#------------------------------------------------------------------------------
# File: MPEG.pm
#
# Description: Read MPEG-1 and MPEG-2 meta information
#
# Revisions: 05/11/2006 - P. Harvey Created
#
# References: 1) http://www.mp3-tech.org/
# 2) http://www.getid3.org/
# 3) http://dvd.sourceforge.net/dvdinfo/dvdmpeg.html
# 4) http://ffmpeg.org/
# 5) http://sourceforge.net/projects/mediainfo/
#------------------------------------------------------------------------------
package Image::ExifTool::MPEG;
use strict;
use vars qw($VERSION);
use Image::ExifTool qw(:DataAccess :Utils);
$VERSION = '1.15';
%Image::ExifTool::MPEG::Audio = (
GROUPS => { 2 => 'Audio' },
'Bit11-12' => {
Name => 'MPEGAudioVersion',
RawConv => '$self->{MPEG_Vers} = $val',
PrintConv => {
0 => 2.5,
2 => 2,
3 => 1,
},
},
'Bit13-14' => {
Name => 'AudioLayer',
RawConv => '$self->{MPEG_Layer} = $val',
PrintConv => {
1 => 3,
2 => 2,
3 => 1,
},
},
# Bit 15 indicates CRC protection
'Bit16-19' => [
{
Name => 'AudioBitrate',
Condition => '$self->{MPEG_Vers} == 3 and $self->{MPEG_Layer} == 3',
Notes => 'version 1, layer 1',
PrintConvColumns => 3,
ValueConv => {
0 => 'free',
1 => 32000,
2 => 64000,
3 => 96000,
4 => 128000,
5 => 160000,
6 => 192000,
7 => 224000,
8 => 256000,
9 => 288000,
10 => 320000,
11 => 352000,
12 => 384000,
13 => 416000,
14 => 448000,
},
PrintConv => 'ConvertBitrate($val)',
},
{
Name => 'AudioBitrate',
Condition => '$self->{MPEG_Vers} == 3 and $self->{MPEG_Layer} == 2',
Notes => 'version 1, layer 2',
PrintConvColumns => 3,
ValueConv => {
0 => 'free',
1 => 32000,
2 => 48000,
3 => 56000,
4 => 64000,
5 => 80000,
6 => 96000,
7 => 112000,
8 => 128000,
9 => 160000,
10 => 192000,
11 => 224000,
12 => 256000,
13 => 320000,
14 => 384000,
},
PrintConv => 'ConvertBitrate($val)',
},
{
Name => 'AudioBitrate',
Condition => '$self->{MPEG_Vers} == 3 and $self->{MPEG_Layer} == 1',
Notes => 'version 1, layer 3',
PrintConvColumns => 3,
ValueConv => {
0 => 'free',
1 => 32000,
2 => 40000,
3 => 48000,
4 => 56000,
5 => 64000,
6 => 80000,
7 => 96000,
8 => 112000,
9 => 128000,
10 => 160000,
11 => 192000,
12 => 224000,
13 => 256000,
14 => 320000,
},
PrintConv => 'ConvertBitrate($val)',
},
{
Name => 'AudioBitrate',
Condition => '$self->{MPEG_Vers} != 3 and $self->{MPEG_Layer} == 3',
Notes => 'version 2 or 2.5, layer 1',
PrintConvColumns => 3,
ValueConv => {
0 => 'free',
1 => 32000,
2 => 48000,
3 => 56000,
4 => 64000,
5 => 80000,
6 => 96000,
7 => 112000,
8 => 128000,
9 => 144000,
10 => 160000,
11 => 176000,
12 => 192000,
13 => 224000,
14 => 256000,
},
PrintConv => 'ConvertBitrate($val)',
},
{
Name => 'AudioBitrate',
Condition => '$self->{MPEG_Vers} != 3 and $self->{MPEG_Layer}',
Notes => 'version 2 or 2.5, layer 2 or 3',
PrintConvColumns => 3,
ValueConv => {
0 => 'free',
1 => 8000,
2 => 16000,
3 => 24000,
4 => 32000,
5 => 40000,
6 => 48000,
7 => 56000,
8 => 64000,
9 => 80000,
10 => 96000,
11 => 112000,
12 => 128000,
13 => 144000,
14 => 160000,
},
PrintConv => 'ConvertBitrate($val)',
},
],
'Bit20-21' => [
{
Name => 'SampleRate',
Condition => '$self->{MPEG_Vers} == 3',
Notes => 'version 1',
PrintConv => {
0 => 44100,
1 => 48000,
2 => 32000,
},
},
{
Name => 'SampleRate',
Condition => '$self->{MPEG_Vers} == 2',
Notes => 'version 2',
PrintConv => {
0 => 22050,
1 => 24000,
2 => 16000,
},
},
{
Name => 'SampleRate',
Condition => '$self->{MPEG_Vers} == 0',
Notes => 'version 2.5',
PrintConv => {
0 => 11025,
1 => 12000,
2 => 8000,
},
},
],
# Bit 22 - padding flag
# Bit 23 - private bit
'Bit24-25' => {
Name => 'ChannelMode',
RawConv => '$self->{MPEG_Mode} = $val',
PrintConv => {
0 => 'Stereo',
1 => 'Joint Stereo',
2 => 'Dual Channel',
3 => 'Single Channel',
},
},
'Bit26' => {
Name => 'MSStereo',
Condition => '$self->{MPEG_Layer} == 1',
Notes => 'layer 3',
PrintConv => { 0 => 'Off', 1 => 'On' },
},
'Bit27' => {
Name => 'IntensityStereo',
Condition => '$self->{MPEG_Layer} == 1',
Notes => 'layer 3',
PrintConv => { 0 => 'Off', 1 => 'On' },
},
'Bit26-27' => {
Name => 'ModeExtension',
Condition => '$self->{MPEG_Layer} > 1',
Notes => 'layer 1 or 2',
PrintConv => {
0 => 'Bands 4-31',
1 => 'Bands 8-31',
2 => 'Bands 12-31',
3 => 'Bands 16-31',
},
},
'Bit28' => {
Name => 'CopyrightFlag',
PrintConv => {
0 => 'False',
1 => 'True',
},
},
'Bit29' => {
Name => 'OriginalMedia',
PrintConv => {
0 => 'False',
1 => 'True',
},
},
'Bit30-31' => {
Name => 'Emphasis',
PrintConv => {
0 => 'None',
1 => '50/15 ms',
2 => 'reserved',
3 => 'CCIT J.17',
},
},
);
%Image::ExifTool::MPEG::Video = (
GROUPS => { 2 => 'Video' },
'Bit00-11' => 'ImageWidth',
'Bit12-23' => 'ImageHeight',
'Bit24-27' => {
Name => 'AspectRatio',
ValueConv => {
1 => 1,
2 => 0.6735,
3 => 0.7031,
4 => 0.7615,
5 => 0.8055,
6 => 0.8437,
7 => 0.8935,
8 => 0.9157,
9 => 0.9815,
10 => 1.0255,
11 => 1.0695,
12 => 1.0950,
13 => 1.1575,
14 => 1.2015,
},
PrintConv => {
1 => '1:1',
0.6735 => '0.6735',
0.7031 => '16:9, 625 line, PAL',
0.7615 => '0.7615',
0.8055 => '0.8055',
0.8437 => '16:9, 525 line, NTSC',
0.8935 => '0.8935',
0.9157 => '4:3, 625 line, PAL, CCIR601',
0.9815 => '0.9815',
1.0255 => '1.0255',
1.0695 => '1.0695',
1.0950 => '4:3, 525 line, NTSC, CCIR601',
1.1575 => '1.1575',
1.2015 => '1.2015',
},
},
'Bit28-31' => {
Name => 'FrameRate',
ValueConv => {
1 => 23.976,
2 => 24,
3 => 25,
4 => 29.97,
5 => 30,
6 => 50,
7 => 59.94,
8 => 60,
},
PrintConv => '"$val fps"',
},
'Bit32-49' => {
Name => 'VideoBitrate',
ValueConv => '$val eq 0x3ffff ? "Variable" : $val * 400',
PrintConv => 'ConvertBitrate($val)',
},
# these tags not very interesting
#'Bit50' => 'MarkerBit',
#'Bit51-60' => 'VBVBufferSize',
#'Bit61' => 'ConstrainedParamFlag',
#'Bit62' => 'IntraQuantMatrixFlag',
);
%Image::ExifTool::MPEG::Xing = (
GROUPS => { 2 => 'Audio' },
VARS => { NO_ID => 1 },
NOTES => 'These tags are extracted from the Xing/Info frame.',
1 => { Name => 'VBRFrames' },
2 => { Name => 'VBRBytes' },
3 => { Name => 'VBRScale' },
4 => { Name => 'Encoder' },
5 => { Name => 'LameVBRQuality' },
6 => { Name => 'LameQuality' },
7 => { # (for documentation only)
Name => 'LameHeader',
SubDirectory => { TagTable => 'Image::ExifTool::MPEG::Lame' },
},
);
# Lame header tags (ref 5)
%Image::ExifTool::MPEG::Lame = (
PROCESS_PROC => \&Image::ExifTool::ProcessBinaryData,
GROUPS => { 2 => 'Audio' },
NOTES => 'Tags extracted from Lame 3.90 or later header.',
9 => {
Name => 'LameMethod',
Mask => 0x0f,
PrintConv => {
1 => 'CBR',
2 => 'ABR',
3 => 'VBR (old/rh)',
4 => 'VBR (new/mtrh)',
5 => 'VBR (old/rh)',
6 => 'VBR',
8 => 'CBR (2-pass)',
9 => 'ABR (2-pass)',
},
},
10 => {
Name => 'LameLowPassFilter',
ValueConv => '$val * 100',
PrintConv => '($val / 1000) . " kHz"',
},
# 19 - EncodingFlags
20 => {
Name => 'LameBitrate',
ValueConv => '$val * 1000',
PrintConv => 'ConvertBitrate($val)',
},
24 => {
Name => 'LameStereoMode',
Mask => 0x1c,
ValueConv => '$val >> 2',
PrintConv => {
0 => 'Mono',
1 => 'Stereo',
2 => 'Dual Channels',
3 => 'Joint Stereo',
4 => 'Forced Joint Stereo',
6 => 'Auto',
7 => 'Intensity Stereo',
},
},
);
# composite tags
%Image::ExifTool::MPEG::Composite = (
Duration => {
Groups => { 2 => 'Video' },
Require => {
0 => 'FileSize',
},
Desire => {
1 => 'ID3Size',
2 => 'MPEG:AudioBitrate',
3 => 'MPEG:VideoBitrate',
4 => 'MPEG:VBRFrames',
5 => 'MPEG:SampleRate',
6 => 'MPEG:MPEGAudioVersion',
},
Priority => -1, # (don't want to replace any other Duration tag)
ValueConv => q{
if ($val[4] and defined $val[5] and defined $val[6]) {
# calculate from number of VBR audio frames
my $mfs = $prt[5] / ($val[6] == 3 ? 144 : 72);
# calculate using VBR length
return 8 * $val[4] / $mfs;
}
# calculate duration as file size divided by total bitrate
# (note: this is only approximate!)
return undef unless $val[2] or $val[3];
return undef if $val[2] and not $val[2] =~ /^\d+$/;
return undef if $val[3] and not $val[3] =~ /^\d+$/;
return (8 * ($val[0] - ($val[1]||0))) / (($val[2]||0) + ($val[3]||0));
},
PrintConv => 'ConvertDuration($val) . " (approx)"',
},
AudioBitrate => {
Groups => { 2 => 'Audio' },
Notes => 'calculated for variable-bitrate MPEG audio',
Require => {
0 => 'MPEG:MPEGAudioVersion',
1 => 'MPEG:SampleRate',
2 => 'MPEG:VBRBytes',
3 => 'MPEG:VBRFrames',
},
ValueConv => q{
return undef unless $val[3];
my $mfs = $prt[1] / ($val[0] == 3 ? 144 : 72);
return $mfs * $val[2] / $val[3];
},
PrintConv => 'ConvertBitrate($val)',
},
);
# add our composite tags
Image::ExifTool::AddCompositeTags('Image::ExifTool::MPEG');
#------------------------------------------------------------------------------
# Process information in an MPEG audio or video frame header
# Inputs: 0) ExifTool object ref, 1) tag table ref, 2-N) list of 32-bit data words
sub ProcessFrameHeader($$@)
{
my ($et, $tagTablePtr, @data) = @_;
my $tag;
foreach $tag (sort keys %$tagTablePtr) {
next unless $tag =~ /^Bit(\d{2})-?(\d{2})?/;
my ($b1, $b2) = ($1, $2 || $1);
my $index = int($b1 / 32);
my $word = $data[$index];
my $mask = 0;
foreach (0 .. ($b2 - $b1)) {
$mask += (1 << $_);
}
my $val = ($word >> (31 + 32*$index - $b2)) & $mask;
$et->HandleTag($tagTablePtr, $tag, $val);
}
}
#------------------------------------------------------------------------------
# Read MPEG audio frame header
# Inputs: 0) ExifTool object reference, 1) Reference to audio data
# 2) flag set if we are trying to recognized MP3 file only
# Returns: 1 on success, 0 if no audio header was found
sub ParseMPEGAudio($$;$)
{
my ($et, $buffPt, $mp3) = @_;
my ($word, $pos);
my $ext = $$et{FILE_EXT} || '';
for (;;) {
# find frame sync
return 0 unless $$buffPt =~ m{(\xff.{3})}sg;
$word = unpack('N', $1); # get audio frame header word
unless (($word & 0xffe00000) == 0xffe00000) {
pos($$buffPt) = pos($$buffPt) - 2; # next possible location for frame sync
next;
}
# validate header as much as possible
if (($word & 0x180000) == 0x080000 or # 01 is a reserved version ID
($word & 0x060000) == 0x000000 or # 00 is a reserved layer description
($word & 0x00f000) == 0x000000 or # 0000 is the "free" bitrate index
($word & 0x00f000) == 0x00f000 or # 1111 is a bad bitrate index
($word & 0x000c00) == 0x000c00 or # 11 is a reserved sampling frequency
($word & 0x000003) == 0x000002 or # 10 is a reserved emphasis
(($mp3 and ($word & 0x060000) != 0x020000))) # must be layer 3 for MP3
{
# give up easily unless this really should be an MP3 file
return 0 unless $ext eq 'MP3';
pos($$buffPt) = pos($$buffPt) - 1;
next;
}
$pos = pos($$buffPt);
last;
}
# set file type if not done already
$et->SetFileType();
my $tagTablePtr = GetTagTable('Image::ExifTool::MPEG::Audio');
ProcessFrameHeader($et, $tagTablePtr, $word);
# extract the VBR information (ref MP3::Info)
my ($v, $m) = ($$et{MPEG_Vers}, $$et{MPEG_Mode});
while (defined $v and defined $m) {
my $len = length $$buffPt;
$pos += $v == 3 ? ($m == 3 ? 17 : 32) : ($m == 3 ? 9 : 17);
last if $pos + 8 > $len;
my $buff = substr($$buffPt, $pos, 8);
last unless $buff =~ /^(Xing|Info)/;
my $xingTable = GetTagTable('Image::ExifTool::MPEG::Xing');
my $vbrScale;
my $flags = unpack('x4N', $buff);
my $isVBR = ($buff !~ /^Info/); # Info frame is not VBR (ref 5)
$pos += 8;
if ($flags & 0x01) { # VBRFrames
last if $pos + 4 > $len;
$et->HandleTag($xingTable, 1, unpack("x${pos}N", $$buffPt)) if $isVBR;
$pos += 4;
}
if ($flags & 0x02) { # VBRBytes
last if $pos + 4 > $len;
$et->HandleTag($xingTable, 2, unpack("x${pos}N", $$buffPt)) if $isVBR;
$pos += 4;
}
if ($flags & 0x04) { # VBR_TOC
last if $pos + 100 > $len;
# (ignore toc for now)
$pos += 100;
}
if ($flags & 0x08) { # VBRScale
last if $pos + 4 > $len;
$vbrScale = unpack("x${pos}N", $$buffPt);
$et->HandleTag($xingTable, 3, $vbrScale) if $isVBR;
$pos += 4;
}
# process Lame header (ref 5)
if ($flags & 0x10) { # Lame
last if $pos + 348 > $len;
} elsif ($pos + 4 <= $len) {
my $lib = substr($$buffPt, $pos, 4);
unless ($lib eq 'LAME' or $lib eq 'GOGO') {
# attempt to identify other encoders
my $n;
if (index($$buffPt, 'RCA mp3PRO Encoder') >= 0) {
$lib = 'RCA mp3PRO';
} elsif (($n = index($$buffPt, 'THOMSON mp3PRO Encoder')) >= 0) {
$lib = 'Thomson mp3PRO';
$n += 22;
$lib .= ' ' . substr($$buffPt, $n, 6) if length($$buffPt) - $n >= 6;
} elsif (index($$buffPt, 'MPGE') >= 0) {
$lib = 'Gogo (<3.0)';
} else {
last;
}
$et->HandleTag($xingTable, 4, $lib);
last;
}
}
my $lameLen = $len - $pos;
last if $lameLen < 9;
my $enc = substr($$buffPt, $pos, 9);
if ($enc ge 'LAME3.90') {
$et->HandleTag($xingTable, 4, $enc);
if ($vbrScale <= 100) {
$et->HandleTag($xingTable, 5, int((100 - $vbrScale) / 10));
$et->HandleTag($xingTable, 6, (100 - $vbrScale) % 10);
}
my %dirInfo = (
DataPt => $buffPt,
DirStart => $pos,
DirLen => length($$buffPt) - $pos,
);
my $subTablePtr = GetTagTable('Image::ExifTool::MPEG::Lame');
$et->ProcessDirectory(\%dirInfo, $subTablePtr);
} else {
$et->HandleTag($xingTable, 4, substr($$buffPt, $pos, 20));
}
last; # (didn't want to loop anyway)
}
return 1;
}
#------------------------------------------------------------------------------
# Read MPEG video frame header
# Inputs: 0) ExifTool object reference, 1) Reference to video data
# Returns: 1 on success, 0 if no video header was found
sub ProcessMPEGVideo($$)
{
my ($et, $buffPt) = @_;
return 0 unless length $$buffPt >= 4;
my ($w1, $w2) = unpack('N2', $$buffPt);
# validate as much as possible
if (($w1 & 0x000000f0) == 0x00000000 or # 0000 is a forbidden aspect ratio
($w1 & 0x000000f0) == 0x000000f0 or # 1111 is a reserved aspect ratio
($w1 & 0x0000000f) == 0 or # frame rate must be 1-8
($w1 & 0x0000000f) > 8)
{
return 0;
}
# set file type if not done already
$et->SetFileType('MPEG') unless $$et{VALUE}{FileType};
my $tagTablePtr = GetTagTable('Image::ExifTool::MPEG::Video');
ProcessFrameHeader($et, $tagTablePtr, $w1, $w2);
return 1;
}
#------------------------------------------------------------------------------
# Read MPEG audio and video frame headers
# Inputs: 0) ExifTool object reference, 1) Reference to audio/video data
# Returns: 1 on success, 0 if no video header was found
# To Do: Properly parse MPEG streams:
# 0xb7 - sequence end
# 0xb9 - end code
# 0xba - pack start code
# 0xbb - system header
# 0xbc - program map <-- should parse this
# 0xbd - private stream 1 --> for VOB, this contains sub-streams:
# 0x20-0x3f - pictures
# 0x80-0x87 - audio (AC3,DTS,SDDS)
# 0xa0-0xa7 - audio (LPCM)
# 0xbe - padding
# 0xbf - private stream 2
# 0xc0-0xdf - audio stream
# 0xe0-0xef - video stream
sub ParseMPEGAudioVideo($$)
{
my ($et, $buffPt) = @_;
my (%found, $didHdr);
my $rtnVal = 0;
my %proc = ( audio => \&ParseMPEGAudio, video => \&ProcessMPEGVideo );
delete $$et{AudioBitrate};
delete $$et{VideoBitrate};
while ($$buffPt =~ /\0\0\x01(\xb3|\xc0)/g) {
my $type = $1 eq "\xb3" ? 'video' : 'audio';
unless ($didHdr) {
# make sure we didn't miss an audio frame sync before this (eg. MP3 file)
# (the last byte of the 4-byte MP3 audio frame header word may be zero,
# but the 2nd last must be non-zero, so we need only check to pos-3)
my $buff = substr($$buffPt, 0, pos($$buffPt) - 3);
$found{audio} = 1 if ParseMPEGAudio($et, \$buff);
$didHdr = 1;
}
next if $found{$type};
my $len = length($$buffPt) - pos($$buffPt);
last if $len < 4;
$len > 256 and $len = 256;
my $dat = substr($$buffPt, pos($$buffPt), $len);
# process MPEG audio or video
if (&{$proc{$type}}($et, \$dat)) {
$rtnVal = 1;
$found{$type} = 1;
# done if we found audio and video
last if scalar(keys %found) == 2;
}
}
return $rtnVal;
}
#------------------------------------------------------------------------------
# Read information from an MPEG file
# Inputs: 0) ExifTool object reference, 1) Directory information reference
# Returns: 1 on success, 0 if this wasn't a valid MPEG file
sub ProcessMPEG($$)
{
my ($et, $dirInfo) = @_;
my $raf = $$dirInfo{RAF};
my $buff;
$raf->Read($buff, 4) == 4 or return 0;
return 0 unless $buff =~ /^\0\0\x01[\xb0-\xbf]/;
$et->SetFileType();
$raf->Seek(0,0);
$raf->Read($buff, 65536*4) or return 0;
return ParseMPEGAudioVideo($et, \$buff);
}
1; # end
__END__
=head1 NAME
Image::ExifTool::MPEG - Read MPEG-1 and MPEG-2 meta information
=head1 SYNOPSIS
This module is used by Image::ExifTool
=head1 DESCRIPTION
This module contains definitions required by Image::ExifTool to read MPEG-1
and MPEG-2 audio/video files.
=head1 NOTES
Since ISO charges money for the official MPEG specification, this module is
based on unofficial sources which may be incomplete, inaccurate or outdated.
=head1 AUTHOR
Copyright 2003-2014, Phil Harvey (phil at owl.phy.queensu.ca)
This library is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
=head1 REFERENCES
=over 4
=item L<http://www.mp3-tech.org/>
=item L<http://www.getid3.org/>
=item L<http://dvd.sourceforge.net/dvdinfo/dvdmpeg.html>
=item L<http://ffmpeg.org/>
=item L<http://sourceforge.net/projects/mediainfo/>
=back
=head1 SEE ALSO
L<Image::ExifTool::TagNames/MPEG Tags>,
L<MP3::Info(3pm)|MP3::Info>,
L<Image::ExifTool(3pm)|Image::ExifTool>
=cut