ILIAS  release_5-1 Revision 5.0.0-5477-g43f3e3fab5f
module.audio.aac.php
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1<?php
4// available at http://getid3.sourceforge.net //
5// or http://www.getid3.org //
7// See readme.txt for more details //
9// //
10// module.audio.aac.php //
11// module for analyzing AAC Audio files //
12// dependencies: NONE //
13// ///
15
16
17class getid3_aac
18{
19
20 // new combined constructor
21 function getid3_aac(&$fd, &$ThisFileInfo, $option) {
22
23 if ($option === 'adif') {
24 $this->getAACADIFheaderFilepointer($fd, $ThisFileInfo);
25 }
26 elseif ($option === 'adts') {
27 $this->getAACADTSheaderFilepointer($fd, $ThisFileInfo);
28 }
29 }
30
31
32
33 function getAACADIFheaderFilepointer(&$fd, &$ThisFileInfo) {
34 $ThisFileInfo['fileformat'] = 'aac';
35 $ThisFileInfo['audio']['dataformat'] = 'aac';
36 $ThisFileInfo['audio']['lossless'] = false;
37
38 fseek($fd, $ThisFileInfo['avdataoffset'], SEEK_SET);
39 $AACheader = fread($fd, 1024);
40 $offset = 0;
41
42 if (substr($AACheader, 0, 4) == 'ADIF') {
43
44 // http://faac.sourceforge.net/wiki/index.php?page=ADIF
45
46 // http://libmpeg.org/mpeg4/doc/w2203tfs.pdf
47 // adif_header() {
48 // adif_id 32
49 // copyright_id_present 1
50 // if( copyright_id_present )
51 // copyright_id 72
52 // original_copy 1
53 // home 1
54 // bitstream_type 1
55 // bitrate 23
56 // num_program_config_elements 4
57 // for (i = 0; i < num_program_config_elements + 1; i++ ) {
58 // if( bitstream_type == '0' )
59 // adif_buffer_fullness 20
60 // program_config_element()
61 // }
62 // }
63
64 $AACheaderBitstream = getid3_lib::BigEndian2Bin($AACheader);
65 $bitoffset = 0;
66
67 $ThisFileInfo['aac']['header_type'] = 'ADIF';
68 $bitoffset += 32;
69 $ThisFileInfo['aac']['header']['mpeg_version'] = 4;
70
71 $ThisFileInfo['aac']['header']['copyright'] = (bool) (substr($AACheaderBitstream, $bitoffset, 1) == '1');
72 $bitoffset += 1;
73 if ($ThisFileInfo['aac']['header']['copyright']) {
74 $ThisFileInfo['aac']['header']['copyright_id'] = getid3_lib::Bin2String(substr($AACheaderBitstream, $bitoffset, 72));
75 $bitoffset += 72;
76 }
77 $ThisFileInfo['aac']['header']['original_copy'] = (bool) (substr($AACheaderBitstream, $bitoffset, 1) == '1');
78 $bitoffset += 1;
79 $ThisFileInfo['aac']['header']['home'] = (bool) (substr($AACheaderBitstream, $bitoffset, 1) == '1');
80 $bitoffset += 1;
81 $ThisFileInfo['aac']['header']['is_vbr'] = (bool) (substr($AACheaderBitstream, $bitoffset, 1) == '1');
82 $bitoffset += 1;
83 if ($ThisFileInfo['aac']['header']['is_vbr']) {
84 $ThisFileInfo['audio']['bitrate_mode'] = 'vbr';
85 $ThisFileInfo['aac']['header']['bitrate_max'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 23));
86 $bitoffset += 23;
87 } else {
88 $ThisFileInfo['audio']['bitrate_mode'] = 'cbr';
89 $ThisFileInfo['aac']['header']['bitrate'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 23));
90 $bitoffset += 23;
91 $ThisFileInfo['audio']['bitrate'] = $ThisFileInfo['aac']['header']['bitrate'];
92 }
93 if ($ThisFileInfo['audio']['bitrate'] == 0) {
94 $ThisFileInfo['error'][] = 'Corrupt AAC file: bitrate_audio == zero';
95 return false;
96 }
97 $ThisFileInfo['aac']['header']['num_program_configs'] = 1 + getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
98 $bitoffset += 4;
99
100 for ($i = 0; $i < $ThisFileInfo['aac']['header']['num_program_configs']; $i++) {
101 // http://www.audiocoding.com/wiki/index.php?page=program_config_element
102
103 // buffer_fullness 20
104
105 // element_instance_tag 4
106 // object_type 2
107 // sampling_frequency_index 4
108 // num_front_channel_elements 4
109 // num_side_channel_elements 4
110 // num_back_channel_elements 4
111 // num_lfe_channel_elements 2
112 // num_assoc_data_elements 3
113 // num_valid_cc_elements 4
114 // mono_mixdown_present 1
115 // mono_mixdown_element_number 4 if mono_mixdown_present == 1
116 // stereo_mixdown_present 1
117 // stereo_mixdown_element_number 4 if stereo_mixdown_present == 1
118 // matrix_mixdown_idx_present 1
119 // matrix_mixdown_idx 2 if matrix_mixdown_idx_present == 1
120 // pseudo_surround_enable 1 if matrix_mixdown_idx_present == 1
121 // for (i = 0; i < num_front_channel_elements; i++) {
122 // front_element_is_cpe[i] 1
123 // front_element_tag_select[i] 4
124 // }
125 // for (i = 0; i < num_side_channel_elements; i++) {
126 // side_element_is_cpe[i] 1
127 // side_element_tag_select[i] 4
128 // }
129 // for (i = 0; i < num_back_channel_elements; i++) {
130 // back_element_is_cpe[i] 1
131 // back_element_tag_select[i] 4
132 // }
133 // for (i = 0; i < num_lfe_channel_elements; i++) {
134 // lfe_element_tag_select[i] 4
135 // }
136 // for (i = 0; i < num_assoc_data_elements; i++) {
137 // assoc_data_element_tag_select[i] 4
138 // }
139 // for (i = 0; i < num_valid_cc_elements; i++) {
140 // cc_element_is_ind_sw[i] 1
141 // valid_cc_element_tag_select[i] 4
142 // }
143 // byte_alignment() VAR
144 // comment_field_bytes 8
145 // for (i = 0; i < comment_field_bytes; i++) {
146 // comment_field_data[i] 8
147 // }
148
149 if (!$ThisFileInfo['aac']['header']['is_vbr']) {
150 $ThisFileInfo['aac']['program_configs'][$i]['buffer_fullness'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 20));
151 $bitoffset += 20;
152 }
153 $ThisFileInfo['aac']['program_configs'][$i]['element_instance_tag'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
154 $bitoffset += 4;
155 $ThisFileInfo['aac']['program_configs'][$i]['object_type'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 2));
156 $bitoffset += 2;
157 $ThisFileInfo['aac']['program_configs'][$i]['sampling_frequency_index'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
158 $bitoffset += 4;
159 $ThisFileInfo['aac']['program_configs'][$i]['num_front_channel_elements'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
160 $bitoffset += 4;
161 $ThisFileInfo['aac']['program_configs'][$i]['num_side_channel_elements'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
162 $bitoffset += 4;
163 $ThisFileInfo['aac']['program_configs'][$i]['num_back_channel_elements'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
164 $bitoffset += 4;
165 $ThisFileInfo['aac']['program_configs'][$i]['num_lfe_channel_elements'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 2));
166 $bitoffset += 2;
167 $ThisFileInfo['aac']['program_configs'][$i]['num_assoc_data_elements'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 3));
168 $bitoffset += 3;
169 $ThisFileInfo['aac']['program_configs'][$i]['num_valid_cc_elements'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
170 $bitoffset += 4;
171 $ThisFileInfo['aac']['program_configs'][$i]['mono_mixdown_present'] = (bool) getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
172 $bitoffset += 1;
173 if ($ThisFileInfo['aac']['program_configs'][$i]['mono_mixdown_present']) {
174 $ThisFileInfo['aac']['program_configs'][$i]['mono_mixdown_element_number'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
175 $bitoffset += 4;
176 }
177 $ThisFileInfo['aac']['program_configs'][$i]['stereo_mixdown_present'] = (bool) getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
178 $bitoffset += 1;
179 if ($ThisFileInfo['aac']['program_configs'][$i]['stereo_mixdown_present']) {
180 $ThisFileInfo['aac']['program_configs'][$i]['stereo_mixdown_element_number'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
181 $bitoffset += 4;
182 }
183 $ThisFileInfo['aac']['program_configs'][$i]['matrix_mixdown_idx_present'] = (bool) getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
184 $bitoffset += 1;
185 if ($ThisFileInfo['aac']['program_configs'][$i]['matrix_mixdown_idx_present']) {
186 $ThisFileInfo['aac']['program_configs'][$i]['matrix_mixdown_idx'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 2));
187 $bitoffset += 2;
188 $ThisFileInfo['aac']['program_configs'][$i]['pseudo_surround_enable'] = (bool) getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
189 $bitoffset += 1;
190 }
191 for ($j = 0; $j < $ThisFileInfo['aac']['program_configs'][$i]['num_front_channel_elements']; $j++) {
192 $ThisFileInfo['aac']['program_configs'][$i]['front_element_is_cpe'][$j] = (bool) getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
193 $bitoffset += 1;
194 $ThisFileInfo['aac']['program_configs'][$i]['front_element_tag_select'][$j] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
195 $bitoffset += 4;
196 }
197 for ($j = 0; $j < $ThisFileInfo['aac']['program_configs'][$i]['num_side_channel_elements']; $j++) {
198 $ThisFileInfo['aac']['program_configs'][$i]['side_element_is_cpe'][$j] = (bool) getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
199 $bitoffset += 1;
200 $ThisFileInfo['aac']['program_configs'][$i]['side_element_tag_select'][$j] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
201 $bitoffset += 4;
202 }
203 for ($j = 0; $j < $ThisFileInfo['aac']['program_configs'][$i]['num_back_channel_elements']; $j++) {
204 $ThisFileInfo['aac']['program_configs'][$i]['back_element_is_cpe'][$j] = (bool) getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
205 $bitoffset += 1;
206 $ThisFileInfo['aac']['program_configs'][$i]['back_element_tag_select'][$j] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
207 $bitoffset += 4;
208 }
209 for ($j = 0; $j < $ThisFileInfo['aac']['program_configs'][$i]['num_lfe_channel_elements']; $j++) {
210 $ThisFileInfo['aac']['program_configs'][$i]['lfe_element_tag_select'][$j] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
211 $bitoffset += 4;
212 }
213 for ($j = 0; $j < $ThisFileInfo['aac']['program_configs'][$i]['num_assoc_data_elements']; $j++) {
214 $ThisFileInfo['aac']['program_configs'][$i]['assoc_data_element_tag_select'][$j] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
215 $bitoffset += 4;
216 }
217 for ($j = 0; $j < $ThisFileInfo['aac']['program_configs'][$i]['num_valid_cc_elements']; $j++) {
218 $ThisFileInfo['aac']['program_configs'][$i]['cc_element_is_ind_sw'][$j] = (bool) getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
219 $bitoffset += 1;
220 $ThisFileInfo['aac']['program_configs'][$i]['valid_cc_element_tag_select'][$j] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
221 $bitoffset += 4;
222 }
223
224 $bitoffset = ceil($bitoffset / 8) * 8;
225
226 $ThisFileInfo['aac']['program_configs'][$i]['comment_field_bytes'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 8));
227 $bitoffset += 8;
228 $ThisFileInfo['aac']['program_configs'][$i]['comment_field'] = getid3_lib::Bin2String(substr($AACheaderBitstream, $bitoffset, 8 * $ThisFileInfo['aac']['program_configs'][$i]['comment_field_bytes']));
229 $bitoffset += 8 * $ThisFileInfo['aac']['program_configs'][$i]['comment_field_bytes'];
230
231
232 $ThisFileInfo['aac']['header']['profile_text'] = $this->AACprofileLookup($ThisFileInfo['aac']['program_configs'][$i]['object_type'], $ThisFileInfo['aac']['header']['mpeg_version']);
233 $ThisFileInfo['aac']['program_configs'][$i]['sampling_frequency'] = $this->AACsampleRateLookup($ThisFileInfo['aac']['program_configs'][$i]['sampling_frequency_index']);
234 $ThisFileInfo['audio']['sample_rate'] = $ThisFileInfo['aac']['program_configs'][$i]['sampling_frequency'];
235 $ThisFileInfo['audio']['channels'] = $this->AACchannelCountCalculate($ThisFileInfo['aac']['program_configs'][$i]);
236 if ($ThisFileInfo['aac']['program_configs'][$i]['comment_field']) {
237 $ThisFileInfo['aac']['comments'][] = $ThisFileInfo['aac']['program_configs'][$i]['comment_field'];
238 }
239 }
240 $ThisFileInfo['playtime_seconds'] = (($ThisFileInfo['avdataend'] - $ThisFileInfo['avdataoffset']) * 8) / $ThisFileInfo['audio']['bitrate'];
241
242 $ThisFileInfo['audio']['encoder_options'] = $ThisFileInfo['aac']['header_type'].' '.$ThisFileInfo['aac']['header']['profile_text'];
243
244
245
246 return true;
247
248 } else {
249
250 unset($ThisFileInfo['fileformat']);
251 unset($ThisFileInfo['aac']);
252 $ThisFileInfo['error'][] = 'AAC-ADIF synch not found at offset '.$ThisFileInfo['avdataoffset'].' (expected "ADIF", found "'.substr($AACheader, 0, 4).'" instead)';
253 return false;
254
255 }
256
257 }
258
259
260 function getAACADTSheaderFilepointer(&$fd, &$ThisFileInfo, $MaxFramesToScan=1000000, $ReturnExtendedInfo=false) {
261 // based loosely on code from AACfile by Jurgen Faul <jfaulØgmx.de>
262 // http://jfaul.de/atl or http://j-faul.virtualave.net/atl/atl.html
263
264
265 // http://faac.sourceforge.net/wiki/index.php?page=ADTS
266
267 // * ADTS Fixed Header: these don't change from frame to frame
268 // syncword 12 always: '111111111111'
269 // ID 1 0: MPEG-4, 1: MPEG-2
270 // layer 2 always: '00'
271 // protection_absent 1
272 // profile 2
273 // sampling_frequency_index 4
274 // private_bit 1
275 // channel_configuration 3
276 // original/copy 1
277 // home 1
278 // emphasis 2 only if ID == 0 (ie MPEG-4)
279
280 // * ADTS Variable Header: these can change from frame to frame
281 // copyright_identification_bit 1
282 // copyright_identification_start 1
283 // aac_frame_length 13 length of the frame including header (in bytes)
284 // adts_buffer_fullness 11 0x7FF indicates VBR
285 // no_raw_data_blocks_in_frame 2
286
287 // * ADTS Error check
288 // crc_check 16 only if protection_absent == 0
289
290 $byteoffset = 0;
291 $framenumber = 0;
292
293 // Init bit pattern array
294 static $decbin = array();
295
296 // Populate $bindec
297 for ($i = 0; $i < 256; $i++) {
298 $decbin[chr($i)] = str_pad(decbin($i), 8, '0', STR_PAD_LEFT);
299 }
300
301 // used to calculate bitrate below
302 $BitrateCache = array();
303
304
305 while (true) {
306 // breaks out when end-of-file encountered, or invalid data found,
307 // or MaxFramesToScan frames have been scanned
308
309 fseek($fd, $byteoffset, SEEK_SET);
310
311 // First get substring
312 $substring = fread($fd, 10);
313 $substringlength = strlen($substring);
314 if ($substringlength != 10) {
315 $ThisFileInfo['error'][] = 'Failed to read 10 bytes at offset '.(ftell($fd) - $substringlength).' (only read '.$substringlength.' bytes)';
316 return false;
317 }
318
319 // Initialise $AACheaderBitstream
320 $AACheaderBitstream = '';
321
322 // Loop thru substring chars
323 for ($i = 0; $i < 10; $i++) {
324 $AACheaderBitstream .= $decbin[$substring{$i}];
325 }
326
327 $bitoffset = 0;
328
329 $synctest = bindec(substr($AACheaderBitstream, $bitoffset, 12));
330
331 $bitoffset += 12;
332 if ($synctest != 0x0FFF) {
333 $ThisFileInfo['error'][] = 'Synch pattern (0x0FFF) not found at offset '.(ftell($fd) - 10).' (found 0x0'.strtoupper(dechex($synctest)).' instead)';
334 if ($ThisFileInfo['fileformat'] == 'aac') {
335 return true;
336 }
337 return false;
338 }
339
340 // Gather info for first frame only - this takes time to do 1000 times!
341 if ($framenumber > 0) {
342
343 if (!$AACheaderBitstream[$bitoffset]) {
344
345 // MPEG-4
346 $bitoffset += 20;
347
348 } else {
349
350 // MPEG-2
351 $bitoffset += 18;
352
353 }
354
355 } else {
356
357 $ThisFileInfo['aac']['header_type'] = 'ADTS';
358 $ThisFileInfo['aac']['header']['synch'] = $synctest;
359 $ThisFileInfo['fileformat'] = 'aac';
360 $ThisFileInfo['audio']['dataformat'] = 'aac';
361
362 $ThisFileInfo['aac']['header']['mpeg_version'] = ((substr($AACheaderBitstream, $bitoffset, 1) == '0') ? 4 : 2);
363 $bitoffset += 1;
364 $ThisFileInfo['aac']['header']['layer'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 2));
365 $bitoffset += 2;
366 if ($ThisFileInfo['aac']['header']['layer'] != 0) {
367 $ThisFileInfo['error'][] = 'Layer error - expected 0x00, found 0x'.dechex($ThisFileInfo['aac']['header']['layer']).' instead';
368 return false;
369 }
370 $ThisFileInfo['aac']['header']['crc_present'] = ((substr($AACheaderBitstream, $bitoffset, 1) == '0') ? true : false);
371 $bitoffset += 1;
372 $ThisFileInfo['aac']['header']['profile_id'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 2));
373 $bitoffset += 2;
374 $ThisFileInfo['aac']['header']['profile_text'] = $this->AACprofileLookup($ThisFileInfo['aac']['header']['profile_id'], $ThisFileInfo['aac']['header']['mpeg_version']);
375
376 $ThisFileInfo['aac']['header']['sample_frequency_index'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
377 $bitoffset += 4;
378 $ThisFileInfo['aac']['header']['sample_frequency'] = $this->AACsampleRateLookup($ThisFileInfo['aac']['header']['sample_frequency_index']);
379 if ($ThisFileInfo['aac']['header']['sample_frequency'] == 0) {
380 $ThisFileInfo['error'][] = 'Corrupt AAC file: sample_frequency == zero';
381 return false;
382 }
383 $ThisFileInfo['audio']['sample_rate'] = $ThisFileInfo['aac']['header']['sample_frequency'];
384
385 $ThisFileInfo['aac']['header']['private'] = (bool) getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
386 $bitoffset += 1;
387 $ThisFileInfo['aac']['header']['channel_configuration'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 3));
388 $bitoffset += 3;
389 $ThisFileInfo['audio']['channels'] = $ThisFileInfo['aac']['header']['channel_configuration'];
390 $ThisFileInfo['aac']['header']['original'] = (bool) getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
391 $bitoffset += 1;
392 $ThisFileInfo['aac']['header']['home'] = (bool) getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
393 $bitoffset += 1;
394
395 if ($ThisFileInfo['aac']['header']['mpeg_version'] == 4) {
396 $ThisFileInfo['aac']['header']['emphasis'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 2));
397 $bitoffset += 2;
398 }
399
400 if ($ReturnExtendedInfo) {
401
402 $ThisFileInfo['aac'][$framenumber]['copyright_id_bit'] = (bool) getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
403 $bitoffset += 1;
404 $ThisFileInfo['aac'][$framenumber]['copyright_id_start'] = (bool) getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
405 $bitoffset += 1;
406
407 } else {
408
409 $bitoffset += 2;
410
411 }
412
413 }
414
415 $FrameLength = bindec(substr($AACheaderBitstream, $bitoffset, 13));
416
417 if (!isset($BitrateCache[$FrameLength])) {
418 $BitrateCache[$FrameLength] = ($ThisFileInfo['aac']['header']['sample_frequency'] / 1024) * $FrameLength * 8;
419 }
420 @$ThisFileInfo['aac']['bitrate_distribution'][$BitrateCache[$FrameLength]]++;
421
422 $ThisFileInfo['aac'][$framenumber]['aac_frame_length'] = $FrameLength;
423 $bitoffset += 13;
424 $ThisFileInfo['aac'][$framenumber]['adts_buffer_fullness'] = bindec(substr($AACheaderBitstream, $bitoffset, 11));
425 $bitoffset += 11;
426 if ($ThisFileInfo['aac'][$framenumber]['adts_buffer_fullness'] == 0x07FF) {
427 $ThisFileInfo['audio']['bitrate_mode'] = 'vbr';
428 } else {
429 $ThisFileInfo['audio']['bitrate_mode'] = 'cbr';
430 }
431 $ThisFileInfo['aac'][$framenumber]['num_raw_data_blocks'] = bindec(substr($AACheaderBitstream, $bitoffset, 2));
432 $bitoffset += 2;
433
434 if ($ThisFileInfo['aac']['header']['crc_present']) {
435 //$ThisFileInfo['aac'][$framenumber]['crc'] = bindec(substr($AACheaderBitstream, $bitoffset, 16));
436 $bitoffset += 16;
437 }
438
439 if (!$ReturnExtendedInfo) {
440 unset($ThisFileInfo['aac'][$framenumber]);
441 }
442
443 $byteoffset += $FrameLength;
444 if ((++$framenumber < $MaxFramesToScan) && (($byteoffset + 10) < $ThisFileInfo['avdataend'])) {
445
446 // keep scanning
447
448 } else {
449
450 $ThisFileInfo['aac']['frames'] = $framenumber;
451 $ThisFileInfo['playtime_seconds'] = ($ThisFileInfo['avdataend'] / $byteoffset) * (($framenumber * 1024) / $ThisFileInfo['aac']['header']['sample_frequency']); // (1 / % of file scanned) * (samples / (samples/sec)) = seconds
452 if ($ThisFileInfo['playtime_seconds'] == 0) {
453 $ThisFileInfo['error'][] = 'Corrupt AAC file: playtime_seconds == zero';
454 return false;
455 }
456 $ThisFileInfo['audio']['bitrate'] = (($ThisFileInfo['avdataend'] - $ThisFileInfo['avdataoffset']) * 8) / $ThisFileInfo['playtime_seconds'];
457 ksort($ThisFileInfo['aac']['bitrate_distribution']);
458
459 $ThisFileInfo['audio']['encoder_options'] = $ThisFileInfo['aac']['header_type'].' '.$ThisFileInfo['aac']['header']['profile_text'];
460
461 return true;
462
463 }
464 }
465 // should never get here.
466 }
467
468 function AACsampleRateLookup($samplerateid) {
469 static $AACsampleRateLookup = array();
470 if (empty($AACsampleRateLookup)) {
471 $AACsampleRateLookup[0] = 96000;
472 $AACsampleRateLookup[1] = 88200;
473 $AACsampleRateLookup[2] = 64000;
474 $AACsampleRateLookup[3] = 48000;
475 $AACsampleRateLookup[4] = 44100;
476 $AACsampleRateLookup[5] = 32000;
477 $AACsampleRateLookup[6] = 24000;
478 $AACsampleRateLookup[7] = 22050;
479 $AACsampleRateLookup[8] = 16000;
480 $AACsampleRateLookup[9] = 12000;
481 $AACsampleRateLookup[10] = 11025;
482 $AACsampleRateLookup[11] = 8000;
483 $AACsampleRateLookup[12] = 0;
484 $AACsampleRateLookup[13] = 0;
485 $AACsampleRateLookup[14] = 0;
486 $AACsampleRateLookup[15] = 0;
487 }
488 return (isset($AACsampleRateLookup[$samplerateid]) ? $AACsampleRateLookup[$samplerateid] : 'invalid');
489 }
490
491 function AACprofileLookup($profileid, $mpegversion) {
492 static $AACprofileLookup = array();
493 if (empty($AACprofileLookup)) {
494 $AACprofileLookup[2][0] = 'Main profile';
495 $AACprofileLookup[2][1] = 'Low Complexity profile (LC)';
496 $AACprofileLookup[2][2] = 'Scalable Sample Rate profile (SSR)';
497 $AACprofileLookup[2][3] = '(reserved)';
498 $AACprofileLookup[4][0] = 'AAC_MAIN';
499 $AACprofileLookup[4][1] = 'AAC_LC';
500 $AACprofileLookup[4][2] = 'AAC_SSR';
501 $AACprofileLookup[4][3] = 'AAC_LTP';
502 }
503 return (isset($AACprofileLookup[$mpegversion][$profileid]) ? $AACprofileLookup[$mpegversion][$profileid] : 'invalid');
504 }
505
506 function AACchannelCountCalculate($program_configs) {
507 $channels = 0;
508 for ($i = 0; $i < $program_configs['num_front_channel_elements']; $i++) {
509 $channels++;
510 if ($program_configs['front_element_is_cpe'][$i]) {
511 // each front element is channel pair (CPE = Channel Pair Element)
512 $channels++;
513 }
514 }
515 for ($i = 0; $i < $program_configs['num_side_channel_elements']; $i++) {
516 $channels++;
517 if ($program_configs['side_element_is_cpe'][$i]) {
518 // each side element is channel pair (CPE = Channel Pair Element)
519 $channels++;
520 }
521 }
522 for ($i = 0; $i < $program_configs['num_back_channel_elements']; $i++) {
523 $channels++;
524 if ($program_configs['back_element_is_cpe'][$i]) {
525 // each back element is channel pair (CPE = Channel Pair Element)
526 $channels++;
527 }
528 }
529 for ($i = 0; $i < $program_configs['num_lfe_channel_elements']; $i++) {
530 $channels++;
531 }
532 return $channels;
533 }
534
535}
536
537
538?>
getid3_aac
getID3() by James Heinrich info@getid3.org //
Definition: module.audio.aac.php:18
getid3_aac\getAACADTSheaderFilepointer
getAACADTSheaderFilepointer(&$fd, &$ThisFileInfo, $MaxFramesToScan=1000000, $ReturnExtendedInfo=false)
Definition: module.audio.aac.php:260
getid3_aac\getid3_aac
getid3_aac(&$fd, &$ThisFileInfo, $option)
Definition: module.audio.aac.php:21
getid3_aac\AACchannelCountCalculate
AACchannelCountCalculate($program_configs)
Definition: module.audio.aac.php:506
getid3_aac\AACsampleRateLookup
AACsampleRateLookup($samplerateid)
Definition: module.audio.aac.php:468
getid3_aac\AACprofileLookup
AACprofileLookup($profileid, $mpegversion)
Definition: module.audio.aac.php:491
getid3_aac\getAACADIFheaderFilepointer
getAACADIFheaderFilepointer(&$fd, &$ThisFileInfo)
Definition: module.audio.aac.php:33
getid3_aac\getAACADIFheaderFilepointer
getAACADIFheaderFilepointer()
Definition: module.audio.aac.php:33
getid3_handler\fseek
fseek($bytes, $whence=SEEK_SET)
Definition: getid3.php:1697
getid3_handler\fread
fread($bytes)
Definition: getid3.php:1685
getid3_lib\BigEndian2Bin
BigEndian2Bin($byteword)
Definition: getid3.lib.php:271
getid3_lib\Bin2String
Bin2String($binstring)
Definition: getid3.lib.php:332
getid3_lib\Bin2Dec
Bin2Dec($binstring, $signed=false)
Definition: getid3.lib.php:316