diff options
Diffstat (limited to 'modules/getid3/module.audio-video.mpeg.php')
| -rw-r--r-- | modules/getid3/module.audio-video.mpeg.php | 324 |
1 files changed, 324 insertions, 0 deletions
diff --git a/modules/getid3/module.audio-video.mpeg.php b/modules/getid3/module.audio-video.mpeg.php new file mode 100644 index 00000000..bab3f321 --- /dev/null +++ b/modules/getid3/module.audio-video.mpeg.php @@ -0,0 +1,324 @@ +<?php +// +----------------------------------------------------------------------+ +// | PHP version 5 | +// +----------------------------------------------------------------------+ +// | Copyright (c) 2002-2006 James Heinrich, Allan Hansen | +// +----------------------------------------------------------------------+ +// | This source file is subject to version 2 of the GPL license, | +// | that is bundled with this package in the file license.txt and is | +// | available through the world-wide-web at the following url: | +// | http://www.gnu.org/copyleft/gpl.html | +// +----------------------------------------------------------------------+ +// | getID3() - http://getid3.sourceforge.net or http://www.getid3.org | +// +----------------------------------------------------------------------+ +// | Authors: James Heinrich <infoØgetid3*org> | +// | Allan Hansen <ahØartemis*dk> | +// +----------------------------------------------------------------------+ +// | module.audio-video.mpeg.php | +// | Module for analyzing MPEG files | +// | dependencies: module.audio.mp3.php | +// +----------------------------------------------------------------------+ +// +// $Id: module.audio-video.mpeg.php,v 1.3 2006/11/02 10:48:00 ah Exp $ + + + +class getid3_mpeg extends getid3_handler +{ + + const VIDEO_PICTURE_START = "\x00\x00\x01\x00"; + const VIDEO_USER_DATA_START = "\x00\x00\x01\xB2"; + const VIDEO_SEQUENCE_HEADER = "\x00\x00\x01\xB3"; + const VIDEO_SEQUENCE_ERROR = "\x00\x00\x01\xB4"; + const VIDEO_EXTENSION_START = "\x00\x00\x01\xB5"; + const VIDEO_SEQUENCE_END = "\x00\x00\x01\xB7"; + const VIDEO_GROUP_START = "\x00\x00\x01\xB8"; + const AUDIO_START = "\x00\x00\x01\xC0"; + + + public function Analyze() { + + $getid3 = $this->getid3; + + $getid3->info['mpeg']['video']['raw'] = array (); + $info_mpeg_video = &$getid3->info['mpeg']['video']; + $info_mpeg_video_raw = &$info_mpeg_video['raw']; + + $getid3->info['video'] = array (); + $info_video = &$getid3->info['video']; + + $getid3->include_module('audio.mp3'); + + if ($getid3->info['avdataend'] <= $getid3->info['avdataoffset']) { + throw new getid3_exception('"avdataend" ('.$getid3->info['avdataend'].') is unexpectedly less-than-or-equal-to "avdataoffset" ('.$getid3->info['avdataoffset'].')'); + } + + $getid3->info['fileformat'] = 'mpeg'; + fseek($getid3->fp, $getid3->info['avdataoffset'], SEEK_SET); + $mpeg_stream_data = fread($getid3->fp, min(100000, $getid3->info['avdataend'] - $getid3->info['avdataoffset'])); + $mpeg_stream_data_length = strlen($mpeg_stream_data); + + $video_chunk_offset = 0; + while (substr($mpeg_stream_data, $video_chunk_offset++, 4) !== getid3_mpeg::VIDEO_SEQUENCE_HEADER) { + if ($video_chunk_offset >= $mpeg_stream_data_length) { + 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?'); + } + } + + // Start code 32 bits + // horizontal frame size 12 bits + // vertical frame size 12 bits + // pixel aspect ratio 4 bits + // frame rate 4 bits + // bitrate 18 bits + // marker bit 1 bit + // VBV buffer size 10 bits + // constrained parameter flag 1 bit + // intra quant. matrix flag 1 bit + // intra quant. matrix values 512 bits (present if matrix flag == 1) + // non-intra quant. matrix flag 1 bit + // non-intra quant. matrix values 512 bits (present if matrix flag == 1) + + $info_video['dataformat'] = 'mpeg'; + + $video_chunk_offset += (strlen(getid3_mpeg::VIDEO_SEQUENCE_HEADER) - 1); + + $frame_size_dword = getid3_lib::BigEndian2Int(substr($mpeg_stream_data, $video_chunk_offset, 3)); + $video_chunk_offset += 3; + + $aspect_ratio_frame_rate_dword = getid3_lib::BigEndian2Int(substr($mpeg_stream_data, $video_chunk_offset, 1)); + $video_chunk_offset += 1; + + $assorted_information = getid3_lib::BigEndian2Bin(substr($mpeg_stream_data, $video_chunk_offset, 4)); + $video_chunk_offset += 4; + + $info_mpeg_video_raw['framesize_horizontal'] = ($frame_size_dword & 0xFFF000) >> 12; // 12 bits for horizontal frame size + $info_mpeg_video_raw['framesize_vertical'] = ($frame_size_dword & 0x000FFF); // 12 bits for vertical frame size + $info_mpeg_video_raw['pixel_aspect_ratio'] = ($aspect_ratio_frame_rate_dword & 0xF0) >> 4; + $info_mpeg_video_raw['frame_rate'] = ($aspect_ratio_frame_rate_dword & 0x0F); + + $info_mpeg_video['framesize_horizontal'] = $info_mpeg_video_raw['framesize_horizontal']; + $info_mpeg_video['framesize_vertical'] = $info_mpeg_video_raw['framesize_vertical']; + + $info_mpeg_video['pixel_aspect_ratio'] = $this->MPEGvideoAspectRatioLookup($info_mpeg_video_raw['pixel_aspect_ratio']); + $info_mpeg_video['pixel_aspect_ratio_text'] = $this->MPEGvideoAspectRatioTextLookup($info_mpeg_video_raw['pixel_aspect_ratio']); + $info_mpeg_video['frame_rate'] = $this->MPEGvideoFramerateLookup($info_mpeg_video_raw['frame_rate']); + + $info_mpeg_video_raw['bitrate'] = bindec(substr($assorted_information, 0, 18)); + $info_mpeg_video_raw['marker_bit'] = (bool)bindec($assorted_information{18}); + $info_mpeg_video_raw['vbv_buffer_size'] = bindec(substr($assorted_information, 19, 10)); + $info_mpeg_video_raw['constrained_param_flag'] = (bool)bindec($assorted_information{29}); + $info_mpeg_video_raw['intra_quant_flag'] = (bool)bindec($assorted_information{30}); + + if ($info_mpeg_video_raw['intra_quant_flag']) { + + // read 512 bits + $info_mpeg_video_raw['intra_quant'] = getid3_lib::BigEndian2Bin(substr($mpeg_stream_data, $video_chunk_offset, 64)); + $video_chunk_offset += 64; + + $info_mpeg_video_raw['non_intra_quant_flag'] = (bool)bindec($info_mpeg_video_raw['intra_quant']{511}); + $info_mpeg_video_raw['intra_quant'] = bindec($assorted_information{31}).substr(getid3_lib::BigEndian2Bin(substr($mpeg_stream_data, $video_chunk_offset, 64)), 0, 511); + + if ($info_mpeg_video_raw['non_intra_quant_flag']) { + $info_mpeg_video_raw['non_intra_quant'] = substr($mpeg_stream_data, $video_chunk_offset, 64); + $video_chunk_offset += 64; + } + + } else { + + $info_mpeg_video_raw['non_intra_quant_flag'] = (bool)bindec($assorted_information{31}); + if ($info_mpeg_video_raw['non_intra_quant_flag']) { + $info_mpeg_video_raw['non_intra_quant'] = substr($mpeg_stream_data, $video_chunk_offset, 64); + $video_chunk_offset += 64; + } + } + + if ($info_mpeg_video_raw['bitrate'] == 0x3FFFF) { // 18 set bits + + $getid3->warning('This version of getID3() cannot determine average bitrate of VBR MPEG video files'); + $info_mpeg_video['bitrate_mode'] = 'vbr'; + + } else { + + $info_mpeg_video['bitrate'] = $info_mpeg_video_raw['bitrate'] * 400; + $info_mpeg_video['bitrate_mode'] = 'cbr'; + $info_video['bitrate'] = $info_mpeg_video['bitrate']; + } + + $info_video['resolution_x'] = $info_mpeg_video['framesize_horizontal']; + $info_video['resolution_y'] = $info_mpeg_video['framesize_vertical']; + $info_video['frame_rate'] = $info_mpeg_video['frame_rate']; + $info_video['bitrate_mode'] = $info_mpeg_video['bitrate_mode']; + $info_video['pixel_aspect_ratio'] = $info_mpeg_video['pixel_aspect_ratio']; + $info_video['lossless'] = false; + $info_video['bits_per_sample'] = 24; + + + //0x000001B3 begins the sequence_header of every MPEG video stream. + //But in MPEG-2, this header must immediately be followed by an + //extension_start_code (0x000001B5) with a sequence_extension ID (1). + //(This extension contains all the additional MPEG-2 stuff.) + //MPEG-1 doesn't have this extension, so that's a sure way to tell the + //difference between MPEG-1 and MPEG-2 video streams. + + $info_video['codec'] = substr($mpeg_stream_data, $video_chunk_offset, 4) == getid3_mpeg::VIDEO_EXTENSION_START ? 'MPEG-2' : 'MPEG-1'; + + $audio_chunk_offset = 0; + while (true) { + while (substr($mpeg_stream_data, $audio_chunk_offset++, 4) !== getid3_mpeg::AUDIO_START) { + if ($audio_chunk_offset >= $mpeg_stream_data_length) { + break 2; + } + } + + for ($i = 0; $i <= 7; $i++) { + // 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 + // I have no idea why or what the difference is, so this is a stupid hack. + // If anybody has any better idea of what's going on, please let me know - info@getid3.org + + // make copy of info + $dummy = $getid3->info; + + // clone getid3 - better safe than sorry + $clone = clone $this->getid3; + + // check + $mp3 = new getid3_mp3($clone); + if ($mp3->decodeMPEGaudioHeader($getid3->fp, ($audio_chunk_offset + 3) + 8 + $i, $dummy, false)) { + + $getid3->info = $dummy; + $getid3->info['audio']['bitrate_mode'] = 'cbr'; + $getid3->info['audio']['lossless'] = false; + break 2; + } + + // destroy copy + unset($dummy); + } + } + + // Temporary hack to account for interleaving overhead: + if (!empty($info_video['bitrate']) && !empty($getid3->info['audio']['bitrate'])) { + $getid3->info['playtime_seconds'] = (($getid3->info['avdataend'] - $getid3->info['avdataoffset']) * 8) / ($info_video['bitrate'] + $getid3->info['audio']['bitrate']); + + // Interleaved MPEG audio/video files have a certain amount of overhead that varies + // by both video and audio bitrates, and not in any sensible, linear/logarithmic patter + // Use interpolated lookup tables to approximately guess how much is overhead, because + // playtime is calculated as filesize / total-bitrate + $getid3->info['playtime_seconds'] *= $this->MPEGsystemNonOverheadPercentage($info_video['bitrate'], $getid3->info['audio']['bitrate']); + + //switch ($info_video['bitrate']) { + // case('5000000'): + // $multiplier = 0.93292642112380355828048824319889; + // break; + // case('5500000'): + // $multiplier = 0.93582895375200989965359777343219; + // break; + // case('6000000'): + // $multiplier = 0.93796247714820932532911373859139; + // break; + // case('7000000'): + // $multiplier = 0.9413264083635103463010117778776; + // break; + // default: + // $multiplier = 1; + // break; + //} + //$getid3->info['playtime_seconds'] *= $multiplier; + //$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.'); + + if ($info_video['bitrate'] < 50000) { + $getid3->warning('Interleaved MPEG audio/video playtime may be slightly inaccurate for video bitrates below 100kbps. Except in extreme low-bitrate situations, error should be less than 1%. Report to info@getid3.org if greater than this.'); + } + } + + return true; + } + + + + public static function MPEGsystemNonOverheadPercentage($video_bitrate, $audio_bitrate) { + + $overhead_percentage = 0; + + $audio_bitrate = max(min($audio_bitrate / 1000, 384), 32); // limit to range of 32kbps - 384kbps (should be only legal bitrates, but maybe VBR?) + $video_bitrate = max(min($video_bitrate / 1000, 10000), 10); // limit to range of 10kbps - 10Mbps (beyond that curves flatten anyways, no big loss) + + //OMBB[audiobitrate] = array ( video-10kbps, video-100kbps, video-1000kbps, video-10000kbps) + static $overhead_multiplier_by_bitrate = array ( + 32 => array (0, 0.9676287944368530, 0.9802276264360310, 0.9844916183244460, 0.9852821845179940), + 48 => array (0, 0.9779100089209830, 0.9787770035359320, 0.9846738664076130, 0.9852683013799960), + 56 => array (0, 0.9731249855367600, 0.9776624308938040, 0.9832606361852130, 0.9843922606633340), + 64 => array (0, 0.9755642683275760, 0.9795256705493390, 0.9836573009193170, 0.9851122539404470), + 96 => array (0, 0.9788025247497290, 0.9798553314148700, 0.9822956869792560, 0.9834815119124690), + 128 => array (0, 0.9816940050925480, 0.9821675936072120, 0.9829756927470870, 0.9839763420152050), + 160 => array (0, 0.9825894094561180, 0.9820913399073960, 0.9823907143253970, 0.9832821783651570), + 192 => array (0, 0.9832038474336260, 0.9825731694317960, 0.9821028622712400, 0.9828262076447620), + 224 => array (0, 0.9836516298538770, 0.9824718601823890, 0.9818302180625380, 0.9823735101626480), + 256 => array (0, 0.9845863022094920, 0.9837229411967540, 0.9824521662210830, 0.9828645172100790), + 320 => array (0, 0.9849565280263180, 0.9837683142805110, 0.9822885275960400, 0.9824424382727190), + 384 => array (0, 0.9856094774357600, 0.9844573394432720, 0.9825970399837330, 0.9824673808303890) + ); + + $bitrate_to_use_min = $bitrate_to_use_max = $previous_bitrate = 32; + + foreach ($overhead_multiplier_by_bitrate as $key => $value) { + + if ($audio_bitrate >= $previous_bitrate) { + $bitrate_to_use_min = $previous_bitrate; + } + if ($audio_bitrate < $key) { + $bitrate_to_use_max = $key; + break; + } + $previous_bitrate = $key; + } + + $factor_a = ($bitrate_to_use_max - $audio_bitrate) / ($bitrate_to_use_max - $bitrate_to_use_min); + + $video_bitrate_log10 = log10($video_bitrate); + $video_factor_min1 = $overhead_multiplier_by_bitrate[$bitrate_to_use_min][floor($video_bitrate_log10)]; + $video_factor_min2 = $overhead_multiplier_by_bitrate[$bitrate_to_use_max][floor($video_bitrate_log10)]; + $video_factor_max1 = $overhead_multiplier_by_bitrate[$bitrate_to_use_min][ceil($video_bitrate_log10)]; + $video_factor_max2 = $overhead_multiplier_by_bitrate[$bitrate_to_use_max][ceil($video_bitrate_log10)]; + $factor_v = $video_bitrate_log10 - floor($video_bitrate_log10); + + $overhead_percentage = $video_factor_min1 * $factor_a * $factor_v; + $overhead_percentage += $video_factor_min2 * (1 - $factor_a) * $factor_v; + $overhead_percentage += $video_factor_max1 * $factor_a * (1 - $factor_v); + $overhead_percentage += $video_factor_max2 * (1 - $factor_a) * (1 - $factor_v); + + return $overhead_percentage; + } + + + + public static function MPEGvideoFramerateLookup($raw_frame_rate) { + + $lookup = array (0, 23.976, 24, 25, 29.97, 30, 50, 59.94, 60); + + return (float)(isset($lookup[$raw_frame_rate]) ? $lookup[$raw_frame_rate] : 0); + } + + + + public static function MPEGvideoAspectRatioLookup($raw_aspect_ratio) { + + $lookup = array (0, 1, 0.6735, 0.7031, 0.7615, 0.8055, 0.8437, 0.8935, 0.9157, 0.9815, 1.0255, 1.0695, 1.0950, 1.1575, 1.2015, 0); + + return (float)(isset($lookup[$raw_aspect_ratio]) ? $lookup[$raw_aspect_ratio] : 0); + } + + + + public static function MPEGvideoAspectRatioTextLookup($raw_aspect_ratio) { + + $lookup = array ('forbidden', 'square pixels', '0.6735', '16:9, 625 line, PAL', '0.7615', '0.8055', '16:9, 525 line, NTSC', '0.8935', '4:3, 625 line, PAL, CCIR601', '0.9815', '1.0255', '1.0695', '4:3, 525 line, NTSC, CCIR601', '1.1575', '1.2015', 'reserved'); + + return (isset($lookup[$raw_aspect_ratio]) ? $lookup[$raw_aspect_ratio] : ''); + } + +} + + +?>
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