ILIAS  release_5-2 Revision v5.2.25-18-g3f80b828510
Public Member Functions | Static Public Member Functions
GetId3\Module\Audio\Aac Class Reference

GetId3() by James Heinrich info@.nosp@m.geti.nosp@m.d3.or.nosp@m.g //. More...

+ Inheritance diagram for GetId3\Module\Audio\Aac:
+ Collaboration diagram for GetId3\Module\Audio\Aac:

Public Member Functions

 analyze ()
 
 getAACADIFheaderFilepointer ()
 
 getAACADTSheaderFilepointer ($MaxFramesToScan=1000000, $ReturnExtendedInfo=false)
 @staticvar array $decbin More...
 
- Public Member Functions inherited from GetId3\Handler\BaseHandler
 __construct (GetId3Core $getid3, $call_module=null)
 
 analyze ()
 Analyze from file pointer. More...
 
 AnalyzeString (&$string)
 Analyze from string instead. More...
 
 saveAttachment (&$ThisFileInfoIndex, $filename, $offset, $length)
 

Static Public Member Functions

static AACsampleRateLookup ($samplerateid)
 @staticvar array $AACsampleRateLookup More...
 
static AACprofileLookup ($profileid, $mpegversion)
 @staticvar array $AACprofileLookup More...
 
static AACchannelCountCalculate ($program_configs)
 

Additional Inherited Members

- Protected Member Functions inherited from GetId3\Handler\BaseHandler
 ftell ()
 
 fread ($bytes)
 
 fseek ($bytes, $whence=SEEK_SET)
 
 feof ()
 
 isDependencyFor ($module)
 
 error ($text)
 
 warning ($text)
 
- Protected Attributes inherited from GetId3\Handler\BaseHandler
 $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 //.

module for analyzing AAC Audio files

Author
James Heinrich info@.nosp@m.geti.nosp@m.d3.or.nosp@m.g http://www.getid3.org

Definition at line 29 of file Aac.php.

Member Function Documentation

◆ AACchannelCountCalculate()

static GetId3\Module\Audio\Aac::AACchannelCountCalculate (   $program_configs)
static
Parameters
type$program_configs
Returns
int

Definition at line 536 of file Aac.php.

537 {
538 $channels = 0;
539 for ($i = 0; $i < $program_configs['num_front_channel_elements']; $i++) {
540 $channels++;
541 if ($program_configs['front_element_is_cpe'][$i]) {
542 // each front element is channel pair (CPE = Channel Pair Element)
543 $channels++;
544 }
545 }
546 for ($i = 0; $i < $program_configs['num_side_channel_elements']; $i++) {
547 $channels++;
548 if ($program_configs['side_element_is_cpe'][$i]) {
549 // each side element is channel pair (CPE = Channel Pair Element)
550 $channels++;
551 }
552 }
553 for ($i = 0; $i < $program_configs['num_back_channel_elements']; $i++) {
554 $channels++;
555 if ($program_configs['back_element_is_cpe'][$i]) {
556 // each back element is channel pair (CPE = Channel Pair Element)
557 $channels++;
558 }
559 }
560 for ($i = 0; $i < $program_configs['num_lfe_channel_elements']; $i++) {
561 $channels++;
562 }
563
564 return $channels;
565 }

Referenced by GetId3\Module\Audio\Aac\getAACADIFheaderFilepointer().

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◆ AACprofileLookup()

static GetId3\Module\Audio\Aac::AACprofileLookup (   $profileid,
  $mpegversion 
)
static

@staticvar array $AACprofileLookup

Parameters
type$profileid
type$mpegversion
Returns
type

Definition at line 514 of file Aac.php.

515 {
516 static $AACprofileLookup = array();
517 if (empty($AACprofileLookup)) {
518 $AACprofileLookup[2][0] = 'Main profile';
519 $AACprofileLookup[2][1] = 'Low Complexity profile (LC)';
520 $AACprofileLookup[2][2] = 'Scalable Sample Rate profile (SSR)';
521 $AACprofileLookup[2][3] = '(reserved)';
522 $AACprofileLookup[4][0] = 'AAC_MAIN';
523 $AACprofileLookup[4][1] = 'AAC_LC';
524 $AACprofileLookup[4][2] = 'AAC_SSR';
525 $AACprofileLookup[4][3] = 'AAC_LTP';
526 }
527
528 return (isset($AACprofileLookup[$mpegversion][$profileid]) ? $AACprofileLookup[$mpegversion][$profileid] : 'invalid');
529 }

Referenced by GetId3\Module\Audio\Aac\getAACADIFheaderFilepointer(), and GetId3\Module\Audio\Aac\getAACADTSheaderFilepointer().

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◆ AACsampleRateLookup()

static GetId3\Module\Audio\Aac::AACsampleRateLookup (   $samplerateid)
static

@staticvar array $AACsampleRateLookup

Parameters
type$samplerateid
Returns
type

Definition at line 482 of file Aac.php.

483 {
484 static $AACsampleRateLookup = array();
485 if (empty($AACsampleRateLookup)) {
486 $AACsampleRateLookup[0] = 96000;
487 $AACsampleRateLookup[1] = 88200;
488 $AACsampleRateLookup[2] = 64000;
489 $AACsampleRateLookup[3] = 48000;
490 $AACsampleRateLookup[4] = 44100;
491 $AACsampleRateLookup[5] = 32000;
492 $AACsampleRateLookup[6] = 24000;
493 $AACsampleRateLookup[7] = 22050;
494 $AACsampleRateLookup[8] = 16000;
495 $AACsampleRateLookup[9] = 12000;
496 $AACsampleRateLookup[10] = 11025;
497 $AACsampleRateLookup[11] = 8000;
498 $AACsampleRateLookup[12] = 0;
499 $AACsampleRateLookup[13] = 0;
500 $AACsampleRateLookup[14] = 0;
501 $AACsampleRateLookup[15] = 0;
502 }
503
504 return (isset($AACsampleRateLookup[$samplerateid]) ? $AACsampleRateLookup[$samplerateid] : 'invalid');
505 }

Referenced by GetId3\Module\Audio\Aac\getAACADIFheaderFilepointer(), and GetId3\Module\Audio\Aac\getAACADTSheaderFilepointer().

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◆ analyze()

GetId3\Module\Audio\Aac::analyze ( )
Returns
boolean

Reimplemented from GetId3\Handler\BaseHandler.

Definition at line 35 of file Aac.php.

36 {
37 $info = &$this->getid3->info;
38 fseek($this->getid3->fp, $info['avdataoffset'], SEEK_SET);
39 if (fread($this->getid3->fp, 4) == 'ADIF') {
40 $this->getAACADIFheaderFilepointer();
41 } else {
42 $this->getAACADTSheaderFilepointer();
43 }
44
45 return true;
46 }
GetId3\Handler\BaseHandler\fseek
fseek($bytes, $whence=SEEK_SET)
Definition: BaseHandler.php:148
GetId3\Module\Audio\Aac\getAACADTSheaderFilepointer
getAACADTSheaderFilepointer($MaxFramesToScan=1000000, $ReturnExtendedInfo=false)
@staticvar array $decbin
Definition: Aac.php:286
GetId3\Module\Audio\Aac\getAACADIFheaderFilepointer
getAACADIFheaderFilepointer()
Definition: Aac.php:52
$info
$info
Definition: example_052.php:80

References $info, GetId3\Handler\BaseHandler\fread(), GetId3\Handler\BaseHandler\fseek(), GetId3\Module\Audio\Aac\getAACADIFheaderFilepointer(), and GetId3\Module\Audio\Aac\getAACADTSheaderFilepointer().

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◆ getAACADIFheaderFilepointer()

GetId3\Module\Audio\Aac::getAACADIFheaderFilepointer ( )
Returns
boolean

Definition at line 52 of file Aac.php.

53 {
54 $info = &$this->getid3->info;
55 $info['fileformat'] = 'aac';
56 $info['audio']['dataformat'] = 'aac';
57 $info['audio']['lossless'] = false;
58
59 fseek($this->getid3->fp, $info['avdataoffset'], SEEK_SET);
60 $AACheader = fread($this->getid3->fp, 1024);
61 $offset = 0;
62
63 if (substr($AACheader, 0, 4) == 'ADIF') {
64
65 // http://faac.sourceforge.net/wiki/index.php?page=ADIF
66
67 // http://libmpeg.org/mpeg4/doc/w2203tfs.pdf
68 // adif_header() {
69 // adif_id 32
70 // copyright_id_present 1
71 // if( copyright_id_present )
72 // copyright_id 72
73 // original_copy 1
74 // home 1
75 // bitstream_type 1
76 // bitrate 23
77 // num_program_config_elements 4
78 // for (i = 0; i < num_program_config_elements + 1; i++) {
79 // if( bitstream_type == '0' )
80 // adif_buffer_fullness 20
81 // program_config_element()
82 // }
83 // }
84
85 $AACheaderBitstream = Helper::BigEndian2Bin($AACheader);
86 $bitoffset = 0;
87
88 $info['aac']['header_type'] = 'ADIF';
89 $bitoffset += 32;
90 $info['aac']['header']['mpeg_version'] = 4;
91
92 $info['aac']['header']['copyright'] = (bool) (substr($AACheaderBitstream, $bitoffset, 1) == '1');
93 $bitoffset += 1;
94 if ($info['aac']['header']['copyright']) {
95 $info['aac']['header']['copyright_id'] = Helper::Bin2String(substr($AACheaderBitstream, $bitoffset, 72));
96 $bitoffset += 72;
97 }
98 $info['aac']['header']['original_copy'] = (bool) (substr($AACheaderBitstream, $bitoffset, 1) == '1');
99 $bitoffset += 1;
100 $info['aac']['header']['home'] = (bool) (substr($AACheaderBitstream, $bitoffset, 1) == '1');
101 $bitoffset += 1;
102 $info['aac']['header']['is_vbr'] = (bool) (substr($AACheaderBitstream, $bitoffset, 1) == '1');
103 $bitoffset += 1;
104 if ($info['aac']['header']['is_vbr']) {
105 $info['audio']['bitrate_mode'] = 'vbr';
106 $info['aac']['header']['bitrate_max'] = Helper::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 23));
107 $bitoffset += 23;
108 } else {
109 $info['audio']['bitrate_mode'] = 'cbr';
110 $info['aac']['header']['bitrate'] = Helper::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 23));
111 $bitoffset += 23;
112 $info['audio']['bitrate'] = $info['aac']['header']['bitrate'];
113 }
114 if ($info['audio']['bitrate'] == 0) {
115 $info['error'][] = 'Corrupt AAC file: bitrate_audio == zero';
116
117 return false;
118 }
119 $info['aac']['header']['num_program_configs'] = 1 + Helper::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
120 $bitoffset += 4;
121
122 for ($i = 0; $i < $info['aac']['header']['num_program_configs']; $i++) {
123 // http://www.audiocoding.com/wiki/index.php?page=program_config_element
124
125 // buffer_fullness 20
126
127 // element_instance_tag 4
128 // object_type 2
129 // sampling_frequency_index 4
130 // num_front_channel_elements 4
131 // num_side_channel_elements 4
132 // num_back_channel_elements 4
133 // num_lfe_channel_elements 2
134 // num_assoc_data_elements 3
135 // num_valid_cc_elements 4
136 // mono_mixdown_present 1
137 // mono_mixdown_element_number 4 if mono_mixdown_present == 1
138 // stereo_mixdown_present 1
139 // stereo_mixdown_element_number 4 if stereo_mixdown_present == 1
140 // matrix_mixdown_idx_present 1
141 // matrix_mixdown_idx 2 if matrix_mixdown_idx_present == 1
142 // pseudo_surround_enable 1 if matrix_mixdown_idx_present == 1
143 // for (i = 0; i < num_front_channel_elements; i++) {
144 // front_element_is_cpe[i] 1
145 // front_element_tag_select[i] 4
146 // }
147 // for (i = 0; i < num_side_channel_elements; i++) {
148 // side_element_is_cpe[i] 1
149 // side_element_tag_select[i] 4
150 // }
151 // for (i = 0; i < num_back_channel_elements; i++) {
152 // back_element_is_cpe[i] 1
153 // back_element_tag_select[i] 4
154 // }
155 // for (i = 0; i < num_lfe_channel_elements; i++) {
156 // lfe_element_tag_select[i] 4
157 // }
158 // for (i = 0; i < num_assoc_data_elements; i++) {
159 // assoc_data_element_tag_select[i] 4
160 // }
161 // for (i = 0; i < num_valid_cc_elements; i++) {
162 // cc_element_is_ind_sw[i] 1
163 // valid_cc_element_tag_select[i] 4
164 // }
165 // byte_alignment() VAR
166 // comment_field_bytes 8
167 // for (i = 0; i < comment_field_bytes; i++) {
168 // comment_field_data[i] 8
169 // }
170
171 if (!$info['aac']['header']['is_vbr']) {
172 $info['aac']['program_configs'][$i]['buffer_fullness'] = Helper::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 20));
173 $bitoffset += 20;
174 }
175 $info['aac']['program_configs'][$i]['element_instance_tag'] = Helper::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
176 $bitoffset += 4;
177 $info['aac']['program_configs'][$i]['object_type'] = Helper::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 2));
178 $bitoffset += 2;
179 $info['aac']['program_configs'][$i]['sampling_frequency_index'] = Helper::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
180 $bitoffset += 4;
181 $info['aac']['program_configs'][$i]['num_front_channel_elements'] = Helper::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
182 $bitoffset += 4;
183 $info['aac']['program_configs'][$i]['num_side_channel_elements'] = Helper::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
184 $bitoffset += 4;
185 $info['aac']['program_configs'][$i]['num_back_channel_elements'] = Helper::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
186 $bitoffset += 4;
187 $info['aac']['program_configs'][$i]['num_lfe_channel_elements'] = Helper::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 2));
188 $bitoffset += 2;
189 $info['aac']['program_configs'][$i]['num_assoc_data_elements'] = Helper::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 3));
190 $bitoffset += 3;
191 $info['aac']['program_configs'][$i]['num_valid_cc_elements'] = Helper::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
192 $bitoffset += 4;
193 $info['aac']['program_configs'][$i]['mono_mixdown_present'] = (bool) Helper::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
194 $bitoffset += 1;
195 if ($info['aac']['program_configs'][$i]['mono_mixdown_present']) {
196 $info['aac']['program_configs'][$i]['mono_mixdown_element_number'] = Helper::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
197 $bitoffset += 4;
198 }
199 $info['aac']['program_configs'][$i]['stereo_mixdown_present'] = (bool) Helper::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
200 $bitoffset += 1;
201 if ($info['aac']['program_configs'][$i]['stereo_mixdown_present']) {
202 $info['aac']['program_configs'][$i]['stereo_mixdown_element_number'] = Helper::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
203 $bitoffset += 4;
204 }
205 $info['aac']['program_configs'][$i]['matrix_mixdown_idx_present'] = (bool) Helper::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
206 $bitoffset += 1;
207 if ($info['aac']['program_configs'][$i]['matrix_mixdown_idx_present']) {
208 $info['aac']['program_configs'][$i]['matrix_mixdown_idx'] = Helper::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 2));
209 $bitoffset += 2;
210 $info['aac']['program_configs'][$i]['pseudo_surround_enable'] = (bool) Helper::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
211 $bitoffset += 1;
212 }
213 for ($j = 0; $j < $info['aac']['program_configs'][$i]['num_front_channel_elements']; $j++) {
214 $info['aac']['program_configs'][$i]['front_element_is_cpe'][$j] = (bool) Helper::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
215 $bitoffset += 1;
216 $info['aac']['program_configs'][$i]['front_element_tag_select'][$j] = Helper::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
217 $bitoffset += 4;
218 }
219 for ($j = 0; $j < $info['aac']['program_configs'][$i]['num_side_channel_elements']; $j++) {
220 $info['aac']['program_configs'][$i]['side_element_is_cpe'][$j] = (bool) Helper::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
221 $bitoffset += 1;
222 $info['aac']['program_configs'][$i]['side_element_tag_select'][$j] = Helper::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
223 $bitoffset += 4;
224 }
225 for ($j = 0; $j < $info['aac']['program_configs'][$i]['num_back_channel_elements']; $j++) {
226 $info['aac']['program_configs'][$i]['back_element_is_cpe'][$j] = (bool) Helper::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
227 $bitoffset += 1;
228 $info['aac']['program_configs'][$i]['back_element_tag_select'][$j] = Helper::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
229 $bitoffset += 4;
230 }
231 for ($j = 0; $j < $info['aac']['program_configs'][$i]['num_lfe_channel_elements']; $j++) {
232 $info['aac']['program_configs'][$i]['lfe_element_tag_select'][$j] = Helper::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
233 $bitoffset += 4;
234 }
235 for ($j = 0; $j < $info['aac']['program_configs'][$i]['num_assoc_data_elements']; $j++) {
236 $info['aac']['program_configs'][$i]['assoc_data_element_tag_select'][$j] = Helper::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
237 $bitoffset += 4;
238 }
239 for ($j = 0; $j < $info['aac']['program_configs'][$i]['num_valid_cc_elements']; $j++) {
240 $info['aac']['program_configs'][$i]['cc_element_is_ind_sw'][$j] = (bool) Helper::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
241 $bitoffset += 1;
242 $info['aac']['program_configs'][$i]['valid_cc_element_tag_select'][$j] = Helper::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
243 $bitoffset += 4;
244 }
245
246 $bitoffset = ceil($bitoffset / 8) * 8;
247
248 $info['aac']['program_configs'][$i]['comment_field_bytes'] = Helper::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 8));
249 $bitoffset += 8;
250 $info['aac']['program_configs'][$i]['comment_field'] = Helper::Bin2String(substr($AACheaderBitstream, $bitoffset, 8 * $info['aac']['program_configs'][$i]['comment_field_bytes']));
251 $bitoffset += 8 * $info['aac']['program_configs'][$i]['comment_field_bytes'];
252
253 $info['aac']['header']['profile'] = self::AACprofileLookup($info['aac']['program_configs'][$i]['object_type'], $info['aac']['header']['mpeg_version']);
254 $info['aac']['program_configs'][$i]['sampling_frequency'] = self::AACsampleRateLookup($info['aac']['program_configs'][$i]['sampling_frequency_index']);
255 $info['audio']['sample_rate'] = $info['aac']['program_configs'][$i]['sampling_frequency'];
256 $info['audio']['channels'] = self::AACchannelCountCalculate($info['aac']['program_configs'][$i]);
257 if ($info['aac']['program_configs'][$i]['comment_field']) {
258 $info['aac']['comments'][] = $info['aac']['program_configs'][$i]['comment_field'];
259 }
260 }
261 $info['playtime_seconds'] = (($info['avdataend'] - $info['avdataoffset']) * 8) / $info['audio']['bitrate'];
262
263 $info['audio']['encoder_options'] = $info['aac']['header_type'].' '.$info['aac']['header']['profile'];
264
265 return true;
266
267 } else {
268
269 unset($info['fileformat']);
270 unset($info['aac']);
271 $info['error'][] = 'AAC-ADIF synch not found at offset '.$info['avdataoffset'].' (expected "ADIF", found "'.substr($AACheader, 0, 4).'" instead)';
272
273 return false;
274
275 }
276
277 }
GetId3\Lib\Helper\Bin2Dec
static Bin2Dec($binstring, $signed=false)
Definition: Helper.php:496
GetId3\Lib\Helper\Bin2String
static Bin2String($binstring)
Definition: Helper.php:519
GetId3\Lib\Helper\BigEndian2Bin
static BigEndian2Bin($byteword)
Definition: Helper.php:423
GetId3\Module\Audio\Aac\AACsampleRateLookup
static AACsampleRateLookup($samplerateid)
@staticvar array $AACsampleRateLookup
Definition: Aac.php:482
GetId3\Module\Audio\Aac\AACprofileLookup
static AACprofileLookup($profileid, $mpegversion)
@staticvar array $AACprofileLookup
Definition: Aac.php:514
GetId3\Module\Audio\Aac\AACchannelCountCalculate
static AACchannelCountCalculate($program_configs)
Definition: Aac.php:536

References $info, GetId3\Module\Audio\Aac\AACchannelCountCalculate(), GetId3\Module\Audio\Aac\AACprofileLookup(), GetId3\Module\Audio\Aac\AACsampleRateLookup(), GetId3\Lib\Helper\BigEndian2Bin(), GetId3\Lib\Helper\Bin2Dec(), GetId3\Lib\Helper\Bin2String(), GetId3\Handler\BaseHandler\fread(), and GetId3\Handler\BaseHandler\fseek().

Referenced by GetId3\Module\Audio\Aac\analyze().

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◆ getAACADTSheaderFilepointer()

GetId3\Module\Audio\Aac::getAACADTSheaderFilepointer (   $MaxFramesToScan = 1000000,
  $ReturnExtendedInfo = false 
)

@staticvar array $decbin

Parameters
type$MaxFramesToScan
type$ReturnExtendedInfo
Returns
boolean

Definition at line 286 of file Aac.php.

287 {
288 $info = &$this->getid3->info;
289
290 // based loosely on code from AACfile by Jurgen Faul <jfaulØgmx.de>
291 // http://jfaul.de/atl or http://j-faul.virtualave.net/atl/atl.html
292
293 // http://faac.sourceforge.net/wiki/index.php?page=ADTS // dead link
294 // http://wiki.multimedia.cx/index.php?title=ADTS
295
296 // * ADTS Fixed Header: these don't change from frame to frame
297 // syncword 12 always: '111111111111'
298 // ID 1 0: MPEG-4, 1: MPEG-2
299 // MPEG layer 2 If you send AAC in MPEG-TS, set to 0
300 // protection_absent 1 0: CRC present; 1: no CRC
301 // profile 2 0: AAC Main; 1: AAC LC (Low Complexity); 2: AAC SSR (Scalable Sample Rate); 3: AAC LTP (Long Term Prediction)
302 // sampling_frequency_index 4 15 not allowed
303 // private_bit 1 usually 0
304 // channel_configuration 3
305 // original/copy 1 0: original; 1: copy
306 // home 1 usually 0
307 // emphasis 2 only if ID == 0 (ie MPEG-4) // not present in some documentation?
308
309 // * ADTS Variable Header: these can change from frame to frame
310 // copyright_identification_bit 1
311 // copyright_identification_start 1
312 // aac_frame_length 13 length of the frame including header (in bytes)
313 // adts_buffer_fullness 11 0x7FF indicates VBR
314 // no_raw_data_blocks_in_frame 2
315
316 // * ADTS Error check
317 // crc_check 16 only if protection_absent == 0
318
319 $byteoffset = $info['avdataoffset'];
320 $framenumber = 0;
321
322 // Init bit pattern array
323 static $decbin = array();
324
325 // Populate $bindec
326 for ($i = 0; $i < 256; $i++) {
327 $decbin[chr($i)] = str_pad(decbin($i), 8, '0', STR_PAD_LEFT);
328 }
329
330 // used to calculate bitrate below
331 $BitrateCache = array();
332
333
334 while (true) {
335 // breaks out when end-of-file encountered, or invalid data found,
336 // or MaxFramesToScan frames have been scanned
337
338 if (!Helper::intValueSupported($byteoffset)) {
339 $info['warning'][] = 'Unable to parse AAC file beyond '.ftell($this->getid3->fp).' (PHP does not support file operations beyond '.round(PHP_INT_MAX / 1073741824).'GB)';
340
341 return false;
342 }
343 fseek($this->getid3->fp, $byteoffset, SEEK_SET);
344
345 // First get substring
346 $substring = fread($this->getid3->fp, 9); // header is 7 bytes (or 9 if CRC is present)
347 $substringlength = strlen($substring);
348 if ($substringlength != 9) {
349 $info['error'][] = 'Failed to read 7 bytes at offset '.(ftell($this->getid3->fp) - $substringlength).' (only read '.$substringlength.' bytes)';
350
351 return false;
352 }
353 // this would be easier with 64-bit math, but split it up to allow for 32-bit:
354 $header1 = Helper::BigEndian2Int(substr($substring, 0, 2));
355 $header2 = Helper::BigEndian2Int(substr($substring, 2, 4));
356 $header3 = Helper::BigEndian2Int(substr($substring, 6, 1));
357
358 $info['aac']['header']['raw']['syncword'] = ($header1 & 0xFFF0) >> 4;
359 if ($info['aac']['header']['raw']['syncword'] != 0x0FFF) {
360 $info['error'][] = 'Synch pattern (0x0FFF) not found at offset '.(ftell($this->getid3->fp) - $substringlength).' (found 0x0'.strtoupper(dechex($info['aac']['header']['raw']['syncword'])).' instead)';
361 //if ($info['fileformat'] == 'aac') {
362 // return true;
363 //}
364 unset($info['aac']);
365
366 return false;
367 }
368
369 // Gather info for first frame only - this takes time to do 1000 times!
370 if ($framenumber == 0) {
371 $info['aac']['header_type'] = 'ADTS';
372 $info['fileformat'] = 'aac';
373 $info['audio']['dataformat'] = 'aac';
374
375 $info['aac']['header']['raw']['mpeg_version'] = ($header1 & 0x0008) >> 3;
376 $info['aac']['header']['raw']['mpeg_layer'] = ($header1 & 0x0006) >> 1;
377 $info['aac']['header']['raw']['protection_absent'] = ($header1 & 0x0001) >> 0;
378
379 $info['aac']['header']['raw']['profile_code'] = ($header2 & 0xC0000000) >> 30;
380 $info['aac']['header']['raw']['sample_rate_code'] = ($header2 & 0x3C000000) >> 26;
381 $info['aac']['header']['raw']['private_stream'] = ($header2 & 0x02000000) >> 25;
382 $info['aac']['header']['raw']['channels_code'] = ($header2 & 0x01C00000) >> 22;
383 $info['aac']['header']['raw']['original'] = ($header2 & 0x00200000) >> 21;
384 $info['aac']['header']['raw']['home'] = ($header2 & 0x00100000) >> 20;
385 $info['aac']['header']['raw']['copyright_stream'] = ($header2 & 0x00080000) >> 19;
386 $info['aac']['header']['raw']['copyright_start'] = ($header2 & 0x00040000) >> 18;
387 $info['aac']['header']['raw']['frame_length'] = ($header2 & 0x0003FFE0) >> 5;
388
389 $info['aac']['header']['mpeg_version'] = ($info['aac']['header']['raw']['mpeg_version'] ? 2 : 4);
390 $info['aac']['header']['crc_present'] = ($info['aac']['header']['raw']['protection_absent'] ? false: true);
391 $info['aac']['header']['profile'] = self::AACprofileLookup($info['aac']['header']['raw']['profile_code'], $info['aac']['header']['mpeg_version']);
392 $info['aac']['header']['sample_frequency'] = self::AACsampleRateLookup($info['aac']['header']['raw']['sample_rate_code']);
393 $info['aac']['header']['private'] = (bool) $info['aac']['header']['raw']['private_stream'];
394 $info['aac']['header']['original'] = (bool) $info['aac']['header']['raw']['original'];
395 $info['aac']['header']['home'] = (bool) $info['aac']['header']['raw']['home'];
396 $info['aac']['header']['channels'] = (($info['aac']['header']['raw']['channels_code'] == 7) ? 8 : $info['aac']['header']['raw']['channels_code']);
397 if ($ReturnExtendedInfo) {
398 $info['aac'][$framenumber]['copyright_id_bit'] = (bool) $info['aac']['header']['raw']['copyright_stream'];
399 $info['aac'][$framenumber]['copyright_id_start'] = (bool) $info['aac']['header']['raw']['copyright_start'];
400 }
401
402 if ($info['aac']['header']['raw']['mpeg_layer'] != 0) {
403 $info['warning'][] = 'Layer error - expected "0", found "'.$info['aac']['header']['raw']['mpeg_layer'].'" instead';
404 }
405 if ($info['aac']['header']['sample_frequency'] == 0) {
406 $info['error'][] = 'Corrupt AAC file: sample_frequency == zero';
407
408 return false;
409 }
410
411 $info['audio']['sample_rate'] = $info['aac']['header']['sample_frequency'];
412 $info['audio']['channels'] = $info['aac']['header']['channels'];
413 }
414
415 $FrameLength = ($header2 & 0x0003FFE0) >> 5;
416
417 if (!isset($BitrateCache[$FrameLength])) {
418 $BitrateCache[$FrameLength] = ($info['aac']['header']['sample_frequency'] / 1024) * $FrameLength * 8;
419 }
420 Helper::safe_inc($info['aac']['bitrate_distribution'][$BitrateCache[$FrameLength]], 1);
421
422 $info['aac'][$framenumber]['aac_frame_length'] = $FrameLength;
423
424 $info['aac'][$framenumber]['adts_buffer_fullness'] = (($header2 & 0x0000001F) << 6) & (($header3 & 0xFC) >> 2);
425 if ($info['aac'][$framenumber]['adts_buffer_fullness'] == 0x07FF) {
426 $info['audio']['bitrate_mode'] = 'vbr';
427 } else {
428 $info['audio']['bitrate_mode'] = 'cbr';
429 }
430 $info['aac'][$framenumber]['num_raw_data_blocks'] = (($header3 & 0x03) >> 0);
431
432 if ($info['aac']['header']['crc_present']) {
433 //$info['aac'][$framenumber]['crc'] = GetId3_lib::BigEndian2Int(substr($substring, 7, 2);
434 }
435
436 if (!$ReturnExtendedInfo) {
437 unset($info['aac'][$framenumber]);
438 }
439
440 /*
441 $rounded_precision = 5000;
442 $info['aac']['bitrate_distribution_rounded'] = array();
443 foreach ($info['aac']['bitrate_distribution'] as $bitrate => $count) {
444 $rounded_bitrate = round($bitrate / $rounded_precision) * $rounded_precision;
445 getid3_lib::safe_inc($info['aac']['bitrate_distribution_rounded'][$rounded_bitrate], $count);
446 }
447 ksort($info['aac']['bitrate_distribution_rounded']);
448 */
449
450 $byteoffset += $FrameLength;
451 if ((++$framenumber < $MaxFramesToScan) && (($byteoffset + 10) < $info['avdataend'])) {
452
453 // keep scanning
454
455 } else {
456
457 $info['aac']['frames'] = $framenumber;
458 $info['playtime_seconds'] = ($info['avdataend'] / $byteoffset) * (($framenumber * 1024) / $info['aac']['header']['sample_frequency']); // (1 / % of file scanned) * (samples / (samples/sec)) = seconds
459 if ($info['playtime_seconds'] == 0) {
460 $info['error'][] = 'Corrupt AAC file: playtime_seconds == zero';
461
462 return false;
463 }
464 $info['audio']['bitrate'] = (($info['avdataend'] - $info['avdataoffset']) * 8) / $info['playtime_seconds'];
465 ksort($info['aac']['bitrate_distribution']);
466
467 $info['audio']['encoder_options'] = $info['aac']['header_type'].' '.$info['aac']['header']['profile'];
468
469 return true;
470
471 }
472 }
473 // should never get here.
474 }
GetId3\Lib\Helper\safe_inc
static safe_inc(&$variable, $increment=1)
Definition: Helper.php:91
GetId3\Lib\Helper\BigEndian2Int
static BigEndian2Int($byteword, $synchsafe=false, $signed=false)
Definition: Helper.php:374
GetId3\Lib\Helper\intValueSupported
static intValueSupported($num)
@staticvar null $hasINT64
Definition: Helper.php:130

References $info, GetId3\Module\Audio\Aac\AACprofileLookup(), GetId3\Module\Audio\Aac\AACsampleRateLookup(), GetId3\Lib\Helper\BigEndian2Int(), GetId3\Handler\BaseHandler\fread(), GetId3\Handler\BaseHandler\fseek(), GetId3\Lib\Helper\intValueSupported(), and GetId3\Lib\Helper\safe_inc().

Referenced by GetId3\Module\Audio\Aac\analyze().

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