A description of tags and tag formats

(Parts of this document is taken from www.id3.org, www.vorbis.com)

 

ID3 v1.0 - The first tag

A number of years ago, when MP3 files (MPEG Layer 3) were quite new, the MP3 file format lacked imbedded textual information describing the file's properties (also called meta-data).
Therefore the ID3 v1.0 tag was invented which is still quite popular today. The ID3 v1.0 tag is a small block of information added to the end of the file, containing fix-length fields for:

  • Album (30 characters)
  • Artist (30 characters)
  • Title (30 characters)
  • Year
  • Genre (from a fixed list of genres)
  • Comment (30 characters)
The data that could be stored in that tag was useful but a little limited because of the fixed length. For example, storing a title like "The Hitchhiker's Guide to the Galaxy from BBC Radio" was not possible and it would be truncated because it is longer than 30 characters.

Anyway, this was the first tag that was invented (and it's still used today and it is possible to use it in Helium). So a tag is an additional block of information contained within a file that describes what the contents of the file are - it does not itself contain the actual file data.
ID3 v1.0 was later revised to ID3 v1.1 with support for track number. The track number was implemented at the cost of a reduced comment length (28 characters instead of 30 characters that it originally had).

ID3 v1.x tags are still highly relevant but mainly for portable players, that don't support other tags, or car stereos with MP3 support and similar such devices.

The "modern" tags

ID3 v1.x had obvious limitations because of the fixed field length and the number of supported fields. Another limitation of the ID3 v1.x tag is that the tag itself is stored at the end of the MP3 file. This is not helpful if the MP3 is streamed from a music server (say via the internet) to a player or a PC. This meant that the playing device wouldn't know what it was playing until it reached the end of the song.

Therefore a new tag "standard" was devised, simply called ID3v2. ID3v2 is often followed by its revision number, for example ID3v2.3 or ID3v2.4 - This tag information is stored at the front of the file and therefore the streaming problem is now resolved as the player will know what it is going to play before it starts playing.

Helium Music Manager supports reading of all ID3v2 revisions (ID3v2.2, ID3v2.3 and ID3v2.4) and the writing of ID3v2.3 and ID3v2.4.

An ID3v2 tag supports many more default fields when compared to ID3V1, much more than textual information (embedded pictures for example), almost unlimited field length and the possibility of defining new fields. ID3v1 and ID3v2 tags are used mainly for MP3 files.

Lyrics 3v2

There is another tag format which is mainly intended to be used with MP3 files, often in combination with ID3v1 tags. As the name implies, this format is in the main used for adding lyrics Meta data to a file. Apart from storing Lyrics, Lyrics 3v2 can also store a much longer comment than ID3v1 can, as well as Album, Artist, Title and Author details of up to 250 characters in length.

Other digital music formats and their tags

Since there are more audio formats than MP3, there also more tag formats. Each file format often has its own tags. There follows below a basic description of the other files and tag formats that are supported by Helium:

Ogg Vorbis and Vorbis Comments

Ogg Vorbis is a new audio compression format. It is roughly comparable to other formats used to store and play digital music, such as MP3, VQF, AAC, and other digital audio formats. It is different from these other formats because it is completely free, open, and unpatented.
Ogg Vorbis has been designed to completely replace all proprietary, patented audio formats. That means that you can encode all your music or audio content in Vorbis and never look back.
Ogg Vorbis is (as MP3) a so called "lossy" format which means that it discards audio data in the encoding process to produce smaller files.

Vorbis Comments
Ogg Vorbis use their own system for tags and this is fully supported by Helium. Their tagging system is called Vorbis Comments.
Vorbis Comments are meant for short, text comments, not arbitrary metadata.
There are a couple of standard tags fields defined, all encoded with UTF-8, thus supporting international characters in their contents.
The format can be extended with new tag fields when required.

Helium Music Manager has extended support for Vorbis Comments, thus supporting more tag fields than the standard defines.

FLAC and Vorbis Comments

FLAC stands for Free Lossless Audio Codec. Grossly oversimplified, FLAC is similar to MP3, but lossless, meaning that the audio is compressed in FLAC without any loss in quality. This is similar to how Zip works, except that with FLAC you will get much better compression, because it is designed specifically for audio, and you can play back compressed FLAC files in your favorite player (or your car or home stereo and other supported devices) just like you would an MP3 file.
FLAC files are generally much larger than MP3 files, but they do have better sound quality.

FLAC uses Vorbis Comments for tag support.

MPEG Plus and APEv2 tags

MPEG Plus is an audio format that has been around for some years. Simplified you could say it's like MP3 but with better quality, especially when encoded at higher bitrates.
The downside with MPEG Plus is the lack of support in players and other devices.

APEv2 tags
MPEG Plus should preferably use APEv2 tags, although it can be used with ID3v2 tags also (not recommended).
APEv2 is quite similar to Vorbis Comments; it supports unlimited tag field length, UTF-8 and custom fields.
Helium supports MPEG Plus files together with APE v2 and ID3 v1 (optional).

Monkey's Audio

Monkey's Audio is a fast and easy way to compress digital music. Unlike traditional methods such as MP3 or Ogg that permanently discard quality to save space, Monkey's Audio only makes perfect, bit-for-bit copies of your music. That means it always sounds perfect - exactly the same as the original.
Monkey's Audio is quite similar to FLAC when it comes to encoding methods (and space taken).

Monkey's Audio is supported in Helium Music Manager with APE v2 and ID3 v1 tag support.

Windows Media Audio (WMA/ASF for short)

The Advanced Systems Format (ASF) is the file format used by Windows Media Audio.

ASF is an extensible file format designed to store synchronized multimedia data. It supports data delivery over a wide variety of networks and protocols while still proving suitable for local playback. ASF supports advanced multimedia capabilities including extensible media types, component download and scaleable media

WMA/ASF Tags
The tag format used for WMA files is a mixture between ID3v2 and APEv2/Vorbis Comments (a very simplified explanation).
The standard is defined in Microsoft's API and it has full support for Unicode text, unlimited field-length, textual and binary information.

Helium Music Manager has full support for WMA files, as well as WMA tags.

Apple iTunes/Nero AAC files

Apple iTunes/Nero AAC (Advanced Audio Coding) files, or in short AAC files, is a fairly new format which has become quite popular mainly because of the wide use of iTunes and the iPod player.
AAC provides audio encoding that compresses much more efficiently than older formats such as MP3, yet delivers quality rivalling that of uncompressed CD audio.

The AAC files created with iTunes or Nero take advantage of the Quicktime container format to allow a format with meta data mixed with the audio data, in a way that is already a standard.

AAC tags have full support for UTF-8 encoded contents, unlimited filed length, custom fields as well as mixing textual and binary data in the tags.

Helium Music Manager has full support for reading and writing iTunes AAC/Nero AAC files.

WAVE files

WAVE files are simply files containing "raw" audio data. WAVE files are uncompressed and lossless (e.g. not loosing any sound quality during encoding).  Tags on WAVE files are commonly saved in RIFF format.

Helium Music Manager as full support for reading and writing RIFF tags.

Supported Tags In Helium Music Manager

Click here to view all supported tags and tag fields in Helium Music Manager. (External link)

 

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