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comparison e2gallerypro/e2upload/Backend/Assets/getid3/module.audio.aac_adts.php @ 3:3f6b44aa6b35 judyates

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[svn r4] added ability to buy stuff, from a Prints page, but it doesn't work well with the css, and it also has not been fitted into the perl make system.
author rlm
date Mon, 22 Feb 2010 08:02:39 -0500
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2:670229c4eb4b 3:3f6b44aa6b35
1 <?php
2 // +----------------------------------------------------------------------+
3 // | PHP version 5 |
4 // +----------------------------------------------------------------------+
5 // | Copyright (c) 2002-2006 James Heinrich, Allan Hansen |
6 // +----------------------------------------------------------------------+
7 // | This source file is subject to version 2 of the GPL license, |
8 // | that is bundled with this package in the file license.txt and is |
9 // | available through the world-wide-web at the following url: |
10 // | http://www.gnu.org/copyleft/gpl.html |
11 // +----------------------------------------------------------------------+
12 // | getID3() - http://getid3.sourceforge.net or http://www.getid3.org |
13 // +----------------------------------------------------------------------+
14 // | Authors: James Heinrich <infoØgetid3*org> |
15 // | Allan Hansen <ahØartemis*dk> |
16 // +----------------------------------------------------------------------+
17 // | module.audio.aac_adts.php |
18 // | Module for analyzing AAC files with ADTS header. |
19 // | dependencies: NONE |
20 // +----------------------------------------------------------------------+
21 //
22 // $Id: module.audio.aac_adts.php,v 1.4 2006/11/02 10:48:01 ah Exp $
23
24
25
26 class getid3_aac_adts extends getid3_handler
27 {
28
29 public $option_max_frames_to_scan = 1000000;
30 public $option_return_extended_info = false;
31
32
33 private $decbin_cache;
34 private $bitrate_cache;
35
36
37
38 public function __construct(getID3 $getid3) {
39
40 parent::__construct($getid3);
41
42 // Populate bindec_cache
43 for ($i = 0; $i < 256; $i++) {
44 $this->decbin_cache[chr($i)] = str_pad(decbin($i), 8, '0', STR_PAD_LEFT);
45 }
46
47 // Init cache
48 $this->bitrate_cache = array ();
49
50 // Fast scanning?
51 if (!$getid3->option_accurate_results) {
52 $this->option_max_frames_to_scan = 200;
53 $getid3->warning('option_accurate_results set to false - bitrate and playing time are not accurate.');
54 }
55 }
56
57
58
59 public function Analyze() {
60
61 $getid3 = $this->getid3;
62
63 // based loosely on code from AACfile by Jurgen Faul <jfaulØgmx.de>
64 // http://jfaul.de/atl or http://j-faul.virtualave.net/atl/atl.html
65
66
67 // http://faac.sourceforge.net/wiki/index.php?page=ADTS
68
69 // * ADTS Fixed Header: these don't change from frame to frame
70 // syncword 12 always: '111111111111'
71 // ID 1 0: MPEG-4, 1: MPEG-2
72 // layer 2 always: '00'
73 // protection_absent 1
74 // profile 2
75 // sampling_frequency_index 4
76 // private_bit 1
77 // channel_configuration 3
78 // original/copy 1
79 // home 1
80 // emphasis 2 only if ID == 0 (ie MPEG-4)
81
82 // * ADTS Variable Header: these can change from frame to frame
83 // copyright_identification_bit 1
84 // copyright_identification_start 1
85 // aac_frame_length 13 length of the frame including header (in bytes)
86 // adts_buffer_fullness 11 0x7FF indicates VBR
87 // no_raw_data_blocks_in_frame 2
88
89 // * ADTS Error check
90 // crc_check 16 only if protection_absent == 0
91
92 $getid3->info['aac']['header'] = array () ;
93 $info_aac = &$getid3->info['aac'];
94 $info_aac_header = & $info_aac['header'];
95
96 $byte_offset = $frame_number = 0;
97
98 while (true) {
99
100 // Breaks out when end-of-file encountered, or invalid data found,
101 // or MaxFramesToScan frames have been scanned
102
103 fseek($getid3->fp, $byte_offset, SEEK_SET);
104
105 // First get substring
106 $sub_string = fread($getid3->fp, 10);
107 $sub_string_length = strlen($sub_string);
108 if ($sub_string_length != 10) {
109 throw new getid3_exception('Failed to read 10 bytes at offset '.(ftell($getid3->fp) - $sub_string_length).' (only read '.$sub_string_length.' bytes)');
110 }
111
112 // Initialise $aac_header_bitstream
113 $aac_header_bitstream = '';
114
115 // Loop thru substring chars
116 for ($i = 0; $i < 10; $i++) {
117 $aac_header_bitstream .= $this->decbin_cache[$sub_string[$i]];
118 }
119
120 $sync_test = bindec(substr($aac_header_bitstream, 0, 12));
121 $bit_offset = 12;
122
123 if ($sync_test != 0x0FFF) {
124 throw new getid3_exception('Synch pattern (0x0FFF) not found at offset '.(ftell($getid3->fp) - 10).' (found 0x0'.strtoupper(dechex($sync_test)).' instead)');
125 }
126
127 // Only gather info once - this takes time to do 1000 times!
128 if ($frame_number > 0) {
129
130 // MPEG-4: 20, // MPEG-2: 18
131 $bit_offset += $aac_header_bitstream[$bit_offset] ? 18 : 20;
132 }
133
134 // Gather info for first frame only - this takes time to do 1000 times!
135 else {
136
137 $info_aac['header_type'] = 'ADTS';
138 $info_aac_header['synch'] = $sync_test;
139 $getid3->info['fileformat'] = 'aac';
140 $getid3->info['audio']['dataformat'] = 'aac';
141
142 $info_aac_header['mpeg_version'] = $aac_header_bitstream{$bit_offset++} == '0' ? 4 : 2;
143 $info_aac_header['layer'] = bindec(substr($aac_header_bitstream, $bit_offset, 2));
144 $bit_offset += 2;
145
146 if ($info_aac_header['layer'] != 0) {
147 throw new getid3_exception('Layer error - expected 0x00, found 0x'.dechex($info_aac_header['layer']).' instead');
148 }
149
150 $info_aac_header['crc_present'] = $aac_header_bitstream{$bit_offset++} == '0' ? true : false;
151
152 $info_aac_header['profile_id'] = bindec(substr($aac_header_bitstream, $bit_offset, 2));
153 $bit_offset += 2;
154
155 $info_aac_header['profile_text'] = getid3_aac_adts::AACprofileLookup($info_aac_header['profile_id'], $info_aac_header['mpeg_version']);
156
157 $info_aac_header['sample_frequency_index'] = bindec(substr($aac_header_bitstream, $bit_offset, 4));
158 $bit_offset += 4;
159
160 $info_aac_header['sample_frequency'] = getid3_aac_adts::AACsampleRateLookup($info_aac_header['sample_frequency_index']);
161
162 $getid3->info['audio']['sample_rate'] = $info_aac_header['sample_frequency'];
163
164 $info_aac_header['private'] = $aac_header_bitstream{$bit_offset++} == 1;
165
166 $info_aac_header['channel_configuration'] = $getid3->info['audio']['channels'] = bindec(substr($aac_header_bitstream, $bit_offset, 3));
167 $bit_offset += 3;
168
169 $info_aac_header['original'] = $aac_header_bitstream{$bit_offset++} == 1;
170 $info_aac_header['home'] = $aac_header_bitstream{$bit_offset++} == 1;
171
172 if ($info_aac_header['mpeg_version'] == 4) {
173 $info_aac_header['emphasis'] = bindec(substr($aac_header_bitstream, $bit_offset, 2));
174 $bit_offset += 2;
175 }
176
177 if ($this->option_return_extended_info) {
178
179 $info_aac[$frame_number]['copyright_id_bit'] = $aac_header_bitstream{$bit_offset++} == 1;
180 $info_aac[$frame_number]['copyright_id_start'] = $aac_header_bitstream{$bit_offset++} == 1;
181
182 } else {
183 $bit_offset += 2;
184 }
185 }
186
187 $frame_length = bindec(substr($aac_header_bitstream, $bit_offset, 13));
188
189 if (!isset($this->bitrate_cache[$frame_length])) {
190 $this->bitrate_cache[$frame_length] = ($info_aac_header['sample_frequency'] / 1024) * $frame_length * 8;
191 }
192 @$info_aac['bitrate_distribution'][$this->bitrate_cache[$frame_length]]++;
193
194 $info_aac[$frame_number]['aac_frame_length'] = $frame_length;
195 $bit_offset += 13;
196
197 $info_aac[$frame_number]['adts_buffer_fullness'] = bindec(substr($aac_header_bitstream, $bit_offset, 11));
198 $bit_offset += 11;
199
200 $getid3->info['audio']['bitrate_mode'] = ($info_aac[$frame_number]['adts_buffer_fullness'] == 0x07FF) ? 'vbr' : 'cbr';
201
202 $info_aac[$frame_number]['num_raw_data_blocks'] = bindec(substr($aac_header_bitstream, $bit_offset, 2));
203 $bit_offset += 2;
204
205 if ($info_aac_header['crc_present']) {
206 $bit_offset += 16;
207 }
208
209 if (!$this->option_return_extended_info) {
210 unset($info_aac[$frame_number]);
211 }
212
213 $byte_offset += $frame_length;
214 if ((++$frame_number < $this->option_max_frames_to_scan) && (($byte_offset + 10) < $getid3->info['avdataend'])) {
215
216 // keep scanning
217
218 } else {
219
220 $info_aac['frames'] = $frame_number;
221 $getid3->info['playtime_seconds'] = ($getid3->info['avdataend'] / $byte_offset) * (($frame_number * 1024) / $info_aac_header['sample_frequency']); // (1 / % of file scanned) * (samples / (samples/sec)) = seconds
222 $getid3->info['audio']['bitrate'] = (($getid3->info['avdataend'] - $getid3->info['avdataoffset']) * 8) / $getid3->info['playtime_seconds'];
223 ksort($info_aac['bitrate_distribution']);
224
225 $getid3->info['audio']['encoder_options'] = $info_aac['header_type'].' '.$info_aac_header['profile_text'];
226
227 return true;
228 }
229 }
230 }
231
232
233
234 public static function AACsampleRateLookup($samplerate_id) {
235
236 static $lookup = array (
237 0 => 96000,
238 1 => 88200,
239 2 => 64000,
240 3 => 48000,
241 4 => 44100,
242 5 => 32000,
243 6 => 24000,
244 7 => 22050,
245 8 => 16000,
246 9 => 12000,
247 10 => 11025,
248 11 => 8000,
249 12 => 0,
250 13 => 0,
251 14 => 0,
252 15 => 0
253 );
254 return (isset($lookup[$samplerate_id]) ? $lookup[$samplerate_id] : 'invalid');
255 }
256
257
258
259 public static function AACprofileLookup($profile_id, $mpeg_version) {
260
261 static $lookup = array (
262 2 => array (
263 0 => 'Main profile',
264 1 => 'Low Complexity profile (LC)',
265 2 => 'Scalable Sample Rate profile (SSR)',
266 3 => '(reserved)'
267 ),
268 4 => array (
269 0 => 'AAC_MAIN',
270 1 => 'AAC_LC',
271 2 => 'AAC_SSR',
272 3 => 'AAC_LTP'
273 )
274 );
275 return (isset($lookup[$mpeg_version][$profile_id]) ? $lookup[$mpeg_version][$profile_id] : 'invalid');
276 }
277
278
279 }
280
281
282 ?>