Watching a movie with AC-3 TrueHD/7.1 - tv plex app connected via HDMI to receiver. Shouldn’t it send the 5.1 core to the receiver? I got stereo.
Most TV’s do not support HD audio. Check to see if your TV supports EARC and if so that you have a EARC HDMI cable. You may have to enable audio passthrough in your TV. If your TV does not support EARC then you will not be able to get HD audio. Check your TV Specs.
Yes, tv supports earc. It won’t pass the true HD but it’s supposed to pass the core 5.1 to the receiver, which it used to do.
Android TV client version? See Authorized Devices.
Receiver make/model?
TrueHD does not have an AC3 5.1 core. TrueHD and AC3 are separate and incompatible audio formats.
Movies released on Blu-ray with TrueHD audio also contain a separate AC3 audio track of the same content (reference). If available, you may want to choose the AC3 audio track. It will direct play and is a studio provided audio mix instead of a Plex provided transcode.
TrueHD cannot be passed from a TV based app over HDMI-eARC. It is not permitted by the TV manufacturers.
However, TrueHD should be transcoded by Plex Media Server to a 5.1 format that can be passed via HDMI-ARC or -eARC.
Check the Sony TV settings for passing audio via HDMI-eARC.
What are the Plex Android TV settings for Passthrough - HDMI/Optical/Disabled?
Play a movie with TrueHD audio selected and subtitles disabled. Monitor playback via Plex Dashboard → Now Playing. What does it show for the video and audio - direct play/direct stream/transcode? If transcoding, to what format?
Just the diagnostic info i was looking for thanks. When backing up the disc, if the software offered multiple audio streams it’s possible i deselected the companion ac-3 track keeping just the DDTHD. I’ll look into all this.
Hi, I didn’t get a chance to test your recommendations yet, but… I switched my passthrough setting on tv plex app from hdmi to optical and selected both checkboxes (ac3 and dts) on next tile, and now the problem video (true hd) plays in dd 5.1. the playback info still said “transcoding” for the video (not sure why), but, what do you think? Problem solved? Do i just leave it in optical from now on?
Thanks for your help!
With passthrough = optical, the Plex app behaves as if it has an optical, not HDMI, connection to the TV.
It fixes the problem for TrueHD, forcing a transcode to AC3 5.1. However, Dolby Digital Plus, including Dolby Digital Plus + Atmos, will also transcode (and Atmos info lost).
Optical audio is limited to AC3 & dts at 5.1 or fewer channels and PCM at 2.0 or 1.0. Dolby Digital Plus (EAC3), TrueHD, and dts-HD is not supported by the optical audio standard.
So, with passthrough = optical:
- AC3 and dts should direct play and passthrough to the receiver.
- TrueHD and Dolby Digital Plus will transcode.
- dts-HD MA will most likely direct play, but pass only the lossy dts 5.1 core.
- I’m not sure what will happen with AAC audio. AAC 2.0 will probably direct play and pass to the receiver as PCM 2.0. No idea with AAC 5.1 audio. It could be downmixed to PCM 2.0 or transcoded to AC3 5.1. You’ll just have to try it to find out (I can’t replicate your setup or I would test it myself).
As long as you are OK with Dolby Digital Plus transcoding and whatever happens with AAC, then it is not a problem running with passthrough = optical.
I can’t decode atmos, 5.1 is fine for me, and Nothing I play has dd+. Seems like the silver bullet approach. One of these days I’ll get a shield, but one remote/no set top boxes/simplicity is paramount for me now.
Truly phenomenal support here. Much thanks! 
Okay looked into it. Monitored playing a bunch of different audio files. It basically has a problem with playing PCM and Dolby true HD. It transcodes the audio to opus. That’s all it says in Plex, however my receiver is outputting it in stereo. Screenshots attached. Other formats are playing fine which is interesting because a couple months ago I couldn’t play DTS master audio without it bugging out.
Ac3 5.1 - direct play
7.1 dts ma - direct play
7.1 pcm- opus stereo
7.1 true hd - opus stereo
5.1 dts ma - direct play
That is with passthrough = HDMI, correct?
I believe this will be fixed in the Plex Android TV 8.29 release, currently in beta.
The topic is discussed in this thread.
If I’m reading the comments correctly, TrueHD will be transcoded to AC3 5.1 or EAC3 5.1 instead of Opus. PCM 7.1 will be transcoded, but should also end up as 5.1 not stereo (I’m not sure to which format it will be converted. I may have missed it in the thread).
It is unknown when 8.29 will go mainstream. Plex never gives out release schedules and a problem could always crop up and delay things.
You may want to stay with passthrough = optical in the meantime, as that forces the TrueHD to AC3 transcode, and AC3 and DTS still passthrough.
You can join the beta program if desired. You’ll receive faster updates (see schedules below). The releases are generally stable, but the purpose of a beta release is to test new features and fixes before they go mainstream, so things do break and there are sometimes weird bugs that crop up.
If you want to try a beta build without signing up for beta releases you may be able to sideload the app. You can download the APK from the release announcement. I’ve sideloaded on a Nvidia Shield and Amazon FireStick. Never tried it on a Sony TV, but it should work. The process is straightforward. You can google “Android TV sideload” or similar terms to get instructions. I used the Downloader app, but there are many other options.
Thanks. Yes, passthrough is hdmi. If I set it to optical it does not pass the dts, it transcodes to dd 5.1, even though I have both checked off.
Just going to drop my two pennys in here… i have the Sony 65XH9005 connected to the STR-DN1080 receiver, using 7.1, which can decode TRUEHD, DTS-HD MA, all done through eArc.
No problems when playing the BD versions… but, when streaming from the network to the tvs plex app, it will not play TrueHD or DTS-HD MA audio properly when HDMI passthrough is enabled.
So, disabling passthrough and letting PMS take the reins is your only option, but, this is also a problem because whatever Plex is doing not all channels are being pushed.
So! lol… My way around this is to convert my BDs using FFWorks and converting the master audio stream to EAC3 7.1, XH9005 will play this directly with HDMI passthrough on, and all channels present.
Yeah I don’t know what is going on. Now, the dtsma streams won’t play without stuttering but they played fine when I made my last post. 
It seems like every day it changes. Kicker is that for the months prior everything was great. (I know the tv is not supposed to be able to pass dtsma but it was passing the core just fine in the past, now the core stutters)
4 options I know of.
1 wait until plex figures this out in an upcoming update as per @FordGuy61
2 use optical setting - though the sound sounds inferior imo.
3 re rip movies to include the dtsma core/ddthd 5.1 track. At least with this i have option to select 5.1 track in movie settings.
4 buy a shield.
Have you tried other devices to play the file? I have a PS5 connected directly to the TV, i generally just use the TV for all apps, using eArc, saves power etc, I may just download the app for it and see how it fares playing DTS-HD MA.
Shows as DTS on the receiver but it’s transcoding to aac, all channels present.
Option 4, buy a Shield. I used the Plex TV app at first and could never get all of the various audio formats to work correctly. Broke down and got a Shield Pro and have been so glad I did. It plays anything I throw at it and handles all my high bit rate 4K HDR movies without any issues.
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Not for me, I have enough devices around the house, really only the HD audio that is the problem, H265 HDR 10 bit plays fine, not bothered by having to convert 7.1 to EAC3, if it’s only a 5.1, I’ll pull out DTS or DD stream natively from my BD, they’ll play fine.
No, the goal was to play everything through tv. One remote, total simplicity.
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@Alucard1 Do u have the plex going to tv and then earc out to receiver? I’d have to do this.
No, Shield->AVR->TV.
@blanker1 Beta release 8.29.0 now plays TrueHD 7.1 by transcoding to EAC3 7.1 and I have to say it’s glorious, and the best we’re going to get via the Android TV app.
