid" version identifier in the same place, but unfortnately the 4 bytes between the syncword and the version identifier are interpreted differently, so grab it here so the following code structure can make sense
  59. unset($tempAC3header);
  60. if ($this->AC3header['syncinfo'] !== self::syncword) {
  61. if (!$this->isDependencyFor('matroska')) {
  62. unset($info['fileformat'], $info['ac3']);
  63. return $this->error('Expecting "'.dechex(self::syncword).'" at offset '.$info['avdataoffset'].', found "'.dechex($this->AC3header['syncinfo']).'"');
  64. }
  65. }
  66. $info['audio']['dataformat'] = 'ac3';
  67. $info['audio']['bitrate_mode'] = 'cbr';
  68. $info['audio']['lossless'] = false;
  69. if ($thisfile_ac3_raw_bsi['bsid'] <= 8) {
  70. $thisfile_ac3_raw_bsi['crc1'] = getid3_lib::Bin2Dec($this->readHeaderBSI(16));
  71. $thisfile_ac3_raw_bsi['fscod'] = $this->readHeaderBSI(2); // 5.4.1.3
  72. $thisfile_ac3_raw_bsi['frmsizecod'] = $this->readHeaderBSI(6); // 5.4.1.4
  73. if ($thisfile_ac3_raw_bsi['frmsizecod'] > 37) { // binary: 100101 - see Table 5.18 Frame Size Code Table (1 word = 16 bits)
  74. $this->warning('Unexpected ac3.bsi.frmsizecod value: '.$thisfile_ac3_raw_bsi['frmsizecod'].', bitrate not set correctly');
  75. }
  76. $thisfile_ac3_raw_bsi['bsid'] = $this->readHeaderBSI(5); // we already know this from pre-parsing the version identifier, but re-read it to let the bitstream flow as intended
  77. $thisfile_ac3_raw_bsi['bsmod'] = $this->readHeaderBSI(3);
  78. $thisfile_ac3_raw_bsi['acmod'] = $this->readHeaderBSI(3);
  79. if ($thisfile_ac3_raw_bsi['acmod'] & 0x01) {
  80. // If the lsb of acmod is a 1, center channel is in use and cmixlev follows in the bit stream.
  81. $thisfile_ac3_raw_bsi['cmixlev'] = $this->readHeaderBSI(2);
  82. $thisfile_ac3['center_mix_level'] = self::centerMixLevelLookup($thisfile_ac3_raw_bsi['cmixlev']);
  83. }
  84. if ($thisfile_ac3_raw_bsi['acmod'] & 0x04) {
  85. // If the msb of acmod is a 1, surround channels are in use and surmixlev follows in the bit stream.
  86. $thisfile_ac3_raw_bsi['surmixlev'] = $this->readHeaderBSI(2);
  87. $thisfile_ac3['surround_mix_level'] = self::surroundMixLevelLookup($thisfile_ac3_raw_bsi['surmixlev']);
  88. }
  89. if ($thisfile_ac3_raw_bsi['acmod'] == 0x02) {
  90. // When operating in the two channel mode, this 2-bit code indicates whether or not the program has been encoded in Dolby Surround.
  91. $thisfile_ac3_raw_bsi['dsurmod'] = $this->readHeaderBSI(2);
  92. $thisfile_ac3['dolby_surround_mode'] = self::dolbySurroundModeLookup($thisfile_ac3_raw_bsi['dsurmod']);
  93. }
  94. $thisfile_ac3_raw_bsi['flags']['lfeon'] = (bool) $this->readHeaderBSI(1);
  95. // This indicates how far the average dialogue level is below digital 100 percent. Valid values are 1-31.
  96. // The value of 0 is reserved. The values of 1 to 31 are interpreted as -1 dB to -31 dB with respect to digital 100 percent.
  97. $thisfile_ac3_raw_bsi['dialnorm'] = $this->readHeaderBSI(5); // 5.4.2.8 dialnorm: Dialogue Normalization, 5 Bits
  98. $thisfile_ac3_raw_bsi['flags']['compr'] = (bool) $this->readHeaderBSI(1); // 5.4.2.9 compre: Compression Gain Word Exists, 1 Bit
  99. if ($thisfile_ac3_raw_bsi['flags']['compr']) {
  100. $thisfile_ac3_raw_bsi['compr'] = $this->readHeaderBSI(8); // 5.4.2.10 compr: Compression Gain Word, 8 Bits
  101. $thisfile_ac3['heavy_compression'] = self::heavyCompression($thisfile_ac3_raw_bsi['compr']);
  102. }
  103. $thisfile_ac3_raw_bsi['flags']['langcod'] = (bool) $this->readHeaderBSI(1); // 5.4.2.11 langcode: Language Code Exists, 1 Bit
  104. if ($thisfile_ac3_raw_bsi['flags']['langcod']) {
  105. $thisfile_ac3_raw_bsi['langcod'] = $this->readHeaderBSI(8); // 5.4.2.12 langcod: Language Code, 8 Bits
  106. }
  107. $thisfile_ac3_raw_bsi['flags']['audprodinfo'] = (bool) $this->readHeaderBSI(1); // 5.4.2.13 audprodie: Audio Production Information Exists, 1 Bit
  108. if ($thisfile_ac3_raw_bsi['flags']['audprodinfo']) {
  109. $thisfile_ac3_raw_bsi['mixlevel'] = $this->readHeaderBSI(5); // 5.4.2.14 mixlevel: Mixing Level, 5 Bits
  110. $thisfile_ac3_raw_bsi['roomtyp'] = $this->readHeaderBSI(2); // 5.4.2.15 roomtyp: Room Type, 2 Bits
  111. $thisfile_ac3['mixing_level'] = (80 + $thisfile_ac3_raw_bsi['mixlevel']).'dB';
  112. $thisfile_ac3['room_type'] = self::roomTypeLookup($thisfile_ac3_raw_bsi['roomtyp']);
  113. }
  114. $thisfile_ac3_raw_bsi['dialnorm2'] = $this->readHeaderBSI(5); // 5.4.2.16 dialnorm2: Dialogue Normalization, ch2, 5 Bits
  115. $thisfile_ac3['dialogue_normalization2'] = '-'.$thisfile_ac3_raw_bsi['dialnorm2'].'dB'; // This indicates how far the average dialogue level is below digital 100 percent. Valid values are 1-31. The value of 0 is reserved. The values of 1 to 31 are interpreted as -1 dB to -31 dB with respect to digital 100 percent.
  116. $thisfile_ac3_raw_bsi['flags']['compr2'] = (bool) $this->readHeaderBSI(1); // 5.4.2.17 compr2e: Compression Gain Word Exists, ch2, 1 Bit
  117. if ($thisfile_ac3_raw_bsi['flags']['compr2']) {
  118. $thisfile_ac3_raw_bsi['compr2'] = $this->readHeaderBSI(8); // 5.4.2.18 compr2: Compression Gain Word, ch2, 8 Bits
  119. $thisfile_ac3['heavy_compression2'] = self::heavyCompression($thisfile_ac3_raw_bsi['compr2']);
  120. }
  121. $thisfile_ac3_raw_bsi['flags']['langcod2'] = (bool) $this->readHeaderBSI(1); // 5.4.2.19 langcod2e: Language Code Exists, ch2, 1 Bit
  122. if ($thisfile_ac3_raw_bsi['flags']['langcod2']) {
  123. $thisfile_ac3_raw_bsi['langcod2'] = $this->readHeaderBSI(8); // 5.4.2.20 langcod2: Language Code, ch2, 8 Bits
  124. }
  125. $thisfile_ac3_raw_bsi['flags']['audprodinfo2'] = (bool) $this->readHeaderBSI(1); // 5.4.2.21 audprodi2e: Audio Production Information Exists, ch2, 1 Bit
  126. if ($thisfile_ac3_raw_bsi['flags']['audprodinfo2']) {
  127. $thisfile_ac3_raw_bsi['mixlevel2'] = $this->readHeaderBSI(5); // 5.4.2.22 mixlevel2: Mixing Level, ch2, 5 Bits
  128. $thisfile_ac3_raw_bsi['roomtyp2'] = $this->readHeaderBSI(2); // 5.4.2.23 roomtyp2: Room Type, ch2, 2 Bits
  129. $thisfile_ac3['mixing_level2'] = (80 + $thisfile_ac3_raw_bsi['mixlevel2']).'dB';
  130. $thisfile_ac3['room_type2'] = self::roomTypeLookup($thisfile_ac3_raw_bsi['roomtyp2']);
  131. }
  132. $thisfile_ac3_raw_bsi['copyright'] = (bool) $this->readHeaderBSI(1); // 5.4.2.24 copyrightb: Copyright Bit, 1 Bit
  133. $thisfile_ac3_raw_bsi['original'] = (bool) $this->readHeaderBSI(1); // 5.4.2.25 origbs: Original Bit Stream, 1 Bit
  134. $thisfile_ac3_raw_bsi['flags']['timecod1'] = $this->readHeaderBSI(2); // 5.4.2.26 timecod1e, timcode2e: Time Code (first and second) Halves Exist, 2 Bits
  135. if ($thisfile_ac3_raw_bsi['flags']['timecod1'] & 0x01) {
  136. $thisfile_ac3_raw_bsi['timecod1'] = $this->readHeaderBSI(14); // 5.4.2.27 timecod1: Time code first half, 14 bits
  137. $thisfile_ac3['timecode1'] = 0;
  138. $thisfile_ac3['timecode1'] += (($thisfile_ac3_raw_bsi['timecod1'] & 0x3E00) >> 9) * 3600; // The first 5 bits of this 14-bit field represent the time in hours, with valid values of 0�23
  139. $thisfile_ac3['timecode1'] += (($thisfile_ac3_raw_bsi['timecod1'] & 0x01F8) >> 3) * 60; // The next 6 bits represent the time in minutes, with valid values of 0�59
  140. $thisfile_ac3['timecode1'] += (($thisfile_ac3_raw_bsi['timecod1'] & 0x0003) >> 0) * 8; // The final 3 bits represents the time in 8 second increments, with valid values of 0�7 (representing 0, 8, 16, ... 56 seconds)
  141. }
  142. if ($thisfile_ac3_raw_bsi['flags']['timecod1'] & 0x02) {
  143. $thisfile_ac3_raw_bsi['timecod2'] = $this->readHeaderBSI(14); // 5.4.2.28 timecod2: Time code second half, 14 bits
  144. $thisfile_ac3['timecode2'] = 0;
  145. $thisfile_ac3['timecode2'] += (($thisfile_ac3_raw_bsi['timecod2'] & 0x3800) >> 11) * 1; // The first 3 bits of this 14-bit field represent the time in seconds, with valid values from 0�7 (representing 0-7 seconds)
  146. $thisfile_ac3['timecode2'] += (($thisfile_ac3_raw_bsi['timecod2'] & 0x07C0) >> 6) * (1 / 30); // The next 5 bits represents the time in frames, with valid values from 0�29 (one frame = 1/30th of a second)
  147. $thisfile_ac3['timecode2'] += (($thisfile_ac3_raw_bsi['timecod2'] & 0x003F) >> 0) * ((1 / 30) / 60); // The final 6 bits represents fractions of 1/64 of a frame, with valid values from 0�63
  148. }
  149. $thisfile_ac3_raw_bsi['flags']['addbsi'] = (bool) $this->readHeaderBSI(1);
  150. if ($thisfile_ac3_raw_bsi['flags']['addbsi']) {
  151. $thisfile_ac3_raw_bsi['addbsi_length'] = $this->readHeaderBSI(6) + 1; // This 6-bit code, which exists only if addbside is a 1, indicates the length in bytes of additional bit stream information. The valid range of addbsil is 0�63, indicating 1�64 additional bytes, respectively.
  152. $this->AC3header['bsi'] .= getid3_lib::BigEndian2Bin($this->fread($thisfile_ac3_raw_bsi['addbsi_length']));
  153. $thisfile_ac3_raw_bsi['addbsi_data'] = substr($this->AC3header['bsi'], $this->BSIoffset, $thisfile_ac3_raw_bsi['addbsi_length'] * 8);
  154. $this->BSIoffset += $thisfile_ac3_raw_bsi['addbsi_length'] * 8;
  155. }
  156. } elseif ($thisfile_ac3_raw_bsi['bsid'] <= 16) { // E-AC3
  157. $this->error('E-AC3 parsing is incomplete and experimental in this version of getID3 ('.$this->getid3->version().'). Notably the bitrate calculations are wrong -- value might (or not) be correct, but it is not calculated correctly. Email info@getid3.org if you know how to calculate EAC3 bitrate correctly.');
  158. $info['audio']['dataformat'] = 'eac3';
  159. $thisfile_ac3_raw_bsi['strmtyp'] = $this->readHeaderBSI(2);
  160. $thisfile_ac3_raw_bsi['substreamid'] = $this->readHeaderBSI(3);
  161. $thisfile_ac3_raw_bsi['frmsiz'] = $this->readHeaderBSI(11);
  162. $thisfile_ac3_raw_bsi['fscod'] = $this->readHeaderBSI(2);
  163. if ($thisfile_ac3_raw_bsi['fscod'] == 3) {
  164. $thisfile_ac3_raw_bsi['fscod2'] = $this->readHeaderBSI(2);
  165. $thisfile_ac3_raw_bsi['numblkscod'] = 3; // six blocks per syncframe
  166. } else {
  167. $thisfile_ac3_raw_bsi['numblkscod'] = $this->readHeaderBSI(2);
  168. }
  169. $thisfile_ac3['bsi']['blocks_per_sync_frame'] = self::blocksPerSyncFrame($thisfile_ac3_raw_bsi['numblkscod']);
  170. $thisfile_ac3_raw_bsi['acmod'] = $this->readHeaderBSI(3);
  171. $thisfile_ac3_raw_bsi['flags']['lfeon'] = (bool) $this->readHeaderBSI(1);
  172. $thisfile_ac3_raw_bsi['bsid'] = $this->readHeaderBSI(5); // we already know this from pre-parsing the version identifier, but re-read it to let the bitstream flow as intended
  173. $thisfile_ac3_raw_bsi['dialnorm'] = $this->readHeaderBSI(5);
  174. $thisfile_ac3_raw_bsi['flags']['compr'] = (bool) $this->readHeaderBSI(1);
  175. if ($thisfile_ac3_raw_bsi['flags']['compr']) {
  176. $thisfile_ac3_raw_bsi['compr'] = $this->readHeaderBSI(8);
  177. }
  178. if ($thisfile_ac3_raw_bsi['acmod'] == 0) { // if 1+1 mode (dual mono, so some items need a second value)
  179. $thisfile_ac3_raw_bsi['dialnorm2'] = $this->readHeaderBSI(5);
  180. $thisfile_ac3_raw_bsi['flags']['compr2'] = (bool) $this->readHeaderBSI(1);
  181. if ($thisfile_ac3_raw_bsi['flags']['compr2']) {
  182. $thisfile_ac3_raw_bsi['compr2'] = $this->readHeaderBSI(8);
  183. }
  184. }
  185. if ($thisfile_ac3_raw_bsi['strmtyp'] == 1) { // if dependent stream
  186. $thisfile_ac3_raw_bsi['flags']['chanmap'] = (bool) $this->readHeaderBSI(1);
  187. if ($thisfile_ac3_raw_bsi['flags']['chanmap']) {
  188. $thisfile_ac3_raw_bsi['chanmap'] = $this->readHeaderBSI(8);
  189. }
  190. }
  191. $thisfile_ac3_raw_bsi['flags']['mixmdat'] = (bool) $this->readHeaderBSI(1);
  192. if ($thisfile_ac3_raw_bsi['flags']['mixmdat']) { // Mixing metadata
  193. if ($thisfile_ac3_raw_bsi['acmod'] > 2) { // if more than 2 channels
  194. $thisfile_ac3_raw_bsi['dmixmod'] = $this->readHeaderBSI(2);
  195. }
  196. if (($thisfile_ac3_raw_bsi['acmod'] & 0x01) && ($thisfile_ac3_raw_bsi['acmod'] > 2)) { // if three front channels exist
  197. $thisfile_ac3_raw_bsi['ltrtcmixlev'] = $this->readHeaderBSI(3);
  198. $thisfile_ac3_raw_bsi['lorocmixlev'] = $this->readHeaderBSI(3);
  199. }
  200. if ($thisfile_ac3_raw_bsi['acmod'] & 0x04) { // if a surround channel exists
  201. $thisfile_ac3_raw_bsi['ltrtsurmixlev'] = $this->readHeaderBSI(3);
  202. $thisfile_ac3_raw_bsi['lorosurmixlev'] = $this->readHeaderBSI(3);
  203. }
  204. if ($thisfile_ac3_raw_bsi['flags']['lfeon']) { // if the LFE channel exists
  205. $thisfile_ac3_raw_bsi['flags']['lfemixlevcod'] = (bool) $this->readHeaderBSI(1);
  206. if ($thisfile_ac3_raw_bsi['flags']['lfemixlevcod']) {
  207. $thisfile_ac3_raw_bsi['lfemixlevcod'] = $this->readHeaderBSI(5);
  208. }
  209. }
  210. if ($thisfile_ac3_raw_bsi['strmtyp'] == 0) { // if independent stream
  211. $thisfile_ac3_raw_bsi['flags']['pgmscl'] = (bool) $this->readHeaderBSI(1);
  212. if ($thisfile_ac3_raw_bsi['flags']['pgmscl']) {
  213. $thisfile_ac3_raw_bsi['pgmscl'] = $this->readHeaderBSI(6);
  214. }
  215. if ($thisfile_ac3_raw_bsi['acmod'] == 0) { // if 1+1 mode (dual mono, so some items need a second value)
  216. $thisfile_ac3_raw_bsi['flags']['pgmscl2'] = (bool) $this->readHeaderBSI(1);
  217. if ($thisfile_ac3_raw_bsi['flags']['pgmscl2']) {
  218. $thisfile_ac3_raw_bsi['pgmscl2'] = $this->readHeaderBSI(6);
  219. }
  220. }
  221. $thisfile_ac3_raw_bsi['flags']['extpgmscl'] = (bool) $this->readHeaderBSI(1);
  222. if ($thisfile_ac3_raw_bsi['flags']['extpgmscl']) {
  223. $thisfile_ac3_raw_bsi['extpgmscl'] = $this->readHeaderBSI(6);
  224. }
  225. $thisfile_ac3_raw_bsi['mixdef'] = $this->readHeaderBSI(2);
  226. if ($thisfile_ac3_raw_bsi['mixdef'] == 1) { // mixing option 2
  227. $thisfile_ac3_raw_bsi['premixcmpsel'] = (bool) $this->readHeaderBSI(1);
  228. $thisfile_ac3_raw_bsi['drcsrc'] = (bool) $this->readHeaderBSI(1);
  229. $thisfile_ac3_raw_bsi['premixcmpscl'] = $this->readHeaderBSI(3);
  230. } elseif ($thisfile_ac3_raw_bsi['mixdef'] == 2) { // mixing option 3
  231. $thisfile_ac3_raw_bsi['mixdata'] = $this->readHeaderBSI(12);
  232. } elseif ($thisfile_ac3_raw_bsi['mixdef'] == 3) { // mixing option 4
  233. $mixdefbitsread = 0;
  234. $thisfile_ac3_raw_bsi['mixdeflen'] = $this->readHeaderBSI(5); $mixdefbitsread += 5;
  235. $thisfile_ac3_raw_bsi['flags']['mixdata2'] = (bool) $this->readHeaderBSI(1); $mixdefbitsread += 1;
  236. if ($thisfile_ac3_raw_bsi['flags']['mixdata2']) {
  237. $thisfile_ac3_raw_bsi['premixcmpsel'] = (bool) $this->readHeaderBSI(1); $mixdefbitsread += 1;
  238. $thisfile_ac3_raw_bsi['drcsrc'] = (bool) $this->readHeaderBSI(1); $mixdefbitsread += 1;
  239. $thisfile_ac3_raw_bsi['premixcmpscl'] = $this->readHeaderBSI(3); $mixdefbitsread += 3;
  240. $thisfile_ac3_raw_bsi['flags']['extpgmlscl'] = (bool) $this->readHeaderBSI(1); $mixdefbitsread += 1;
  241. if ($thisfile_ac3_raw_bsi['flags']['extpgmlscl']) {
  242. $thisfile_ac3_raw_bsi['extpgmlscl'] = $this->readHeaderBSI(4); $mixdefbitsread += 4;
  243. }
  244. $thisfile_ac3_raw_bsi['flags']['extpgmcscl'] = (bool) $this->readHeaderBSI(1); $mixdefbitsread += 1;
  245. if ($thisfile_ac3_raw_bsi['flags']['extpgmcscl']) {
  246. $thisfile_ac3_raw_bsi['extpgmcscl'] = $this->readHeaderBSI(4); $mixdefbitsread += 4;
  247. }
  248. $thisfile_ac3_raw_bsi['flags']['extpgmrscl'] = (bool) $this->readHeaderBSI(1); $mixdefbitsread += 1;
  249. if ($thisfile_ac3_raw_bsi['flags']['extpgmrscl']) {
  250. $thisfile_ac3_raw_bsi['extpgmrscl'] = $this->readHeaderBSI(4);
  251. }
  252. $thisfile_ac3_raw_bsi['flags']['extpgmlsscl'] = (bool) $this->readHeaderBSI(1); $mixdefbitsread += 1;
  253. if ($thisfile_ac3_raw_bsi['flags']['extpgmlsscl']) {
  254. $thisfile_ac3_raw_bsi['extpgmlsscl'] = $this->readHeaderBSI(4); $mixdefbitsread += 4;
  255. }
  256. $thisfile_ac3_raw_bsi['flags']['extpgmrsscl'] = (bool) $this->readHeaderBSI(1); $mixdefbitsread += 1;
  257. if ($thisfile_ac3_raw_bsi['flags']['extpgmrsscl']) {
  258. $thisfile_ac3_raw_bsi['extpgmrsscl'] = $this->readHeaderBSI(4); $mixdefbitsread += 4;
  259. }
  260. $thisfile_ac3_raw_bsi['flags']['extpgmlfescl'] = (bool) $this->readHeaderBSI(1); $mixdefbitsread += 1;
  261. if ($thisfile_ac3_raw_bsi['flags']['extpgmlfescl']) {
  262. $thisfile_ac3_raw_bsi['extpgmlfescl'] = $this->readHeaderBSI(4); $mixdefbitsread += 4;
  263. }
  264. $thisfile_ac3_raw_bsi['flags']['dmixscl'] = (bool) $this->readHeaderBSI(1); $mixdefbitsread += 1;
  265. if ($thisfile_ac3_raw_bsi['flags']['dmixscl']) {
  266. $thisfile_ac3_raw_bsi['dmixscl'] = $this->readHeaderBSI(4); $mixdefbitsread += 4;
  267. }
  268. $thisfile_ac3_raw_bsi['flags']['addch'] = (bool) $this->readHeaderBSI(1); $mixdefbitsread += 1;
  269. if ($thisfile_ac3_raw_bsi['flags']['addch']) {
  270. $thisfile_ac3_raw_bsi['flags']['extpgmaux1scl'] = (bool) $this->readHeaderBSI(1); $mixdefbitsread += 1;
  271. if ($thisfile_ac3_raw_bsi['flags']['extpgmaux1scl']) {
  272. $thisfile_ac3_raw_bsi['extpgmaux1scl'] = $this->readHeaderBSI(4); $mixdefbitsread += 4;
  273. }
  274. $thisfile_ac3_raw_bsi['flags']['extpgmaux2scl'] = (bool) $this->readHeaderBSI(1); $mixdefbitsread += 1;
  275. if ($thisfile_ac3_raw_bsi['flags']['extpgmaux2scl']) {
  276. $thisfile_ac3_raw_bsi['extpgmaux2scl'] = $this->readHeaderBSI(4); $mixdefbitsread += 4;
  277. }
  278. }
  279. }
  280. $thisfile_ac3_raw_bsi['flags']['mixdata3'] = (bool) $this->readHeaderBSI(1); $mixdefbitsread += 1;
  281. if ($thisfile_ac3_raw_bsi['flags']['mixdata3']) {
  282. $thisfile_ac3_raw_bsi['spchdat'] = $this->readHeaderBSI(5); $mixdefbitsread += 5;
  283. $thisfile_ac3_raw_bsi['flags']['addspchdat'] = (bool) $this->readHeaderBSI(1); $mixdefbitsread += 1;
  284. if ($thisfile_ac3_raw_bsi['flags']['addspchdat']) {
  285. $thisfile_ac3_raw_bsi['spchdat1'] = $this->readHeaderBSI(5); $mixdefbitsread += 5;
  286. $thisfile_ac3_raw_bsi['spchan1att'] = $this->readHeaderBSI(2); $mixdefbitsread += 2;
  287. $thisfile_ac3_raw_bsi['flags']['addspchdat1'] = (bool) $this->readHeaderBSI(1); $mixdefbitsread += 1;
  288. if ($thisfile_ac3_raw_bsi['flags']['addspchdat1']) {
  289. $thisfile_ac3_raw_bsi['spchdat2'] = $this->readHeaderBSI(5); $mixdefbitsread += 5;
  290. $thisfile_ac3_raw_bsi['spchan2att'] = $this->readHeaderBSI(3); $mixdefbitsread += 3;
  291. }
  292. }
  293. }
  294. $mixdata_bits = (8 * ($thisfile_ac3_raw_bsi['mixdeflen'] + 2)) - $mixdefbitsread;
  295. $mixdata_fill = (($mixdata_bits % 8) ? 8 - ($mixdata_bits % 8) : 0);
  296. $thisfile_ac3_raw_bsi['mixdata'] = $this->readHeaderBSI($mixdata_bits);
  297. $thisfile_ac3_raw_bsi['mixdatafill'] = $this->readHeaderBSI($mixdata_fill);
  298. unset($mixdefbitsread, $mixdata_bits, $mixdata_fill);
  299. }
  300. if ($thisfile_ac3_raw_bsi['acmod'] < 2) { // if mono or dual mono source
  301. $thisfile_ac3_raw_bsi['flags']['paninfo'] = (bool) $this->readHeaderBSI(1);
  302. if ($thisfile_ac3_raw_bsi['flags']['paninfo']) {
  303. $thisfile_ac3_raw_bsi['panmean'] = $this->readHeaderBSI(8);
  304. $thisfile_ac3_raw_bsi['paninfo'] = $this->readHeaderBSI(6);
  305. }
  306. if ($thisfile_ac3_raw_bsi['acmod'] == 0) { // if 1+1 mode (dual mono, so some items need a second value)
  307. $thisfile_ac3_raw_bsi['flags']['paninfo2'] = (bool) $this->readHeaderBSI(1);
  308. if ($thisfile_ac3_raw_bsi['flags']['paninfo2']) {
  309. $thisfile_ac3_raw_bsi['panmean2'] = $this->readHeaderBSI(8);
  310. $thisfile_ac3_raw_bsi['paninfo2'] = $this->readHeaderBSI(6);
  311. }
  312. }
  313. }
  314. $thisfile_ac3_raw_bsi['flags']['frmmixcfginfo'] = (bool) $this->readHeaderBSI(1);
  315. if ($thisfile_ac3_raw_bsi['flags']['frmmixcfginfo']) { // mixing configuration information
  316. if ($thisfile_ac3_raw_bsi['numblkscod'] == 0) {
  317. $thisfile_ac3_raw_bsi['blkmixcfginfo'][0] = $this->readHeaderBSI(5);
  318. } else {
  319. for ($blk = 0; $blk < $thisfile_ac3_raw_bsi['numblkscod']; $blk++) {
  320. $thisfile_ac3_raw_bsi['flags']['blkmixcfginfo'.$blk] = (bool) $this->readHeaderBSI(1);
  321. if ($thisfile_ac3_raw_bsi['flags']['blkmixcfginfo'.$blk]) { // mixing configuration information
  322. $thisfile_ac3_raw_bsi['blkmixcfginfo'][$blk] = $this->readHeaderBSI(5);
  323. }
  324. }
  325. }
  326. }
  327. }
  328. }
  329. $thisfile_ac3_raw_bsi['flags']['infomdat'] = (bool) $this->readHeaderBSI(1);
  330. if ($thisfile_ac3_raw_bsi['flags']['infomdat']) { // Informational metadata
  331. $thisfile_ac3_raw_bsi['bsmod'] = $this->readHeaderBSI(3);
  332. $thisfile_ac3_raw_bsi['flags']['copyrightb'] = (bool) $this->readHeaderBSI(1);
  333. $thisfile_ac3_raw_bsi['flags']['origbs'] = (bool) $this->readHeaderBSI(1);
  334. if ($thisfile_ac3_raw_bsi['acmod'] == 2) { // if in 2/0 mode
  335. $thisfile_ac3_raw_bsi['dsurmod'] = $this->readHeaderBSI(2);
  336. $thisfile_ac3_raw_bsi['dheadphonmod'] = $this->readHeaderBSI(2);
  337. }
  338. if ($thisfile_ac3_raw_bsi['acmod'] >= 6) { // if both surround channels exist
  339. $thisfile_ac3_raw_bsi['dsurexmod'] = $this->readHeaderBSI(2);
  340. }
  341. $thisfile_ac3_raw_bsi['flags']['audprodi'] = (bool) $this->readHeaderBSI(1);
  342. if ($thisfile_ac3_raw_bsi['flags']['audprodi']) {
  343. $thisfile_ac3_raw_bsi['mixlevel'] = $this->readHeaderBSI(5);
  344. $thisfile_ac3_raw_bsi['roomtyp'] = $this->readHeaderBSI(2);
  345. $thisfile_ac3_raw_bsi['flags']['adconvtyp'] = (bool) $this->readHeaderBSI(1);
  346. }
  347. if ($thisfile_ac3_raw_bsi['acmod'] == 0) { // if 1+1 mode (dual mono, so some items need a second value)
  348. $thisfile_ac3_raw_bsi['flags']['audprodi2'] = (bool) $this->readHeaderBSI(1);
  349. if ($thisfile_ac3_raw_bsi['flags']['audprodi2']) {
  350. $thisfile_ac3_raw_bsi['mixlevel2'] = $this->readHeaderBSI(5);
  351. $thisfile_ac3_raw_bsi['roomtyp2'] = $this->readHeaderBSI(2);
  352. $thisfile_ac3_raw_bsi['flags']['adconvtyp2'] = (bool) $this->readHeaderBSI(1);
  353. }
  354. }
  355. if ($thisfile_ac3_raw_bsi['fscod'] < 3) { // if not half sample rate
  356. $thisfile_ac3_raw_bsi['flags']['sourcefscod'] = (bool) $this->readHeaderBSI(1);
  357. }
  358. }
  359. if (($thisfile_ac3_raw_bsi['strmtyp'] == 0) && ($thisfile_ac3_raw_bsi['numblkscod'] != 3)) { // if both surround channels exist
  360. $thisfile_ac3_raw_bsi['flags']['convsync'] = (bool) $this->readHeaderBSI(1);
  361. }
  362. if ($thisfile_ac3_raw_bsi['strmtyp'] == 2) { // if bit stream converted from AC-3
  363. if ($thisfile_ac3_raw_bsi['numblkscod'] != 3) { // 6 blocks per syncframe
  364. $thisfile_ac3_raw_bsi['flags']['blkid'] = 1;
  365. } else {
  366. $thisfile_ac3_raw_bsi['flags']['blkid'] = (bool) $this->readHeaderBSI(1);
  367. }
  368. if ($thisfile_ac3_raw_bsi['flags']['blkid']) {
  369. $thisfile_ac3_raw_bsi['frmsizecod'] = $this->readHeaderBSI(6);
  370. }
  371. }
  372. $thisfile_ac3_raw_bsi['flags']['addbsi'] = (bool) $this->readHeaderBSI(1);
  373. if ($thisfile_ac3_raw_bsi['flags']['addbsi']) {
  374. $thisfile_ac3_raw_bsi['addbsil'] = $this->readHeaderBSI(6);
  375. $thisfile_ac3_raw_bsi['addbsi'] = $this->readHeaderBSI(($thisfile_ac3_raw_bsi['addbsil'] + 1) * 8);
  376. }
  377. } else {
  378. $this->error('Bit stream identification is version '.$thisfile_ac3_raw_bsi['bsid'].', but getID3() only understands up to version 16. Please submit a support ticket with a sample file.');
  379. unset($info['ac3']);
  380. return false;
  381. }
  382. if (isset($thisfile_ac3_raw_bsi['fscod2'])) {
  383. $thisfile_ac3['sample_rate'] = self::sampleRateCodeLookup2($thisfile_ac3_raw_bsi['fscod2']);
  384. } else {
  385. $thisfile_ac3['sample_rate'] = self::sampleRateCodeLookup($thisfile_ac3_raw_bsi['fscod']);
  386. }
  387. if ($thisfile_ac3_raw_bsi['fscod'] <= 3) {
  388. $info['audio']['sample_rate'] = $thisfile_ac3['sample_rate'];
  389. } else {
  390. $this->warning('Unexpected ac3.bsi.fscod value: '.$thisfile_ac3_raw_bsi['fscod']);
  391. }
  392. if (isset($thisfile_ac3_raw_bsi['frmsizecod'])) {
  393. $thisfile_ac3['frame_length'] = self::frameSizeLookup($thisfile_ac3_raw_bsi['frmsizecod'], $thisfile_ac3_raw_bsi['fscod']);
  394. $thisfile_ac3['bitrate'] = self::bitrateLookup($thisfile_ac3_raw_bsi['frmsizecod']);
  395. } elseif (!empty($thisfile_ac3_raw_bsi['frmsiz'])) {
  396. // this isn't right, but it's (usually) close, roughly 5% less than it should be.
  397. // but WHERE is the actual bitrate value stored in EAC3?? email info@getid3.org if you know!
  398. $thisfile_ac3['bitrate'] = ($thisfile_ac3_raw_bsi['frmsiz'] + 1) * 16 * 30; // The frmsiz field shall contain a value one less than the overall size of the coded syncframe in 16-bit words. That is, this field may assume a value ranging from 0 to 2047, and these values correspond to syncframe sizes ranging from 1 to 2048.
  399. // kludge-fix to make it approximately the expected value, still not "right":
  400. $thisfile_ac3['bitrate'] = round(($thisfile_ac3['bitrate'] * 1.05) / 16000) * 16000;
  401. }
  402. $info['audio']['bitrate'] = $thisfile_ac3['bitrate'];
  403. if (isset($thisfile_ac3_raw_bsi['bsmod']) && isset($thisfile_ac3_raw_bsi['acmod'])) {
  404. $thisfile_ac3['service_type'] = self::serviceTypeLookup($thisfile_ac3_raw_bsi['bsmod'], $thisfile_ac3_raw_bsi['acmod']);
  405. }
  406. $ac3_coding_mode = self::audioCodingModeLookup($thisfile_ac3_raw_bsi['acmod']);
  407. foreach($ac3_coding_mode as $key => $value) {
  408. $thisfile_ac3[$key] = $value;
  409. }
  410. switch ($thisfile_ac3_raw_bsi['acmod']) {
  411. case 0:
  412. case 1:
  413. $info['audio']['channelmode'] = 'mono';
  414. break;
  415. case 3:
  416. case 4:
  417. $info['audio']['channelmode'] = 'stereo';
  418. break;
  419. default:
  420. $info['audio']['channelmode'] = 'surround';
  421. break;
  422. }
  423. $info['audio']['channels'] = $thisfile_ac3['num_channels'];
  424. $thisfile_ac3['lfe_enabled'] = $thisfile_ac3_raw_bsi['flags']['lfeon'];
  425. if ($thisfile_ac3_raw_bsi['flags']['lfeon']) {
  426. $info['audio']['channels'] .= '.1';
  427. }
  428. $thisfile_ac3['channels_enabled'] = self::channelsEnabledLookup($thisfile_ac3_raw_bsi['acmod'], $thisfile_ac3_raw_bsi['flags']['lfeon']);
  429. $thisfile_ac3['dialogue_normalization'] = '-'.$thisfile_ac3_raw_bsi['dialnorm'].'dB';
  430. return true;
  431. }
  432. /**
  433. * @param int $length
  434. *
  435. * @return float|int
  436. */
  437. private function readHeaderBSI($length) {
  438. $data = substr($this->AC3header['bsi'], $this->BSIoffset, $length);
  439. $this->BSIoffset += $length;
  440. return bindec($data);
  441. }
  442. /**
  443. * @param int $fscod
  444. *
  445. * @return int|string|false
  446. */
  447. public static function sampleRateCodeLookup($fscod) {
  448. static $sampleRateCodeLookup = array(
  449. 0 => 48000,
  450. 1 => 44100,
  451. 2 => 32000,
  452. 3 => 'reserved' // If the reserved code is indicated, the decoder should not attempt to decode audio and should mute.
  453. );
  454. return (isset($sampleRateCodeLookup[$fscod]) ? $sampleRateCodeLookup[$fscod] : false);
  455. }
  456. /**
  457. * @param int $fscod2
  458. *
  459. * @return int|string|false
  460. */
  461. public static function sampleRateCodeLookup2($fscod2) {
  462. static $sampleRateCodeLookup2 = array(
  463. 0 => 24000,
  464. 1 => 22050,
  465. 2 => 16000,
  466. 3 => 'reserved' // If the reserved code is indicated, the decoder should not attempt to decode audio and should mute.
  467. );
  468. return (isset($sampleRateCodeLookup2[$fscod2]) ? $sampleRateCodeLookup2[$fscod2] : false);
  469. }
  470. /**
  471. * @param int $bsmod
  472. * @param int $acmod
  473. *
  474. * @return string|false
  475. */
  476. public static function serviceTypeLookup($bsmod, $acmod) {
  477. static $serviceTypeLookup = array();
  478. if (empty($serviceTypeLookup)) {
  479. for ($i = 0; $i <= 7; $i++) {
  480. $serviceTypeLookup[0][$i] = 'main audio service: complete main (CM)';
  481. $serviceTypeLookup[1][$i] = 'main audio service: music and effects (ME)';
  482. $serviceTypeLookup[2][$i] = 'associated service: visually impaired (VI)';
  483. $serviceTypeLookup[3][$i] = 'associated service: hearing impaired (HI)';
  484. $serviceTypeLookup[4][$i] = 'associated service: dialogue (D)';
  485. $serviceTypeLookup[5][$i] = 'associated service: commentary (C)';
  486. $serviceTypeLookup[6][$i] = 'associated service: emergency (E)';
  487. }
  488. $serviceTypeLookup[7][1] = 'associated service: voice over (VO)';
  489. for ($i = 2; $i <= 7; $i++) {
  490. $serviceTypeLookup[7][$i] = 'main audio service: karaoke';
  491. }
  492. }
  493. return (isset($serviceTypeLookup[$bsmod][$acmod]) ? $serviceTypeLookup[$bsmod][$acmod] : false);
  494. }
  495. /**
  496. * @param int $acmod
  497. *
  498. * @return array|false
  499. */
  500. public static function audioCodingModeLookup($acmod) {
  501. // array(channel configuration, # channels (not incl LFE), channel order)
  502. static $audioCodingModeLookup = array (
  503. 0 => array('channel_config'=>'1+1', 'num_channels'=>2, 'channel_order'=>'Ch1,Ch2'),
  504. 1 => array('channel_config'=>'1/0', 'num_channels'=>1, 'channel_order'=>'C'),
  505. 2 => array('channel_config'=>'2/0', 'num_channels'=>2, 'channel_order'=>'L,R'),
  506. 3 => array('channel_config'=>'3/0', 'num_channels'=>3, 'channel_order'=>'L,C,R'),
  507. 4 => array('channel_config'=>'2/1', 'num_channels'=>3, 'channel_order'=>'L,R,S'),
  508. 5 => array('channel_config'=>'3/1', 'num_channels'=>4, 'channel_order'=>'L,C,R,S'),
  509. 6 => array('channel_config'=>'2/2', 'num_channels'=>4, 'channel_order'=>'L,R,SL,SR'),
  510. 7 => array('channel_config'=>'3/2', 'num_channels'=>5, 'channel_order'=>'L,C,R,SL,SR'),
  511. );
  512. return (isset($audioCodingModeLookup[$acmod]) ? $audioCodingModeLookup[$acmod] : false);
  513. }
  514. /**
  515. * @param int $cmixlev
  516. *
  517. * @return int|float|string|false
  518. */
  519. public static function centerMixLevelLookup($cmixlev) {
  520. static $centerMixLevelLookup;
  521. if (empty($centerMixLevelLookup)) {
  522. $centerMixLevelLookup = array(
  523. 0 => pow(2, -3.0 / 6), // 0.707 (-3.0 dB)
  524. 1 => pow(2, -4.5 / 6), // 0.595 (-4.5 dB)
  525. 2 => pow(2, -6.0 / 6), // 0.500 (-6.0 dB)
  526. 3 => 'reserved'
  527. );
  528. }
  529. return (isset($centerMixLevelLookup[$cmixlev]) ? $centerMixLevelLookup[$cmixlev] : false);
  530. }
  531. /**
  532. * @param int $surmixlev
  533. *
  534. * @return int|float|string|false
  535. */
  536. public static function surroundMixLevelLookup($surmixlev) {
  537. static $surroundMixLevelLookup;
  538. if (empty($surroundMixLevelLookup)) {
  539. $surroundMixLevelLookup = array(
  540. 0 => pow(2, -3.0 / 6),
  541. 1 => pow(2, -6.0 / 6),
  542. 2 => 0,
  543. 3 => 'reserved'
  544. );
  545. }
  546. return (isset($surroundMixLevelLookup[$surmixlev]) ? $surroundMixLevelLookup[$surmixlev] : false);
  547. }
  548. /**
  549. * @param int $dsurmod
  550. *
  551. * @return string|false
  552. */
  553. public static function dolbySurroundModeLookup($dsurmod) {
  554. static $dolbySurroundModeLookup = array(
  555. 0 => 'not indicated',
  556. 1 => 'Not Dolby Surround encoded',
  557. 2 => 'Dolby Surround encoded',
  558. 3 => 'reserved'
  559. );
  560. return (isset($dolbySurroundModeLookup[$dsurmod]) ? $dolbySurroundModeLookup[$dsurmod] : false);
  561. }
  562. /**
  563. * @param int $acmod
  564. * @param bool $lfeon
  565. *
  566. * @return array
  567. */
  568. public static function channelsEnabledLookup($acmod, $lfeon) {
  569. $lookup = array(
  570. 'ch1'=>($acmod == 0),
  571. 'ch2'=>($acmod == 0),
  572. 'left'=>($acmod > 1),
  573. 'right'=>($acmod > 1),
  574. 'center'=>(bool) ($acmod & 0x01),
  575. 'surround_mono'=>false,
  576. 'surround_left'=>false,
  577. 'surround_right'=>false,
  578. 'lfe'=>$lfeon);
  579. switch ($acmod) {
  580. case 4:
  581. case 5:
  582. $lookup['surround_mono'] = true;
  583. break;
  584. case 6:
  585. case 7:
  586. $lookup['surround_left'] = true;
  587. $lookup['surround_right'] = true;
  588. break;
  589. }
  590. return $lookup;
  591. }
  592. /**
  593. * @param int $compre
  594. *
  595. * @return float|int
  596. */
  597. public static function heavyCompression($compre) {
  598. // The first four bits indicate gain changes in 6.02dB increments which can be
  599. // implemented with an arithmetic shift operation. The following four bits
  600. // indicate linear gain changes, and require a 5-bit multiply.
  601. // We will represent the two 4-bit fields of compr as follows:
  602. // X0 X1 X2 X3 . Y4 Y5 Y6 Y7
  603. // The meaning of the X values is most simply described by considering X to represent a 4-bit
  604. // signed integer with values from -8 to +7. The gain indicated by X is then (X + 1) * 6.02 dB. The
  605. // following table shows this in detail.
  606. // Meaning of 4 msb of compr
  607. // 7 +48.16 dB
  608. // 6 +42.14 dB
  609. // 5 +36.12 dB
  610. // 4 +30.10 dB
  611. // 3 +24.08 dB
  612. // 2 +18.06 dB
  613. // 1 +12.04 dB
  614. // 0 +6.02 dB
  615. // -1 0 dB
  616. // -2 -6.02 dB
  617. // -3 -12.04 dB
  618. // -4 -18.06 dB
  619. // -5 -24.08 dB
  620. // -6 -30.10 dB
  621. // -7 -36.12 dB
  622. // -8 -42.14 dB
  623. $fourbit = str_pad(decbin(($compre & 0xF0) >> 4), 4, '0', STR_PAD_LEFT);
  624. if ($fourbit[0] == '1') {
  625. $log_gain = -8 + bindec(substr($fourbit, 1));
  626. } else {
  627. $log_gain = bindec(substr($fourbit, 1));
  628. }
  629. $log_gain = ($log_gain + 1) * getid3_lib::RGADamplitude2dB(2);
  630. // The value of Y is a linear representation of a gain change of up to -6 dB. Y is considered to
  631. // be an unsigned fractional integer, with a leading value of 1, or: 0.1 Y4 Y5 Y6 Y7 (base 2). Y can
  632. // represent values between 0.111112 (or 31/32) and 0.100002 (or 1/2). Thus, Y can represent gain
  633. // changes from -0.28 dB to -6.02 dB.
  634. $lin_gain = (16 + ($compre & 0x0F)) / 32;
  635. // The combination of X and Y values allows compr to indicate gain changes from
  636. // 48.16 - 0.28 = +47.89 dB, to
  637. // -42.14 - 6.02 = -48.16 dB.
  638. return $log_gain - $lin_gain;
  639. }
  640. /**
  641. * @param int $roomtyp
  642. *
  643. * @return string|false
  644. */
  645. public static function roomTypeLookup($roomtyp) {
  646. static $roomTypeLookup = array(
  647. 0 => 'not indicated',
  648. 1 => 'large room, X curve monitor',
  649. 2 => 'small room, flat monitor',
  650. 3 => 'reserved'
  651. );
  652. return (isset($roomTypeLookup[$roomtyp]) ? $roomTypeLookup[$roomtyp] : false);
  653. }
  654. /**
  655. * @param int $frmsizecod
  656. * @param int $fscod
  657. *
  658. * @return int|false
  659. */
  660. public static function frameSizeLookup($frmsizecod, $fscod) {
  661. // LSB is whether padding is used or not
  662. $padding = (bool) ($frmsizecod & 0x01);
  663. $framesizeid = ($frmsizecod & 0x3E) >> 1;
  664. static $frameSizeLookup = array();
  665. if (empty($frameSizeLookup)) {
  666. $frameSizeLookup = array (
  667. 0 => array( 128, 138, 192), // 32 kbps
  668. 1 => array( 160, 174, 240), // 40 kbps
  669. 2 => array( 192, 208, 288), // 48 kbps
  670. 3 => array( 224, 242, 336), // 56 kbps
  671. 4 => array( 256, 278, 384), // 64 kbps
  672. 5 => array( 320, 348, 480), // 80 kbps
  673. 6 => array( 384, 416, 576), // 96 kbps
  674. 7 => array( 448, 486, 672), // 112 kbps
  675. 8 => array( 512, 556, 768), // 128 kbps
  676. 9 => array( 640, 696, 960), // 160 kbps
  677. 10 => array( 768, 834, 1152), // 192 kbps
  678. 11 => array( 896, 974, 1344), // 224 kbps
  679. 12 => array(1024, 1114, 1536), // 256 kbps
  680. 13 => array(1280, 1392, 1920), // 320 kbps
  681. 14 => array(1536, 1670, 2304), // 384 kbps
  682. 15 => array(1792, 1950, 2688), // 448 kbps
  683. 16 => array(2048, 2228, 3072), // 512 kbps
  684. 17 => array(2304, 2506, 3456), // 576 kbps
  685. 18 => array(2560, 2786, 3840) // 640 kbps
  686. );
  687. }
  688. $paddingBytes = 0;
  689. if (($fscod == 1) && $padding) {
  690. // frame lengths are padded by 1 word (16 bits) at 44100
  691. // (fscode==1) means 44100Hz (see sampleRateCodeLookup)
  692. $paddingBytes = 2;
  693. }
  694. return (isset($frameSizeLookup[$framesizeid][$fscod]) ? $frameSizeLookup[$framesizeid][$fscod] + $paddingBytes : false);
  695. }
  696. /**
  697. * @param int $frmsizecod
  698. *
  699. * @return int|false
  700. */
  701. public static function bitrateLookup($frmsizecod) {
  702. // LSB is whether padding is used or not
  703. $padding = (bool) ($frmsizecod & 0x01);
  704. $framesizeid = ($frmsizecod & 0x3E) >> 1;
  705. static $bitrateLookup = array(
  706. 0 => 32000,
  707. 1 => 40000,
  708. 2 => 48000,
  709. 3 => 56000,
  710. 4 => 64000,
  711. 5 => 80000,
  712. 6 => 96000,
  713. 7 => 112000,
  714. 8 => 128000,
  715. 9 => 160000,
  716. 10 => 192000,
  717. 11 => 224000,
  718. 12 => 256000,
  719. 13 => 320000,
  720. 14 => 384000,
  721. 15 => 448000,
  722. 16 => 512000,
  723. 17 => 576000,
  724. 18 => 640000,
  725. );
  726. return (isset($bitrateLookup[$framesizeid]) ? $bitrateLookup[$framesizeid] : false);
  727. }
  728. /**
  729. * @param int $numblkscod
  730. *
  731. * @return int|false
  732. */
  733. public static function blocksPerSyncFrame($numblkscod) {
  734. static $blocksPerSyncFrameLookup = array(
  735. 0 => 1,
  736. 1 => 2,
  737. 2 => 3,
  738. 3 => 6,
  739. );
  740. return (isset($blocksPerSyncFrameLookup[$numblkscod]) ? $blocksPerSyncFrameLookup[$numblkscod] : false);
  741. }
  742. }