Lossless codec-Ape code interpretation series (3)

Ape code interpretation series (1)

Ape code interpretation series (2)

Ape tag details

 

Apev1Is an older version of apev2 and uses essential tially the same format. apev1 has all info values stored as ASCII, while apev2 uses UTF-8. also apev2 has a header that marks the beginning of the tag, making it easier to detect when streaming etc.

Apev1 is used by older versions of monkey's audio.

Apev1 Specification

 

This is how information is laid out in an apev1 Tag:

The only difference between apev1 and apev2 is that apev1 has no header. Therefore, it is stronugly recommended that developers adopt V2 instead of V1 as standard tagging system for their formats.

ape tag Item 1	10 .. bytes
ape tag Item 2	10 .. bytes
...	10 .. bytes
ape tag item n-1	10 .. bytes
ape tag item n	10 .. bytes
ape tags footer	32 bytes

Ape tag items shocould be sorted Ascending by size. When streaming, parts of the ape tags can be dropped to reduce danger of drop outs between titles. This is notMust,StronuglyRecommended. actually the items shocould be sorted by importance/byte, but this is not feasible. only break this rule if you add less important small items and you don't want to rewrite the whole tag. an ape tag at the end of a file (stronugly recommended) must have at least a footer, an ape tag in the beginning of a file (strongly unrecommended) must have at least a header. when located at the end of an MP3 file, an ape tag shocould be placed after the last frame, just before the id3v1 tag (if any ).

 

Apev2Is a tagging format derived from apev1 originally developed for MPC audio files, and is now also used in monkey's audio, wavpack and optimfrog. it can also be used with other formats when using programs like foobar2000 or tag (a program that can create and read tags ). it is comparable in functionality to Vorbis comment. just like Vorbis comment it defines some standard fields, but it also defines some formats for those fields (like what a date shocould look like ).

Apev2 also differs from Vorbis comment in the way lists of values are handled. suppose a certain song has two artists. in Vorbis comment this will result in two artist entries, but in apev2 this will result in one artist field with the two artists separated by a null character (a byte with the value zero ).

 

Apev2 Specification

 

 

This is how information is laid out in an apev2 Tag:

Ape tags Header	32 bytes
Ape tag Item 1	10 .. bytes
Ape tag Item 2	10 .. bytes
...	10 .. bytes
Ape tag item n-1	10 .. bytes
Ape tag item n	10 .. bytes
Ape tags footer	32 bytes

Ape tag items shocould be sorted Ascending by size. When streaming, parts of the ape tags can be dropped to reduce danger of drop outs between titles. This is notMust,StronuglyRecommended. actually the items shocould be sorted by importance/byte, but this is not feasible. only break this rule if you add less important small items and you don't want to rewrite the whole tag. an ape tag at the end of a file (stronugly recommended) must have at least a footer, an ape tag in the beginning of a file (strongly unrecommended) must have at least a header. when located at the end of an MP3 file, an ape tag shocould be placed after the last frame, just before the id3v1 tag (if any ).

 

Link: http://wiki.hydrogenaudio.org/index.php? Title = apev2_specification