What are ID3 Tags in MP3 Files?
Filed under Podcasting
MP3 files usually contain track data embedded within the file in addition to the audio data. This additional data is contained in ID3 tags and typically include the track’s title, artist and album details. However, these tags are much more versatile and can also contain a lot of extra information about the file in question.
A plain MP3 file just contains audio data with no further information about the artist or type of audio contained within it. To be able to include such additional data in an MP3, tag data is usually added to either the beginning or end of the audio file in an ID3 format.
While the original ID3 specification was quite limited with regards to the information that it could store about a file, later versions allow for great flexibility in the type and amount of data that can be stored.
Metadata
ID3 tag data contained within MP3 files is sometimes referred to as metadata. While this sounds a bit scary and complex, it’s really not. Metadata is just data describing other data. In this case, the ID3 tag data within an MP3 is the metadata, and it describes the audio data of the MP3, e.g. the track title, artist name etc..
A Brief History
When the MP3 audio file format was formally defined in 1991, the specification didn’t cater for the storage of any additional information (metadata) about the audio data within the file itself.
It wasn’t until 1996, when the initial specification for ID3v1 was proposed, that metadata could be added to an MP3 file in a defined format. The ID3v1 specification defined the addition of metadata to the end of an MP3 file, and by doing so enabled older MP3 players to still play the files without too many problems.
However, as is often the case, the initial ID3 specification suffered limitations, not least of which were restricted field lengths (only 30 characters) and limited support for international languages.
In 1998 ID3v2 was released, addressing these and other issues with the original specification. However, the ID3v2 specification now defined the addition of metadata to the beginning of an MP3 file rather than the end, as previously, to facilitate increasingly popular streaming media.
Which Version?
Whilst ID3v1 tags are technically the safest option to use for compatibility with older equipment, they are also more limited in their capabilities. As ID3v2 tags have been around for almost 10 years now, there are probably very few MP3 players or systems that aren’t capable of supporting them, and as such, should be the version to adopt.
Tag Data
The latest version of the ID3v2 specification defines over 80 data fields, although invariably only a subset of these are ever used. The most common metadata fields added to MP3 files are:
- Title – The track title
- Artist – The artist that recorded the track
- Album – Which album the track belongs to (if applicable
- Track – The track number from the album (if applicable)
- Year – The year that the track was published
- Genre – The type of track, e.g. speech, rock, pop
- Comment – Additional notes about the track
- Copyright – Copyright notice by the copyright holder
- Album Art – Thumbnail of the album art or artist
In addition to these common fields, other data can be included such as: web addresses, composer, conductor, orchestra…
Usage
Tag data embedded within MP3 files is used by your playback system (MP3 player or your computer’s media player) to display useful information about the track being played.
While it’s nice to see information about the currently playing track on your MP3 player, the tag data is much more beneficial when it comes to searching for tracks, enabling you to search by artist, genre, year etc..
Editing Tag Data
While a lot of track data may already be included in your downloaded MP3 files, or may get added automatically by your ripping software when you rip a track from a CD, this data can be easily edited or added to if you wish.
By using a tag editor, you can add new track data to MP3s, or edit existing tags within your MP3 files. Some CD ripping software may include limited tag editing options, although dedicated tag editors tend to offer much more sophisticated editing capabilities.
If you’d like to try editing the ID3 tags of your MP3 files, some popular examples of ID3 tag editing software are:
Posted on 15 June 2008
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Thanks for this. Very useful!
Very useful – what I’d like to know is how / who actually adds this info to the file – and how come it’s so inaccurate sometimes (Chieftains as Reggae!!) Is it an automated process or does some jobsworth have to encode it manually?
I’m afraid I don’t know who adds this information to the files, I suspect it varies, but at some point in the chain, someone will have to add this information manually.
After this, certain programs such as Mp3tag can extract the song information from databases like http://www.freedb.org, although they may get it wrong in the automation process sometimes and try extracting the wrong information.
You can always edit the tag information yourself with a tag editor if you really feel the need.
I have mp3 files with their respective artwork added but somehow I cannot make itunes show this artwork in my library. Should I still add all artwork manually from different files? I am hoping I can somehow show itunes where to look into the mp3 file to retrieve the artwork part. I just don’t know how to…
Wish I could help, but unfortunately I have no experience of itunes. Anyone else got any suggestions?
[...] information like tag, name etc. In order to add such extra attributes you’ve to put these in ID3 format at the beginning or end portion of audio [...]