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source: extensions/charlies_content/getid3/getid3/module.audio-video.mpeg.php @ 3318

Last change on this file since 3318 was 3318, checked in by vdigital, 15 years ago
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[3318]	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-video.mpeg.php \|
	18	// \| Module for analyzing MPEG files \|
	19	// \| dependencies: module.audio.mp3.php \|
	20	// +----------------------------------------------------------------------+
	21	//
	22	// $Id: module.audio-video.mpeg.php 3318 2009-05-20 21:54:10Z vdigital $
	23
	24
	25
	26	class getid3_mpeg extends getid3_handler
	27	{
	28
	29	const VIDEO_PICTURE_START = "\x00\x00\x01\x00";
	30	const VIDEO_USER_DATA_START = "\x00\x00\x01\xB2";
	31	const VIDEO_SEQUENCE_HEADER = "\x00\x00\x01\xB3";
	32	const VIDEO_SEQUENCE_ERROR = "\x00\x00\x01\xB4";
	33	const VIDEO_EXTENSION_START = "\x00\x00\x01\xB5";
	34	const VIDEO_SEQUENCE_END = "\x00\x00\x01\xB7";
	35	const VIDEO_GROUP_START = "\x00\x00\x01\xB8";
	36	const AUDIO_START = "\x00\x00\x01\xC0";
	37
	38
	39	public function Analyze() {
	40
	41	$getid3 = $this->getid3;
	42
	43	$getid3->info['mpeg']['video']['raw'] = array ();
	44	$info_mpeg_video = &$getid3->info['mpeg']['video'];
	45	$info_mpeg_video_raw = &$info_mpeg_video['raw'];
	46
	47	$getid3->info['video'] = array ();
	48	$info_video = &$getid3->info['video'];
	49
	50	$getid3->include_module('audio.mp3');
	51
	52	if ($getid3->info['avdataend'] <= $getid3->info['avdataoffset']) {
	53	throw new getid3_exception('"avdataend" ('.$getid3->info['avdataend'].') is unexpectedly less-than-or-equal-to "avdataoffset" ('.$getid3->info['avdataoffset'].')');
	54	}
	55
	56	$getid3->info['fileformat'] = 'mpeg';
	57	fseek($getid3->fp, $getid3->info['avdataoffset'], SEEK_SET);
	58	$mpeg_stream_data = fread($getid3->fp, min(100000, $getid3->info['avdataend'] - $getid3->info['avdataoffset']));
	59	$mpeg_stream_data_length = strlen($mpeg_stream_data);
	60
	61	$video_chunk_offset = 0;
	62	while (substr($mpeg_stream_data, $video_chunk_offset++, 4) !== getid3_mpeg::VIDEO_SEQUENCE_HEADER) {
	63	if ($video_chunk_offset >= $mpeg_stream_data_length) {
	64	throw new getid3_exception('Could not find start of video block in the first 100,000 bytes (or before end of file) - this might not be an MPEG-video file?');
	65	}
	66	}
	67
	68	// Start code 32 bits
	69	// horizontal frame size 12 bits
	70	// vertical frame size 12 bits
	71	// pixel aspect ratio 4 bits
	72	// frame rate 4 bits
	73	// bitrate 18 bits
	74	// marker bit 1 bit
	75	// VBV buffer size 10 bits
	76	// constrained parameter flag 1 bit
	77	// intra quant. matrix flag 1 bit
	78	// intra quant. matrix values 512 bits (present if matrix flag == 1)
	79	// non-intra quant. matrix flag 1 bit
	80	// non-intra quant. matrix values 512 bits (present if matrix flag == 1)
	81
	82	$info_video['dataformat'] = 'mpeg';
	83
	84	$video_chunk_offset += (strlen(getid3_mpeg::VIDEO_SEQUENCE_HEADER) - 1);
	85
	86	$frame_size_dword = getid3_lib::BigEndian2Int(substr($mpeg_stream_data, $video_chunk_offset, 3));
	87	$video_chunk_offset += 3;
	88
	89	$aspect_ratio_frame_rate_dword = getid3_lib::BigEndian2Int(substr($mpeg_stream_data, $video_chunk_offset, 1));
	90	$video_chunk_offset += 1;
	91
	92	$assorted_information = getid3_lib::BigEndian2Bin(substr($mpeg_stream_data, $video_chunk_offset, 4));
	93	$video_chunk_offset += 4;
	94
	95	$info_mpeg_video_raw['framesize_horizontal'] = ($frame_size_dword & 0xFFF000) >> 12; // 12 bits for horizontal frame size
	96	$info_mpeg_video_raw['framesize_vertical'] = ($frame_size_dword & 0x000FFF); // 12 bits for vertical frame size
	97	$info_mpeg_video_raw['pixel_aspect_ratio'] = ($aspect_ratio_frame_rate_dword & 0xF0) >> 4;
	98	$info_mpeg_video_raw['frame_rate'] = ($aspect_ratio_frame_rate_dword & 0x0F);
	99
	100	$info_mpeg_video['framesize_horizontal'] = $info_mpeg_video_raw['framesize_horizontal'];
	101	$info_mpeg_video['framesize_vertical'] = $info_mpeg_video_raw['framesize_vertical'];
	102
	103	$info_mpeg_video['pixel_aspect_ratio'] = $this->MPEGvideoAspectRatioLookup($info_mpeg_video_raw['pixel_aspect_ratio']);
	104	$info_mpeg_video['pixel_aspect_ratio_text'] = $this->MPEGvideoAspectRatioTextLookup($info_mpeg_video_raw['pixel_aspect_ratio']);
	105	$info_mpeg_video['frame_rate'] = $this->MPEGvideoFramerateLookup($info_mpeg_video_raw['frame_rate']);
	106
	107	$info_mpeg_video_raw['bitrate'] = bindec(substr($assorted_information, 0, 18));
	108	$info_mpeg_video_raw['marker_bit'] = (bool)bindec($assorted_information{18});
	109	$info_mpeg_video_raw['vbv_buffer_size'] = bindec(substr($assorted_information, 19, 10));
	110	$info_mpeg_video_raw['constrained_param_flag'] = (bool)bindec($assorted_information{29});
	111	$info_mpeg_video_raw['intra_quant_flag'] = (bool)bindec($assorted_information{30});
	112
	113	if ($info_mpeg_video_raw['intra_quant_flag']) {
	114
	115	// read 512 bits
	116	$info_mpeg_video_raw['intra_quant'] = getid3_lib::BigEndian2Bin(substr($mpeg_stream_data, $video_chunk_offset, 64));
	117	$video_chunk_offset += 64;
	118
	119	$info_mpeg_video_raw['non_intra_quant_flag'] = (bool)bindec($info_mpeg_video_raw['intra_quant']{511});
	120	$info_mpeg_video_raw['intra_quant'] = bindec($assorted_information{31}).substr(getid3_lib::BigEndian2Bin(substr($mpeg_stream_data, $video_chunk_offset, 64)), 0, 511);
	121
	122	if ($info_mpeg_video_raw['non_intra_quant_flag']) {
	123	$info_mpeg_video_raw['non_intra_quant'] = substr($mpeg_stream_data, $video_chunk_offset, 64);
	124	$video_chunk_offset += 64;
	125	}
	126
	127	} else {
	128
	129	$info_mpeg_video_raw['non_intra_quant_flag'] = (bool)bindec($assorted_information{31});
	130	if ($info_mpeg_video_raw['non_intra_quant_flag']) {
	131	$info_mpeg_video_raw['non_intra_quant'] = substr($mpeg_stream_data, $video_chunk_offset, 64);
	132	$video_chunk_offset += 64;
	133	}
	134	}
	135
	136	if ($info_mpeg_video_raw['bitrate'] == 0x3FFFF) { // 18 set bits
	137
	138	$getid3->warning('This version of getID3() cannot determine average bitrate of VBR MPEG video files');
	139	$info_mpeg_video['bitrate_mode'] = 'vbr';
	140
	141	} else {
	142
	143	$info_mpeg_video['bitrate'] = $info_mpeg_video_raw['bitrate'] * 400;
	144	$info_mpeg_video['bitrate_mode'] = 'cbr';
	145	$info_video['bitrate'] = $info_mpeg_video['bitrate'];
	146	}
	147
	148	$info_video['resolution_x'] = $info_mpeg_video['framesize_horizontal'];
	149	$info_video['resolution_y'] = $info_mpeg_video['framesize_vertical'];
	150	$info_video['frame_rate'] = $info_mpeg_video['frame_rate'];
	151	$info_video['bitrate_mode'] = $info_mpeg_video['bitrate_mode'];
	152	$info_video['pixel_aspect_ratio'] = $info_mpeg_video['pixel_aspect_ratio'];
	153	$info_video['lossless'] = false;
	154	$info_video['bits_per_sample'] = 24;
	155
	156
	157	//0x000001B3 begins the sequence_header of every MPEG video stream.
	158	//But in MPEG-2, this header must immediately be followed by an
	159	//extension_start_code (0x000001B5) with a sequence_extension ID (1).
	160	//(This extension contains all the additional MPEG-2 stuff.)
	161	//MPEG-1 doesn't have this extension, so that's a sure way to tell the
	162	//difference between MPEG-1 and MPEG-2 video streams.
	163
	164	$info_video['codec'] = substr($mpeg_stream_data, $video_chunk_offset, 4) == getid3_mpeg::VIDEO_EXTENSION_START ? 'MPEG-2' : 'MPEG-1';
	165
	166	$audio_chunk_offset = 0;
	167	while (true) {
	168	while (substr($mpeg_stream_data, $audio_chunk_offset++, 4) !== getid3_mpeg::AUDIO_START) {
	169	if ($audio_chunk_offset >= $mpeg_stream_data_length) {
	170	break 2;
	171	}
	172	}
	173
	174	for ($i = 0; $i <= 7; $i++) {
	175	// some files have the MPEG-audio header 8 bytes after the end of the $00 $00 $01 $C0 signature, some have it up to 13 bytes (or more?) after
	176	// I have no idea why or what the difference is, so this is a stupid hack.
	177	// If anybody has any better idea of what's going on, please let me know - info@getid3.org
	178
	179	// make copy of info
	180	$dummy = $getid3->info;
	181
	182	// clone getid3 - better safe than sorry
	183	$clone = clone $this->getid3;
	184
	185	// check
	186	$mp3 = new getid3_mp3($clone);
	187	if ($mp3->decodeMPEGaudioHeader($getid3->fp, ($audio_chunk_offset + 3) + 8 + $i, $dummy, false)) {
	188
	189	$getid3->info = $dummy;
	190	$getid3->info['audio']['bitrate_mode'] = 'cbr';
	191	$getid3->info['audio']['lossless'] = false;
	192	break 2;
	193	}
	194
	195	// destroy copy
	196	unset($dummy);
	197	}
	198	}
	199
	200	// Temporary hack to account for interleaving overhead:
	201	if (!empty($info_video['bitrate']) && !empty($getid3->info['audio']['bitrate'])) {
	202	$getid3->info['playtime_seconds'] = (($getid3->info['avdataend'] - $getid3->info['avdataoffset']) * 8) / ($info_video['bitrate'] + $getid3->info['audio']['bitrate']);
	203
	204	// Interleaved MPEG audio/video files have a certain amount of overhead that varies
	205	// by both video and audio bitrates, and not in any sensible, linear/logarithmic patter
	206	// Use interpolated lookup tables to approximately guess how much is overhead, because
	207	// playtime is calculated as filesize / total-bitrate
	208	$getid3->info['playtime_seconds'] *= $this->MPEGsystemNonOverheadPercentage($info_video['bitrate'], $getid3->info['audio']['bitrate']);
	209
	210	//switch ($info_video['bitrate']) {
	211	// case('5000000'):
	212	// $multiplier = 0.93292642112380355828048824319889;
	213	// break;
	214	// case('5500000'):
	215	// $multiplier = 0.93582895375200989965359777343219;
	216	// break;
	217	// case('6000000'):
	218	// $multiplier = 0.93796247714820932532911373859139;
	219	// break;
	220	// case('7000000'):
	221	// $multiplier = 0.9413264083635103463010117778776;
	222	// break;
	223	// default:
	224	// $multiplier = 1;
	225	// break;
	226	//}
	227	//$getid3->info['playtime_seconds'] *= $multiplier;
	228	//$getid3->warning('Interleaved MPEG audio/video playtime may be inaccurate. With current hack should be within a few seconds of accurate. Report to info@getid3.org if off by more than 10 seconds.');
	229
	230	if ($info_video['bitrate'] < 50000) {
	231	$getid3->warning('Interleaved MPEG audio/video playtime may be slightly inaccurate for video bitrates below 100kbps. Except in extreme low-bitrate situations, error should be less than 1%. Report to info@getid3.org if greater than this.');
	232	}
	233	}
	234
	235	return true;
	236	}
	237
	238
	239
	240	public static function MPEGsystemNonOverheadPercentage($video_bitrate, $audio_bitrate) {
	241
	242	$overhead_percentage = 0;
	243
	244	$audio_bitrate = max(min($audio_bitrate / 1000, 384), 32); // limit to range of 32kbps - 384kbps (should be only legal bitrates, but maybe VBR?)
	245	$video_bitrate = max(min($video_bitrate / 1000, 10000), 10); // limit to range of 10kbps - 10Mbps (beyond that curves flatten anyways, no big loss)
	246
	247	//OMBB[audiobitrate] = array ( video-10kbps, video-100kbps, video-1000kbps, video-10000kbps)
	248	static $overhead_multiplier_by_bitrate = array (
	249	32 => array (0, 0.9676287944368530, 0.9802276264360310, 0.9844916183244460, 0.9852821845179940),
	250	48 => array (0, 0.9779100089209830, 0.9787770035359320, 0.9846738664076130, 0.9852683013799960),
	251	56 => array (0, 0.9731249855367600, 0.9776624308938040, 0.9832606361852130, 0.9843922606633340),
	252	64 => array (0, 0.9755642683275760, 0.9795256705493390, 0.9836573009193170, 0.9851122539404470),
	253	96 => array (0, 0.9788025247497290, 0.9798553314148700, 0.9822956869792560, 0.9834815119124690),
	254	128 => array (0, 0.9816940050925480, 0.9821675936072120, 0.9829756927470870, 0.9839763420152050),
	255	160 => array (0, 0.9825894094561180, 0.9820913399073960, 0.9823907143253970, 0.9832821783651570),
	256	192 => array (0, 0.9832038474336260, 0.9825731694317960, 0.9821028622712400, 0.9828262076447620),
	257	224 => array (0, 0.9836516298538770, 0.9824718601823890, 0.9818302180625380, 0.9823735101626480),
	258	256 => array (0, 0.9845863022094920, 0.9837229411967540, 0.9824521662210830, 0.9828645172100790),
	259	320 => array (0, 0.9849565280263180, 0.9837683142805110, 0.9822885275960400, 0.9824424382727190),
	260	384 => array (0, 0.9856094774357600, 0.9844573394432720, 0.9825970399837330, 0.9824673808303890)
	261	);
	262
	263	$bitrate_to_use_min = $bitrate_to_use_max = $previous_bitrate = 32;
	264
	265	foreach ($overhead_multiplier_by_bitrate as $key => $value) {
	266
	267	if ($audio_bitrate >= $previous_bitrate) {
	268	$bitrate_to_use_min = $previous_bitrate;
	269	}
	270	if ($audio_bitrate < $key) {
	271	$bitrate_to_use_max = $key;
	272	break;
	273	}
	274	$previous_bitrate = $key;
	275	}
	276
	277	$factor_a = ($bitrate_to_use_max - $audio_bitrate) / ($bitrate_to_use_max - $bitrate_to_use_min);
	278
	279	$video_bitrate_log10 = log10($video_bitrate);
	280	$video_factor_min1 = $overhead_multiplier_by_bitrate[$bitrate_to_use_min][floor($video_bitrate_log10)];
	281	$video_factor_min2 = $overhead_multiplier_by_bitrate[$bitrate_to_use_max][floor($video_bitrate_log10)];
	282	$video_factor_max1 = $overhead_multiplier_by_bitrate[$bitrate_to_use_min][ceil($video_bitrate_log10)];
	283	$video_factor_max2 = $overhead_multiplier_by_bitrate[$bitrate_to_use_max][ceil($video_bitrate_log10)];
	284	$factor_v = $video_bitrate_log10 - floor($video_bitrate_log10);
	285
	286	$overhead_percentage = $video_factor_min1 * $factor_a * $factor_v;
	287	$overhead_percentage += $video_factor_min2 * (1 - $factor_a) * $factor_v;
	288	$overhead_percentage += $video_factor_max1 * $factor_a * (1 - $factor_v);
	289	$overhead_percentage += $video_factor_max2 * (1 - $factor_a) * (1 - $factor_v);
	290
	291	return $overhead_percentage;
	292	}
	293
	294
	295
	296	public static function MPEGvideoFramerateLookup($raw_frame_rate) {
	297
	298	$lookup = array (0, 23.976, 24, 25, 29.97, 30, 50, 59.94, 60);
	299
	300	return (float)(isset($lookup[$raw_frame_rate]) ? $lookup[$raw_frame_rate] : 0);
	301	}
	302
	303
	304
	305	public static function MPEGvideoAspectRatioLookup($raw_aspect_ratio) {
	306
	307	$lookup = array (0, 1, 0.6735, 0.7031, 0.7615, 0.8055, 0.8437, 0.8935, 0.9157, 0.9815, 1.0255, 1.0695, 1.0950, 1.1575, 1.2015, 0);
	308
	309	return (float)(isset($lookup[$raw_aspect_ratio]) ? $lookup[$raw_aspect_ratio] : 0);
	310	}
	311
	312
	313
	314	public static function MPEGvideoAspectRatioTextLookup($raw_aspect_ratio) {
	315
	316	$lookup = array ('forbidden', 'square pixels', '0.6735', '16:9, 625 line, PAL', '0.7615', '0.8055', '16:9, 525 line, NTSC', '0.8935', '4:3, 625 line, PAL, CCIR601', '0.9815', '1.0255', '1.0695', '4:3, 525 line, NTSC, CCIR601', '1.1575', '1.2015', 'reserved');
	317
	318	return (isset($lookup[$raw_aspect_ratio]) ? $lookup[$raw_aspect_ratio] : '');
	319	}
	320
	321	}
	322
	323
	324	?>

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