I just got a new Roku Premeire+ and running plex. aac 5.1 and DTS 5.1 works great on it but whenever i try a ac3 5.1, there is about a 3 sec audio sync issue (sound comes firdst before video). These files works fine on plex for Chromecast and Amazon fire stick.
I tried every possible combinations of direct play / directstream options in the roku plex but nothing fixes the issue. I tried changing the audio options on Roku and some options either did not do anything or gave no audio.
Hdmi plugs directly in my receiver Onkyo TX-NR646. Running the latest Plex Media Server on a laptop supporting a 4th gen i5 processor. It can transcode most of everything I throw at it including multiple HEVC streams.
I love the roku in both video quality and processing speed. I also like how it can play DTS without transcoding it. It's just that I have many files with ac3 audio and this is a major issue. I hope there is a simple work around that does not involve changing the audio format to stereo to force a transcode to stereo. I do not mind forcing a transcode from ac3 to aac but do not know how to do it.