<?php
/////////////////////////////////////////////////////////////////
/// getID3() by James Heinrich <info@getid3.org> //
// available at http://getid3.sourceforge.net ///
// or http://www.getid3.org ///
/////////////////////////////////////////////////////////////////
// //
// getid3.mpeg.php - part of getID3() //
// See getid3.readme.txt for more details //
// //
/////////////////////////////////////////////////////////////////
define('MPEG_VIDEO_PICTURE_START', "\x00\x00\x01\x00");
//define('MPEG_VIDEO_SLICE_START', "\x00\x00\x01\x01" .. 00\x00\x01\xAF);
//define('MPEG_VIDEO_RESERVED1', "\x00\x00\x01\xB0");
//define('MPEG_VIDEO_RESERVED2', "\x00\x00\x01\xB1");
define('MPEG_VIDEO_USER_DATA_START', "\x00\x00\x01\xB2");
define('MPEG_VIDEO_SEQUENCE_HEADER', "\x00\x00\x01\xB3");
define('MPEG_VIDEO_SEQUENCE_ERROR', "\x00\x00\x01\xB4");
define('MPEG_VIDEO_EXTENSION_START', "\x00\x00\x01\xB5");
//define('MPEG_VIDEO_RESERVED3', "\x00\x00\x01\xB6");
define('MPEG_VIDEO_SEQUENCE_END', "\x00\x00\x01\xB7");
define('MPEG_VIDEO_GROUP_START', "\x00\x00\x01\xB8");
//define('MPEG_VIDEO_SYSTEM_START', "\x00\x00\x01\xB9" .. \x00\x00\x01\xFF);
define('MPEG_AUDIO_START', "\x00\x00\x01\xC0");
function getMPEGHeaderFilepointer(&$fd, &$ThisFileInfo) {
$ThisFileInfo['fileformat'] = 'mpeg';
fseek($fd, $ThisFileInfo['avdataoffset'], SEEK_SET);
$MPEGstreamData = fread($fd, min(100000, $ThisFileInfo['avdataend'] - $ThisFileInfo['avdataoffset']));
$MPEGstreamDataLength = strlen($MPEGstreamData);
$foundVideo = true;
$VideoChunkOffset = 0;
while (substr($MPEGstreamData, $VideoChunkOffset++, 4) !== MPEG_VIDEO_SEQUENCE_HEADER) {
if ($VideoChunkOffset >= $MPEGstreamDataLength) {
$foundVideo = false;
break;
}
}
if ($foundVideo) {
// 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)
$ThisFileInfo['video']['dataformat'] = 'mpeg';
// I don't know how to differentiate between MPEG-1 and MPEG-2 video stream
// Any information appreciated: info@getid3.org
//$ThisFileInfo['video']['codec'] = 'MPEG-1';
//$ThisFileInfo['video']['codec'] = 'MPEG-2';
$ThisFileInfo['video']['codec'] = 'MPEG';
$VideoChunkOffset += (strlen(MPEG_VIDEO_SEQUENCE_HEADER) - 1);
$FrameSizeDWORD = BigEndian2Int(substr($MPEGstreamData, $VideoChunkOffset, 3));
$VideoChunkOffset += 3;
$AspectRatioFrameRateDWORD = BigEndian2Int(substr($MPEGstreamData, $VideoChunkOffset, 1));
$VideoChunkOffset += 1;
$assortedinformation = BigEndian2Bin(substr($MPEGstreamData, $VideoChunkOffset, 4));
$VideoChunkOffset += 4;
$ThisFileInfo['mpeg']['video']['raw']['framesize_horizontal'] = ($FrameSizeDWORD & 0xFFF000) >> 12; // 12 bits for horizontal frame size
$ThisFileInfo['mpeg']['video']['raw']['framesize_vertical'] = ($FrameSizeDWORD & 0x000FFF); // 12 bits for vertical frame size
$ThisFileInfo['mpeg']['video']['raw']['pixel_aspect_ratio'] = ($AspectRatioFrameRateDWORD & 0xF0) >> 4;
$ThisFileInfo['mpeg']['video']['raw']['frame_rate'] = ($AspectRatioFrameRateDWORD & 0x0F);
$ThisFileInfo['mpeg']['video']['framesize_horizontal'] = $ThisFileInfo['mpeg']['video']['raw']['framesize_horizontal'];
$ThisFileInfo['mpeg']['video']['framesize_vertical'] = $ThisFileInfo['mpeg']['video']['raw']['framesize_vertical'];
$ThisFileInfo['mpeg']['video']['pixel_aspect_ratio'] = MPEGvideoAspectRatioLookup($ThisFileInfo['mpeg']['video']['raw']['pixel_aspect_ratio']);
$ThisFileInfo['mpeg']['video']['pixel_aspect_ratio_text'] = MPEGvideoAspectRatioTextLookup($ThisFileInfo['mpeg']['video']['raw']['pixel_aspect_ratio']);
$ThisFileInfo['mpeg']['video']['frame_rate'] = MPEGvideoFramerateLookup($ThisFileInfo['mpeg']['video']['raw']['frame_rate']);
$ThisFileInfo['mpeg']['video']['raw']['bitrate'] = Bin2Dec(substr($assortedinformation, 0, 18));
$ThisFileInfo['mpeg']['video']['raw']['marker_bit'] = Bin2Dec(substr($assortedinformation, 18, 1));
$ThisFileInfo['mpeg']['video']['raw']['vbv_buffer_size'] = Bin2Dec(substr($assortedinformation, 19, 10));
$ThisFileInfo['mpeg']['video']['raw']['constrained_param_flag'] = Bin2Dec(substr($assortedinformation, 29, 1));
$ThisFileInfo['mpeg']['video']['raw']['intra_quant_flag'] = Bin2Dec(substr($assortedinformation, 30, 1));
if ($ThisFileInfo['mpeg']['video']['raw']['bitrate'] == 0x3FFFF) { // 18 set bits
$ThisFileInfo['warning'] .= "\n".'This version of getID3() ['.GETID3VERSION.'] cannot determine average bitrate of VBR MPEG video files';
$ThisFileInfo['mpeg']['video']['bitrate_mode'] = 'vbr';
} else {
$ThisFileInfo['mpeg']['video']['bitrate'] = $ThisFileInfo['mpeg']['video']['raw']['bitrate'] * 400;
$ThisFileInfo['mpeg']['video']['bitrate_mode'] = 'cbr';
$ThisFileInfo['video']['bitrate'] = $ThisFileInfo['mpeg']['video']['bitrate'];
}
$ThisFileInfo['video']['resolution_x'] = $ThisFileInfo['mpeg']['video']['framesize_horizontal'];
$ThisFileInfo['video']['resolution_y'] = $ThisFileInfo['mpeg']['video']['framesize_vertical'];
$ThisFileInfo['video']['frame_rate'] = $ThisFileInfo['mpeg']['video']['frame_rate'];
$ThisFileInfo['video']['bitrate_mode'] = $ThisFileInfo['mpeg']['video']['bitrate_mode'];
$ThisFileInfo['video']['pixel_aspect_ratio'] = $ThisFileInfo['mpeg']['video']['pixel_aspect_ratio'];
$ThisFileInfo['video']['lossless'] = false;
$ThisFileInfo['video']['bits_per_sample'] = 24;
} else {
$ThisFileInfo['error'] .= "\n".'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?';
}
$AudioChunkOffset = 0;
while (true) {
while (substr($MPEGstreamData, $AudioChunkOffset++, 4) !== MPEG_AUDIO_START) {
if ($AudioChunkOffset >= $MPEGstreamDataLength) {
break 2;
}
}
require_once(GETID3_INCLUDEPATH.'getid3.mp3.php');
for ($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
$dummy = $ThisFileInfo;
if (decodeMPEGaudioHeader($fd, ($AudioChunkOffset + 3) + 8 + $i, $dummy, false)) {
$ThisFileInfo = $dummy;
$ThisFileInfo['audio']['bits_per_sample'] = 16;
$ThisFileInfo['audio']['bitrate_mode'] = 'cbr';
$ThisFileInfo['audio']['lossless'] = false;
break 2;
}
}
}
// Temporary hack to account for interleaving overhead:
if (!empty($ThisFileInfo['video']['bitrate']) && !empty($ThisFileInfo['audio']['bitrate'])) {
$ThisFileInfo['playtime_seconds'] = (($ThisFileInfo['avdataend'] - $ThisFileInfo['avdataoffset']) * 8) / $ThisFileInfo['video']['bitrate'];
switch ($ThisFileInfo['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;
}
$ThisFileInfo['playtime_seconds'] *= $multiplier;
$ThisFileInfo['warning'] .= "\n".'Interleaved MPEG audio/video playtime may be inaccurate. With current hack should be within a few seconds of accurate. Report to info@getid3.org if off by more than 10 seconds.';
}
return true;
}
function MPEGvideoFramerateLookup($rawframerate) {
$MPEGvideoFramerateLookup = array(0, 23.976, 24, 25, 29.97, 30, 50, 59.94, 60);
return (isset($MPEGvideoFramerateLookup[$rawframerate]) ? (float) $MPEGvideoFramerateLookup[$rawframerate] : (float) 0);
}
function MPEGvideoAspectRatioLookup($rawaspectratio) {
$MPEGvideoAspectRatioLookup = array(0, 1, 0.6735, 0.7031, 0.7615, 0.8055, 0.8437, 0.8935, 0.9157, 0.9815, 1.0255, 1.0695, 1.0950, 1.1575, 1.2015, 0);
return (isset($MPEGvideoAspectRatioLookup[$rawaspectratio]) ? (float) $MPEGvideoAspectRatioLookup[$rawaspectratio] : (float) 0);
}
function MPEGvideoAspectRatioTextLookup($rawaspectratio) {
$MPEGvideoAspectRatioTextLookup = array('forbidden', 'square pixels', '0.6735', '16:9, 625 line, PAL', '0.7615', '0.8055', '16:9, 525 line, NTSC', '0.8935', '4:3, 625 line, PAL, CCIR601', '0.9815', '1.0255', '1.0695', '4:3, 525 line, NTSC, CCIR601', '1.1575', '1.2015', 'reserved');
return (isset($MPEGvideoAspectRatioTextLookup[$rawaspectratio]) ? $MPEGvideoAspectRatioTextLookup[$rawaspectratio] : '');
}
?>
