#------------------------------------------------------------------------------ # 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/ #------------------------------------------------------------------------------ package Image::ExifTool::MPEG; use strict; use vars qw($VERSION); use Image::ExifTool qw(:DataAccess :Utils); $VERSION = '1.06'; %Image::ExifTool::MPEG::Audio = ( GROUPS => { 2 => 'Audio' }, 'Bit11-12' => { Name => 'MPEGAudioVersion', RawConv => '$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 $self->{MPEG_Layer} == 3', Notes => 'version 1, layer 1', PrintConv => { 0 => 'free', 1 => 32000, 2 => 64000, 3 => 96000, 4 => 128000, 5 => 160000, 6 => 192000, 7 => 224000, 8 => 256000, 9 => 288000, 10 => 320000, 11 => 352000, 12 => 384000, 13 => 416000, 14 => 448000, }, }, { Name => 'AudioBitrate', Condition => '$self->{MPEG_Vers} == 3 and $self->{MPEG_Layer} == 2', Notes => 'version 1, layer 2', PrintConv => { 0 => 'free', 1 => 32000, 2 => 48000, 3 => 56000, 4 => 64000, 5 => 80000, 6 => 96000, 7 => 112000, 8 => 128000, 9 => 160000, 10 => 192000, 11 => 224000, 12 => 256000, 13 => 320000, 14 => 384000, }, }, { Name => 'AudioBitrate', Condition => '$self->{MPEG_Vers} == 3 and $self->{MPEG_Layer} == 1', Notes => 'version 1, layer 3', PrintConv => { 0 => 'free', 1 => 32000, 2 => 40000, 3 => 48000, 4 => 56000, 5 => 64000, 6 => 80000, 7 => 96000, 8 => 112000, 9 => 128000, 10 => 160000, 11 => 192000, 12 => 224000, 13 => 256000, 14 => 320000, }, }, { Name => 'AudioBitrate', Condition => '$self->{MPEG_Vers} != 3 and $self->{MPEG_Layer} == 3', Notes => 'version 2 or 2.5, layer 1', PrintConv => { 0 => 'free', 1 => 32000, 2 => 48000, 3 => 56000, 4 => 64000, 5 => 80000, 6 => 96000, 7 => 112000, 8 => 128000, 9 => 144000, 10 => 160000, 11 => 176000, 12 => 192000, 13 => 224000, 14 => 256000, }, }, { Name => 'AudioBitrate', Condition => '$self->{MPEG_Vers} != 3 and $self->{MPEG_Layer}', Notes => 'version 2 or 2.5, layer 2 or 3', PrintConv => { 0 => 'free', 1 => 8000, 2 => 16000, 3 => 24000, 4 => 32000, 5 => 40000, 6 => 48000, 7 => 56000, 8 => 64000, 9 => 80000, 10 => 96000, 11 => 112000, 12 => 128000, 13 => 144000, 14 => 160000, }, }, ], 'Bit20-21' => [ { Name => 'SampleRate', Condition => '$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" : $val * 400', }, # these tags not very interesting #'Bit50' => 'MarkerBit', #'Bit51-60' => 'VBVBufferSize', #'Bit61' => 'ConstrainedParamFlag', #'Bit62' => 'IntraQuantMatrixFlag', ); %Image::ExifTool::MPEG::VBR = ( GROUPS => { 2 => 'Audio' }, VARS => { NO_ID => 1 }, NOTES => 'These tags are extracted for variable bitrate audio.', 1 => { Name => 'VBRFrames' }, 2 => { Name => 'VBRBytes' }, 3 => { Name => 'VBRScale' }, ); # composite tags %Image::ExifTool::MPEG::Composite = ( Duration => { Groups => { 2 => 'Video' }, Require => { 0 => 'FileSize', }, Desire => { 1 => 'ID3Size', 2 => 'MPEG:AudioBitrate', 3 => 'MPEG:VideoBitrate', 4 => 'MPEG:VBRFrames', 5 => 'MPEG:SampleRate', 6 => 'MPEG:MPEGAudioVersion', }, ValueConv => q{ if ($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 $prt[2] and not $prt[2] =~ /^\d+$/; return undef if $val[3] and not $val[3] =~ /^\d+$/; return (8 * ($val[0] - ($val[1]||0))) / (($prt[2]||0) + ($val[3]||0)); }, PrintConv => 'ConvertDuration($val) . " (approx)"', }, ); # 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($$@) { my ($exifTool, $tagTablePtr, @data) = @_; my $tag; foreach $tag (sort keys %$tagTablePtr) { next unless $tag =~ /^Bit(\d{2})-?(\d{2})?/; my ($b1, $b2) = ($1, $2 || $1); my $index = int($b1 / 32); my $word = $data[$index]; my $mask = 0; foreach (0 .. ($b2 - $b1)) { $mask += (1 << $_); } my $val = ($word >> (31 + 32*$index - $b2)) & $mask; $exifTool->HandleTag($tagTablePtr, $tag, $val); } } #------------------------------------------------------------------------------ # Read MPEG audio frame header # Inputs: 0) ExifTool object reference, 1) Reference to audio data # Returns: 1 on success, 0 if no audio header was found sub ProcessMPEGAudio($$) { my ($exifTool, $buffPt) = @_; my ($word, $pos); 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($$buffPt) - 2; # next possible location for frame sync next; } # validate header as much as possible if (($word & 0x180000) == 0x080000 or # 01 is a reserved version ID ($word & 0x060000) == 0x000000 or # 00 is a reserved layer description ($word & 0x00f000) == 0x00f000 or # 1111 is a bad bitrate index ($word & 0x000600) == 0x000600 or # 11 is a reserved sampling frequency ($word & 0x000003) == 0x000002) # 10 is a reserved emphasis { return 0; # invalid frame header } $pos = pos($$buffPt); last; } # set file type if not done already $exifTool->SetFileType() unless $exifTool->{VALUE}->{FileType}; my $tagTablePtr = GetTagTable('Image::ExifTool::MPEG::Audio'); ProcessFrameHeader($exifTool, $tagTablePtr, $word); # extract the VBR information (ref MP3::Info) my ($v, $m) = ($$exifTool{MPEG_Vers}, $$exifTool{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 $vbrTable = GetTagTable('Image::ExifTool::MPEG::VBR'); my $flags = unpack('x4N', $buff); $pos += 8; if ($flags & 0x01) { # VBRFrames last if $pos + 4 > $len; $exifTool->HandleTag($vbrTable, 1, unpack("x${pos}N", $$buffPt)); $pos += 4; } if ($flags & 0x02) { # VBRBytes last if $pos + 4 > $len; $exifTool->HandleTag($vbrTable, 2, unpack("x${pos}N", $$buffPt)); $pos += 4; } if ($flags & 0x04) { # VBR_TOC last if $pos + 100 > $len; # (ignore toc for now) $pos += 100; } if ($flags & 0x08) { # VBRScale last if $pos + 4 > $len; $exifTool->HandleTag($vbrTable, 3, unpack("x${pos}N", $$buffPt)); $pos += 4; } last; } return 1; } #------------------------------------------------------------------------------ # Read MPEG video frame header # Inputs: 0) ExifTool object reference, 1) Reference to video data # Returns: 1 on success, 0 if no video header was found sub ProcessMPEGVideo($$) { my ($exifTool, $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 $exifTool->SetFileType('MPEG') unless $exifTool->{VALUE}->{FileType}; my $tagTablePtr = GetTagTable('Image::ExifTool::MPEG::Video'); ProcessFrameHeader($exifTool, $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 sub ProcessMPEGAudioVideo($$) { my ($exifTool, $buffPt) = @_; my %found; my $rtnVal = 0; my %proc = ( audio => \&ProcessMPEGAudio, video => \&ProcessMPEGVideo ); delete $exifTool->{AudioBitrate}; delete $exifTool->{VideoBitrate}; while ($$buffPt =~ /\0\0\x01(\xb3|\xc0)/g) { my $type = $1 eq "\xb3" ? 'video' : 'audio'; 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{$type}}($exifTool, \$dat)) { $rtnVal = 1; $found{$type} = 1; # done if we found audio and video last if scalar(keys %found) == 2; } } return $rtnVal; } #------------------------------------------------------------------------------ # Read information frame 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($$) { my ($exifTool, $dirInfo) = @_; my $raf = $$dirInfo{RAF}; my $buff; $raf->Read($buff, 4) == 4 or return 0; return 0 unless $buff =~ /^\0\0\x01[\xb0-\xbf]/; $exifTool->SetFileType(); $raf->Seek(0,0); $raf->Read($buff, 65536*4) or return 0; return ProcessMPEGAudioVideo($exifTool, \$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 2003-2008, 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 =item L =back =head1 SEE ALSO L, L, L =cut