What is a .ogg file?

Ogg Vorbis is a free, open-source lossy audio format — a patent-free alternative to MP3 that sounds better at equivalent bitrates and costs nothing to license. The open-source audio underdog. Spotify uses Vorbis internally for streaming. Video games rely on it because the licence is free and the quality is good. But it never reached mainstream consumer adoption. Most phones and portable players do not support it natively, and the name did not help. If you need universal playback, convert to MP3. If you care about open standards and your player supports it, OGG is the better format.