Vorbis is an open source audio codec developed by the Xiph.Org Foundation. It is framed within the Ogg project, using the container of the same name, and its main objective is to offer the maximum possible flexibility to the encoder, reaching very wide bitrate ranges.
It has a quality quite similar to MPEG-2, and we can compare it with AAC in terms of bitrates. The encoding process it uses is the lossy compression algorithm, and aims to remove relevant information to reduce the data volume of the files.
Its reference library is distributed under a BSD-like license, so anyone is free to implement it, even in their own applications. The Ogg format is quite well recognized internationally and is used by large audio streaming applications such as Spotify.
The Xiph.Org Foundation’s main goal is to protect multimedia content from large private interests, which is why they decided to create Vorbis as an open source codec.