APEv2 tag
Encyclopedia
An APE tag is a tag
Tag (metadata)
In online computer systems terminology, a tag is a non-hierarchical keyword or term assigned to a piece of information . This kind of metadata helps describe an item and allows it to be found again by browsing or searching...

 used to add metadata
Metadata
The term metadata is an ambiguous term which is used for two fundamentally different concepts . Although the expression "data about data" is often used, it does not apply to both in the same way. Structural metadata, the design and specification of data structures, cannot be about data, because at...

, such as the title, artist, or track number, to digital audio
Digital audio
Digital audio is sound reproduction using pulse-code modulation and digital signals. Digital audio systems include analog-to-digital conversion , digital-to-analog conversion , digital storage, processing and transmission components...

 files.

APEv1

The APEv1 tag was designed for the Monkey's Audio
Monkey's Audio
Monkey's Audio is a file format for audio data compression. Being a lossless format, Monkey's Audio does not discard data during the process of encoding, unlike lossy compression methods such as AAC, MP3, Vorbis and Musepack....

 format.
  • In MP3
    MP3
    MPEG-1 or MPEG-2 Audio Layer III, more commonly referred to as MP3, is a patented digital audio encoding format using a form of lossy data compression...

    -type files, the Ape Tag is stored right at the end of the file, with no inline declaration in the body of the file. The software handles the writing and access to the tag, and does not interfere with MP3 contents.

APEv2

The Musepack
Musepack
Musepack or MPC is an open source lossy audio codec, specifically optimized for transparent compression of stereo audio at bitrates of 160–180 kbit/s...

 format developer Frank Klemm extended the original APE tag format to add a header, allowing APE tags to be at the beginning of files, and also allowed metadata values to be Unicode
Unicode
Unicode is a computing industry standard for the consistent encoding, representation and handling of text expressed in most of the world's writing systems...

 rather than simply ASCII.
Because of its simplicity and flexibility, the WavPack
WavPack
WavPack is a free, open source lossless audio compression format developed by David Bryant.-Features:WavPack compression can compress 8-, 16-, 24-, and 32-bit fixed-point, and 32-bit floating point audio files in the .WAV file format. It also supports surround sound streams and high frequency...

 and OptimFROG
OptimFROG
OptimFROG is a proprietary lossless audio data compression codec developed by Florin Ghido. OptimFROG is optimized for very high compression ratios, even for the price of slower encoding and decoding.-OptimFROG DualStream:...

 formats also adopted it as their primary tag format. Version 3.99 of Monkey's Audio also switched from using APEv1 to APEv2.

foobar2000
Foobar2000
foobar2000 is a freeware audio player for Windows developed by Peter Pawlowski, a former freelance contractor for Nullsoft. It is known for its highly modular design and extensive SDK which allows third-party developers to do such things as completely replace the interface...

, and Jack! The Knife software can tag MP3
MP3
MPEG-1 or MPEG-2 Audio Layer III, more commonly referred to as MP3, is a patented digital audio encoding format using a form of lossy data compression...

 files with APEv2 tags instead of ID3
ID3
ID3 is a metadata container most often used in conjunction with the MP3 audio file format. It allows information such as the title, artist, album, track number, and other information about the file to be stored in the file itself....

 tags. Some music library managers and mass taggers like MusicBee
MusicBee
MusicBee is a free digital media player and media library application for organizing and playing audio on Microsoft Windows operating systems using the BASS Audio Library.-Features:...

, Mp3tag
Mp3tag
Mp3tag is a freeware metadata editor for many audio file formats. It runs on Microsoft Windows.It includes support for the following audio formats: AAC, FLAC, APE, MP3, MPEG-4 , MPC, OGG, OptimFROG OFR, OFS, SPX, TAK, TTA, WMA, WV-Features:*Batch Tag Editing...

 also support this feature. The tagging string APETAGEX signals the start of a APEv2 record, and the string TAG signals the start of an ID3v1 tag. The popular media player software "Winamp
Winamp
Winamp is a media player for Windows-based PCs and Android devices, written by Nullsoft, now a subsidiary of AOL. It is proprietary freeware/shareware, multi-format, extensible with plug-ins and skins, and is noted for its graphical sound visualization, playlist, and media library features.Winamp...

" also support reading and writing of APEv2 tags in mp3 files.

Features

APE tags are closer to Vorbis comment
Vorbis comment
A Vorbis comment is a metadata container used in the Vorbis, FLAC, Theora and Speex file formats. It allows information such as the title, artist, album, track number or other information about the file to be added to the file itself. However, as the official Ogg Vorbis documentation notes:- Format...

s than ID3
ID3
ID3 is a metadata container most often used in conjunction with the MP3 audio file format. It allows information such as the title, artist, album, track number, and other information about the file to be stored in the file itself....

 tags. Like Vorbis comments, they are unstructured key/value pairs. However, unlike Vorbis comments, they do not allow for inter-key ordering. This is because they store a list of values with each key, rather than a key per value.

APE values can also be flagged as text, binary, or external types. Because of this, tag editing software can avoid presenting blocks of unreadable data to users. Binary data cannot be easily stored in Vorbis comment
Vorbis comment
A Vorbis comment is a metadata container used in the Vorbis, FLAC, Theora and Speex file formats. It allows information such as the title, artist, album, track number or other information about the file to be added to the file itself. However, as the official Ogg Vorbis documentation notes:- Format...

s for this reason (though this is by design).

APEv2 supports Unicode using UTF-8
UTF-8
UTF-8 is a multibyte character encoding for Unicode. Like UTF-16 and UTF-32, UTF-8 can represent every character in the Unicode character set. Unlike them, it is backward-compatible with ASCII and avoids the complications of endianness and byte order marks...

for key values. For key names, an ASCII subset (control characters from 0x00 to 0x1f are not allowed) must be used.

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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