Buffering LG C7 Bottleneck?

Plex Players Smart TVs
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Hi I need help on which i need to configure or upgrade right.

my Server

Windows 10 Pro
i5 4460
16GB memory
Crucial SSD main Disk
WD Blue 4TB (Movie Repository)
GTX 1070
Wired Gigabit

Movies 4k.

Issues:
when playing 4k movies with less than 13GB files, im able to play it on my LG C7 (Original Quality) Test movie (Captain America: Civil War)
When Playing 4k movies with more than 20GB file, it buffers every 30 seconds. (Original Quality) Test Movie “DoLittle”

I have tried to check the the performance of my server which there are no resources that are maxed out, everything seems normal usage. (LG C7 is wired on a gigabit network, and this is local network with the server).

Is there a configuration that i need to do?
Transcoding was set to automatic and tested “make my CPU hurt” and same issue…

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To be super blunt… your CPU is not up to the job of transcoding 4K material.
Based on your summary I suppose your LG C7 can deal with those smaller (optimized) 4K videos “as-is”. When it comes to higher quality 4K files, the client will request your server to do the optimization (e.g. lowering the bitrate or even lowering the resolution).

Video transcoding is quite power hungry.
Transcoding a higher quality 4K file to 1080p will easily require a Passmark score of 15000-17000 (CPU benchmark). Your CPU is pretty old (released in 2013 from what I could find) and only has a Passmark score of approx. 6800.
That’s good enough to transcode 2-3 1080p videos – but far from enough to deal with 4K material.

Your best shot is to push for streaming in Original quality (if supported by your device) or to create an optimized version of that video on a more powerful device.

Alternatively you could consider activating your GPU for hw accelerated transcoding. However that feature requires a Plex Pass membership.

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Hi Tom,
thanks thanks for the quick response, i want to balance the expenses, do you think that buying Plex pass membership will compensate with my CPU? or just upgrade my server by buying a new cpu?

THanks,
Joe

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I would just try it for a month and see

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I agree with SE56’s comment.
It’s certainly cheaper than buying a new CPU or machine.

According to the NVENC wikipedia page your GPU should be able to deal with 4K transcoding (incl. 10bit HDR but without B frame support for h265).

Keep in mind that HW accelerated streaming does not work if you the player needs Plex to burn in a subtitle into the video. That’ll still require a CPU.

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Thanks thanks guys,
will try to avail Plex pass for now, those 2k benchmark CPU’s cost a fortune… :slight_smile:

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Something else you may want to consider is a potential network bottleneck. I don’t know the specifics of that model, but if it like every other smart TV on the market it only has a 100 Mb/s Ethernet port. That could pose a problem for high-bitrate media. From what I can tell, it does support 802.11ac wireless. So, if you have a good Wi-Fi network, you could try connecting that way to see if performance improves. This obviously won’t help if the issue is with transcoding as mentioned above.

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Media Playback and Transcoding

Avoid transcoding if possible, especially 4K HDR material. Besides CPU/GPU requirements, transcoded HDR generally looks poor, with washed out colors.

To find out if the video is transcoding, monitor playback via Plex Dashboard -> Now Playing.

Understand the limitations of the Plex app on LG TVs:

  • Enabling image based subtitles, PGS & VOBSUB, forces a video transcode.
  • Enabling ASS/SAA subtitles with positioning, font, color, etc info forces a video transcode.
  • If the audio is transcoding, enabling SRT subtitles forces a video transcode.
  • TrueHD audio always transcodes.
  • Dolby Digital/AC-3, Dolby Digital Plus/EAC-3, and dts direct play (*).

(*) 2018 & earlier LG TVs decode dts so the audio direct plays in the Plex app. 2019 & later LG TVs transcode dts, as LG no longer includes dts decoding with those TVs.

Blu-ray discs with TrueHD audio also contain a Dolby Digital version of the audio. Re-rip the disc with MakeMKV or re-acquire the movie if needed.

dts audio should direct play on your TV. If you are using a soundbar/receiver connected via HDMI-ARC, the TV will pass the dts 5.1 core audio. The -HD portion is discarded.

Network Limitations

@pshanew is correct regarding the network. The Ethernet port is 100 Mbps. A strong 5 GHz 802.11ac connection will be faster than wired Ethernet. It can help avoid buffering due to network limitations.

If the 100 Mbps connection is the limitation and you do not have a strong WiFi signal at the TV location, consider adding a 802.11ac access point. Use the existing Ethernet cable to link it to your home network. This will give you better WiFi coverage for all devices in the area, not just the LG TV.

Bandwidth vs File Size

Investigate Media Information and Formats has details on how to obtain this info.

The size of the movie file does not matter. Required bandwidth matters. Use Plex Get Info or the MediaInfo app to display the average bandwidth of the file. A movie will have peaks above the average, and 4K HDR material may peak above 100 Mbps. The Plex XML information contains more detailed bandwidth information, showing the bandwidth at various points in the file. Look for the RequiredBandwidth lines in the XML information.

Note: Plex Media Server must perform a Deep Analysis of the media to determine the Required Bandwidth information. This occurs during scheduled tasks, configured in Settings -> Server -> Scheduled Tasks. Check the box for Upgrade media analysis during maintenance.

Example from a 4K HDR Blu-ray rip:

File Size via Media Info:  51.68 GB
Media Bitrate via Media Info: 80123 kbps
Video Bitrate via Media Info: 77051 kbps
Video Required Bandwidth (kbps) via XML: requiredBandwidths="123366,98658,94912,93759,92924,92089,87834,82523"
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Hi Fordguy,

That is great information.

  1. I tried connecting it to 5ghz frequency and same isssue.
  2. Tried Plex Pass and hardware acceleration and same issue.
  3. For the video, it is mentioned as Direct Stream “4k(HEVC Main 10HDR) - Direct Stream” while for the audio it is “English (TrueHD 71.) - EAC3-Transscode”
  4. I have 2.1 sound system, yamaha, but my my audio is just connected via Optic cable from TV to receiver.

a minute ago i tried to change the audio to 5.1 on movie “DoLittle” then i didnt encounter any buffer, then transfer it again to 7.1 TrueHD just to check if it will buffer, and no buffering encountered. not sure what is going on… :slight_smile:

Edit: Then i have tried Hunger games and getting a lot of buffer or totally washed out video, then, change the audio from 7.1 to 5.1 and everything works as a charm, in case i will i upgrade home audio system from 2.1 to 7.1, i think i will encounter this issue as well? so I just need to aim for 5.1 audio system only? or if i will be using ARC everything will be fine?

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7.1 channel is the issue, you can get 7.1 channel to work if you have a NVIDIA Shield Pro and a AV Receiver that’s compatible for codecs required. Connecting a AV Receiver via HDMI directly from the shield and not using your LAN as the bit rate peak can not exceed the TV Ethernet limitation of 100Mbs. ( this may not be possible) But as you may not be aware a Plex server can be installed on the Shield with your drive/ drives connected with USB.

Before shelling out any hard earned cash, research everything Shield. As for AV Receiver, most recommend Denon. You will also need a 7.1 speaker system to be compliant.

Now I have spent thousands for you, think hard and do your due diligence.

cheers

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You want to avoid transcoding, especially video. With the Plex LG app, this generally means avoiding subtitles and using AC3 or AAC audio, 5.1 channels or less (or dts if supported by the TV).

Connecting audio equipment via optical / coax / HDMI-ARC will still limit you to 5.1 AC3/EAC3/dts audio. HDMI-ARC does not support passthrough for TrueHD or dts-HD audio due to bandwidth limitations.

So, if you went and bought a soundbar/receiver/etc that supported TrueHD + Atmos and dts-HD/dts:X audio, and connected it to the TV via HDMI-ARC, you would still have avoid 7.1 audio streams.

As @SE56 mentions, do your research. If you want to direct play 7.1 audio you need a streaming device and audio system that supports those formats. Right now, the Nvidia Shield is the only off the shelf device that will passthrough TrueHD (including Atmos) and dts-HD/dts:X audio.

You will also need audio equipment that supports those formats. There are many receivers and soundbars on the market from which you can choose.

7.1 speakers is nice, but not a requirement. My Denon maps the 7.1 audio to available speakers. I’m sure AVRs from other manufacturers do the same.

My setup:
Shield ← HDMI → Denon AVR-X4300H ← HDMI-ARC → LG B7 OLED
Speakers in a 5.1.2 setup.

TrueHD 7.1 and dts-HD MA 7.1 audio direct play, even though I do not have a traditional 7.1 layout. The Surround Left and Back Surround Left play out of the same speaker. Same for the right surround speakers.

That is very, very easy to do. :laughing:

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Wow, thanks a lot guys, im learning a lot, before i didnt encounter this issue with 1080p movies with stereo sounds then use chromecast on samsung TV…
it seems that i need to study a lot to get that great experience for 7.1. or i think i wont go with the 7.1 path, for i already have invested in my yamaha rx-v481 receiver which is just 5.1.
thanks…

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