— AAC is a codec used primarily in Apple portable technology to improve Bluetooth audio. In this sense, it is similar to aptX (see the relevant paragraphs), but noticeably inferior to it in terms of capabilities: if aptX sounds like an Audio CD, then AAC is at the level of a medium-quality MP3 file. However, this is quite enough for listening to the same MP3s, the difference becomes noticeable only on more advanced formats.
