Huge problem of LG Plex app and I cannot fix it

[philpw99_gmail_com]

Server Version#: 1.21.0.3711
Player Version#:
Client Version#: 5.5.1
Platform Version#: 5.1.1

I recently purchased a LG 65CX and having great fun with it. The TV doesn’t support DTS, but Plex solved the problem with 5.1ch audio transcoding. Everything works beautifully until last week, sudden when I play any video with DTS transcoding audio, the whole screen will turn into a green, red or other random color mess. The sound was audible, but the picture is constantly corrupted. When I switched the audio stream to normal AC3, the picture is normal, but the audio is completely silent. This bug drove me crazy. This is a brand-new TV with less than 1 month of use. Now all movies with DTS are unplayable!

I had to dig further with the issue. I looked at the logs but found nothing ( the log are really not for everybody). I uninstall the Plex Server and install the older versions. Nothing was fixed. Meanwhile all the videos are played just fine in my PC.
Finally I go to the “Settings” in LG’s Plex App, there in the “Advanced” there is a “Reset App” button. I hit it and it was reset, then asked me to link the account again. Once the account is relinked, Plex App works beautifully again !

Update: Now I know why it appeared to be “fixed”. When I reset the App, the settings will roll back to “Audio codecs: TrueHD AC-3 DTS …”
So for some reason, when I play a video with DTS, the LG TV was able to play it with normal sound, but as soon as I uncheck the DTS setting, the problem just comes back.
I tried multiple server versions, I tried early-access and normal versions of the App, I looked at the logs… but nothing really helped.
This is quite a frustrating night. I hope someone know how to fix it and let me know. Thank you!

[SE56]

It may well be this as your problem.

Also are you sure this is a 5.1 Channel title and not 7.1Channel HD-MA

[doggeh]

I’m having this exact same issue and in fact I posted about it last night just before you did (No audio from 4k HEVC Main 10 HDR playback (not DTS issue)). I can confirm that ticking that DTS is supported in the audio settings does in fact make it work again when you select the DTS track for playback. This makes no sense though as the TV doesn’t support DTS and I can see in the dashboard that PMS is using Direct Play!

What’s more, after the reset the AC3 audio still doesn’t work!

I’m so confused!

[philpw99_gmail_com]

The whole idea of “disable video transcoding” make sense to me, because my server computer has a hard time re-econding 4k movies, and if my friends try to play my movies at the same time, the whole experience became terrible. So I cannot let Plex to re-enconde video streams. It’s simply not an option for me.

[philpw99_gmail_com]

I know why it works this way. Because when Plex play a video in “Direct Play”, it will pass the whole file to the player, the player tries to play the DTS track and fail, then it will switch to the next audio stream, usually AC3, then it will be able to the video. I see the way it plays in video details. It’s not a good way to fix it, but right now it’s the only way for me to play a 4k DTS movie. I just disable the “direct stream”, and the movie will play just fine.