/ 
Audio-Scan-0.01
River stage one • 2 direct dependents • 2 total dependents
/ Audio::Scan

NAME

Audio::Scan - Fast C scanning of audio file metadata

SYNOPSIS

use Audio::Scan;

my $data = Audio::Scan->scan('/path/to/file.mp3');

# Just file info
my $info = Audio::Scan->scan_info('/path/to/file.mp3');

# Just tags
my $tags = Audio::Scan->scan_tags('/path/to/file.mp3');

DESCRIPTION

Audio::Scan is a C-based scanner for audio file metadata and tag information. It currently supports MP3 via an included version of libid3tag, Ogg Vorbis, and FLAC (if libFLAC is installed). A future release will add support for AAC, WMA, WAV, and possibly others.

See below for specific details about each file format.

METHODS

scan( $path )

Scans $path for both metadata and tag information. The type of scan performed is determined by the file's extension. Supported extensions are:

MP3:  mp3, mp2
Ogg:  ogg, oga
FLAC: flc, flac, fla

This method returns a hashref containing two other hashrefs: info and tags. The contents of the info and tag hashes vary depending on file format, see below for details.

scan_info( $path )

If you only need file metadata and don't care about tags, you can use this method.

scan_tags( $path )

If you only need the tags and don't care about the metadata, use this method.

MP3 DETAILS

INFO

The following metadata about a file may be returned:

id3_version (i.e. "ID3v2.4.0")
song_length_ms (duration in milliseconds)
layer (i.e. 3)
stereo
samples_per_frame
padding
audio_size (size of all audio frames)
audio_offset (byte offset to first audio frame)
bitrate (in bps, determined using Xing/LAME/VBRI if possible, or average in the worst case)
samplerate (in kHz)
vbr (1 if file is VBR)

If a Xing header is found:
xing_frames
xing_bytes
xing_quality

If a VBRI header is found:
vbri_delay
vbri_frames
vbri_bytes
vbri_quality

If a LAME header is found:
lame_encoder_version
lame_tag_revision
lame_vbr_method
lame_lowpass
lame_replay_gain_radio
lame_replay_gain_audiophile
lame_encoder_delay
lame_encoder_padding
lame_noise_shaping
lame_stereo_mode
lame_unwise_settings
lame_source_freq
lame_surround
lame_preset

TAGS

Raw tags are returned as found by libid3tag. This means older tags such as ID3v1 and ID3v2.2 are converted to ID3v2.4 tag names. Multiple instances of a tag in a file will be returned as arrays. Complex tags such as APIC and COMM are returned as arrays. All tag fields are converted to upper-case. Sample tag data:

tags => {
      ALBUMARTISTSORT => "Solar Fields",
      APIC => [ 0, "image/jpeg", 3, "", <binary data snipped> ],
      CATALOGNUMBER => "INRE 017",
      COMM => [0, "eng", "", "Amazon.com Song ID: 202981429"],
      "MUSICBRAINZ ALBUM ARTIST ID" => "a2af1f31-c9eb-4fff-990c-c4f547a11b75",
      "MUSICBRAINZ ALBUM ID" => "282143c9-6191-474d-a31a-1117b8c88cc0",
      "MUSICBRAINZ ALBUM RELEASE COUNTRY" => "FR",
      "MUSICBRAINZ ALBUM STATUS" => "official",
      "MUSICBRAINZ ALBUM TYPE" => "album",
      "MUSICBRAINZ ARTIST ID" => "a2af1f31-c9eb-4fff-990c-c4f547a11b75",
      "REPLAYGAIN_ALBUM_GAIN" => "-2.96 dB",
      "REPLAYGAIN_ALBUM_PEAK" => "1.045736",
      "REPLAYGAIN_TRACK_GAIN" => "+3.60 dB",
      "REPLAYGAIN_TRACK_PEAK" => "0.892606",
      TALB => "Leaving Home",
      TCOM => "Magnus Birgersson",
      TCON => "Ambient",
      TCOP => "2005 ULTIMAE RECORDS",
      TDRC => "2004-10",
      TIT2 => "Home",
      TPE1 => "Solar Fields",
      TPE2 => "Solar Fields",
      TPOS => "1/1",
      TPUB => "Ultimae Records",
      TRCK => "1/11",
      TSOP => "Solar Fields",
      UFID => [
            "http://musicbrainz.org",
            "1084278a-2254-4613-a03c-9fed7a8937ca",
      ],
},

OGG VORBIS

INFO

The following metadata about a file is returned:

version
channels
stereo
samplerate (in kHz)
bitrate_average (in bps)
bitrate_upper
bitrate_nominal
bitrate_lower
blocksize_0
blocksize_1
audio_offset (byte offset to audio)
song_length_ms (duration in milliseconds)

TAGS

Raw Vorbis comments are returned. All comment keys are capitalized.

FLAC

INFO

The following metadata about a file is returned:

channels
samplerate (in kHz)
bitrate (in bps)
file_size
audio_offset (byte offset to audio)
song_length_ms (duration in milliseconds)
bits_per_sample
frames
minimum_blocksize
maximum_blocksize
minimum_framesize
maximum_framesize
md5
total_samples

TAGS

Raw FLAC comments are returned. All comment keys are capitalized. Some data returned is special:

APPLICATION

Each application block is returned in the APPLICATION tag keyed by application ID.

CUESHEET

The CUESHEET tag is an array containing each line of the cue sheet.

PICTURE

Embedded pictures are returned in an ALLPICTURES array.  Each picture has the following metadata:

    mime_type
    description
    width
    height
    depth
    color_index
    image_data
    picture_type

THANKS

Some of the file format parsing code was derived from the mt-daapd project, and adapted by Netgear. It has been heavily rewritten to fix bugs and add more features.

The source to the original Netgear C scanner for SqueezeCenter is located at http://svn.slimdevices.com/repos/slim/7.3/trunk/platforms/readynas/contrib/scanner

AUTHORS

Andy Grundman, <andy@slimdevices.com>

Dan Sully, <daniel@cpan.org>

COPYRIGHT AND LICENSE

Copyright (C) 2009 Logitech, Inc.

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.