Audio::Scan(3p)

NAME
Audio::Scan - XS parser for MP3, MP4, Ogg Vorbis, FLAC, ASF, WAV, AIFF, Musepack, Monkey's Audio

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');

    # Scan a filehandle
    open my $fh, '<', 'my.mp3';
    my $data = Audio::Scan->scan_fh( mp3 => $fh );
    close $fh;

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, MP4, Ogg Vorbis, FLAC (if libFLAC is installed), ASF, WAV, AIFF, Musepack, and Monkey's Audio.

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
    MP4:  mp4, m4a, m4b, m4p, m4v, m4r, k3g, skm, 3gp, 3g2, mov
    AAC (ADTS): aac
    Ogg:  ogg, oga
    FLAC: flc, flac, fla
    ASF:  wma, wmv, asf
    Musepack:  mpc, mpp, mp+
    Monkey's Audio:  ape, apl
    WAV: wav
    AIFF: aiff, aif

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.

  scan_fh( $type => $fh )
Scans a filehandle. $type is the type of file to scan as, i.e. "mp3" or "ogg". Note that FLAC does not support reading from a filehandle.

  find_frame( $path, $offset )
Returns the byte offset to the first audio frame starting from $offset.

The offset value is different depending on the file type:

MP3, Ogg, FLAC
    Offset is the byte offset to start searching from. The byte offset to the first audio packet/frame past this point will be returned.

ASF, MP4
    Offset is a timestamp in milliseconds. The byte offset to the data packet containing this timestamp will be returned.

WAV, AIFF, Musepack, Monkey's Audio
    Not supported by find_frame.

  find_frame_fh( $type => $fh, $offset )
Same as "find_frame", but with a filehandle.

  has_flac()
Returns 1 if FLAC support was compiled in, or 0 if not.

  is_supported( $path )
Returns 1 if the given path can be scanned by Audio::Scan, or 0 if not.

MP3

  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",
          ],
    },

MP4

  INFO
The following metadata about a file may be returned:

    audio_offset (byte offset to start of mdat)
    compatible_brands
    file_size
    leading_mdat (if file has mdat before moov)
    major_brand
    minor_version
    song_length_ms
    timescale
    tracks (array of tracks in the file)
        Each track may contain:

        audio_type
        avg_bitrate
        bits_per_sample
        channels
        duration
        encoding
        handler_name
        handler_type
        id
        max_bitrate
        samplerate

  TAGS
Tags are returned in a hash with all keys converted to upper-case. Keys starting with 0xA9 (copyright symbol) will have this character stripped out. Sample tag data:

    tags => {
       AART              => "Album Artist",
       ALB               => "Album",
       ART               => "Artist",
       CMT               => "Comments",
       COVR              => <binary data snipped>,
       CPIL              => 1,
       DAY               => 2009,
       DESC              => "Video Description",
       DISK              => "1/2",
       "ENCODING PARAMS" => "vers\0\0\0\1acbf\0\0\0\2brat\0\1w\0cdcv\0\1\6\5",
       GNRE              => "Jazz",
       GRP               => "Grouping",
       ITUNNORM          => " 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000",
       ITUNSMPB          => " 00000000 00000840 000001E4 00000000000001DC 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000",
       LYR               => "Lyrics",
       NAM               => "Name",
       PGAP              => 1,
       SOAA              => "Sort Album Artist",
       SOAL              => "Sort Album",
       SOAR              => "Sort Artist",
       SOCO              => "Sort Composer",
       SONM              => "Sort Name",
       SOSN              => "Sort Show",
       TMPO              => 120,
       TOO               => "iTunes 8.1.1, QuickTime 7.6",
       TRKN              => "1/10",
       TVEN              => "Episode ID",
       TVES              => 12,
       TVSH              => "Show",
       TVSN              => 12,
       WRT               => "Composer",
    },

AAC (ADTS)

  INFO
The following metadata about a file is returned:

    audio_offset
    bitrate (in bps)
    channels
    file_size
    profile (Main, LC, or SSR)
    samplerate (in kHz)
    song_length_ms (duration in milliseconds)

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_BLOCK

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

ALLPICTURES

    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

ASF (Windows Media Audio/Video)

  INFO
The following metadata about a file may be returned. Reading the ASF spec is encouraged if you want to find out more about any of these values.

    audio_offset (byte offset to first data packet)
    broadcast (boolean, whether the file is a live broadcast or not)
    codec_list (array of information about codecs used in the file)
    creation_date (UNIX timestamp when file was created)
    data_packets
    drm_key
    drm_license_url
    drm_protection_type
    drm_data
    file_id (unique file ID)
    file_size
    index_blocks
    index_entry_interval (in milliseconds)
    index_offsets (byte offsets for each second of audio, per stream. Useful for seeking)
    index_specifiers (indicates which stream a given index_offset points to)
    language_list (array of languages referenced by the file's metadata)
    lossless (boolean)
    max_bitrate
    max_packet_size
    min_packet_size
    mutex_list (mutually exclusive stream information)
    play_duration_ms
    preroll
    script_commands
    script_types
    seekable (boolean, whether the file is seekable or not)
    send_duration_ms
    song_length_ms (the actual length of the audio, in milliseconds)

STREAMS

The streams array contains metadata related to an individul stream within the file. The following metadata may be returned:

    DeviceConformanceTemplate
    IsVBR
    alt_bitrate
    alt_buffer_fullness
    alt_buffer_size
    avg_bitrate (most accurate bitrate for this stream)
    avg_bytes_per_sec (audio only)
    bitrate
    bits_per_sample (audio only)
    block_alignment (audio only)
    bpp (video only)
    buffer_fullness
    buffer_size
    channels (audio only)
    codec_id (audio only)
    compression_id (video only)
    encode_options
    encrypted (boolean)
    error_correction_type
    flag_seekable (boolean)
    height (video only)
    index_type
    language_index (offset into language_list array)
    max_object_size
    samplerate (in kHz) (audio only)
    samples_per_block
    stream_number
    stream_type
    super_block_align
    time_offset
    width (video only)

  TAGS
Raw tags are returned. Tags that occur more than once are returned as arrays. In contrast to the other formats, tag keys are NOT capitalized. There is one special key:

WM/Picture

Pictures are returned as a hash with the following keys:

    image_type (numeric type, same as ID3v2 APIC)
    mime_type
    description
    image

WAV

  INFO
The following metadata about a file may be returned.

    audio_offset
    bitrate (in bps)
    bits_per_sample
    block_align
    channels
    file_size
    format (WAV format code, 1 == PCM)
    id3_version (if an ID3v2 tag is found)
    samplerate (in kHz)
    song_length_ms

  TAGS
WAV files can contain several different types of tags. "Native" WAV tags found in a LIST block may include these and others:

    IARL - Archival Location
    IART - Artist
    ICMS - Commissioned
    ICMT - Comment
    ICOP - Copyright
    ICRD - Creation Date
    ICRP - Cropped
    IENG - Engineer
    IGNR - Genre
    IKEY - Keywords
    IMED - Medium
    INAM - Name (Title)
    IPRD - Product (Album)
    ISBJ - Subject
    ISFT - Software
    ISRC - Source
    ISRF - Source Form
    TORG - Label
    LOCA - Location
    TVER - Version
    TURL - URL
    TLEN - Length
    ITCH - Technician
    TRCK - Track
    ITRK - Track

ID3v2 tags can also be embedded within WAV files. These are returned exactly as for MP3 files.

AIFF

  INFO
The following metadata about a file may be returned.

    audio_offset
    bitrate (in bps)
    bits_per_sample
    block_align
    channels
    compression_name (if AIFC)
    compression_type (if AIFC)
    file_size
    id3_version (if an ID3v2 tag is found)
    samplerate (in kHz)
    song_length_ms

  TAGS
ID3v2 tags can be embedded within AIFF files. These are returned exactly as for MP3 files.

MONKEY'S AUDIO (APE)

  INFO
The following metadata about a file may be returned.

    bitrate (in bps)
    channels
    compression
    file_size
    samplerate (in kHz)
    song_length_ms
    version

  TAGS
APEv2 tags are returned as a hash of key/value pairs.

MUSEPACK

  INFO
The following metadata about a file may be returned.

    audio_offset
    bitrate (in bps)
    channels
    encoder
    file_size
    profile
    samplerate (in kHz)
    song_length_ms

  TAGS
Musepack uses APEv2 tags. They are returned as a hash of key/value pairs.

THANKS
Some code from the Rockbox project was very helpful in implementing ASF and MP4 seeking.

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>

SEE ALSO
ASF Spec <http://www.microsoft.com/windows/windowsmedia/forpros/format/asfspec.aspx>

MP4 Info: <http://standards.iso.org/ittf/PubliclyAvailableStandards/c051533_ISO_IEC_14496-12_2008.zip> <http://www.geocities.com/xhelmboyx/quicktime/formats/mp4-layout.txt>

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.