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MP4::Info.3pm

NAME

MP4::Info - Fetch info from MPEG-4 files (.mp4, .m4a, .m4p, .3gp)

SYNOPSIS

         #!perl -w
         use MP4::Info;
         my $file = 'Pearls_Before_Swine.m4a';
 
         my $tag = get_mp4tag($file) or die "No TAG info";
         printf "$file is a %s track\n", $tag->{GENRE};
 
         my $info = get_mp4info($file);
         printf "$file length is %d:%d\n", $info->{MM}, $info->{SS};
 
         my $mp4 = new MP4::Info $file;
         printf "$file length is %s, title is %s\n",
                 $mp4->time, $mp4->title;
 
 

DESCRIPTION

The MP4::Info module can be used to extract tag and meta information from MPEG-4 audio (AAC) and video files. It is designed as a drop-in replacement for MP3::Info.

Note that this module does not allow you to update the information in MPEG-4 files.

$mp4 = MP4::Info->new(FILE)

OOP interface to the rest of the module. The same keys available via "get_mp4info" and "get_mp4tag" are available via the returned object (using upper case or lower case; but note that all-caps 'VERSION' will return the module version, not the MPEG-4 version).

Passing a value to one of the methods will not set the value for that tag in the MPEG-4 file.

use_mp4_utf8([STATUS])

Tells MP4::Info whether to assume that ambiguously encoded TAG info is UTF-8 or Latin-1. 1 is UTF-8, 0 is Latin-1. Default is UTF-8.

Function returns new status (1/0). If no argument is supplied, or an unaccepted argument is supplied, function merely returns existing status.

This function is not exported by default, but may be exported with the ":utf8" or ":all" export tag.

get_mp4tag (FILE)

Returns hash reference containing the tag information from the MP4 file. The following keys may be defined:

         ALB     Album
         APID    Apple Store ID
         ART     Artist
         CMT     Comment
         COVR    Album art (typically JPEG or PNG data)
         CPIL    Compilation (boolean)
         CPRT    Copyright statement
         DAY     Year
         DISK    Disk number & total (2 integers)
         GNRE    Genre
         GRP     Grouping
         NAM     Title
         RTNG    Rating (integer)
         TMPO    Tempo (integer)
         TOO     Encoder
         TRKN    Track number & total (2 integers)
         WRT     Author or composer
 
 

For compatibility with MP3::Info, the MP3 ID3v1-style keys TITLE, ARTIST, ALBUM, YEAR, COMMENT, GENRE and TRACKNUM are defined as synonyms for NAM, ART, ALB, DAY, CMT, GNRE and TRKN[0].

Any and all of these keys may be undefined if the corresponding information is missing from the MPEG-4 file.

On error, returns nothing and sets $@.

get_mp4info (FILE)

Returns hash reference containing file information from the MPEG-4 file. The following keys may be defined:

         VERSION         MPEG version (=4)
         LAYER           MPEG layer description (=1 for compatibility with MP3::Info)
         BITRATE         bitrate in kbps (average for VBR files)
         FREQUENCY       frequency in kHz
         SIZE            bytes in audio stream
 
         SECS            total seconds, rounded to nearest second
         MM              minutes
         SS              leftover seconds
         MS              leftover milliseconds, rounded to nearest millisecond
         TIME            time in MM:SS, rounded to nearest second
 
         COPYRIGHT       boolean for audio is copyrighted
         ENCODING        audio codec name. Possible values include:
                         'mp4a' - AAC, aacPlus
                         'alac' - Apple lossless
                         'drms' - Apple encrypted AAC
                         'samr' - 3GPP narrow-band AMR
                         'sawb' - 3GPP wide-band AMR
                         'enca' - Unspecified encrypted audio
         ENCRYPTED       boolean for audio data is encrypted
 
 

Any and all of these keys may be undefined if the corresponding information is missing from the MPEG-4 file.

On error, returns nothing and sets $@.

BUGS

Doesn't support writing tag information to MPEG-4 files.

The calculation of bitrate is not very accurate, and tends to be under the real bitrate.

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 MP4 file in a place where I can get it (preferably via FTP, or HTTP) and send me mail regarding where I can get the file, with a detailed description of the problem. I will keep a copy of the file only for as long as necessary to debug the problem.

AUTHOR

Jonathan Harris <jhar@cpan.org>.

THANKS

Chris Nandor <pudge@pobox.com> for writing MP3::Info

Dan Sully at Slim Devices for cover art and iTunes/aacgain metadata patches.

Ruben Laguna for PSP support.

SEE ALSO

MP4::Info Project Page

<http://search.cpan.org/~jhar/MP4-Info>

ISO 14496-12:2004 - Coding of audio-visual objects - Part 12: ISO base media file format

<http://www.iso.ch/iso/en/ittf/PubliclyAvailableStandards/c038539_ISO_IEC_14496-12_2004(E).zip>

ISO 14496-14:2003 - Coding of audio-visual objects - Part 14: MP4 file format

<http://www.iso.org/iso/en/CatalogueDetailPage.CatalogueDetail?CSNUMBER=38538> (Not worth buying - the interesting stuff is in Part 12).

3GPP TS 26.244 - 3GPP file format (3GP)

<http://www.3gpp.org/ftp/Specs/html-info/26244.htm>

QuickTime File Format

<http://developer.apple.com/documentation/QuickTime/QTFF/>

ISO 14496-1 Media Format

<http://www.geocities.com/xhelmboyx/quicktime/formats/mp4-layout.txt>

MP3::Info

<http://search.cpan.org/~cnandor/MP3-Info/>

COPYRIGHT and LICENSE

Copyright (c) 2004, 2005, 2006, Jonathan Harris <jhar@cpan.org>

This program is free software; you can redistribute it and/or modify it under the the same terms as Perl itself.