ILIAS  release_5-4 Revision v5.4.26-12-gabc799a52e6
Public Member Functions | Static Public Member Functions
getid3_aac Class Reference

getID3() by James Heinrich info@.nosp@m.geti.nosp@m.d3.or.nosp@m.g // More...

+ Inheritance diagram for getid3_aac:
+ Collaboration diagram for getid3_aac:

Public Member Functions

 Analyze ()
 
 getAACADIFheaderFilepointer ()
 
 getAACADTSheaderFilepointer ($MaxFramesToScan=1000000, $ReturnExtendedInfo=false)
 
- Public Member Functions inherited from getid3_handler
 __construct (getID3 $getid3, $call_module=null)
 
 Analyze ()
 
 AnalyzeString ($string)
 
 setStringMode ($string)
 
 saveAttachment ($name, $offset, $length, $image_mime=null)
 

Static Public Member Functions

static AACsampleRateLookup ($samplerateid)
 
static AACprofileLookup ($profileid, $mpegversion)
 
static AACchannelCountCalculate ($program_configs)
 

Additional Inherited Members

- Protected Member Functions inherited from getid3_handler
 ftell ()
 
 fread ($bytes)
 
 fseek ($bytes, $whence=SEEK_SET)
 
 feof ()
 
 isDependencyFor ($module)
 
 error ($text)
 
 warning ($text)
 
 notice ($text)
 
- Protected Attributes inherited from getid3_handler
 $getid3
 
 $data_string_flag = false
 
 $data_string = ''
 
 $data_string_position = 0
 
 $data_string_length = 0
 

Detailed Description

getID3() by James Heinrich info@.nosp@m.geti.nosp@m.d3.or.nosp@m.g //

Definition at line 18 of file module.audio.aac.php.

Member Function Documentation

◆ AACchannelCountCalculate()

static getid3_aac::AACchannelCountCalculate (   $program_configs)
static

Definition at line 484 of file module.audio.aac.php.

484 {
485 $channels = 0;
486 for ($i = 0; $i < $program_configs['num_front_channel_elements']; $i++) {
487 $channels++;
488 if ($program_configs['front_element_is_cpe'][$i]) {
489 // each front element is channel pair (CPE = Channel Pair Element)
490 $channels++;
491 }
492 }
493 for ($i = 0; $i < $program_configs['num_side_channel_elements']; $i++) {
494 $channels++;
495 if ($program_configs['side_element_is_cpe'][$i]) {
496 // each side element is channel pair (CPE = Channel Pair Element)
497 $channels++;
498 }
499 }
500 for ($i = 0; $i < $program_configs['num_back_channel_elements']; $i++) {
501 $channels++;
502 if ($program_configs['back_element_is_cpe'][$i]) {
503 // each back element is channel pair (CPE = Channel Pair Element)
504 $channels++;
505 }
506 }
507 for ($i = 0; $i < $program_configs['num_lfe_channel_elements']; $i++) {
508 $channels++;
509 }
510 return $channels;
511 }
$i
$i
Definition: disco.tpl.php:19

References $i.

Referenced by getAACADIFheaderFilepointer().

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◆ AACprofileLookup()

static getid3_aac::AACprofileLookup (   $profileid,
  $mpegversion 
)
static

Definition at line 469 of file module.audio.aac.php.

469 {
470 static $AACprofileLookup = array();
471 if (empty($AACprofileLookup)) {
472 $AACprofileLookup[2][0] = 'Main profile';
473 $AACprofileLookup[2][1] = 'Low Complexity profile (LC)';
474 $AACprofileLookup[2][2] = 'Scalable Sample Rate profile (SSR)';
475 $AACprofileLookup[2][3] = '(reserved)';
476 $AACprofileLookup[4][0] = 'AAC_MAIN';
477 $AACprofileLookup[4][1] = 'AAC_LC';
478 $AACprofileLookup[4][2] = 'AAC_SSR';
479 $AACprofileLookup[4][3] = 'AAC_LTP';
480 }
481 return (isset($AACprofileLookup[$mpegversion][$profileid]) ? $AACprofileLookup[$mpegversion][$profileid] : 'invalid');
482 }

Referenced by getAACADIFheaderFilepointer(), and getAACADTSheaderFilepointer().

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◆ AACsampleRateLookup()

static getid3_aac::AACsampleRateLookup (   $samplerateid)
static

Definition at line 446 of file module.audio.aac.php.

446 {
447 static $AACsampleRateLookup = array();
448 if (empty($AACsampleRateLookup)) {
449 $AACsampleRateLookup[0] = 96000;
450 $AACsampleRateLookup[1] = 88200;
451 $AACsampleRateLookup[2] = 64000;
452 $AACsampleRateLookup[3] = 48000;
453 $AACsampleRateLookup[4] = 44100;
454 $AACsampleRateLookup[5] = 32000;
455 $AACsampleRateLookup[6] = 24000;
456 $AACsampleRateLookup[7] = 22050;
457 $AACsampleRateLookup[8] = 16000;
458 $AACsampleRateLookup[9] = 12000;
459 $AACsampleRateLookup[10] = 11025;
460 $AACsampleRateLookup[11] = 8000;
461 $AACsampleRateLookup[12] = 0;
462 $AACsampleRateLookup[13] = 0;
463 $AACsampleRateLookup[14] = 0;
464 $AACsampleRateLookup[15] = 0;
465 }
466 return (isset($AACsampleRateLookup[$samplerateid]) ? $AACsampleRateLookup[$samplerateid] : 'invalid');
467 }

Referenced by getAACADIFheaderFilepointer(), and getAACADTSheaderFilepointer().

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◆ Analyze()

getid3_aac::Analyze ( )

Reimplemented from getid3_handler.

Definition at line 20 of file module.audio.aac.php.

20 {
21 $info = &$this->getid3->info;
22 $this->fseek($info['avdataoffset']);
23 if ($this->fread(4) == 'ADIF') {
24 $this->getAACADIFheaderFilepointer();
25 } else {
26 $this->getAACADTSheaderFilepointer();
27 }
28 return true;
29 }
getid3_aac\getAACADTSheaderFilepointer
getAACADTSheaderFilepointer($MaxFramesToScan=1000000, $ReturnExtendedInfo=false)
Definition: module.audio.aac.php:261
getid3_aac\getAACADIFheaderFilepointer
getAACADIFheaderFilepointer()
Definition: module.audio.aac.php:33
getid3_handler\fseek
fseek($bytes, $whence=SEEK_SET)
Definition: getid3.php:1711
getid3_handler\fread
fread($bytes)
Definition: getid3.php:1683
$info
$info
Definition: index.php:5

References $info, getid3_handler\fread(), getid3_handler\fseek(), getAACADIFheaderFilepointer(), and getAACADTSheaderFilepointer().

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◆ getAACADIFheaderFilepointer()

getid3_aac::getAACADIFheaderFilepointer ( )

Definition at line 33 of file module.audio.aac.php.

33 {
34 $info = &$this->getid3->info;
35 $info['fileformat'] = 'aac';
36 $info['audio']['dataformat'] = 'aac';
37 $info['audio']['lossless'] = false;
38
39 $this->fseek($info['avdataoffset']);
40 $AACheader = $this->fread(1024);
41 $offset = 0;
42
43 if (substr($AACheader, 0, 4) == 'ADIF') {
44
45 // http://faac.sourceforge.net/wiki/index.php?page=ADIF
46
47 // http://libmpeg.org/mpeg4/doc/w2203tfs.pdf
48 // adif_header() {
49 // adif_id 32
50 // copyright_id_present 1
51 // if( copyright_id_present )
52 // copyright_id 72
53 // original_copy 1
54 // home 1
55 // bitstream_type 1
56 // bitrate 23
57 // num_program_config_elements 4
58 // for (i = 0; i < num_program_config_elements + 1; i++ ) {
59 // if( bitstream_type == '0' )
60 // adif_buffer_fullness 20
61 // program_config_element()
62 // }
63 // }
64
65 $AACheaderBitstream = getid3_lib::BigEndian2Bin($AACheader);
66 $bitoffset = 0;
67
68 $info['aac']['header_type'] = 'ADIF';
69 $bitoffset += 32;
70 $info['aac']['header']['mpeg_version'] = 4;
71
72 $info['aac']['header']['copyright'] = (bool) (substr($AACheaderBitstream, $bitoffset, 1) == '1');
73 $bitoffset += 1;
74 if ($info['aac']['header']['copyright']) {
75 $info['aac']['header']['copyright_id'] = getid3_lib::Bin2String(substr($AACheaderBitstream, $bitoffset, 72));
76 $bitoffset += 72;
77 }
78 $info['aac']['header']['original_copy'] = (bool) (substr($AACheaderBitstream, $bitoffset, 1) == '1');
79 $bitoffset += 1;
80 $info['aac']['header']['home'] = (bool) (substr($AACheaderBitstream, $bitoffset, 1) == '1');
81 $bitoffset += 1;
82 $info['aac']['header']['is_vbr'] = (bool) (substr($AACheaderBitstream, $bitoffset, 1) == '1');
83 $bitoffset += 1;
84 if ($info['aac']['header']['is_vbr']) {
85 $info['audio']['bitrate_mode'] = 'vbr';
86 $info['aac']['header']['bitrate_max'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 23));
87 $bitoffset += 23;
88 } else {
89 $info['audio']['bitrate_mode'] = 'cbr';
90 $info['aac']['header']['bitrate'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 23));
91 $bitoffset += 23;
92 $info['audio']['bitrate'] = $info['aac']['header']['bitrate'];
93 }
94 if ($info['audio']['bitrate'] == 0) {
95 $this->error('Corrupt AAC file: bitrate_audio == zero');
96 return false;
97 }
98 $info['aac']['header']['num_program_configs'] = 1 + getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
99 $bitoffset += 4;
100
101 for ($i = 0; $i < $info['aac']['header']['num_program_configs']; $i++) {
102 // http://www.audiocoding.com/wiki/index.php?page=program_config_element
103
104 // buffer_fullness 20
105
106 // element_instance_tag 4
107 // object_type 2
108 // sampling_frequency_index 4
109 // num_front_channel_elements 4
110 // num_side_channel_elements 4
111 // num_back_channel_elements 4
112 // num_lfe_channel_elements 2
113 // num_assoc_data_elements 3
114 // num_valid_cc_elements 4
115 // mono_mixdown_present 1
116 // mono_mixdown_element_number 4 if mono_mixdown_present == 1
117 // stereo_mixdown_present 1
118 // stereo_mixdown_element_number 4 if stereo_mixdown_present == 1
119 // matrix_mixdown_idx_present 1
120 // matrix_mixdown_idx 2 if matrix_mixdown_idx_present == 1
121 // pseudo_surround_enable 1 if matrix_mixdown_idx_present == 1
122 // for (i = 0; i < num_front_channel_elements; i++) {
123 // front_element_is_cpe[i] 1
124 // front_element_tag_select[i] 4
125 // }
126 // for (i = 0; i < num_side_channel_elements; i++) {
127 // side_element_is_cpe[i] 1
128 // side_element_tag_select[i] 4
129 // }
130 // for (i = 0; i < num_back_channel_elements; i++) {
131 // back_element_is_cpe[i] 1
132 // back_element_tag_select[i] 4
133 // }
134 // for (i = 0; i < num_lfe_channel_elements; i++) {
135 // lfe_element_tag_select[i] 4
136 // }
137 // for (i = 0; i < num_assoc_data_elements; i++) {
138 // assoc_data_element_tag_select[i] 4
139 // }
140 // for (i = 0; i < num_valid_cc_elements; i++) {
141 // cc_element_is_ind_sw[i] 1
142 // valid_cc_element_tag_select[i] 4
143 // }
144 // byte_alignment() VAR
145 // comment_field_bytes 8
146 // for (i = 0; i < comment_field_bytes; i++) {
147 // comment_field_data[i] 8
148 // }
149
150 if (!$info['aac']['header']['is_vbr']) {
151 $info['aac']['program_configs'][$i]['buffer_fullness'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 20));
152 $bitoffset += 20;
153 }
154 $info['aac']['program_configs'][$i]['element_instance_tag'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
155 $bitoffset += 4;
156 $info['aac']['program_configs'][$i]['object_type'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 2));
157 $bitoffset += 2;
158 $info['aac']['program_configs'][$i]['sampling_frequency_index'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
159 $bitoffset += 4;
160 $info['aac']['program_configs'][$i]['num_front_channel_elements'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
161 $bitoffset += 4;
162 $info['aac']['program_configs'][$i]['num_side_channel_elements'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
163 $bitoffset += 4;
164 $info['aac']['program_configs'][$i]['num_back_channel_elements'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
165 $bitoffset += 4;
166 $info['aac']['program_configs'][$i]['num_lfe_channel_elements'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 2));
167 $bitoffset += 2;
168 $info['aac']['program_configs'][$i]['num_assoc_data_elements'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 3));
169 $bitoffset += 3;
170 $info['aac']['program_configs'][$i]['num_valid_cc_elements'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
171 $bitoffset += 4;
172 $info['aac']['program_configs'][$i]['mono_mixdown_present'] = (bool) getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
173 $bitoffset += 1;
174 if ($info['aac']['program_configs'][$i]['mono_mixdown_present']) {
175 $info['aac']['program_configs'][$i]['mono_mixdown_element_number'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
176 $bitoffset += 4;
177 }
178 $info['aac']['program_configs'][$i]['stereo_mixdown_present'] = (bool) getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
179 $bitoffset += 1;
180 if ($info['aac']['program_configs'][$i]['stereo_mixdown_present']) {
181 $info['aac']['program_configs'][$i]['stereo_mixdown_element_number'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
182 $bitoffset += 4;
183 }
184 $info['aac']['program_configs'][$i]['matrix_mixdown_idx_present'] = (bool) getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
185 $bitoffset += 1;
186 if ($info['aac']['program_configs'][$i]['matrix_mixdown_idx_present']) {
187 $info['aac']['program_configs'][$i]['matrix_mixdown_idx'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 2));
188 $bitoffset += 2;
189 $info['aac']['program_configs'][$i]['pseudo_surround_enable'] = (bool) getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
190 $bitoffset += 1;
191 }
192 for ($j = 0; $j < $info['aac']['program_configs'][$i]['num_front_channel_elements']; $j++) {
193 $info['aac']['program_configs'][$i]['front_element_is_cpe'][$j] = (bool) getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
194 $bitoffset += 1;
195 $info['aac']['program_configs'][$i]['front_element_tag_select'][$j] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
196 $bitoffset += 4;
197 }
198 for ($j = 0; $j < $info['aac']['program_configs'][$i]['num_side_channel_elements']; $j++) {
199 $info['aac']['program_configs'][$i]['side_element_is_cpe'][$j] = (bool) getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
200 $bitoffset += 1;
201 $info['aac']['program_configs'][$i]['side_element_tag_select'][$j] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
202 $bitoffset += 4;
203 }
204 for ($j = 0; $j < $info['aac']['program_configs'][$i]['num_back_channel_elements']; $j++) {
205 $info['aac']['program_configs'][$i]['back_element_is_cpe'][$j] = (bool) getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
206 $bitoffset += 1;
207 $info['aac']['program_configs'][$i]['back_element_tag_select'][$j] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
208 $bitoffset += 4;
209 }
210 for ($j = 0; $j < $info['aac']['program_configs'][$i]['num_lfe_channel_elements']; $j++) {
211 $info['aac']['program_configs'][$i]['lfe_element_tag_select'][$j] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
212 $bitoffset += 4;
213 }
214 for ($j = 0; $j < $info['aac']['program_configs'][$i]['num_assoc_data_elements']; $j++) {
215 $info['aac']['program_configs'][$i]['assoc_data_element_tag_select'][$j] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
216 $bitoffset += 4;
217 }
218 for ($j = 0; $j < $info['aac']['program_configs'][$i]['num_valid_cc_elements']; $j++) {
219 $info['aac']['program_configs'][$i]['cc_element_is_ind_sw'][$j] = (bool) getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
220 $bitoffset += 1;
221 $info['aac']['program_configs'][$i]['valid_cc_element_tag_select'][$j] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
222 $bitoffset += 4;
223 }
224
225 $bitoffset = ceil($bitoffset / 8) * 8;
226
227 $info['aac']['program_configs'][$i]['comment_field_bytes'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 8));
228 $bitoffset += 8;
229 $info['aac']['program_configs'][$i]['comment_field'] = getid3_lib::Bin2String(substr($AACheaderBitstream, $bitoffset, 8 * $info['aac']['program_configs'][$i]['comment_field_bytes']));
230 $bitoffset += 8 * $info['aac']['program_configs'][$i]['comment_field_bytes'];
231
232
233 $info['aac']['header']['profile'] = self::AACprofileLookup($info['aac']['program_configs'][$i]['object_type'], $info['aac']['header']['mpeg_version']);
234 $info['aac']['program_configs'][$i]['sampling_frequency'] = self::AACsampleRateLookup($info['aac']['program_configs'][$i]['sampling_frequency_index']);
235 $info['audio']['sample_rate'] = $info['aac']['program_configs'][$i]['sampling_frequency'];
236 $info['audio']['channels'] = self::AACchannelCountCalculate($info['aac']['program_configs'][$i]);
237 if ($info['aac']['program_configs'][$i]['comment_field']) {
238 $info['aac']['comments'][] = $info['aac']['program_configs'][$i]['comment_field'];
239 }
240 }
241 $info['playtime_seconds'] = (($info['avdataend'] - $info['avdataoffset']) * 8) / $info['audio']['bitrate'];
242
243 $info['audio']['encoder_options'] = $info['aac']['header_type'].' '.$info['aac']['header']['profile'];
244
245
246
247 return true;
248
249 } else {
250
251 unset($info['fileformat']);
252 unset($info['aac']);
253 $this->error('AAC-ADIF synch not found at offset '.$info['avdataoffset'].' (expected "ADIF", found "'.substr($AACheader, 0, 4).'" instead)');
254 return false;
255
256 }
257
258 }
getid3_aac\AACprofileLookup
static AACprofileLookup($profileid, $mpegversion)
Definition: module.audio.aac.php:469
getid3_aac\AACsampleRateLookup
static AACsampleRateLookup($samplerateid)
Definition: module.audio.aac.php:446
getid3_aac\AACchannelCountCalculate
static AACchannelCountCalculate($program_configs)
Definition: module.audio.aac.php:484
getid3_handler\error
error($text)
Definition: getid3.php:1752
getid3_lib\BigEndian2Bin
static BigEndian2Bin($byteword)
Definition: getid3.lib.php:297
getid3_lib\Bin2String
static Bin2String($binstring)
Definition: getid3.lib.php:358
getid3_lib\Bin2Dec
static Bin2Dec($binstring, $signed=false)
Definition: getid3.lib.php:342

References $i, $info, AACchannelCountCalculate(), AACprofileLookup(), AACsampleRateLookup(), getid3_lib\BigEndian2Bin(), getid3_lib\Bin2Dec(), getid3_lib\Bin2String(), getid3_handler\error(), getid3_handler\fread(), and getid3_handler\fseek().

Referenced by Analyze().

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◆ getAACADTSheaderFilepointer()

getid3_aac::getAACADTSheaderFilepointer (   $MaxFramesToScan = 1000000,
  $ReturnExtendedInfo = false 
)

Definition at line 261 of file module.audio.aac.php.

261 {
262 $info = &$this->getid3->info;
263
264 // based loosely on code from AACfile by Jurgen Faul <jfaulØgmx.de>
265 // http://jfaul.de/atl or http://j-faul.virtualave.net/atl/atl.html
266
267
268 // http://faac.sourceforge.net/wiki/index.php?page=ADTS // dead link
269 // http://wiki.multimedia.cx/index.php?title=ADTS
270
271 // * ADTS Fixed Header: these don't change from frame to frame
272 // syncword 12 always: '111111111111'
273 // ID 1 0: MPEG-4, 1: MPEG-2
274 // MPEG layer 2 If you send AAC in MPEG-TS, set to 0
275 // protection_absent 1 0: CRC present; 1: no CRC
276 // profile 2 0: AAC Main; 1: AAC LC (Low Complexity); 2: AAC SSR (Scalable Sample Rate); 3: AAC LTP (Long Term Prediction)
277 // sampling_frequency_index 4 15 not allowed
278 // private_bit 1 usually 0
279 // channel_configuration 3
280 // original/copy 1 0: original; 1: copy
281 // home 1 usually 0
282 // emphasis 2 only if ID == 0 (ie MPEG-4) // not present in some documentation?
283
284 // * ADTS Variable Header: these can change from frame to frame
285 // copyright_identification_bit 1
286 // copyright_identification_start 1
287 // aac_frame_length 13 length of the frame including header (in bytes)
288 // adts_buffer_fullness 11 0x7FF indicates VBR
289 // no_raw_data_blocks_in_frame 2
290
291 // * ADTS Error check
292 // crc_check 16 only if protection_absent == 0
293
294 $byteoffset = $info['avdataoffset'];
295 $framenumber = 0;
296
297 // Init bit pattern array
298 static $decbin = array();
299
300 // Populate $bindec
301 for ($i = 0; $i < 256; $i++) {
302 $decbin[chr($i)] = str_pad(decbin($i), 8, '0', STR_PAD_LEFT);
303 }
304
305 // used to calculate bitrate below
306 $BitrateCache = array();
307
308
309 while (true) {
310 // breaks out when end-of-file encountered, or invalid data found,
311 // or MaxFramesToScan frames have been scanned
312
313 if (!getid3_lib::intValueSupported($byteoffset)) {
314 $this->warning('Unable to parse AAC file beyond '.$this->ftell().' (PHP does not support file operations beyond '.round(PHP_INT_MAX / 1073741824).'GB)');
315 return false;
316 }
317 $this->fseek($byteoffset);
318
319 // First get substring
320 $substring = $this->fread(9); // header is 7 bytes (or 9 if CRC is present)
321 $substringlength = strlen($substring);
322 if ($substringlength != 9) {
323 $this->error('Failed to read 7 bytes at offset '.($this->ftell() - $substringlength).' (only read '.$substringlength.' bytes)');
324 return false;
325 }
326 // this would be easier with 64-bit math, but split it up to allow for 32-bit:
327 $header1 = getid3_lib::BigEndian2Int(substr($substring, 0, 2));
328 $header2 = getid3_lib::BigEndian2Int(substr($substring, 2, 4));
329 $header3 = getid3_lib::BigEndian2Int(substr($substring, 6, 1));
330
331 $info['aac']['header']['raw']['syncword'] = ($header1 & 0xFFF0) >> 4;
332 if ($info['aac']['header']['raw']['syncword'] != 0x0FFF) {
333 $this->error('Synch pattern (0x0FFF) not found at offset '.($this->ftell() - $substringlength).' (found 0x0'.strtoupper(dechex($info['aac']['header']['raw']['syncword'])).' instead)');
334 //if ($info['fileformat'] == 'aac') {
335 // return true;
336 //}
337 unset($info['aac']);
338 return false;
339 }
340
341 // Gather info for first frame only - this takes time to do 1000 times!
342 if ($framenumber == 0) {
343 $info['aac']['header_type'] = 'ADTS';
344 $info['fileformat'] = 'aac';
345 $info['audio']['dataformat'] = 'aac';
346
347 $info['aac']['header']['raw']['mpeg_version'] = ($header1 & 0x0008) >> 3;
348 $info['aac']['header']['raw']['mpeg_layer'] = ($header1 & 0x0006) >> 1;
349 $info['aac']['header']['raw']['protection_absent'] = ($header1 & 0x0001) >> 0;
350
351 $info['aac']['header']['raw']['profile_code'] = ($header2 & 0xC0000000) >> 30;
352 $info['aac']['header']['raw']['sample_rate_code'] = ($header2 & 0x3C000000) >> 26;
353 $info['aac']['header']['raw']['private_stream'] = ($header2 & 0x02000000) >> 25;
354 $info['aac']['header']['raw']['channels_code'] = ($header2 & 0x01C00000) >> 22;
355 $info['aac']['header']['raw']['original'] = ($header2 & 0x00200000) >> 21;
356 $info['aac']['header']['raw']['home'] = ($header2 & 0x00100000) >> 20;
357 $info['aac']['header']['raw']['copyright_stream'] = ($header2 & 0x00080000) >> 19;
358 $info['aac']['header']['raw']['copyright_start'] = ($header2 & 0x00040000) >> 18;
359 $info['aac']['header']['raw']['frame_length'] = ($header2 & 0x0003FFE0) >> 5;
360
361 $info['aac']['header']['mpeg_version'] = ($info['aac']['header']['raw']['mpeg_version'] ? 2 : 4);
362 $info['aac']['header']['crc_present'] = ($info['aac']['header']['raw']['protection_absent'] ? false: true);
363 $info['aac']['header']['profile'] = self::AACprofileLookup($info['aac']['header']['raw']['profile_code'], $info['aac']['header']['mpeg_version']);
364 $info['aac']['header']['sample_frequency'] = self::AACsampleRateLookup($info['aac']['header']['raw']['sample_rate_code']);
365 $info['aac']['header']['private'] = (bool) $info['aac']['header']['raw']['private_stream'];
366 $info['aac']['header']['original'] = (bool) $info['aac']['header']['raw']['original'];
367 $info['aac']['header']['home'] = (bool) $info['aac']['header']['raw']['home'];
368 $info['aac']['header']['channels'] = (($info['aac']['header']['raw']['channels_code'] == 7) ? 8 : $info['aac']['header']['raw']['channels_code']);
369 if ($ReturnExtendedInfo) {
370 $info['aac'][$framenumber]['copyright_id_bit'] = (bool) $info['aac']['header']['raw']['copyright_stream'];
371 $info['aac'][$framenumber]['copyright_id_start'] = (bool) $info['aac']['header']['raw']['copyright_start'];
372 }
373
374 if ($info['aac']['header']['raw']['mpeg_layer'] != 0) {
375 $this->warning('Layer error - expected "0", found "'.$info['aac']['header']['raw']['mpeg_layer'].'" instead');
376 }
377 if ($info['aac']['header']['sample_frequency'] == 0) {
378 $this->error('Corrupt AAC file: sample_frequency == zero');
379 return false;
380 }
381
382 $info['audio']['sample_rate'] = $info['aac']['header']['sample_frequency'];
383 $info['audio']['channels'] = $info['aac']['header']['channels'];
384 }
385
386 $FrameLength = ($header2 & 0x0003FFE0) >> 5;
387
388 if (!isset($BitrateCache[$FrameLength])) {
389 $BitrateCache[$FrameLength] = ($info['aac']['header']['sample_frequency'] / 1024) * $FrameLength * 8;
390 }
391 getid3_lib::safe_inc($info['aac']['bitrate_distribution'][$BitrateCache[$FrameLength]], 1);
392
393 $info['aac'][$framenumber]['aac_frame_length'] = $FrameLength;
394
395 $info['aac'][$framenumber]['adts_buffer_fullness'] = (($header2 & 0x0000001F) << 6) & (($header3 & 0xFC) >> 2);
396 if ($info['aac'][$framenumber]['adts_buffer_fullness'] == 0x07FF) {
397 $info['audio']['bitrate_mode'] = 'vbr';
398 } else {
399 $info['audio']['bitrate_mode'] = 'cbr';
400 }
401 $info['aac'][$framenumber]['num_raw_data_blocks'] = (($header3 & 0x03) >> 0);
402
403 if ($info['aac']['header']['crc_present']) {
404 //$info['aac'][$framenumber]['crc'] = getid3_lib::BigEndian2Int(substr($substring, 7, 2);
405 }
406
407 if (!$ReturnExtendedInfo) {
408 unset($info['aac'][$framenumber]);
409 }
410
411 /*
412 $rounded_precision = 5000;
413 $info['aac']['bitrate_distribution_rounded'] = array();
414 foreach ($info['aac']['bitrate_distribution'] as $bitrate => $count) {
415 $rounded_bitrate = round($bitrate / $rounded_precision) * $rounded_precision;
416 getid3_lib::safe_inc($info['aac']['bitrate_distribution_rounded'][$rounded_bitrate], $count);
417 }
418 ksort($info['aac']['bitrate_distribution_rounded']);
419 */
420
421 $byteoffset += $FrameLength;
422 if ((++$framenumber < $MaxFramesToScan) && (($byteoffset + 10) < $info['avdataend'])) {
423
424 // keep scanning
425
426 } else {
427
428 $info['aac']['frames'] = $framenumber;
429 $info['playtime_seconds'] = ($info['avdataend'] / $byteoffset) * (($framenumber * 1024) / $info['aac']['header']['sample_frequency']); // (1 / % of file scanned) * (samples / (samples/sec)) = seconds
430 if ($info['playtime_seconds'] == 0) {
431 $this->error('Corrupt AAC file: playtime_seconds == zero');
432 return false;
433 }
434 $info['audio']['bitrate'] = (($info['avdataend'] - $info['avdataoffset']) * 8) / $info['playtime_seconds'];
435 ksort($info['aac']['bitrate_distribution']);
436
437 $info['audio']['encoder_options'] = $info['aac']['header_type'].' '.$info['aac']['header']['profile'];
438
439 return true;
440
441 }
442 }
443 // should never get here.
444 }
getid3_handler\ftell
ftell()
Definition: getid3.php:1676
getid3_handler\warning
warning($text)
Definition: getid3.php:1758
getid3_lib\intValueSupported
static intValueSupported($num)
Definition: getid3.lib.php:80
getid3_lib\safe_inc
static safe_inc(&$variable, $increment=1)
Definition: getid3.lib.php:56
getid3_lib\BigEndian2Int
static BigEndian2Int($byteword, $synchsafe=false, $signed=false)
Definition: getid3.lib.php:263

References $i, $info, AACprofileLookup(), AACsampleRateLookup(), getid3_lib\BigEndian2Int(), getid3_handler\error(), getid3_handler\fread(), getid3_handler\fseek(), getid3_handler\ftell(), getid3_lib\intValueSupported(), getid3_lib\safe_inc(), and getid3_handler\warning().

Referenced by Analyze().

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The documentation for this class was generated from the following file: