4K Content on Plex

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gehenna

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#223756 16-Oct-2017 10:54

Hi team

I have a file server at home where I've put, a whole lot of home videos in various resolutions and encoding, such as H264 and H265. They're in all kinds of formats, mainly so I can test what does/doesn't work on my devices.

The server runs Plex Media Server, and has been doing so happily for ages. Content up to 1080p streams very nicely both Direct to devices in my home network, and externally to family via my Plex Pass account.

Recently I have been playing around with 4K content as I just purchased a 65" LG 4K HDR telly (which is all kinds of awesome!). The TV runs the WebOS Plex Smart TV app. When playing 4K Plex content it seems to have a hard time. It'll buffer quite regularly is the main complaint.

I have an AC WiFi connection at home which is working very well, and the server is connected to the switch via gigabit ethernet and gigabit ports, which are also gigabit to the Access Point. I figured WiFi would be the issue here, struggling to maintain the right Mbps throughput for the 4K content (some of which is around 50Mbps encoding). So I tried ethernet direct from the TV to the switch. Therefore I have gigabit from source to player. This also has problems, though I suspect the TV only has a 100Mbps port - it should still be plenty given ethernet is far more sustainable than WiFi.

H264 content direct playing does work a lot better, but still buffers every 30-60 seconds. H265 content needs to transcode and buffers pretty much every 15 seconds. I wondered if my server was at fault with its transcoding, but it's never had a problem before. I noticed it was overheating a lot, so I got a new CPU cooler and it's working very nicely now. It can regularly transcode 6+ streams of 1080p with no issues, so a single 4K transcode should be fine!

I wondered if my Plex Smart TV app was at fault, so tested on the the Xbox app, and it does the same. The browser doesn't seem to support 4K, and I haven't yet tested the iOS app. The TV plays Netflix 4K with zero issues at all.

Does anyone have any advice? I feel like I've covered all my bases so far.

billgates

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#1884266 16-Oct-2017 12:31

I bought Vero 4K for 4K videos and HDR. Use Plex for non 4K videos. My Plex app on Xbox suffers from same issue.

Do whatever you want to do man.

gehenna

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#1884277 16-Oct-2017 12:46

Apparently I need KabyLake at a minimum to be able to successfully transcode H265. Interesting, and annoying. As I mentioned, H264 doesn't suffer the same issues - at least not as frequently so I suspect the latter is network congestion and the former is CPU ability. The latter I can hopefully resolve soon, the former might mean I need a new CPU - which was on the cards anyway.

maxeon

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#1884286 16-Oct-2017 13:01

I have a Synology 4 Bay NAS with 8GB ram and running Plex on it. Have a bunch of 4K files and remote and inside the home network (Gigabit all through) works absolute fine with no lag or streaming issues. Even on the WiFi. I have Android TV's at home and have Plex app. All are wired and work fine. I don't think your problem is with WebOS App it might be something to do with the transcoding power on your server.

gehenna

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#1884345 16-Oct-2017 13:43

^It's a very powerful server, much more powerful than a Synology NAS. So that gets me wondering what is different with your setup to mine.

maxeon

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#1884438 16-Oct-2017 16:10

gehenna:

^It's a very powerful server, much more powerful than a Synology NAS. So that gets me wondering what is different with your setup to mine.

Just read this on Plex forums.

PMS recommends a CPU with a passmark score of 2000 for a 10 Mbps video so an 80 Mbps video would need a score of 16,000. This is also assuming you are referring to H264 video. H265 takes a lot more power, so consider at least double the score needed if it is H265.

PMS when transcoding runs at 100% cpu load for the first minute to build up a buffer, so looking at the first minute is not a good indicator of the cpu usage needed. Either look later or check the server log itself for the "speed=" value.

maxeon

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#1884441 16-Oct-2017 16:13

gehenna:

^It's a very powerful server, much more powerful than a Synology NAS. So that gets me wondering what is different with your setup to mine.

Also reading further here. Looks like the WebOS app you have got on your TV is not really great? Perhaps the reason why my Android TV Plex App works flawlessly on 4k?

Have you tried any other devices like Android or IOS to check if you can replicate the problem with the same connection / WiFi?

gehenna

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#1884476 16-Oct-2017 17:38

Yep I read the same re passmark on the CPU. I have just tested and have a passmark of 2893 and a cpu mark of 8824. That could be my issue. But still, that's gotta be better than a Synology?

In terms of the WebOS app - it's aesthetically identical to the Plex app on Xbox and PS4, and a few other platforms I've seen, and as I mentioned it's got no issues at all with 4K from other sources. Also it has no problems with any other content within the Plex app. But I am prepared that it might be the bottleneck.....I just need another platform to compare the tests on so I'll have a play on my Xbox One S tonight.

iOS seems to down convert to 1080p, even if I manually try to select 4K direct play, so the app may not support it yet.