Plex on LG webOS buffering while watching 4K HDR movies

Plex Players Smart TVs
1

Server Version#: 1.14.1.5488
Player Version#: latest webOS version

Hi!
I have rare problems while playing 4K HDR movies that I have buffering during watching the movies.
During the movie I end up a handful of times with buffering - today it even was so bad that the sound was then gone and I had to switch to another sound channel and back again.
This doesn’t always happen.
But it happens. Right now with a movie it states „4K HEVC Main 10 HDR, DTS-HD MA 5.1“ as quality.
My pc is using 2x2 WiFi connection and should be able to keep up and my TV LG C8 also has 2x2 WiFi connectors according to my FritzBox.

Also my app on the tv is allowing insecure connections and working 75% fine with that movie and 95% fine in general.
I am not decoding the movie while watching.

My pc is using a RAID0 from multiple Seagate IronWolf drives, here the read/write speed is fine normally as well.

Other hardware I use is 8GB RAM, AMD FX 8350.

Would be really glad if someone knows a trick to solve this annoying mystery. Thanks!

2

It’ll be interesting to see what average bitrate your movie has.
You can find this information using Plex or some 3rd party tools:
https://support.plex.tv/articles/201998867-investigate-media-information-and-formats/

Keep in mind… this is the average bitrate – peaks can demand a significantly higher bandwidth.

That’s for the “demand” side… as for the capacity your home WLAN provides… this can be tricky as there’s a lot of factors beyond your control that can influence your WLAN performance (e.g. walls, circuitry, even furniture, neighboring WLANs or other radio equipment). The Fritz!Box management app should give you some indication on max. vs. currently available max. bandwidth – however, keep in mind that just an indication and your actual connection can be significantly lower.

3

Hi
It would be roughly 60000kbp/s if I am not mistaken.

Indeed if you look at windows it can be up to 100-120mbit/s and the WiFi is fine normally.

If it’s too much I can try on another PC with that file and different WiFi.

Mit freundlichen Grüßen / Best regards
Ricardo

4

Sounds like the file you’re trying to stream is a remux (as opposed to a re-encode) from Bluray. 60mbit/s sustained is a lot to ask from wifi, imho. That high bitrate also means that the TV can buffer less, time wise, as there’s more data per second coming through. This means any activity on your wireless network from other clients (or neighbours on the same channel) can interfere with the smooth streaming you’re expecting. Smart TVs are designed with Internet streaming in mind, so a maximum of 30-40mbit/s for 4k/HDR, which is why they tend to have 100mbit/s NICs in them and less RAM for buffering.

Personally, I wouldn’t try to stream 4k wirelessly, but that’s just me. I’d suggest sticking to re-encodes or web-sourced content if you’re using the TV’s built-in client, too. If you want the best quality possible, from remuxes, you’d be better off with an external client device like a Shield.

5

Indeed it’s a remux.

Well I tried it then with the Xbox One app however that didn’t give out 5.1 sound to me and I believe there are also limits with 4K content right now?

So that’s also not very satisfying. But that might also just be an issue with the config?

Well I have barely any WiFi’s and neighbores around so that’s why I am fine from the WiFi side of things I believe I thought at least.

6

You’ve got to remember that the multiplexed streams on a 4k BluRay disc aren’t intended to be streamed across a network. No thought is given to the constraints of a residential network, or capabilities of a smart TV’s NIC and decoding engine. These streams are intended to be read from an optical disc straight into decoder hardware within the Bluray player, then output over HDMI to display and audio hardware. As such, and as Tom pointed out, the bitrate of the stream could peak way higher than the 60mbit/s average that PMS is suggesting.

I sometimes struggle to smoothly play back 4k re-encodes on my LG B8 over a wired LAN connection. It often helps to strip out the TrueHD audio stream in these cases and just leave the AC3 (as I can’t do anything with a TrueHD track on the TV anyway).

7

Ok thanks well I will give it a try then without TrueHD audio as well.

8

Is it better to run an LG tv over LAN vs wifi? I’m having issues streaming 4k movies via my plex too. Works on Netflix though. The CPU readout in Plex is all over the place, the RAM is pretty stable. I can send logs too if needed. The 4k movies are pretty much impossible to watch.

Thanks for any input.

Plex Version: 15.6.1079

Router: Nighthawk X10

Server Info:
total used free shared buff/cache available
Mem: 7716 1133 842 8 5741 6215
Swap: 7935 0 7935

CPU:
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 42
model name : Intel® Core™ i7-2600K CPU @ 3.40GHz
stepping : 7
microcode : 0x2d
cpu MHz : 1599.975
cache size : 8192 KB
physical id : 0
siblings : 8
core id : 0
cpu cores : 4
apicid : 0
initial apicid : 0
fpu : yes
fpu_exception : yes
cpuid level : 13
wp : yes

Server running: CentOS Linux release 7.5.1804 (Core)

Test movie:
Matrix - 37G
MKV 2160p
36.9 Mbps

Transcoder settings:
Automatic
Throttle buffer: 60
Background transcoding: Very Fast
Hardware acceleration: yes
Simultaneous video: unlimited

9

You’ll need to investigate 2 potential issues:

1. Does your TV support direct playback of the file?

From what you’ve posted, it appears the CPU of your server might not support intel‘s quick sync technology which is required for HW transcoding. So the moment the file requires transcoding you’ll be in trouble…

2. Any details on your WIFI?

You’re not sharing any details on your local network (except for the router)…
Generally speaking, LAN connections are more stable/reliable (less easily impacted by external factors). That being said… a proper 5 GHz WIFI (AC generation) should deal fine with your file unless you’ve encased your tv in a metal case :wink:
Question is… does your TV support that kind of WIFI or does it only connect to lower bandwidth WIFI flavors?

10

Sorry, thought I covered everything. Figures I missed something. I’ve been a Plex supporter (pass holder) since early on, but never really got into the weeds with adjusting everything. Now that’s coming to bite me back with not understanding it.

Okay so the TV is an LG OLED65B7A

Looks like is supports 802.11ac, but I noticed the NIC is only 10/100 I have that as an option as I ran the cat5e but I’m not using it. Am I missing any other info for you? Sure I just need to rebuild this now old shuttle box I built for Plex many years ago. It’s also pulling from an MDADM Raid 5. Thanks again for the help.

11

You can check out if it works through wired LAN.
I suspect this is about the WebOS client requiring the video to be transcoded. You can verify this by accessing your server using Plex Web while playing the video… click on Now Playing / Activities and then Dashboard. The dashboard should contain information if the video is transcoding (using HW transcoding or not and if it’s transcoding fast enough)

12

Watch out for subtitles causing video transcoding with the Plex LG client.

PGS & VOBSUB subtitles force a video transcode.
SRT subtitles will direct play.
However, audio transcoding + SRT subtitles results in a video transcode.

The Plex app on your TV will direct play AAC, AC3, dts, and dts-HD 5.1 & 7.1 audio. TrueHD audio will transcode.

Also, note that when Plex transcodes 4K HDR video, it results in 1080p SDR video, so you’ll lose both 4K and HDR if that happens.

Also, the i7-2600K will not hardware transcode HEVC video, so if it happens it will be on the CPU (which will be at 100% on all cores).

1 Like
13

LG lists the specs as maximum of 50Mbps even for UHD models. Many 4K HDR (8 and 10 bit) videos are well in excess of 50Mbps. Sony, LG, Samsung and others have sample videos in the 70 to 80Mbps. These should all work fine with the 100Mbps ethernet on your TV without any transcoding. If you use DLNA, even with transcoding any TrueHD audio to EAC3/AC3/AAC, there should be no buffering. With the Plex client on WebOS there may be issues with it transcoding to AAC and getting very low or no audio. There are also some limitations with the html based client Plex must use, so specific video/audio codecs that work over DLNA or an attached USB drive do not always work using the Plex client. I do notice that Plex often shows EAC3 and AC3 as direct play:true but direct stream:false. Flac and Vorbis both work in DLNA, but there can be issues with Plex client.

With video files with a higher bitrate than 80Mbps you will find well setup 5Ghz wireless preferable to ethernet. Search for Jellyfish videos for sample videos (without audio) that have bitrates as high as 400Mbps, with or without HDR and 8 or 10 bit colour to check the performance of your TV and wireless. You should be able to get 120Mbps working with only minimal buffering at the beginning of the video where there are numerous moving objects on the screen. Your current CPU will not be capable of transcoding 4K without buffering. Best to avoid or remux anything 4K that won’t direct play. It should be ok if you only need to direct stream audio.

14

Hi
Well it worked fine for me until an Update or updates from windows, plex and my

Lg tv.

But xplay does work better for 4K then originally plex app - too bad!

On my Xbox it also doesn’t work and transcodes for no valid reason. Using (x265) mkv NOT mp4.

Mit freundlichen Grüßen / Best regards
Richi

1 Like
15

xbox has a number of its own problems, it is otherwise not comparable to a smart tvs built in apps (plex or others).

the same applies to netflix/hulu/amazon/etc, they are not comparable to plex, because those providers control both the content and their clients, they can create streams that fit exactly within whatever the client can playback, while plex has to deal with an infinite number of codecs, file types, and encodings.

16

Hi,
I can follow your thoughts but why does a 3rd party app manage to get it played without issues?

It’s still just plex! Also it worked way better in the past - with only small small delays in playback.

Mit freundlichen Grüßen / Best regards
Richi

17

3rd party apps are often developed with their own internal codecs and decoder routines.

plex clients use what the device is directly compatible with, and rely on the server to convert the media as needed.

as to why it worked better for you in the past, there is no way to know unless you are able to compare logs with the same content playing on both old and current versions.

18

I too occasionally experience buffering when using the Plex for LG WebOS app. I am running webOS 3.8.0 and the client is Plex for LG 3.103.1. My PMS is the latest server version from the official Plexinc Docker container: 1.16.0.1226.

I do have a hard-wired LAN connection to the TV (a LG 65B7P in my case). Even super-high bitrate (73.6Mbps according to Plex) titles like the UHD remux of 13 Hours: The Secret Soldiers of Benghazi had no problems with buffering. Of course the LG down-converted the audio from the TrueHD 7.1 track to DD+ for transmission over the HDMI ARC channel to my receiver.

Other titles also play without buffering with an even higher bitrate like the new 4K release of ‘The Scorpion King’ - 86.5Mbps according to Plex. This title has a DTS-HD 7.1 soundtrack so it passes through to my receiver.

But then, out of the blue, I’ll get buffering on a simple 1080p remux, say Armageddon (1998) with a DTS-HD 5.1 soundtrack and a Plex reported bitrate of 36.7Mbps. If I experience buffering with the Plex for LG client, I then go to try it on either the Plex client or Infuse Pro on my Apple TV 4K. Often the Plex for ATV4K client has issues too, but Infuse Pro (6.0.8) seems to handle everything I throw at it with no buffering.

The gotcha for any playback from the ATV4K is that Apple forces the container to be dumped as raw LPCM, so my receiver doesn’t see or decode the native containers for TrueHD or DTS-HD. Instead it shows on my receiver as Multi-in, with the audio coming in via full bitrate LPCM.

It’ll be nice when newer 2019+ TVs have HDMI 2.1 and eARC so they can transmit the native TrueHD and Atmos containers to the receiver. Until I upgrade, which is a few years off, I’ll put up with the way the LG and ATV4K clients handle things, but I’m also considering purchase of a NVidia Shield as another player option.

One other note: the Plex for LG client often gets confused just navigating the menus and sometimes I’m forced to turn the TV off and on again to reset the client and let it load freshly. I suspect this is a ‘out of memory issue’ as most smart TVs are very limited in the amount of ram available to apps.

I also note that since upgrading to the latest Plex for LG client, the initial launch shows my ‘online’ media sources like News, Podcasts and Web Shows as ‘offline’ until I navigate to that section. Then they immediately connect and the warning ‘!’ symbol disappears from the client home screen.

19

I also own a B7 and C7. I just mentioned the high bitrate as LG states it only supports 50Mbps, maybe to justify putting a cheap 100Mb ethernet port instead of a $2.00 1Gb ethernet port. The 50Mbps is for UHD models, less for HD. I did not see anything specific for OLED. Their info may be outdated as well, as some unspecified codecs like vorbis direct play without issues. They also mention that specific codecs that work using USB may not work using DLNA, although I haven’t had any issues with that. I suspect any file you see buffering on is more likely due to transcoding of either audio/video or both. The only buffering I have seen for files that direct play video have been over 100Mbps. Like the sample files from Jellyfish. The Plex client/server does not seem to agree regarding what the capabilities of the TV are, and transcodes when it shouldn’t have to. Plex appears to use the HTML TV App.xml profile for LG TVs. I have created a custom profile by that same name to alter the behavior of what gets direct played.

Yes the standards are constantly changing, which is why I wasn’t interested initially in anything UHD. The problem is nothing at the high end is 1080P. I suspect a lot more will be changing especially with regards to audio, HDMI, USB, CPU plus the 8K TVs which are already released now.

20

Hello I have this buffering problem since the beginning with my LG 65C8, even with 1080p movies.
PMS runs on a Shield TV, media are stored on a QNAP TS-451 NAS, everything is connected through LAN (cat6 cables) through one switch. I have no problem watching on my iPads, phones, pc or Mac… I already tried a full reset of the TV but the problem is still there.

I don’t know what to do to fix the problem (is it possible anyway). Any help will be appreciated.