My OLED55-H1 plays everything with and without a receiver as I mentioned earlier. As of v. 5.7.2 app the only audio that still gets transcoded by the server is AAC 5.1 which the tv can play directly as well.
Please, don’t remove DTS and TrueHD audio options in app settings! My tv needs those for direct play and especially for subtitles without video transcoding. As a matter of fact I am in process of transcoding audio of my entire movie collection (1000+ titles) to from AAC to DD just to get Plex to display subtitles without transcoding video…
