Which AudioClip formats will decompress using hardware?

I'd like to know for iOS and Android (and maybe also Windows and MacOS), which compressed formats will use hardware to decompress? On iOS and Android with Unity 5.5, you can select either Vorbis, ADPCM or MP3 format. Is MP3 the only format that can decompress using hardware on iOS and Android?

The other related question I have is I've heard from other forums that only one stream of audio can decompress in hardware on iOS at a time. If more than one playing AudioClip is set to CompressedInMemory or Streaming, then the concern is you'll end up back using CPU resources for decompression.

Thanks!