Environment: Windows 10, Nightly 55.0a1 (2017-05-23) (32-bit) STR: I tried to play . But the video is not loaded since I don't see any information on about:media. From web console, it only shows "TypeError: i.subscribe is not a function." If I use Edge, it can play  well. https://www.netflix.com/watch/80018294?trkid=14170032&tctx=1%2C0%2C62a138d2-1527-490d-9409-b6795d9fb4a6-275925209
Chris, Is there anything I can check to see what is going on?
I can reproduce this in 32bit Firefox, but not 64 bit Firefox... Which is why I didn't see it; my local Nightly was 64bit. Interesting. I will investigate.
Thanks! This problem is not seen on 54.
This is a regression from bug 1355252; Netflix are passing a MediaKeySystemConfiguration with no audio or video capabilities, so we're now rejecting it. I'll email Netflix to see if they can fix this on their side, as our behaviour matches the spec now.
I've emailed Netflix about this, and requested that when they call navigator.requestMediaKeySystemAccess() they request a MediaKeySystemConfiguration with videoCapabilities.
Netflix fixed their player. We should probably reland bug 1355252 now, I need to check that.