Sonnox Fraunhofer Pro-Codec - Manual (Page 77)

9.2 Manager 9 SPECIFICATIONS
9.2 Manager
9.2.1 Metadata
Text
Encoding
Text encoding formats are a way of describing the internal byte representation of
individual characters. The ID3 and iTunes metadata formats strictly define which text
encodings are supported, so that any text tags (e.g. Title, Artist) can be read and written
by different applications. This section describes how the Manager handles metadata text
encoding for the different metadata formats supported by the Manager.
There are 3 different types of text encoding defined in the ID3 and iTunes metadata
standards:
Latin–1
This is an extension of ASCII. It is very space efficient, storing only 1 byte per
character; however it has very limited character support.
UTF–16
This standard was introduced in 1990 to address universal character support. It is
far more comprehensive than latin–1, but is also significantly less space efficient.
UTF–8
This is a later revision of UTF–16. It supports the same number of characters as
UTF–16, but has the benefit of being far more space efficient. UTF–8 is generally
accepted as the de facto text encoding standard, and is what the Manager uses to
store metadata tags internally.
The Manager always writes iTunes metadata text tags using UTF–8 encoding. The
handling of ID3 text encoding, however, is more subtle, as it supports Latin–1, UTF–16
and UTF–8 text encoding formats. It is important to note that UTF–8 support is only
available in ID3v2.4.
To ensure maximum space efficiency, all text tags less than or equal to ID3v2.3 are written
with Latin–1 encoding. However if some characters in the tag are not in the Latin–1
subset, the tag is written as UTF–16. Files with ID3v2.4 text tags will always have the text
encoding fixed to UTF–8.
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