[throw0101b]

AAC has licensing / patents:

> However, a patent license is required for all manufacturers or developers of AAC "end-user" codecs.[52] The terms (as disclosed to SEC) uses per-unit pricing. In the case of software, each computer running the software is to be considered a separate "unit".[53]

[…]

> The AAC patent holders include Bell Labs, Dolby, ETRI, Fraunhofer, JVC Kenwood, LG Electronics, Microsoft, NEC, NTT (and its subsidiary NTT Docomo), Panasonic, Philips, and Sony Corporation.[16][1] Based on the list of patents from the SEC terms, the last baseline AAC patent expires in 2028, and the last patent for all AAC extensions mentioned expires in 2031.[57]

* https://en.wikipedia.org/wiki/Advanced_Audio_Coding#Licensin...

[etchalon]

Yes, AAC is also patent encumbered, but the structure of the fees was apparently "better" for Apple. This was heavily discussed … Jesus, 15 years ago now … when everyone was pissed Apple didn't use MP3s.

Basically, AAC was cheaper for Apple so that's what they used.

But AAC was as "open" as MP3 and there was never any "lock in".