This tool is used to convert Advanced Audio Coding (aac) to Ogg Vorbis (ogg).

Advanced Audio Coding is an audio coding standard for lossy digital audio compression. Designed to be the successor of the MP3 format, AAC generally achieves better sound quality than MP3 at the same bit rate.

Ogg is a free, open container format maintained by the Xiph.Org Foundation. The creators of the Ogg format claim that it is unrestricted by software patents and is designed to provide for efficient streaming and manipulation of high-quality digital multimedia.