@unascribed the standard allows for the two devices to agree on any codec so in an ideal world you could just stream the raw audio files
@noiob and also the only storage codec supported by headphones (and only a very small number of them) is AAC
@unascribed I mean you could theoretically include more decoders, that's allowed
@unascribed obvs no one does that because it'd be a bit more effort to figure out and make reliable