LG WebOS 2020 AC3 - No sound on some files

[darkspirit510]

Hi all!

I have an issue and can’t tell if this is a problem of my device or Plex. Any help appreciated!

Background story: I’m reading all my (4K) BluRays using MakeMKV. I use ffmpeg to convert the video codec to x265 and keep the best available german and english audio stream (most times DTS[HD]) while dropping the others. Since my television does not support DTS, Plex has to transcode the DTS streams. For 1080p, this works fine, but for some 4K (Harry Potter…) the audio works while the video stream (although TV should support direct play) glitches. According to the net I should transcode the audio to AC3 and add this to my video files.

Transcoding the following audio streams, the english one works fine but the german one does not output anything:

Audio #1
ID                                       : 1
ID in the original source medium         : 4352 (0x1100)
Format                                   : DTS XLL X
Format/Info                              : Digital Theater Systems
Commercial name                          : DTS-HD Master Audio
Codec ID                                 : A_DTS
Duration                                 : 2 h 21 min
Bit rate mode                            : Variable
Bit rate                                 : 4 227 kb/s
Channel(s)                               : 8 channels
Channel(s)_Original                      : Object Based
ChannelLayout_Original                   : Object Based
Sampling rate                            : 48.0 kHz
Frame rate                               : 93.750 FPS (512 SPF)
Bit depth                                : 24 bits
Delay relative to video                  : 5 ms
Stream size                              : 4.18 GiB (6%)
Title                                    : Surround 7.1
Language                                 : English
Default                                  : Yes
Forced                                   : No
Original source medium                   : Blu-ray

Audio #2
ID                                       : 2
ID in the original source medium         : 4352 (0x1100)
Format                                   : AC-3
Format/Info                              : Audio Coding 3
Commercial name                          : Dolby Digital
Codec ID                                 : A_AC3
Duration                                 : 2 h 21 min
Bit rate mode                            : Constant
Bit rate                                 : 448 kb/s
Channel(s)                               : 6 channels
Channel layout                           : L R C LFE Ls Rs
Sampling rate                            : 48.0 kHz
Frame rate                               : 31.250 FPS (1536 SPF)
Bit depth                                : 24 bits
Compression mode                         : Lossy
Stream size                              : 4.18 GiB (6%)
Title                                    : Surround 7.1
Writing library                          : Lavc58.91.100 ac3
Language                                 : English
Service kind                             : Complete Main
Default                                  : No
Forced                                   : No
Original source medium                   : Blu-ray

Audio #3
ID                                       : 3
ID in the original source medium         : 4356 (0x1104)
Format                                   : DTS XLL
Format/Info                              : Digital Theater Systems
Commercial name                          : DTS-HD Master Audio
Codec ID                                 : A_DTS
Duration                                 : 2 h 21 min
Bit rate mode                            : Variable
Bit rate                                 : 2 209 kb/s
Channel(s)                               : 6 channels
Channel layout                           : C L R Ls Rs LFE
Sampling rate                            : 48.0 kHz
Frame rate                               : 93.750 FPS (512 SPF)
Bit depth                                : 16 bits
Compression mode                         : Lossless
Delay relative to video                  : 5 ms
Stream size                              : 2.19 GiB (3%)
Title                                    : Surround 5.1
Language                                 : German
Default                                  : No
Forced                                   : No
Original source medium                   : Blu-ray

Audio #4
ID                                       : 4
ID in the original source medium         : 4356 (0x1104)
Format                                   : AC-3
Format/Info                              : Audio Coding 3
Commercial name                          : Dolby Digital
Codec ID                                 : A_AC3
Duration                                 : 2 h 21 min
Bit rate mode                            : Constant
Bit rate                                 : 448 kb/s
Channel(s)                               : 6 channels
Channel layout                           : L R C LFE Ls Rs
Sampling rate                            : 48.0 kHz
Frame rate                               : 31.250 FPS (1536 SPF)
Bit depth                                : 16 bits
Compression mode                         : Lossy
Stream size                              : 2.19 GiB (3%)
Title                                    : Surround 5.1
Writing library                          : Lavc58.91.100 ac3
Language                                 : German
Service kind                             : Complete Main
Default                                  : No
Forced                                   : No
Original source medium                   : Blu-ray

Server Hardware: Synology DS920+, 20GB RAM
Player Hardware: LG 65GX9LA
Server Version#: 1.21.0.3616
Player Version#: 5.6.1 (and Platform 5.1.1, whatever this means)

I also checked the 1080p (no modification/transcoding of the audio) BluRays - some AC3 audio streams work while other don’t?

Working example: Matrix

ID                                       : 2
ID in the original source medium         : 4354 (0x1102)
Format                                   : AC-3
Format/Info                              : Audio Coding 3
Commercial name                          : Dolby Digital
Codec ID                                 : A_AC3
Duration                                 : 2 h 16 min
Bit rate mode                            : Constant
Bit rate                                 : 640 kb/s
Channel(s)                               : 6 channels
Channel layout                           : L R C LFE Ls Rs
Sampling rate                            : 48.0 kHz
Frame rate                               : 31.250 FPS (1536 SPF)
Bit depth                                : 32 bits
Compression mode                         : Lossy
Delay relative to video                  : -42 ms
Stream size                              : 624 MiB (6%)
Title                                    : Surround 5.1
Language                                 : German
Service kind                             : Complete Main
Default                                  : Yes
Forced                                   : No
Original source medium                   : Blu-ray

Non-working (no audio) example: Inception

Moderator: Removed duplicate entry

Edit: The audio streams work in VLC media player.

[jppodo]

I’m having the exact same problem with my LG OLED65CXPUA. Doesn’t matter the audio type. It just won’t work for some files. With another file, the audio worked though the first half of the movie and then just cut out completely. When I tried rewinding to parts that already had audio, I could no longer hear the audio which I had previously. Then I tried restarting the movie from the beginning only to hear nothing. I’ve restarted the PMS. I’ve updated it. I’ve reset my TV to factory settings. What is going on here?

[xavichu]

Exactly same issue here in my LG OLED55CX6LA
DTS-MA not possible, so when switching to AC-3, no sound.
If DTS-MA is selected, transcoding occurs so a lot of glitching in the video playback.

[philpw99_gmail_com]

Guys, I also have a LG OLED65CPUA. This is some funny observation I have.
If in Plex I tell it the TV cannot handle DTS, Plex will try to transcode the DTS audio to AC3, but somehow the transcoding corrupts the file and turns the whole screen into garbages.

But, if I tell Plex that my LG TV can handle DTS, and use direct play to play the same video file. Plex will skip over the DTS track and play the AC3 track instead, and the picture and sound will be perfect again.

One interesting senario: In that video file there are 3 audio tracks: TrueHD, DTS-HD, and AC3., if I want to play TrueHD with subtitle, Plex will fail. If I choose AC3 with subtitle, the video will play, subtitle appears, but there is no audio. Guess how did I fix it?
I play the video choosing DTS-HD with subtitle. Plex will skip over the DTS-HD track and use AC3 track, therefore the sound will be fine. The subtitle will also be OK.

[alabama44]

Same problem. Some AC3 audio tracks are muted on LGCX48OLED

As far as I understand, it must be the LG’s fault. Plex only uses the WebOS built-in capabilities. Here, I’m talking about Direct Play, off course.

Also, to complicate the situation: I can across at least 10-15% of the time, that the audio-tracks are incorrectly labelled. E.g. it shows the same amount of audio tracks and labels as in the mkv file. But the labels are misplaced. I have to select English sometimes for Hungarian audio. This part of the malfunction I don’t know, if it’s error from Plex or the TV. But this part seems to be more on the Plex side. (Actually, I didn’t check in these cases, if the Plex building DLNA player, has the same incorrect recognition of audio track. In these case, I could try out also another DLNA server, like MediaPlayer DLNA. Maybe that could shed light on the issue.)

Update: I checked now, and my latest case, the LG’s build-in DLNA player played the AC3 audio correctly!!! (The build-in DLNA player only showed the supported audio tracks. So DTS audio tracks were not shown at all. So in this case the audio-track mix-up can be ruled out.)

(I have WebOS version: 03.21.16
Plex Client 5.8.0
Platform 5.2.0)

Audio #4
ID : 4355 (0x1103)
Menu ID : 1 (0x1)
Format : AC-3
Format/Info : Audio Coding 3
Commercial name : Dolby Digital
Codec ID : 129
Duration : 3 h 48 min
Bit rate mode : Constant
Bit rate : 640 kb/s
Channel(s) : 6 channels
Channel layout : L R C LFE Ls Rs
Sampling rate : 48.0 kHz
Frame rate : 31.250 FPS (1536 SPF)
Compression mode : Lossy
Stream size : 1.02 GiB (1%)
Language : Hungarian
Service kind : Complete Main

[alabama44]

Here are related forum threads for incorrect audio track selection.

(LG WebOS bug) Wrong audio track despite of what is chosen

Steps to reproduce the bug Play a file (like the one linked below) with multiple audio tracks. One of them has to be a Dolby TrueHD Atmos track. Expected behavior The chosen audio track is played. Actual behavior The chosen audio track is not played. Instead it will be an other track present on the file. 400 MB Test clip from 4K Blu-ray of BlacKkKlansman with multiple audio languages Earlier bug reports of the same issue Hardware and software (all latest versions at the time of writing) …

Audio streams titled wrong

Server Version#: 4.12.3 Player Version#: lg-webos (newest version on app store) I am very new to Plex so don’t please judge me. I got a Plex server wich locally accessed by my LG OLED B97, which is the only player that has the problem. On my Mac there isn’t any problem of that kind. So now my problem: the video file has a Dolby Atmos german stream, AC-3 german stream, Dolby Atmos english stream and AC-3 english stream (in that order). But the german and english stream is titled wrong on the…

[philhilton]

Just another “me too”. Hopefully the model number will help add another data point.

LG 55UN7300PUF 73 Series 55"

The only pattern I’ve noticed in what doesn’t work, consistently, is most anything with ac3 5.1. In our case that’s usually 4k rips and TV shows.

[S70n3]

@jppodo

OLED65CXPUA

Having the same problem.
I start a tv show and the audio plays. But suddenly, in the middle of the episode, the audio stops working. Or the sounds “broken”.
The only way to solve it is to turn off and back again the tv.
Any updates why this is happening?

1080p (H.264)
AUDIO English (EAC3 Stereo)

[SE56]

What version of the server are you using?

[S70n3]

The LG app is 2.2.0
The server Versión 1.21.4.4079 (Just updated yesterday)

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Today I watched 2 episodes of the same tv show. Everything worked fine.
Sometime the audio stops working, and sometimes works perfect.