Square Enix release a special FF XV Soundtrack album in Japan on December 20, 2016 for the PlayStation Plus users in the local PSN.
The FINAL FANTASY XV Original Soundtrack PlayStation Plus Edition which comes with 96 selected tracks will be available only for the PS Plus users and you can download it until February 28, 2017.

However, the release announced in Japan, the soundtrack collection will be available in selected countries in Asia such as Thailand, Singapore, Malaysia, Indonesia, Taiwan, Hong Kong.
The soundtrack comes with a special application which includes special moment, events and pictures from the game what you can watch while you are listening the special music.
Above you can watch the official promotion video.

Blog URL: https://www.jp.playstation.com/blog/detail/4161/20161207-psplus.html