Tagging some more Employees to get to the bottom of this.
@IanDBird
@BigWheel
@DaveBinM
@anon18523487
My situation is the same as above:
Plex:
DTS 7.1 is received as stereo PCM by soundsystem.
DTS 5.1 is converted to EAC3 5.1 and received as such by soundsystem.
Kodi
DTS 7.1 is received as DTS by soundsystem.
DTS 5.1 is received as DTS by soundsystem.
Setup:
Philips TV with ARC connected to Philips Soundbar B97/10.
If Kodi can handle it, so should plex.
Tested some more:
Passthrough on optical (while connected over HDMI). AC3 and DTS enabled.
–> DTS is detected now on soundbar but very stutter and it crashed my soundbar after half a minute. Need to really take the power off to get it back alive.
Passthrough on optical (while connected over HDMI). AC3 enabled DTS disabled.
–> DTS is now converted by plex but from DTS 7.1 -> EAC3 5.1 Seems to work fine but I miss 2 channels.
Passthrough on HDMI. No possibility to change any codec setting.
–> DTS5.1 is converted to EAC3 5.1
–> DTS7.1 is coming in as PCM Stereo.
Same setup, but now with a Roku 4K Ultra stick with Plex App: plays everything fine the way it should be. DTS detected in all cases.
So clearly a bug in the Android TV app of Plex. I have my workaround, but I hope you guys fix this for all the other peeps out there that suffer from this annoying bug.
I’ll need to see logs from your device after playing back a file with DTS.
This sounds like your device is reporting to the app that it does support DTS, but the DTS decoder it has isn’t working correctly. Or the Plex app is calling the wrong decoder to use. I need the logs to see what is going on.
I have this issue as well. Dts does not work on Android app. Dts works on kodi with plex plugin and displays dts on receiver.
Hello,
I did some tests. You will find the logfile attached.
Filename: DTS-HD_MA_SOUND_CHECK_51
Detected as 5.1 DTS in Plex
Tautulli: Direct Play (DCA-MA 5.1)
Soundbar: PCM (Stereo)
Filename: dts-hd-master-audio-sound-check-7-1-lossless
Detected as 7.1 DTS
Tautulli:Direct Play (DCA-MA 7.1)
Soundbar: PCM (Stereo)
Filename: DTS-HD_MA_SOUND_CHECK_51
Detected as 5.1 DTS
Tautulli: Transcode (DCA 5.1 --> AC3 5.1)
Soundbar: Dolby Digital
Filename: dts-hd-master-audio-sound-check-7-1-lossless
Detected as 7.1 DTS
Tautulli: Transcode (DCA 7.1 --> AC3 5.1)
Soundbar: Dolby Digital
As you can see, When setting the passhtrough to HDMI - which is the correct one - everything is converted to PCM Stereo.
When I change passhtrough to Optical and only select AC3 codec (since my soundbar crashes when also enabling DTS codec) - things get converted but to a max of 5.1.
I can also send you the logfiles from my Roku device if needed, where those files play perfectly.
Please keep us up to date.Plex Android TV DTS issue.txt (575.1 KB)
It’s as I thought. Your TV reports to the app that it supports DTS audio, but indicates only 1 channel, which is definitely wrong.
01-05 17:08:29.474 i: [MediaCodecCaps] Support detected: (audio/vnd.dts, Max: 1)
01-05 17:08:29.479 i: [MediaCodecCaps] Support detected: (audio/vnd.dts.hd, Max: 1)
Since the app can’t know exactly how many channels are supported, it defaults to using stereo. This is the intended behavior.
Cool, thanks!. What can we do about that? Who is giving the wrong information: TV or soundbar?
Anything we can do to go deeper into this to get this resolved?
As said, Roku HDMI stick on the same TV is playing the files correctly. So the Roku Plex app is getting the correct information, which I would think is also coming from the TV?
Just trying to find out where the culprit is here. Philips TV? Android TV OS? Soundbar?
Also, why is Tautulli saying it is “Direct Play” the audio when in the end it is getting converted to PCM stereo? Why is Tautulli not picking this up?
It’s coming from the Android TV OS on your TV. The Roku connected via HDMI can only detect the codec, not channel count, so it just outputs however many channels there are, even if they would otherwise fail.
So I need to go talk to Philips or Google. 
Any hints on where to start?
This would be a Philips issue. I would first check to see if they have a firmware update that might already have a fix.
But then why does it work with other apps?
Good question! Something that I overlooked!
Same TV, same OS, but with the Kodi App: same files play fine and DTS detected on soundbar…
The TV’s built in DLNA player and Kodi both bypass the hardware and use pure software decoding. Plex prefers to use the hardware so in general you would get better performance.
The TV does not support DTS decoding so I don’t think that is the case.
Software decoding does not need the device to support it. That’s the point.
Gotcha, but then there should be some kind of fail-safe, cuz what kind of TV does only support one channel on DTS?
Yes, the failsafe is to use stereo so that you will at least get some audio. It could be more channels might not be supported, then you’d get 0 sound.
Your change to the optical settings is a workaround. There isn’t a way to get 5.1 DTS to work in this situation.
Could fall back to software if this happens. Would be an even better fail-safe.
Or at least give the option in the settings.
I also tend to not fully agree with this statement, although I have no ammo to counter this at this moment.
I do know that Kodi uses HW acceleration to play the video files and I also do know that you can select what kind of audio to just bypass without any decodingin Kodi itself. This is how I got DTS working in Kodi on this TV.
So “bypass DTS” in Kodi is not the same as “Passtrough HDMI” in Plex.
