For the ID tags used by military forces, see Dog tag (identifier). A dog tag is the informal name for the identification tags worn by military personnel because of their resemblance to actual Dog tags The tag is primarily used for the

For the gene whose official symbol is ID3, see ID3 (gene). Inhibitor of DNA binding 3 dominant negative helix-loop-helix protein, also known as ID3, is a human Gene.

ID3 is a metadata container most often used in conjunction with the MP3 audio file format. Metadata ( meta data, or sometimes metainformation) is "data about data" of any sort in any media MPEG-1 Audio Layer 3, more commonly referred to as MP3, is a Digital audio encoding format using a form of Lossy data compression An audio file format is a Container format for storing audio data on a Computer system It allows information such as the title, artist, album, track number, or other information about the file to be stored in the file itself.

Versions of ID3

There are two unrelated versions of ID3: ID3v1 and ID3v2.

ID3v1

After the creation of the MP3 standard, there appeared a problem with storing data about the file. Standalone MP3s didn't have any special method of doing this. In 1996 Eric Kemp came up with the idea to add a small chunk of data to the audio file, thus solving the problem. Year 1996 ( MCMXCVI) was a Leap year starting on Monday (link will display full 1996 Gregorian calendar) The standard was called ID3v1 and it quickly became the de facto standard for storing metadata in MP3s. The format was released by Damaged Cybernetics, an underground group that specialized in cracking console gaming systems. This format was first used to identify ROMs for the 8bit Nintendo decrypted by the leader MindRape, Donald Ray Moore Jr, in 1996. There were no identifying information for any of the ROMS, thus an id tagging system was created to make tracking easier. Eric and gang naturally carried this over into mp3 files. This format was used for a number of file formats unknown at that time.

The ID3v1 tag occupies 128 bytes, beginning with the string TAG. A byte (pronounced "bite" baɪt is the basic unit of measurement of information storage in Computer science. The tag was placed at the end of the file to maintain compatibility with older media players. Media Player was a media player originally included in Windows 3 Some players would play a small burst of static when they read the tag, but most ignored it, and almost all modern players will correctly skip it. This tag allows 30 bytes for the title, artist, album, and a "comment", 4 bytes for the year, and a byte to identify the genre of the song from a predefined list of 80 values (Winamp later extended this list to 148 values). A genre (ˈʒɑːnrə also /ˈdʒɑːnrə/ from French "kind" or "sort" from Latin: genus (stem gener-) is a loose set Winamp is a proprietary media player written by Nullsoft, now a subsidiary of Time Warner.

One improvement to ID3v1 was made by Michael Mutschler in 1997. Year 1997 ( MCMXCVII) was a Common year starting on Wednesday (link will display full 1997 Gregorian calendar Since the comment field was too small to write anything useful, he decided to trim it by 2 bytes and use it to store the track number. Such tags are referred to as ID3v1. 1.

Criticisms and problems

ID3v1 tags were criticized for several problems. One problem was that the fields were too short for most of the data they were meant to contain. 30 bytes is not enough to store long song or album titles, so they would be simply truncated.

The approach to defining the song genre also had obvious disadvantages. Many users criticized the predefined genre list, which did not contain some common genres like minimalist or Baroque. Minimalist music is an originally American genre of experimental or Downtown music named in the 1960s based mostly in consonant harmony, steady Baroque music describes an era and a set of styles of European classical music which were in widespread use between approximately 1600 and 1750.

ID3v1 also lacked support for internationalization. In Computing, Internationalization and localization (also spelled internationalisation and localisation, see spelling differences) are means of adapting It is stated in the standard that all the strings must be encoded in ISO-8859-1. ISO 8859-1, more formally cited as ISO/IEC 8859-1 is part 1 of ISO/IEC 8859, a standard Character encoding of the Latin alphabet. But in practice, users usually used local encodings, which is why mojibake is a common problem in ID3v1 tags. Mojibake is the happenstance of incorrect unreadable characters (garbage characters shown when Computer software fails to render a text correctly according to its associated

ID3v2

In response to these criticisms, a new standard called ID3v2 was created in 1998. Year 1998 ( MCMXCVIII) was a Common year starting on Thursday (link will display full 1998 Gregorian calendar) Although it bears the name ID3, it has little to no relation to the ID3v1 standard.

ID3v2 tags are of variable size, and usually occur at the start of the file, to aid streaming media. Streaming multimedia is Multimedia that is constantly received by and normally presented to an end-user while it is being delivered by a streaming provider (the They consist of a number of frames, each of which contains a piece of metadata. For example, the TIT2 frame contains the title, and the WOAR frame contains the URL of the artist's website. Uniform Resource Locator is an URI which also specifies where the identified resource is available and the protocol for retrieving it Frames can be up to 16MB in length, while total tag size is limited to 256MB. The internationalization problem was solved by allowing the encoding of strings not only with ISO-8859-1, but also with UTF-16. ISO 8859-1, more formally cited as ISO/IEC 8859-1 is part 1 of ISO/IEC 8859, a standard Character encoding of the Latin alphabet. In Computing, UTF-16 (16- Bit Unicode Transformation Format is a variable-length Character encoding for Unicode, capable of encoding Textual frames are marked with an encoding bit, though mojibake is still common when using local encoding instead of UTF-16. Mojibake is the happenstance of incorrect unreadable characters (garbage characters shown when Computer software fails to render a text correctly according to its associated

In the latest ID3v2 standard there are 84 types of frame, and applications can also define their own types. There are standard frames for containing cover art, BPM, copyright and license, lyrics, and arbitrary text and URL data, as well as other things. Beats per minute ( BPM) is a unit typically used as either a measure of Tempo in music or a measure of one's Heart rate.

There are three versions of ID3v2. ID3v2. 2 was the first public version of ID3v2. It used three character frame identifiers rather than four (TT2 for the title instead of TIT2). Most of the common v2. 3 and v2. 4 frames have direct analogues in v2. 2. Now this standard is considered obsolete.

ID3v2. 3 expanded the frame identifier to four characters, and added a number of frames. A frame could contain multiple values, separated with a / character. This is the most widely used version of ID3v2 tags.

ID3v2. 4 is the latest version of the standard, dated November 1, 2000. Events 996 - Emperor Otto III issues a deed to Gottschalk Bishop of Freising which is the oldest known document using the name Ostarrîchi 2000 ( MM) was a Leap year that started on Saturday of the Common Era, in accordance with the Gregorian calendar. Notably, it allows textual data to be encoded in UTF-8, which was a common practice in earlier tags despite the standard because it has several noticeable advantages over UTF-16. UTF-8 (8- Bit UCS / Unicode Transformation Format) is a variable-length Character encoding for Unicode. In Computing, UTF-16 (16- Bit Unicode Transformation Format is a variable-length Character encoding for Unicode, capable of encoding It uses a null byte to separate multiple values, so the character "/" can appear in text data again. The null character (also null terminator) is a character with the value zero present in the ASCII and Unicode character sets and available Another new feature introduced in ID3v2. 4 is to allow the addition of a tag to the end of the file before other tags (like ID3v1).

ID3v2 Chapters

The ID3v2 Chapter Addendum was published in December 2005 but is not widely supported as yet. It allows users to jump easily to specific locations or chapters within an audio file and can provide a synchronized slide show of images and titles during playback. Typical applications include Enhanced podcasts and it can be used in ID3v2. An enhanced podcast is a Podcast Multimedia format that allows Images to be displayed in time with audio. 3 or ID3v2. 4 tags. ^[1]

Criticisms and problems

Although the different versions of ID3v2 are conceptually similar, implementing an algorithm to read and write them is difficult. There are subtle but critical differences between all the versions. Even within a version, the structure of frames differs greatly. For example, the TIT2 frame which contains the title, and the USLT which contains a lyrics transcription, require different algorithms to extract the data. With 84 different frames, dozens of such sub-parsers are required. Other tagging formats such as APEv2 avoid this, and use a single key/value pair for the internal structure of every frame. This is at the expense of pushing the interpretation of the value on to the decoder, rather than being defined within the core standard.

ID3v2 stores many things in the tag that are more commonly left to the audio format itself. Some examples are the TLEN frame which stores the audio length, or the AENC frame which contains the encryption scheme of the audio. (However, the information provided by TLEN is often not derived trivially. In general, the duration of a variable bitrate stream can be calculated only after examining each frame of the entire stream. Thus, TLEN can be useful for streaming audio and inadequate hardware. )

Only with the ID3v2. 4 standard has it been possible to place the tag data at the end of the file, in common with ID3v1. ID3v2. 2 and 2. 3 require that the tag data precede the file. Whilst for streaming data this is absolutely required, for static data it means that the entire audio file must be updated to insert data at the front of the file. For initial tagging this incurs a large penalty as every file must be re-written. Tag writers are encouraged to introduce padding after the tag data in order to allow for edits to the tag data without requiring the entire audio file to be re-written, but these are not standard and the tag requirements may vary greatly, especially if APIC (associated pictures) are also embedded.

Software adoption for ID3v2. 4 has come around in the last couple of years; however, the majority of files still use older versions of ID3v2 and there are very few applications that fully support all of the frame types enumerated in the ID3v2 specification.

Another problem occurs when it comes to Windows Explorer. When ID3v2. 4 is used to tag MP3 files, any info on the files cannot be seen by Windows Explorer due to the lack of UTF-8 encoding support, unlike previous ID3 tag versions which are properly seen.

Editing ID3 tags

ID3 tags may be edited in a variety of ways. On some platforms the file's properties may be edited by viewing extended information in the file manager. Additionally most audio players allow editing single or groups of files. The following comparison of media players compares general and technical information for a number of software media player programs Editing groups of files is often referred to as "batch tagging". There are also specialized applications, called taggers, which concentrate specifically on editing the tags and related tasks. These often offer advanced features such as advanced batch tagging or editing based on regular expressions. In Computing, regular expressions provide a concise and flexible means for identifying strings of text of interest such as particular characters words or patterns of characters

Usage with non-MP3 files

ID3 tags were designed with MP3 in mind, so they would work without problems with MP3 and MP3Pro files. MPEG-1 Audio Layer 3, more commonly referred to as MP3, is a Digital audio encoding format using a form of Lossy data compression mp3PRO is an Audio compression algorithm (or Codec) that combines the MP3 audio format with Spectral band replication compression methods However, the tagsets are an independent part of the MP3 file and should be usable elsewhere. In practice, the only other format which has wide usage of ID3v2 tags is AIFF, where the tag is stored inside a RIFF chunk named "ID3". The same could be accomplished in WAV, but isn't. WAV (or WAVE) short for Waveform Audio format, is a Microsoft and IBM Audio file format standard for storing an audio bitstream on The only tagging system in wide usage for WAV is "Broadcast WAV", stored as a RIFF chunk. Windows media ASF files (WMA, WMV) have their own tagging formats but also supports ID3 Tags embedded as attributes. Advanced Systems Format (formerly Advanced Streaming Format, Active Streaming Format) is Microsoft 's proprietary Digital audio Windows Media Audio ( WMA) is an Audio data compression technology developed by Microsoft. Windows Media Video ( WMV) is a compressed Video file format for several proprietary Codecs developed by Microsoft. ^[2] MP4 also allows the embedding of an ID3 tag ^[3] although this isn't widely supported. MPEG-4 Part 14, formally ISO / IEC 14496-142003, is a Multimedia Container format standard specified as a part of MPEG-4 Other Container-based formats like Ogg use their own tagging formats. To learn how to create video or audio files for Wikipedia and its sister projects check WikipediaCreation and usage of media files. Adding an ID3 tag to them would break the container structure.

See also

• APEv2 tag
• Vorbis comment
• Tag editor
• getID3()

References

External links

• Official site for ID3, including the format specifications
• List of genres in ID3v1
• ID3v1 Specification