I just purchased a new Roku Streaming Stick 4K (3820). I use my Roku extensively with my DLNA server and library of videos. I have noticed that any video encoded with HEVC is much darker than the same video encoded with h264 or any other codec.
I have taken a good h264 video and re-encoded it with HEVC and the difference is striking. The pixel format is the same, so that's not to blame. I can take an uncompressed video stream, and compress it with both HEVC and h264, and the h264 looks indistinguishable from the original whereas the HEVC is dark and hard to make out.
Is this something wrong with the hardware decoder in the new 3820 streaming sticks? I had two older ones and didn't have this issue. I'm hoping it's a firmware and not a hardware decoder issue.