NAME Audio::Scan - Fast C metadata and tag reader for all common audio file formats 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 without reading (possibly large) artwork into memory. # Instead of binary artwork data, the size of the artwork will be returned instead. { local $ENV{AUDIO_SCAN_NO_ARTWORK} = 1; my $data = Audio::Scan->scan('/path/to/file.mp3'); } # Scan a filehandle open my $fh, '<', 'my.mp3'; my $data = Audio::Scan->scan_fh( mp3 => $fh ); close $fh; # Scan and compute an audio MD5 checksum my $data = Audio::Scan->scan( '/path/to/file.mp3', { md5_size => 100 * 1024 } ); my $md5 = $data->{info}->{audio_md5}; DESCRIPTION Audio::Scan is a C-based scanner for audio file metadata and tag information. It currently supports MP3, MP4, Ogg Vorbis, FLAC, ASF, WAV, AIFF, Musepack, Monkey's Audio, and WavPack. See below for specific details about each file format. METHODS scan( $path, [ \%OPTIONS ] ) 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 WavPack: wv 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. An optional hashref may be provided. Currently this supports one item: md5_size => $audio_bytes_to_checksum An MD5 will be computed of the first N audio bytes. Any tags in the file are automatically skipped, so this is a useful way of determining if a file's audio content is the same even if tags may have been changed. The hex MD5 value is returned in the $info->{audio_md5} key. This option will reduce performance, so choose a small enough size that works for you, you should probably avoid using more than 64K for example. scan_info( $path, [ \%OPTIONS ] ) If you only need file metadata and don't care about tags, you can use this method. scan_tags( $path, [ \%OPTIONS ] ) If you only need the tags and don't care about the metadata, use this method. scan_fh( $type => $fh, [ \%OPTIONS ] ) 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, $timestamp_in_ms ) Returns the byte offset to the first audio frame starting from the given timestamp (in milliseconds). MP3, Ogg, FLAC, ASF, MP4 The byte offset to the data packet containing this timestamp will be returned. For file formats that don't provide timestamp information such as MP3, the best estimate for the location of the timestamp will be returned. This will be more accurate if the file has a Xing header or is CBR for example. WAV, AIFF, Musepack, Monkey's Audio, WavPack Not yet supported by find_frame. find_frame_return_info( $mp4_path, $timestamp_in_ms ) The header of an MP4 file contains various metadata that refers to the structure of the audio data, making seeking more difficult to perform. This method will return the usual $info hash with 2 additional keys: seek_offset - The seek offset in bytes seek_header - A rewritten MP4 header that can be prepended to the audio data found at seek_offset to construct a valid bitstream. Specifically, the following boxes are rewritten: stts, stsc, stsz, stco For example, to seek 30 seconds into a file and write out a new MP4 file seeked to this point: my $info = Audio::Scan->find_frame_return_info( $file, 30000 ); open my $f, '<', $file; sysseek $f, $info->{seek_offset}, 1; open my $fh, '>', 'seeked.m4a'; print $fh $info->{seek_header}; while ( sysread( $f, my $buf, 65536 ) ) { print $fh $buf; } close $f; close $fh; find_frame_fh( $type => $fh, $offset ) Same as "find_frame", but with a filehandle. find_frame_fh_return_info( $type => $fh, $offset ) Same as "find_frame_return_info", but with a filehandle. has_flac() Deprecated. Always returns 1 now that FLAC is always enabled. is_supported( $path ) Returns 1 if the given path can be scanned by Audio::Scan, or 0 if not. get_types() Returns an array of strings of the file types supported by Audio::Scan. extensions_for( $type ) Returns an array of strings of the file extensions that are considered to be the file type *$type*. type_for( $extension ) Returns file type for a given extension. Returns *undef* for unsupported extensions. 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. This means older tags such as ID3v1 and ID3v2.2/v2.3 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. All text is converted to UTF-8. Sample tag data: tags => { ALBUMARTISTSORT => "Solar Fields", APIC => [ "image/jpeg", 3, "", ], CATALOGNUMBER => "INRE 017", COMM => ["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) audio_size 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 => , 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 audio_size 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) audio_size 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 first audio frame) audio_size 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) audio_size 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 audio_size 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 audio_size 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. audio_offset audio_size 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 audio_size 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. WAVPACK The following metadata about a file may be returned. audio_offset audio_size bitrate (in bps) bits_per_sample channels encoder_version file_size hybrid (1 if file is lossy) (v4 only) lossless (1 if file is lossless) (v4 only) samplerate song_length_ms total_samples TAGS WavPack 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 The audio MD5 feature uses an MD5 implementation by L. Peter Deutsch, . SEE ALSO ASF Spec MP4 Info: AUTHORS Andy Grundman, Dan Sully, COPYRIGHT AND LICENSE Copyright (C) 2010 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.