I just recently noticed that Plex on my Amazon Firestick 4k is only outputting stereo sound when I’m playing a movie with DTS 5.1 or 7.1 audio. Dolby Digital 5.1 & 7.1 output correctly. I used to get surround channels from DTS audio, so this issue must have appeared within the past month or so. I have not made any changes to my equipment setup, so I’m assuming there must have been an update from either Plex or Amazon that triggered this.
Looking at my Plex server, it shows Direct Play when I’m watching a DTS movie (no transcoding), and the On-Screen Playback Info also doesn’t indicate any transcoding going on. I know the Firestick doesn’t natively support DTS, but I know I’ve gotten all the surround channels from DTS in the past, through whatever passthrough or converting magic Plex does.
Has anyone else experienced this change recently? Any ideas on how to get my DTS movies playing properly again?
none of the FireTVs support DTS passthrough. FireOs does appear to support DTS decoding, which is downmixed to stereo. This is why DTS is direct playing and you are only getting stereo.
It’s not likely that you were ever getting multichannel DTS in Plex. It’s possible that you were transcoding multichannel DTS to multichannel AC3? Or you have an AVR that was upmixing the stereo output.
What equipment do you have, how are things configured and connected?
My setup:
FireStick 4K Max ← HDMI → Denon AVR-X4300H ← HDMI-ARC → LG TV
Plex App: 8.30.1.31022
Plex Server: 1.25.6.5577
FireStick Audio = Best Available
Plex App: Passthrough = HDMI
dts 5.1 and dts-HD MA 5.1/7.1 audio direct play. The FireStick sends the audio to the Denon as Dolby Digital Plus 5.1. When playing dts-HD MA, only the core dts audio is processed.
This issue has now seemed to have fixed itself. So I’ll just assume that an update (from either Plex or Amazon) broke something, and then another update later fixed it.
To verify it’s working, I checked the Plex dashboard while playing a DTS movie, and I see it is transcoding the DTS to AC3 5.1. My audio receiver reports that it’s receiving 5.1 channels (not doing any virtual surround/Dolby Pro Logic extrapolation). I can play a DTS Master audio test video, and each speaker discreetly plays each channel correctly. So it’s doing what it’s supposed to do now… Just weird that it started acting like that for a couple months, and then went back to working properly, without me changing anything.
