As I understand it, streaming via bluetooth is handled via the A2DP profile. While the SBC codec is default, A2DP supports AAC, MP3, and a few other Codecs.
My question is, since spotify files are in the OGG VORBIS format (OGG Container, Vorbis Codec), what is the best way to handle streaming via Bluetooth without quality loss? Is there a specific A2DP implementation? Are folks like Jambox, etc just using the SBC implementation?
Spotify's streaming format is an implementation detail to all clients, and making the assumption that it's OGG Vorbis is not something you should do, and in some circumstances is actually a false assumption.
Since you've managed to use every single Spotify tag in your question, I don't know which platform you're developing for. However, the correct thing to do is take the PCM data the Spotify playback library gives you and use whatever playback stack your target platform gives you. On Android, iOS, Mac OS, etc the system will handle audio output devices for you, including Bluetooth streaming.
