Perpetual mixed reality headset disappointment Magic Leap has bagged an exclusive deal with AT&T to offer its $2,295 VR headset in-store and online as of next week, in tandem with a marketing campaign allowing footfall to experience an in-store Game of Thrones VR demo involving fighting White Walkers. AT&T is an investor in Magic Leap and a DirecTV app for Magic Leap headsets is in the works. US technology and multimedia company Avid has joined the SRT Alliance, supporting development of the Secure Reliable Transport low latency protocol (see full story in this issue for more detail on developments). Orange has signed up for a blockchain-based certification program called Safe.press, developed by French start-up Block Expert, which aims…