While Microsoft Edge is a fairly solid browser in most respects, it lags behind in quite a few areas. One key problem the browser has is its problems with some video playing websites, such as Rabb.it. This issue is beginning to be addressed by the introduction of WebRTC 1.0 support.
We’re excited to announce the preview availability of the WebRTC 1.0 API, and support for the H.264/AVC and VP8 video codecs for RTC in Microsoft Edge, enabling plugin-free, interoperable video communications solutions across browsers and platforms.
You can start testing out WebRTC 1.0 right now if you've got access to Windows 10 Insider build 15019. If you don't feel like entering the Insider program, the feature should be entering Microsoft Edge with the Windows 10 Creators update later this year.