Info(3)

NAME
MP3::Info - Manipulate / fetch info from MP3 audio files

SYNOPSIS
        #!perl -w
        use MP3::Info;
        my $file = 'Pearls_Before_Swine.mp3';
        set_mp3tag($file, 'Pearls Before Swine', q"77's",
                'Sticks and Stones', '1990',
                q"(c) 1990 77's LTD.", 'rock & roll');

        my $tag = get_mp3tag($file) or die "No TAG info";
        $tag->{GENRE} = 'rock';
        set_mp3tag($file, $tag);

        my $info = get_mp3info($file);
        printf "$file length is %d:%d\n", $info->{MM}, $info->{SS};

        my $mp3 = new MP3::Info $file;
        printf "$file length is %s, title is %s\n",
                $mp3->time, $mp3->title;

DESCRIPTION

use_winamp_genres()
    Puts WinAmp genres into @mp3_genres and %mp3_genres (adds 68 additional genres to the default list of 80). This is a separate function because these are non-standard genres, but they are included because they are widely used.

    You can import the data structures with one of:

            use MP3::Info qw(:genres);
            use MP3::Info qw(:DEFAULT :genres);
            use MP3::Info qw(:all);

remove_mp3tag (FILE [, VERSION, BUFFER])
    Can remove ID3v1 or ID3v2 tags. VERSION should be 1 for ID3v1, 2 for ID3v2, and "ALL" for both.

    For ID3v1, removes last 128 bytes from file if those last 128 bytes begin with the text 'TAG'. File will be 128 bytes shorter.

    For ID3v2, removes ID3v2 tag. Because an ID3v2 tag is at the beginning of the file, we rewrite the file after removing the tag data. The buffer for rewriting the file is 4MB. BUFFER (in bytes) ca change the buffer size.

    Returns the number of bytes removed, or -1 if no tag removed, or undef if there is an error.

set_mp3tag (FILE, TITLE, ARTIST, ALBUM, YEAR, COMMENT, GENRE [, TRACKNUM])
set_mp3tag (FILE, $HASHREF)
    Adds/changes tag information in an MP3 audio file. Will clobber any existing information in file.

    Fields are TITLE, ARTIST, ALBUM, YEAR, COMMENT, GENRE. All fields have a 30-byte limit, except for YEAR, which has a four-byte limit, and GENRE, which is one byte in the file. The GENRE passed in the function is a case-insensitive text string representing a genre found in @mp3_genres.

    Will accept either a list of values, or a hashref of the type returned by "get_mp3tag".

    If TRACKNUM is present (for ID3v1.1), then the COMMENT field can only be 28 bytes.

    ID3v2 support may come eventually.

get_mp3tag (FILE [, VERSION, RAW_V2])
    Returns hash reference containing tag information in MP3 file. Same info as described in "set_mp3tag".

    If VERSION is 1, the information is taken from the ID3v1 tag (if present). If VERSION is 2, the information is taken from the ID3v2 tag (if present). If VERSION is not supplied, the ID3v1 tag is read if present, and then, if present, the ID3v2 tag information will override any existing ID3v1 tag info.

    If the ID3v2 version is older than ID3v2.2.0, it will not be read (and a warning will be issued if -w is on).

    If RAW_V2 is false or not supplied and VERSION is 2, only the tags corresponding to ID3v1 tags are returned, with the same keys in the returned hashref.

    If RAW_V2 is true and VERSION is 2, "get_mp3tag" will return a hash of tag four-character IDs and their data. Tag IDs and their meanings are in the global hash (not exported) %v2_tag_names.

            my $tag = get_mp3tag('mysong.mp3', 2, 1);   # ID3v2, raw ID3v2 tags
            for (keys %$tag) {
                    printf "%s => %s\n", $MP3::Info::v2_tag_names{$_}, $tag->{$_};
            }

get_mp3info (FILE)
    Returns hash reference containing file information for MP3 file. This data cannot be changed. Returned data:

            VERSION         MPEG audio version (1, 2, 2.5)
            LAYER           MPEG layer description (1, 2, 3)
            STEREO          boolean for audio is in stereo

            VBR             boolean for variable bitrate
            BITRATE         bitrate in kbps (average for VBR files)
            FREQUENCY       frequency in kHz
            SIZE            bytes in audio stream

            SECS            total seconds
            MM              minutes
            SS              leftover seconds
            MS              leftover milliseconds
            TIME            time in MM:SS

            COPYRIGHT       boolean for audio is copyrighted
            PADDING         boolean for MP3 frames are padded
            MODE            channel mode (0 = stereo, 1 = joint stereo,
                            2 = dual channel, 3 = single channel)
            FRAMES          approximate number of frames
            FRAME_LENGTH    approximate length of a frame
            VBR_SCALE       VBR scale from VBR header

TROUBLESHOOTING
If you find a bug, please send me a patch. If you cannot figure out why it does not work for you, please put the MP3 file in a place where I can get it (preferably via FTP) and send me mail regarding where I can get the file, with a detailed description of the problem.

If I download the file, after debugging the problem I will not keep the MP3 file if it is not legal for me to have it. Just let me know if it is legal for me ot keep it or not.

TODO

ID3v2 Support
    First go at adding support for reading ID3v2 tags. Still need to do more, such as using Compress::Zlib to decompress compressed tags. But until I see this in use more, I won't bother. I might not be able to support Unicode at all, until Perl supports 16-bit Unicode. If something does not work properly with reading, follow the instructions above for troubleshooting.

    I think I might just use Matt DiMeo's MPEG::ID3v2Tag; the problem is that right now it requires 5.005, and MacPerl uses 5.004 (for now).

Get data from scalar
    Instead of passing a file spec or filehandle, pass the data itself. Would take some work, converting the seeks, etc.

Padding bit ?
    Do something with padding bit.

ID3v2.4.0
    It's the new standard. There are no specific plans to update to 2.4.0. I'd like it to be done, but there is no pressing need, and I don't really have the time right now. Patches welcome! :-)

Test suite
    Test suite could use a bit of an overhaul and update.

HISTORY

v0.91, Saturday, February 10, 2001
    Fix dumb bug with /o. (David Reuteler)

    Fix bug where "get_mp3tag" would return an empty hashref instead of undef if ID3v1 tag is asked for, and there is no ID3v1 tag, but there is an ID3v2 tag. (Stuart)

v0.90, Sunday, January 14, 2001
    Added experimental OOP support for getting and setting data; doesn't work for removing tags.

    Made all functions optionally accept filehandle in place of filename.

    Remove all croaks/dies and replace with simple returns or carps/warns. (Jeffrey Sumler)

    Fix various input data problems, bad warnings, division by zero, etc.

    Undef $/ in set_mp3tag() so caller can't mess up the print.

    Fix bitrate if ID == 0 and VBR. (Kyle Farrell, Per Bolmstedt)

    Split off _get_info() from get_mp3info(), so, eventually, programmers can access that functionality without passing in a file or filehandle. Not supported yet, but available for playing.

    Added total frames, leftover milliseconds, and formatted time.

    Fixed sample frequency for MPEG 2.5 files (perhaps not including VBR, though ... see bug above).

    Add in some additional genres. (Peter Marschall)

    Added ID3v2 tag removal. (Ronan Waide) NOTE: this is DANGEROUS. It is tested, but needs more testing. The file is rewritten entirely. Lots of data moving around.

    Added ID3v2.2.0 tag reading. (Ronan Waide, Kee Hinckley)

    Changed ID3v2 tag recognition to only match [A-Z0-9] instead of \w. (Christoph Oberauer)

v0.80, Monday, March 6, 2000
    Better stripping of bad data (after nulls) in ID3 tags (Dave O'Neill)

    Fixed VERSION in get_mp3info to properly return 2 when appropriate. (Bogdan Surdu)

    Added VBR support. Average bitrate is returned as BITRATE, and minutes and seconds (MM and SS) should be accurate. (Andy Waite for pointer to MP3Ext)

    Made time calculation better overall.

    Made MP3 header validation routines more comprehensive. (Matthew Sachs for pointer to xmms source)

    Changed name to MP3::Info (with wrapper still named MP3::Info).

v0.71, Thursday, July 8, 1999
    Several fixes to ID3v2 support unpack unsigned instead of signed, don't bail out after 4096-byte offsets on long ID3v2 headers. Thanks much to Matthew Sachs.

v0.70, Saturday, July 3, 1999
    Added preliminary ID3v2 reading support in "get_mp3tag". Thanks much to Tom Brown.

v0.64, Thursday, July 1, 1999
    Found bug in checking TRACKNUM parameter, used \d instead of \d+. Only gives spurious warnings, doesn't affect anything else.

    Cleaned up a bit, prepare for impending ID3v2 support.

    NOTE: truncate() broken in some builds of ActivePerl (517, maybe others). No changes to module to fix problem. (Brian Goodwin)

v0.63, Friday, April 30, 1999
    Added ID3v1.1 support. (Trond Michelsen, Pass F. B. Travis)

    Added 255 (\xFF) as default genre. (Andrew Phillips)

    I think I fixed bug relating to spaces in ID3v2 headers. (Tom Brown)

v0.62, Sunday, March 7, 1999
    Doc updates.

    Fix small unnoticable bug where ID3v2 offset is tag size plus 10, not just tag size.

    Not publickly released.

v0.61, Monday, March 1, 1999
    Fixed problem of not removing nulls on return from "get_mp3tag" (was using spaces for padding before ... now trailing whitespace and all nulls are removed before returning tag info).

    Made tests more extensive (more for my own sanity when making all these changes than to make sure it works on other platforms and machines :).

v0.60, Sunday, February 28, 1999
    Cleaned up a lot of stuff, added more comments, made "get_mp3info" much faster and much more reliable, and added recognition of ID3v2 headers. (Tom Brown)

v0.52, Sunday, February 21, 1999
    Fixed problem in "get_mp3tag" that changed value of $_ in caller (Todd Hanneken).

v0.51, Saturday, February 20, 1999
    Fixed problem with %winamp_genres having the wrong numbers (Matthew Sachs).

v0.50, Friday, February 19, 1999
    Added "remove_mp3tag". Addeed VERSION to the hash returned by "get_mp3info", and fixed a bug where STEREO was not being set correctly.

    Export all genre data structures on request. Added "use_winamp_genres" to use WinAmp genres. (Roland Steinbach)

    Added a $MPEG::MP3Info::try_harder ($MP3::Info::try_harder) variable that will try harder to find the MP3 header in a file. False by default. Can take a long time to fail, but should find most headers at any offsets if set to true.

    Thanks to Matthew Sachs for his input and fixes, and for mp3tools.

v0.20, Saturday, October 17, 1998
    Changed name from "MPEG::MP3Tag" to "MPEG::MP3Info", because it does more than just TAG stuff now.

    Made header stuff even more reliable. Lots of help and testing from Meng Weng Wong again. :-)

v0.13, Thursday, October 8, 1998
    Had some problems with header verification, got some code from Predrag Supurovic with his mpgtools. Great stuff. Also did some looping to find a header if it is not in the "right" place. I did what I think it is a smart way to do it, since some files have the header as far down as 2 kbytes into the file. First, I look at position 0, then at position 36 (a position where I have found many headers), then I start at 0 again and jump in 128-byte chunks. Once I do that a bunch of times, I go back at the beginning and try at 0 and go ahead in 1-byte chunks for a bunch more times.

    If you have an MP3 that has the header begin at an odd place like byte 761, then I suggest you strip out the junk before the header begins. :-)

v0.12, Friday, October 2, 1998
    Added "get_mp3info". Thanks again to mp3tool source from Johann Lindvall, because I basically stole it straight (after converting it from C to Perl, of course).

    I did everything I could to find the header info, but if anyone has valid MP3 files that are not recognized, or has suggestions for improvement of the algorithms, let me know.

v0.04, Tuesday, September 29, 1998
    Changed a few things, replaced a regex with an "unpack". (Meng Weng Wong)

v0.03, Tuesday, September 8, 1998
    First public release.

THANKS
Edward Allen <allenej@c51844-a.spokn1.wa.home.com>, Vittorio Bertola <v.bertola@vitaminic.com>, Michael Blakeley <mike@blakeley.com>, Per Bolmstedt <tomten@kol14.com>, Tony Bowden <tony@tmtm.com>, Tom Brown <thecap@usa.net>, Sergio Camarena <scamarena@users.sourceforge.net>, Chris Dawson <cdawson@webiphany.com>, Luke Drumm <lukedrumm@mypad.com>, Kyle Farrell <kyle@cantametrix.com>, Brian Goodwin <brian@fuddmain.com>, Todd Hanneken <thanneken@hds.harvard.edu>, Kee Hinckley <nazgul@somewhere.com>, Roman Hodek <Roman.Hodek@informatik.uni-erlangen.de>, Peter Kovacs <kovacsp@egr.uri.edu>, Johann Lindvall, Peter Marschall <peter.marschall@mayn.de>, Trond Michelsen <mike@crusaders.no>, Dave O'Neill <dave@nexus.carleton.ca>, Christoph Oberauer <christoph.oberauer@sbg.ac.at>, Andrew Phillips <asp@wasteland.org>, David Reuteler <reuteler@visi.com>, Matthew Sachs <matthewg@zevils.com>, Hermann Schwaerzler <Hermann.Schwaerzler@uibk.ac.at>, Chris Sidi <sidi@angband.org>, Roland Steinbach <roland@support-system.com>, Stuart <schneis@users.sourceforge.net>, Jeffery Sumler <jsumler@mediaone.net>, Predrag Supurovic <mpgtools@dv.co.yu>, Bogdan Surdu <tim@go.ro>, Pass F. B. Travis <pftravis@bellsouth.net>, Tobias Wagener <tobias@wagener.nu>, Ronan Waide <waider@stepstone.ie>, Andy Waite <andy@mailroute.com>, Ken Williams <ken@forum.swarthmore.edu>, Meng Weng Wong <mengwong@pobox.com>.

AUTHOR AND COPYRIGHT
Chris Nandor <pudge@pobox.com>, http://pudge.net/

Copyright (c) 1998-2001 Chris Nandor. All rights reserved. This program is free software; you can redistribute it and/or modify it under the terms of the Artistic License, distributed with Perl.

SEE ALSO

SourceForge Page
            http://sourceforge.net/projects/mp3-info/

mp3tools
            http://www.zevils.com/linux/mp3tools/

mpgtools
            http://www.dv.co.yu/mpgscript/mpgtools.htm
            http://www.dv.co.yu/mpgscript/mpeghdr.htm

mp3tool
            http://www.dtek.chalmers.se/~d2linjo/mp3/mp3tool.html

ID3v2
            http://www.id3.org/

Xing Variable Bitrate
            http://www.xingtech.com/support/partner_developer/mp3/vbr_sdk/

MP3Ext
            http://rupert.informatik.uni-stuttgart.de/~mutschml/MP3ext/

Xmms
            http://www.xmms.org/

VERSION
v0.91, Saturday, February 10, 2001