HD videos on amazon prime on ubuntu are not working becuase of some HDCP issues, I tried to use prime on windows on the same machine, where it works, so I know that the problem is not with the components. At long last I figured out that the problem is that I need to use silverlight which I installed using pipelight-multi, it worked for a while but now I am back to SD videos for some reason, and I see installing flash plugin dialogue box again and again. How can I get HD videos working on prime without any issues?
Got the same issue here too, running on ubuntu 18.10 not able to play any movies in HD because of the HDCP issue, earlier the TV series was streaming in HD but since last couple of months it stopped working too, but i found a workaround for TV series not playing in HD by installing a User Agent Switcher extension and make it change it to Chrome on Windows, for now its working, but still no luck on playing movies in HD in ubuntu.
i was using the first one, but for some reason its not available on the chrome store, second one i just tested it and works fine.
EDIT: APR 25 2019
Seems like this method is not working anymore all the videos play is SD even if we select a windows user agent.