One hand clapping » compilation http://warped.org/blog Max Baker -- A Man with a Hand Mon, 10 May 2010 03:26:25 +0000 http://wordpress.org/?v=2.8.6 en hourly 1 iTunes – Setting the Compilation Flag on MP3’s using Perl http://warped.org/blog/2009/05/02/itunes-setting-the-compilation-flag-on-mp3s-using-perl/ http://warped.org/blog/2009/05/02/itunes-setting-the-compilation-flag-on-mp3s-using-perl/#comments Sun, 03 May 2009 00:10:13 +0000 max http://warped.org/blog/?p=50 Update

I’ve consolidated this script into a new one. GO HERE : http://warped.org/blog/2009/05/03/itunes-fixing-id3-tags-in-mp3s-take-two/

Overview

If you have an album that’s a compilation or DJ mix, then Cover Flow gets confused and does not group all the tracks together into an album because there is a different “Artist” for each track.

iTunes gets around this by setting it’s own custom flag in the ID3 tag : the TCMP frame in ID3v2 to be specific.

The Script

The following script uses MP3::Tag to set the TCMP flag on all the MP3’s in the current directory, or the files specified on the command line.

#!/usr/bin/perl -w
# mp3_make_comp
# Max Baker
# 4/29/09
#
# This script will set the I-Tunes Compilation Tag (TCMP)
# on Files passed to it.   If no files are passed, it works on *.mp3 in the current directory.
#
 
use MP3::Tag;
 
unless (scalar @ARGV) {
    @ARGV = glob("*.mp3");
}
 
foreach my $f (@ARGV) {
    next unless -r $f;
    add_comp($f);
}
 
sub add_comp {
    my $file = shift;
    my $mp3 = MP3::Tag->new($file);
    $mp3->config('write_v24' => 1);
 
    # scan file for existing tags
    $mp3->get_tags;
 
    unless (exists $mp3->{ID3v2}) {
        $mp3->new_tag("ID3v2");
    }
 
    # check for existing tag
    my ($info, $name, @rest) = $mp3->{ID3v2}->get_frame("TCMP");
    if (defined($info)) {
        print "$file : TCMP=$info already set.\n";
        return;
    }   
 
    print "$file : Setting TCMP=1\n";
    $mp3->{ID3v2}->add_frame("TCMP", "1") or die "$file : Adding TCMP frame failed.\n";
    $mp3->{ID3v2}->write_tag;
    $mp3->close();
}

Prerequisites

I managed to find a bug in MP3::Tag, so you may have to do the patch found here.

$data = pack("N", length($data)) . compress $data
unless $frame->flags->{unchanged};

Becomes:

$data = pack("N", length($data)) . compress $data
unless $frame->{flags}->{unchanged};

On line 585 of ID3v2.pm.

Next Up : Copying ID3v1 tags to ID3v2 tags.

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