Support for additional iTunes tags

[Hyronimus]

I'd like support for following iTunes tags (Apple Lossless):

Gapless Playback (pgap)
Media Type (stik)
Content Rating (rtng)
Long description (ldes)

Taken from:

http://code.google.com/p/mp4v2/wiki/iTunesMetadata

[biggles]

Re: Support for additional iTunes tags

I'd also like to see support for the gapless tag(s) to speed up library loading. But I am confused as to what iTunes tags are used by mp3 versus m4a versus other formats.

In various places I've seen references to ITUNESGAPLESS (0/1), COMMENT ITUNSMPB (hex), or COMMENT ITUNPGAP (0/1), but don't feel I understand how these are used.

Whatever needs to be done for iTunes compatibility, I like.