FLAC is the audiophile's handshake: CD-perfect sound at roughly half the shelf space. It was born in 2001, Josh Coalson; now kept by the open Xiph.Org Foundation, and its real weak spot is fitting in pockets: lossless is still large: and charming Apple's own apps.
OGG is the free spirit of audio: open, patent-free, and quietly brilliant at looping game sound. A container usually carrying Vorbis or Opus audio, both open and royalty-free. That makes it the right destination when what you need is games and open projects that want seamless loops and zero licensing strings.