Server Version: 1.21.3.4046
Player Version: 5.9.2
I have a new LG 55NANO867NA TV and installed the plex app to play 4K HDR movies. But it is not possible to play 4K with direct play. All 4K movies are transcoded to 1080p.
Here are the movie file.
I have read, that the audio track could be the reason for the issue. First audio track is DTS 5.1 and the second audio track is AC 5.1. How I can solve this issue? My Plex Server is a Synology, so I can not transcode any 4K movie.
cmdr_tom
I would Multiplex it in MKVToolNix and remove DTS track. But you can select the second audio track from your LG Plex client as a alternative.
Something looks amiss in the information you posted:
4K (H.264 HDR).Is the posted info correct? If so, it seems Plex is misidentifying the movie.
In addition to the codec mismatch (H.264 vs H.265), HDR video is 10-bit or 12-bit, not 8-bit.
Try analyzing the movie with MediaInfo and look at the text formatted output. How does it align with what is shown by Plex?
Hi,
I have found a solution - My TV is connected with HDMI and I use ARC to stream sound to the avr. After I activate eARC on the LG TV settings, the Plex App plays 4K direct, but no sound with the DTS track (It’s a shame that LG removed DTS support in the newer models). So I deactivate the DTS option in the LG Plex App and so AC3 works well and video and sound are direct played.
Glad you have things working.
Be aware of the effects of subtitles with the LG Plex app.
While the video may be transcoded in hardware, subtitle burning occurs in software on Linux based systems. Subtitle burning is also a single threaded process.
The Celeron CPUs in Synology NAS have low single threaded scored.
Therefore, do not be surprised if you have issues burning in subtitles even when playing 1080p video.
So is there a way to avoid burning subtitles in case of Synology and LG? It seems that subtitles are burnt every time if transcoding is needed.
With the Plex LG app, the only way to avoid burning in subtitles is to use text subtitles and audio that does not transcode.
If the video is transcoding and subtitles are enabled, they will be burned into the video stream.
You do have some options.
If the movie does not have a supported audio track (AC3/EAC3/AAC), you can add one using tools such as XMedia Recode. You can use it to transcode dts/TrueHD/etc audio tracks to formats that do not transcode, such as AC3/EAC3/AAC. Set XMedia Recode to copy the video track and convert the audio track (you can keep the original audio track if desired). Converting audio is not CPU intensive and takes a few minutes.
Another alternative is to use a different Plex client such as a Amazon FireTV 4K or Nvidia Shield Pro. Plex Android TV clients direct play subtitles, including when the video or audio is transcoding (Release Notes).
I do not know how other Plex clients such as the AppleTV and Roku handle subtitles.
I dont wanna mess with my library. I installed Plex in my parents house in hope that they can enjoy my content. The problem is that some of 4K movies cannot be remote streamed due to the upload speed limitation.
What I don’t understand is why Plex burns subtitles while transcoding for LG TVs but doesn’t in case of Mac, Windows, iOS, etc. Is it a lack of care from Plex or LG?
Suggest it is best to not stream 4K movies remotely unless you have the necessary bandwidth, especially if they are HDR movies.
On Synology NAS, HDR to SDR tonemapping is not yet implemented using h/w acceleration. A Celeron CPU is not strong enough to perform tonemapping in software.
Without HDR to SDR tonemapping, the colors in transcoded 4K HDR media will be incorrect, giving the video a “washed out” look.
I run Plex on a DS918+. I keep my 4K movies in a separate library and do not share them with remote users. I’ve 1080p versions of the movies in my main movie library which I do share with remote users.
Trying to transcode 4K HDR movies on a low power Synology NAS is like trying to tow a yacht with a Yugo. You can try it, but at some point things will break.
It is a limitation of the HLS protocol, which Plex uses to stream media to LG TVs (mentioned in other threads, I can’t find the reference right now).
AFAIK it is a LG limitation that Plex has to use the HLS protocol. I’ve never seen this explicitly stated by someone from Plex, but they use other, less limited protocols on other platforms (such as Android).
Well… I use docker linuxserver.io PMS on my Gemini lake based Synology which supports HW tone mapping and is capable of 2-3 tone mapped HDR streams. Only issue is LG TVs and burn in subtitles.
Thanks for explaining why my parents can’t watch some of my content on their 2K EUR TV once a week. 
Seems like a reasonable solution would be to obtain movies with lower bitrate for them or better ISP.
Forgot about that option. I’ll have to give it a try. I won’t get the same performance as the newer units, but will be interesting to see how well tonemapping works.
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