Initial support will be restricted to streaming through the browser when used with MP4 or AAC audio. Microsoft is considering adding additional audio codecs—Opus is often used with VP9, and Microsoft is also considering Ogg and Vorbis support—and extending support to support local playback. Microsoft intends to support both software decoding and, where possible, hardware decoding.
September 8, 2015
Google’s VP9 Codec Coming to Microsoft’s Edge Browser
Microsoft has started developing support for Google's VP9 codec in its Edge browser.
Read more at Ars Technica