PMS randomly mixes DTS 5.1 to Stereo PCM missing center channel

Plex Media Server
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Server Version#: 1.24.4.5081
Player Version#: 8.23.1.28053

We have a randomly painful issue. Half of our movies are DTS 5.1 audio. Sonos does not support DTS audio. I disabled all DTS audio on our nVidia Shield 2019s to be sure DTS doesn’t come through.

Randomly, say 1 in 30 plays, PMS will serve PCM STEREO with only the channels carrying music and background noise and no center (dialogue) channel. Rebooting nVidia, killing apps, etc, does not resolve it. The PMS instance must be restarted.

The odd thing is that PMS says direct play DTS 5.1 in the dashboard when content is streaming.

Happy to supply logs if you tell me which of the log from the bundled log ZIP to submit.

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I’ve had this problem too for about a month now with all of the same problems. Any video with 5.1 audio will not play the center channel.

I’ve also tried setting the passthrough to optical which has been suggested on Reddit with no luck.

Any other streaming app on the Shield does not share this issue.

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On a weird side note, if I cast Plex to the Shield, it has no problems playing the audio. Only the Plex AndroidTV app has this issue.

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Please be careful in your naming . There exists both Android TV and Nvidia Shield apps.

Which version are you using and please confirm the app as I’m not able to reproduce using the Shield 2019 Pro with Onkyo AVR

If you’re using an ARC channel, make certain it’s EARC to ensure the codec comes through properly.

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On 16 November, Sonos announced dts support (link). If applicable to any of your Sonos devices, it might let you re-enable dts in the Shield audio settings and/or the Plex Android TV client app (if passthrough = optical).

If the Sonos announcement is not applicable to your setup, and you set passthrough = optical in the Plex Android TV client app, remember to deselect dts in the optical codecs setting. The setting appears next to passthrough only when passthrough = optical. It is not visible if passthrough = hdmi or disabled.

If I set Passthrough = Optical and deselect dts:

  • AAC 2.0 direct plays and is passed to my receiver as PCM 2.0
  • AC3 5.1 direct plays and is passed through as AC3 5.1.
  • All other codecs - dts 5.1, AAC 5.1, EAC3 5.1, TrueHD 7.1 - are transcoded by Plex Media Server to AC3 5.1 and passed to my receiver as AC3 5.1.

My setup:
Nvidia Shield 2015 Pro ← HDMI → Denon AVR-X4300H ← HDMI-ARC → LG TV
PMS: 1.25.1.5286 on Synology DS918+
Plex Android TV client: 8.27.0.29542

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Please verify the HDMI-ARC

  1. You need the good cables (48 Ghz) for 4K + UHD + DV (if your TV supports it ) + EARC.

  2. Make certain you’re using the right TV port. Initially, my LG only had EARC on HDMI port 2. It wasn’t until later firmware that I have EARC on all ports.

  3. Lastly, my Onkyo only supports ARC so I miss out on anything above 5.1. Not doubting your Denon but do check if there are any prerequisite settings requirements like I had. (biggest one was ‘MAIN’ vs ‘MAIN+SUB’ on the HDMI out. ‘HDMI + SUB’ (sub woofer attached to the TV) messes up ARC, I needed to switch the output to MAIN since my LFE is directly attached to the Onkyo)

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@clubizzare did not explicitly mention deselecting dts in the Plex app, so I wanted to mention that was a necessary step.

I was just providing a reference point for how my system behaves when I set passthrough = optical. I cannot replicate a Sonos setup, but it should be similar given the limitations when setting passthrough = optical.

I normally run passthrough = HDMI since the Shield is attached directly to the Denon. No audio restrictions since ARC or eARC does not come into play. Neither my TV (B7 OLED) nor receiver support eARC, which is why the Shield is not attached to the TV.

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Sorry for any confusion I caused.

My Shield is HDMI direct to the Onkyo and has always worked.

The addition of ARC from the LG (WebOS) Plex app added the new twist.

I now have both , full 7.1 from the Shield directly and ARC from the LG

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My solution was to buy this: 4K Arcana 18Gbps | HDFury.com | Connect and Fix everything in HDMI

No issues anymore.

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Hi and a happy new year to everyone.

I’m also facing this issue using a Chromecast with GoogleTV (AndroidTV) and the Sonos Beam Gen 2.
Apps and Soundbar are up to date. So the DTS-Support-Update for the Sonos Soundbar is installed.
The HDMI-Cable I use is applicable for high throughputs and I get DTS and Dolby Atmos without problems in other apps (Netflix, AppleTV+).
Wish there will be a fix soon.

Kind Regards

P.S.
Server Version#: 1.25.2.5319 (TrueNAS Plugin)
Player Version#: 8.28.0.30077

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