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- #------------------------------------------------------------------------------
- # File: FLAC.pm
- #
- # Description: Read Free Lossless Audio Codec information
- #
- # Revisions: 11/13/2006 - P. Harvey Created
- #
- # References: 1) http://flac.sourceforge.net/
- #------------------------------------------------------------------------------
- package Image::ExifTool::FLAC;
- use strict;
- use vars qw($VERSION);
- use Image::ExifTool qw(:DataAccess :Utils);
- $VERSION = '1.07';
- sub ProcessBitStream($$$);
- # FLAC metadata blocks
- %Image::ExifTool::FLAC::Main = (
- NOTES => q{
- Free Lossless Audio Codec (FLAC) meta information. ExifTool also extracts
- ID3 information from these files.
- },
- 0 => {
- Name => 'StreamInfo',
- SubDirectory => { TagTable => 'Image::ExifTool::FLAC::StreamInfo' },
- },
- 1 => { Name => 'Padding', Binary => 1, Unknown => 1 },
- 2 => { Name => 'Application', Binary => 1, Unknown => 1 },
- 3 => { Name => 'SeekTable', Binary => 1, Unknown => 1 },
- 4 => {
- Name => 'VorbisComment',
- SubDirectory => { TagTable => 'Image::ExifTool::Vorbis::Comments' },
- },
- 5 => { Name => 'CueSheet', Binary => 1, Unknown => 1 },
- 6 => {
- Name => 'Picture',
- SubDirectory => { TagTable => 'Image::ExifTool::FLAC::Picture' },
- },
- # 7-126 - Reserved
- # 127 - Invalid
- );
- %Image::ExifTool::FLAC::StreamInfo = (
- PROCESS_PROC => \&ProcessBitStream,
- NOTES => 'FLAC is big-endian, so bit 0 is the high-order bit in this table.',
- GROUPS => { 2 => 'Audio' },
- 'Bit000-015' => 'BlockSizeMin',
- 'Bit016-031' => 'BlockSizeMax',
- 'Bit032-055' => 'FrameSizeMin',
- 'Bit056-079' => 'FrameSizeMax',
- 'Bit080-099' => 'SampleRate',
- 'Bit100-102' => {
- Name => 'Channels',
- ValueConv => '$val + 1',
- },
- 'Bit103-107' => {
- Name => 'BitsPerSample',
- ValueConv => '$val + 1',
- },
- 'Bit108-143' => 'TotalSamples',
- );
- %Image::ExifTool::FLAC::Picture = (
- PROCESS_PROC => \&Image::ExifTool::ProcessBinaryData,
- GROUPS => { 2 => 'Image' },
- FORMAT => 'int32u',
- 0 => {
- Name => 'PictureType',
- PrintConv => { # (Note: Duplicated in ID3, ASF and FLAC modules!)
- 0 => 'Other',
- 1 => '32x32 PNG Icon',
- 2 => 'Other Icon',
- 3 => 'Front Cover',
- 4 => 'Back Cover',
- 5 => 'Leaflet',
- 6 => 'Media',
- 7 => 'Lead Artist',
- 8 => 'Artist',
- 9 => 'Conductor',
- 10 => 'Band',
- 11 => 'Composer',
- 12 => 'Lyricist',
- 13 => 'Recording Studio or Location',
- 14 => 'Recording Session',
- 15 => 'Performance',
- 16 => 'Capture from Movie or Video',
- 17 => 'Bright(ly) Colored Fish',
- 18 => 'Illustration',
- 19 => 'Band Logo',
- 20 => 'Publisher Logo',
- },
- },
- 1 => {
- Name => 'PictureMIMEType',
- Format => 'var_pstr32',
- },
- 2 => {
- Name => 'PictureDescription',
- Format => 'var_pstr32',
- ValueConv => '$self->Decode($val, "UTF8")',
- },
- 3 => 'PictureWidth',
- 4 => 'PictureHeight',
- 5 => 'PictureBitsPerPixel',
- 6 => 'PictureIndexedColors',
- 7 => 'PictureLength',
- 8 => {
- Name => 'Picture',
- Groups => { 2 => 'Preview' },
- Format => 'undef[$val{7}]',
- Binary => 1,
- },
- );
- # FLAC composite tags
- %Image::ExifTool::FLAC::Composite = (
- Duration => {
- Require => {
- 0 => 'FLAC:SampleRate',
- 1 => 'FLAC:TotalSamples',
- },
- ValueConv => '($val[0] and $val[1]) ? $val[1] / $val[0] : undef',
- PrintConv => 'ConvertDuration($val)',
- },
- );
- # add our composite tags
- Image::ExifTool::AddCompositeTags('Image::ExifTool::FLAC');
- #------------------------------------------------------------------------------
- # Process information in a bit stream
- # Inputs: 0) ExifTool object ref, 1) dirInfo ref, 2) tag table ref
- # Notes: Byte order is used to determine the ordering of bits in the stream:
- # 'MM' = bit 0 is most significant, 'II' = bit 0 is least significant
- # - can handle arbitrarily wide values (eg. 8-byte or larger integers)
- sub ProcessBitStream($$$)
- {
- my ($et, $dirInfo, $tagTablePtr) = @_;
- my $dataPt = $$dirInfo{DataPt};
- my $dataPos = $$dirInfo{DataPos};
- my $dirStart = $$dirInfo{DirStart} || 0;
- my $dirLen = $$dirInfo{DirLen} || (length($$dataPt) - $dirStart);
- my $verbose = $et->Options('Verbose');
- my $byteOrder = GetByteOrder();
- my $tag;
- if ($verbose) {
- $et->VPrint(0, " + [BitStream directory, $dirLen bytes, '$byteOrder' order]\n");
- }
- foreach $tag (sort keys %$tagTablePtr) {
- next unless $tag =~ /^Bit(\d+)-?(\d+)?/;
- my ($b1, $b2) = ($1, $2 || $1); # start/end bit numbers in stream
- my ($i1, $i2) = (int($b1 / 8), int($b2 / 8)); # start/end byte numbers
- my ($f1, $f2) = ($b1 % 8, $b2 % 8); # start/end bit numbers within each byte
- last if $i2 >= $dirLen;
- my $val = 0;
- my ($i, $mask, $extra);
- $extra = ', Mask=0x' if $verbose and ($f1 != 0 or $f2 != 7);
- if ($byteOrder eq 'MM') {
- # loop from high byte to low byte
- for ($i=$i1; $i<=$i2; ++$i) {
- $mask = 0xff;
- if ($i == $i1 and $f1) {
- # mask off high bits in first word (0 is high bit)
- foreach ((8-$f1) .. 7) { $mask ^= (1 << $_) }
- }
- if ($i == $i2 and $f2 < 7) {
- # mask off low bits in last word (7 is low bit)
- foreach (0 .. (6-$f2)) { $mask ^= (1 << $_) }
- }
- $val = $val * 256 + ($mask & Get8u($dataPt, $i + $dirStart));
- $extra .= sprintf('%.2x', $mask) if $extra;
- }
- } else {
- # (FLAC is big-endian, but support little-endian bit streams
- # so this routine can be used by other modules)
- # loop from high byte to low byte
- for ($i=$i2; $i>=$i1; --$i) {
- $mask = 0xff;
- if ($i == $i1 and $f1) {
- # mask off low bits in first word (0 is low bit)
- foreach (0 .. ($f1-1)) { $mask ^= (1 << $_) }
- }
- if ($i == $i2 and $f2 < 7) {
- # mask off high bits in last word (7 is high bit)
- foreach (($f2+1) .. 7) { $mask ^= (1 << $_) }
- }
- $val = $val * 256 + ($mask & Get8u($dataPt, $i + $dirStart));
- $extra .= sprintf('%.2x', $mask) if $extra;
- }
- }
- # shift word down until low bit is in position 0
- until ($mask & 0x01) {
- $val /= 2;
- $mask >>= 1;
- }
- $et->HandleTag($tagTablePtr, $tag, $val,
- DataPt => $dataPt,
- DataPos => $dataPos,
- Start => $dirStart + $i1,
- Size => $i2 - $i1 + 1,
- Extra => $extra,
- );
- }
- return 1;
- }
- #------------------------------------------------------------------------------
- # Extract information from an Ogg FLAC file
- # Inputs: 0) ExifTool object reference, 1) dirInfo reference
- # Returns: 1 on success, 0 if this wasn't a valid Ogg FLAC file
- sub ProcessFLAC($$)
- {
- my ($et, $dirInfo) = @_;
- # must first check for leading/trailing ID3 information
- unless ($$et{DoneID3}) {
- require Image::ExifTool::ID3;
- Image::ExifTool::ID3::ProcessID3($et, $dirInfo) and return 1;
- }
- my $raf = $$dirInfo{RAF};
- my $verbose = $et->Options('Verbose');
- my $out = $et->Options('TextOut');
- my ($buff, $err);
- # check FLAC signature
- $raf->Read($buff, 4) == 4 and $buff eq 'fLaC' or return 0;
- $et->SetFileType();
- SetByteOrder('MM');
- my $tagTablePtr = GetTagTable('Image::ExifTool::FLAC::Main');
- for (;;) {
- # read next metadata block header
- $raf->Read($buff, 4) == 4 or last;
- my $flag = unpack('C', $buff);
- my $size = unpack('N', $buff) & 0x00ffffff;
- $raf->Read($buff, $size) == $size or $err = 1, last;
- my $last = $flag & 0x80; # last-metadata-block flag
- my $tag = $flag & 0x7f; # tag bits
- if ($verbose) {
- print $out "FLAC metadata block, type $tag:\n";
- $et->VerboseDump(\$buff, DataPos => $raf->Tell() - $size);
- }
- $et->HandleTag($tagTablePtr, $tag, undef,
- DataPt => \$buff,
- DataPos => $raf->Tell() - $size,
- );
- last if $last; # all done if is set
- }
- $err and $et->Warn('Format error in FLAC file');
- return 1;
- }
- 1; # end
- __END__
- =head1 NAME
- Image::ExifTool::FLAC - Read Free Lossless Audio Codec information
- =head1 SYNOPSIS
- This module is used by Image::ExifTool
- =head1 DESCRIPTION
- This module contains definitions required by Image::ExifTool to extract meta
- information from Free Lossless Audio Codec (FLAC) audio files.
- =head1 AUTHOR
- Copyright 2003-2016, 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://flac.sourceforge.net/>
- =back
- =head1 SEE ALSO
- L<Image::ExifTool::TagNames/FLAC Tags>,
- L<Image::ExifTool::TagNames/Ogg Tags>,
- L<Image::ExifTool(3pm)|Image::ExifTool>
- =cut
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