After updating to 1.41.7.9799 when I try to play the same file (and other TrueHD files) I get a playback error:
When I go back to 1.41.6.9685 it works fine again.
Thanks for confirming.
That makes three confirmations in the same manner.
Chris is on it.
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ChuckPA, thanks for stepping in on this. Is there any chance you can let us know what happened to cause this issue when you know? I’m interested in what the root cause was.
Additionally, it would be nice if they could add something into the troubleshooting area to give us finer control of audio. We have the ability to switch between x264 and HEVC (somewhat) and control the quality, but audio seems to have been left out. Alternately, they might have an audio menu in the clients allowing users to force the number of channels. This would also allow us to work with our users and narrow things down somewhat. Just some thoughts.
I ran into a crash issue too attempting to play 4K material with TrueHD with Atmos today. Plex completely crashes and I have to get on the server to restart it. I did NOT note the version prior to 1.41.7.9799 but that version everything was being transcoded, i.e., video was transcoded from 4K HDR to 4K, THD Atmos down to EAC3. After updating to 1.41.7.9799, I did notice it crashes when the video starts to transcode but instead of HEVC it showed h264 for a split second before it crashed. Also, on the version prior to 1.41.7.9799, the EAC3 transcode was seen as DD+ on my AVR and NOT with Atmos. I could have sworn it was working fine several weeks ago.
When using the AVR, I use a Roku Ultra model 4640X. The Plex channel is version 7.36.14.10147-6754caeec.
PMS 1.41.7.9823 was released as beta earlier today. It fixes the problem transcoding audio to EAC3. Release Notes: Plex Media Server - #677 by chris_decker08
Atmos does not survive the transcoding process.
Great. Will give it a try later today. Thanks.
I downloaded the beta and it’s no longer crashing.
However, the video is being transcoded and looks like stripping the HDR10 info. IIRC, the Roku Ultra does support HDR10 so not sure why it’s transcoding. If I play the same using my Samsung built-in app, the video is streamed (not direct play). In both cases the TrueHD+Atmos is transcoded to EAC3 which makes sense for the TV. Appreciate the quick turnaround on this fix.
[UPDATE] I added info about the Plex app on the Samsung Q70R which I set up to use ARC and has Atmos compatibility turned on. Plex is still transcoding the audio instead of streaming it. Plex app version is 5.91.0. There’s only one audio setting to normalize multi-channel audio and it’s off (not checked).
Roku Video Transcoding
PGS subtitles cause the transcode
Roku devices do not support PGS subtitles. Enabling them forces Plex Media Server to transcode the video and burn the subtitles (add the subtitles to the video image).
Transcoding to HEVC should preserve HDR. Note that the Plex Dashboard displays 4K (HEVC) not 4K HDR10 (HEVC Main 10) even when preserving HDR. FYI, Tautulli does show the transcode to 4K HDR10.
As a test, turn off the subtitles so the video direct streams. The Roku should display a HDR banner in the top right corner of the screen when the video first starts. Now enable PGS subtitles and repeat. You should still see the HDR banner when the video starts.
TrueHD Audio
Neither Roku or Samsung support TrueHD audio. Therefore, it will be transcoded by Plex Media Server.
If you are passing audio from the Samsung to a receiver, soundbar, etc.:
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HDMI-ARC does not support passthrough of TrueHD or DTS-HD audio. It is limited to AC3/EAC3 (including Atmos)/DTS up to 5.1 channels and PCM 2.0.
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HDMI-eARC supports passthrough of TrueHD (including Atmos) & DTS-HD (including DTS:X) audio. PCM up to 7.1 channels is also supported.
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No TV on the market supports passthrough of TrueHD audio from a TV based app. Therefore, when using the Plex app on a SmartTV, TrueHD audio will always be transcoded. Some TVs support passthrough of DTS audio, but Samsung does not.
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Some TVs support passthrough of DTS/DTS-HD/TrueHD from devices attached to HDMI inputs. However, it varies by manufacturer (and sometimes by model) which codecs are passed.
Thank you for the detailed explanation. You’re right about the subtitles which now makes sense as the series has forced subs.
BTW, it works fine when I turn on DLNA and use my UHD player that’s set to bitstream. So, if anyone else has a unit like a UHD player that’s able to stream via DLNA, NVIDIA Shield Pro, etc. it’s one way to work around these issues to get full lossless audio. I can’t believe in 2025 we’re still dealing with this stuff on devices like Roku “Ultra” ha!
Do you know, if a UHD player has the Plex app, that it would be able to stream the audio without transcoding? I have a very old player, Samsung UBD-K8500, on which the Plex app doesn’t even work any longer but am wondering if more recent versions on newer hardware do. Thanks.
Anyone have any experience with the Amazon Fire Cube? Was just looking at the specs and the audio specs list:
...Audio: AAC-LC, AC3, eAC3 (Dolby Digital Plus), FLAC, MP3, PCM/Wave, Vorbis, Dolby Atmos (EC3_JOC), Dolby MAT, Dolby TrueHD passthrough, DTS passthrough, DTS-HD passthrough (basic profile)...
Anyone know for sure if Plex would work as expected and properly stream the TrueHD with Atmos? Thanks much.
UHD Player
I’m not aware of any current UHD player with the Plex app.
Most companies quit making UHD players years ago and AFAIK, the models still for sale have not been updated in years.
Plex updated security requirements for PMS & clients several years ago. That stopped many older devices from logging in to Plex accounts. Any fix would require a firmware update from the manufacturer, which probably won’t happen for years old devices.
Amazon Fire TV Cube v3
The Amazon Fire TV Cube v3 will passthrough AC3, EAC3 + Atmos, and TrueHD + Atmos.
It has a bug with DTS audio passthrough. It affects Plex and has to be fixed by Amazon, which has not happened. As a result, Plex blocked DTS passthrough from the Cube. DTS is transcoded by Plex Media Server to a supported format.
Note that the Cube only passed the lossy DTS 5.1 core anyway. If playing DTS-HD, the -HD (lossless) was dropped by the Cube.
Other Devices
If you’re looking for a device that passes all audio formats and supports HDR video:
- Nvidia Shield Pro
- Ugoos 6B+ with CoreELEC OS, Kodi, and Plex Mod for Kodi (PM4K)
You will get passthrough for AC3/EAC3 + Atmos/TrueHD + Atmos, DTS/DTS-HD/DTS:X, and PCM 7.1.
An Amazon FireStick 4K Max Gen 2 is also an option. It will passthrough the same audio formats except for DTS. It is not afflicted with the same bug as the Cube, but DTS is still limited to the lossy DTS 5.1 core. DTS-HD MA & DTS:X direct play, but only the lossy core is passed.
All three support HDR10.
The FireStick also supports HDR10+ and HLG. I think the Ugoos does as well, but not 100% certain.
Additional Info: Dolby Vision
Samsung TVs do not support Dolby Vision.
Playing DV video on any of above devices should act the same as using the Plex Samsung app or Plex on the Roku.
- Dolby Vision profile 7 & 8 will play as HDR10/10+.
- Dolby Vision profile 5 video will refuse to play and display a “color space not supported” error (or it will play with the colors horribly wrong).
If you had a DV capable display, the Ugoos fully supports DV profile 7 video. The Shield and FireStick apparently play it as DV profile 8.
TBH, I don’t know the differences. I don’t have an Ugoos and don’t have any DVp7 movies/shows.
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Can you tell me if the same is valid for Fire Stick 4K Gen 2?
I hate the Ambient TV crap that the Max Gen 2 has and recently learned that the 4K Gen 2 doesn’t seem to have that.
As far as I know they behave the same.
The device specs are the same, except the Max has a slightly faster CPU/GPU and more storage.
FireStick 4K Max Gen 2 Tech Specs
Here’s the main pages for Fire device tech specs:
Amazon FireTV Device Specifications
Amazon Fire Tablet Device Specifications
I confirmed that the Amazon Fire Cube works great with 4K HDR and TrueHD w/Atmos and both direct play. Roku Ultra has been downgraded to a much simpler role now. LOL Kinda’ sad actually that the top-of-the-line Roku still can’t accomplish what the Fire can. I got the Cube because I wanted to use a direct network connection but am sure the FireStick can do the same based on the specs.
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