Vorbis

Vorbis is the name of a specific audio compression scheme that's designed to be contained in Ogg. Note that other formats are capable of being embedded in Ogg such as FLAC and Speex.

As described on the Tiki Wiki, Ogg Vorbis can be used to stream music into Second Life, but at the current time it cannot be used to upload audio as an inventory item.

Compare with MP3.