webOS stuttering on high-bitrate videos

Plex Players Smart TVs
1

Server Version#: plexmediaserver-1.21.2.3939-3945797bd.x86_64.rpm
Player Version#: 5.7.1

Hi,

problem:
Any file that has 70+ Mbps stutters for both video and audio.
Anything below 70 Mbps plays fine.

plex server is on linux box:

  • Intel Core i7 X980 @ 3.33GHz (10 year old westmere, 6 cores)
  • 12 GB RAM
  • test file is on RAMdisk (to eliminate I/O performance issue)

TV:

  • LG B8
  • firmware 05.30.10 (latest at Jan 30, 2021)
  • connected to linux box directly with Ethernet, link is 100 Mbps
  • TV is connected via toslink to Bose CineMate II 2+1 set

Tested files:
Sony HDR demos:

  • Mont Blanc 70 Mbps
  • Swordsmith
  • Whale in Tonga
  • other files with 70+ Mbps overall bitrate

It seems that both video and audio is direct played.

I checked network utilization - it does not exceed 75 Mbps while playing.

Secure connection is off.

If I put the same file on a pendrive and stick it to TV USB port it plays fine!

Attached are screenshot from plex app and mediainfo dump.

Kindly help me identify where is the bottleneck.

I will be happy to provide any additional info, if necessary.

big thanks !
P

20210130_201840
20210130_201840806×454 105 KB
20210130_201920
20210130_201920806×454 116 KB

4k_sony_hdr-mont_blanc.mp4.mediainfo.txt (3.1 KB)

2

Keep in mind that those 72 Mbps are the average bitrate… the actual bitrate will vary and max. bitrate can be significantly higher. Many smart TVs only use a 100 Mbps LAN port… so the stuttering will likely be related to insufficient bandwidth.

If you have a good WLAN you might get more bandwidth than thought he wired connection…

3

I’ve a B7 OLED. The Ethernet port is 100 Mbps. When connected via Ethernet, high bit-rate videos would stutter, as they peaked above 100 Mbps.

I dropped a WiFi access point behind my TV, using the Ethernet cable for backhaul to the network.

Problem solved. No more buffering and that section of the house now has much better WiFi coverage.

You’ll want an AP, mesh node, etc that supports 802.11 AC on 5 GHz. The TV has a basic radio that connects at a rate of 433 Mbps (actual is less due to overhead). You may want a more advanced unit so phones, laptops, etc can take advantage, but the TV just needs the basics.

4

Hello,

thanks for replies!

Indeed, my LG B8 has 100 Mbps Ethernet interface. Shame.

I switched to 5GHz wifi. Mesh node is nearby and shows max signal strength.

Stuttering is significantly smaller but it’s still there.
Please note that plex client is not showing buffering. It just stutters.

I tuned network config on linux server (tcp memory, window sizes, etc). Did not help.

What is interesting, jellyfish 120Mbps demo plays fine! However it is very short (30s), no HDR and no sound.

Any more tips?
p

5

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