My new LG telivision can't play 4K HDR and no Dolby Atmos

Plex Players Smart TVs
1

Update: Also dolby atmos is not working

First day everything went fine, but now it doesnt work anymore. I tried reseting the app and google stuff but nobody knows the anwser, there is also no way of turning the HDR on in the telivision itself. I use the WebOS app you can download out of the webstore.

Server Version#: Latest plex pass update
Player Version#: Client: 4.10.0, Platform 5.2.1
image
Plex Media Server Logs_2021-03-05_00-02-50.zip (3.8 MB)

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Pgs will always be transcoded. Disable subtitles and check if it stops transcoding

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So HDR only works without subtitels?
Is there a posibility to still have subtitels?

4

I don’t have 4k content, but try the same movie with a .srt file

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5

Yes just did, sadly it also goes to HW transcoding. My server cant handle that. :frowning:

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Another strange thing is when I load the movie it doesnt pop up as a dolby atmos movie, but the blue-ray I got it from has dolby atoms

7

Don’t you have another audio option. TrueHD and Atmos are usually transcoded since few clients can play it.
Other than that I would check the bandwidth. Are your server and Tv connected to a gigabit ethernet? If the tv is on wifi, it has to be 5g/n at least

8

Only shield support truehd/atmos.

Pgs subtitles need transcoding on many clients, srt are more compatible.

See @ [INFO] Plex, 4k, transcoding, and you - aka the rules of 4k

2 Likes
9

You’re running into the limitations of the Plex client for LG TVs and the LG TV itself.

Plex app for LG TV

  1. Enabling image based subtitles, PGS & VOBSUB, results in a video transcode.
  2. If the audio is transcoding, enabling any subtitle results in a video transcode.
  3. If the audio is not transcoding, enabling SRT or VTT subtitles will not cause a video transcode.
  4. SSA/ASS Subtitles: If Burn Subtitles = Automatic, enabling SSA/ASS subtitles results in a video transcode. If Burn Subtitles = Image Formats Only and audio is not transcoding, SSA/ASS subtitles will not result in a video transcode, but some formatting may be lost.

LG TVs

  • 2020 & newer LG TVs do not support TrueHD or dts audio formats. If you play media with one of those audio formats it will be transcoded by the Plex Media Server to a supported format (EAC3, AC3, etc).
  • 2019 & older sets support dts and dts-HD, but not TrueHD.

Plex Media Server

  • Transcoded video is converted to 8-bit H.264, which does not support HDR.
  • If TrueHD or Dolby Digital Plus audio is transcoded, any accompanying Atmos information is lost.

Therefore, when playing HDR media using the Plex LG app:

  • Do not enable image based subtitles.
  • If possible, avoid TrueHD & dts audio. If they cannot be avoided, do not enable subtitles.

Note:

  1. Movies on Blu-ray discs with TrueHD audio also include a Dolby Digital (AC-3) version of the audio track.
  2. Movies with dts-HD audio also have a dts version of the audio track. They do not have to include a Dolby Digital version.
1 Like
10

I’ve an LG B7 OLED.

There is no on-screen indication for Atmos audio when playing Dolby Digital Plus + Atmos audio (the Atmos format used by Netflix, etc). TrueHD + Atmos (the format on Blu-ray discs) is not supported by the TV, so there would not be any indication for that audio format anyway.

The only onscreen notification is for HDR or Dolby Vision video (I’ve no DV movies on my Plex server. The TV displays “Dolby Vision” when streaming such content via Netflix & Amazon Prime Video).

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Thanks, so if I use no subs, and TrueHD it will not transcode but I will lose the Dolby Atmos expirence from my tv?

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Wich audio need it to be beforehand to keep atmos working?

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And the strange thing is, with the glassblowing video I get a pop up of Dobly Atmos:
https://www.makemkv.com/download/dvtest/P81_GlassBlowing2_3840x2160@59_94fps_15200kbps.mkv

14

The video will not transcode.
The TrueHD audio will transcode to a supported format. Atmos information is lost in the process.

Not possible if TrueHD + Atmos.
If available, choose Dolby Digital Plus + Atmos. I’ve never seen Dolby Digital Plus + Atmos on Blu-ray discs, only on streaming media.

The issue is the TV does not support TrueHD + Atmos audio. If you use the LG Plex app it will always be transcoded and the Atmos information lost. There is no workaround.

If you want TrueHD + Atmos information, you have one choice: Use an Nvidia Shield Pro (as mentioned by @TeknoJunky).

The Nvidia Shield is the only Plex client that supports TrueHD + Atmos audio and HDR video.

Connect the Shield like this:
Nvidia Shield ← HDMI → Atmos compatible Receiver/Soundbar ← HDMI → TV

Do not buy the non-Pro “tube” model. It has issues with high bit rate media such as 4K HDR movies.

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The audio is Dolby Digital Plus + Atmos, which is supported by the TV.

Nice that you get an Atmos notification. Not shown on my TV, but I’ve an older model.

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Using external .srt subtitles doesn’t trigger any transcoding whatsoever.

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