Thank you both for answers.I found The dashboard.
Now I checked this problematic one and it seems to Be transcoding The video!
4K (HEVC Main 10) -> 4K (H264). The audio DTS-HD MA 5.1 is on Direct play
Well I’m updating the setup so I think Ryzen 5 5600X Will handle these situasions on future.
cpu is less important if you have a supported gpu, ie an nvidia 1050 or higher. you really don’t want to rely on cpu for 4k transcoding.
see the gpu links in the top post above.
I just found this thread and it’s a very informative one. I’m having an issue when playing 4k videos on the Plex Tizen app in my Samsung TV.
I have a 4k video downloaded from Youtube sitting on my Plex server running on a Macbook running Ubuntu 16 with 8 cores (i7-4980HQ CPU @ 2.80GHz) and 16 gigs of RAM. This server is dedicated for plex and storage is a Synology drive mounted over nfs. This Video is encoded with VP9/Opus.
When I play this video on the Plex app on Apple TV, on the Plex Web App in Firefox, and on the Plex app on Pixel 4 running Android 10, it plays always nicely, without issues neither any buffering. On htop I don’t see any transcoding happening, so it’s direct playing.
When I play it on the native Plex Tizen app on my Samsung (QN65Q80RAFXZA Flat 65-Inch QLED 4K Q80 Series Ultra HD Smart TV with HDR) over wifi (Mesh Google Wifi with three wifi points) I experience constant buffering, like every 5 seconds. I see a transcoding process running when it starts:
/usr/lib/plexmediaserver/Plex Transcoder -codec:0 vp9 -hwaccel:0 nvdec -hwaccel_fallback_threshold:0 10 -hwaccel_output_format:0 cuda -hwaccel_device:0 cuda -codec:1 opus -ss 71 -analyzeduration 20000000 -probesize 20000000 -i /mnt/4kvideo.webm -filter_complex [0:0]hwupload[0];[0]scale_cuda=w=3840:h=2160:format=nv12[1] -filter_complex [0:1] aresample=async=1:ocl='stereo':rematrix_maxval=0.000000dB:osr=48000[2] -map [1] -metadata:s:0 language=eng -codec:0 h264_nvenc -b:0 45000k -maxrate:0 60000k -bufsize:0 120000k -forced-idr:0 1 -r:0 25 -force_key_frames:0 expr:gte(t,71+n_forced*1) -map [2] -metadata:s:1 language=eng -codec:1 aac -b:1 258k -f dash -seg_duration 1 -init_seg_name init-stream$RepresentationID$.m4s -media_seg_name chunk-stream$RepresentationID$-$Number%05d$.m4s -window_size 5 -delete_removed false -skip_to_segment 72 -time_delta 0.0625 -manifest_name http://127.0.0.1:32400/video/:/transcode/session/7s0oawoyctc062obw95mw4fm/984a4472-7f86-489e-816e-5ae585b1128e/manifest?X-Plex-Http-Pipeline=infinite -avoid_negative_ts disabled -map_metadata -1 -map_chapters -1 dash -start_at_zero -copyts -init_hw_device cuda=cuda: -filter_hw_device cuda -y -nostats -loglevel quiet -loglevel_plex error -progressurl http://127.0.0.1:32400/video/:/transcode/session/7s0oawoyctc062obw95mw4fm/984a4472-7f86-489e-816e-5ae585b1128e/progress
When I play this same video from Youtube, on this same TV, I don’t experience any buffering and it plays smoothly. When I turn the stats for nerds I see the connection speed is 35 Mb/s.
So I think wifi issues are ruled out here, and it seems that Plex for Tizen is not able to direct play 4k movies and requires transcoding which is also not efficient enough (I see all 8 cores spinning like crazy).
This is definitely sad. Not being able to experience 4k movies on my local network because of software issues is definitely a bummer, and this issue should be prioritized.
I don’t want to hook yet another streaming device to my TV but use the native Tizen app. I also don’t want to upgrade my plex server hardware, that would required another laptop.
I’m wondering what’s the issue here. Why is Plex for Tizen not able to direct play Vp9 and Opus? When I play other VP9/Opus videos on this client I can see the transcoding happen in the server.
My laptop has a GeForce GT 750M Mac Edition GPU and I saw some posts saying that Plex supports using GPU to transcode. Is there some setting that I need to enable or that should be auto-detected by the server? Is there a list with supported GPUs somewhere?
Thanks in advance
Few, or at least much fewer, devices support vp9. Hevc is the normal 4K codec.
As for the gpu question, I’d suggest you re-read the faq again.
Ok, I consider myself a newbie to Plex and especially this topic of 4k media server streaming. The information you provided is very helpful and explains what I have been running into in my system (media server, Marrantz surround processor, 11.2 setup, LG OLED 65")
Anyway, my 2 cents: Just got a Roku Ultra mainly to get access to HBO Max, seeing the handwriting on the wall that streaming will be doing more 4k with Dolby Atmos. I use an Oppo UHD Blu-Ray player and have a number of 4k movies. Set the Roku up and totally blown away about how it works much better (better sound, video and ease of app use) than the LG apps (I use Hulu, Prime, Spotify mainly).
Today when searching for why I cannot seem to get the same video quality (darker, some stuttering, audio out of sync) via the Plex Player vs VLC or when streaming. I happened to see that my new Roku has the Plex app. Bingo!
The Roku-Plex app recognized my media server after I turned on the media server computer and now I have access to all my media server shows/movies and yes the video is very close to the original (with some compression softening) and most important, Dolby Atmos comes through without any problems.
This is not an advertisement!, but the Roku Ultra solved all my complaints about using Plex Player in Windows 10. Plex in Roku is awesome. Very happy with my purchase now after going through a mild buyer’s remorse.
I believe that the Roku Ultra may be an alternative to the NVIDIA Shield Pro, based on the discussion.
Hope this helps others who have the same issues with the Plex player.
You might get be getting EAC3+atmos (ie streaming dolby digital+atmos) but I don’t believe the roku ultra passes through the truehd+atmos (that comes from a full size 4k bluray remux)
the plex dashboard or tautulli will show you if you are direct play/transcoding
I agree based on the discussion, but practically, the result is that I have full 11.2 surround sound and it sounds like the original source material, and I was not able to get that before. The video looks like the original, too, except for the compression stuff I mentioned.
The Roku Ultra displays via the surround processor “Dolby Atmos”, but I have no idea what that really means.
Thank you again for the post.
Oh, btw, what is “tautulli?”
its a pretty cool web based monitoring for plex, so you can see more details on your active streams, library stats and history etc.
check it out
Thank you for that. I installed Tautulli on my media server and yes confirmed that what I have for the 4K movies is Dolby Digital+ with Atmos as you suspected. BTW, it still sounds really good and better than the Plex Media Player in Windows. Not sure how much I will use Tautulli since I only serve the Roku at this point, i.e. no remote viewers, and I’m the only one here, so having a history, etc, is not so important to me. But, having the details of a movie’s file format is helpful. On a blu-ray/1080p movie that I ripped myself, then compressed with handbrake, it did show TrueHD, but the original disc does not have Atmos. Again, thank you, for the post; it cleared up a lot of confusion I had about 4K and Atmos.
I did notice that the TV shows do not have file format information in Tautulli. Did I miss something?
All streamed media should have some details including audio/music, were you browsing a show ? You might have to navigate to an episode to see any file details?
You can download various demo videos from Kodi’s Wiki, linked below…
The “Dolby Atmos Helicopter Demo” has both TrueHD/Atmos and EAC3/Atmos audio tracks.
You can use it to test if the Roku Ultra will passthrough TrueHD/Atmos audio.
Put the file in an “Other Videos” library, so Plex won’t try to match it. Monitor playback via Plex Dashboard/Tautulli to make sure the file is direct playing / direct streaming.
Note: Some links are dead, and links to demo-world.eu may no longer work, as that site is shutting down.
https://kodi.wiki/view/Samples
Thank you for the links. I found 5 that I downloaded and added to Other Videos then added that to the Plex player library. All played the 11.2 channels through Roku Ultra.
The most amazing one is the P5_Dolby_Amaze clip.
On viewing the Tautulli file format info (not sure why but I could not find the Dashboard. Plex Windows is different from Plex Roku.)
The Helicopter was Dolby TrueHD Atmos, The lossless Dolby Atmos Folding was also. The rest were Dolby Digital +/Atmos. They all played fine and all 11.2 speakers fired as expected.
The Dolby Amaze clip is great way to test your system (Dolby Vision and all channels, with deep bass and sharp percussions and natural sounds). Kind of made made me jump in a couple of places.
I see myself using these clips to test Handbrake settings. I have found the settings which seem to work best for me for 1080p with Dolby sound on my LG OLED 65"–I found a little less compression than most used was better: RF 17, H265, 4.1, Audio Pass through, with other settings that I found on the internet. On some ripped Blu-Ray TV shows, that RF17 created too large of files and I found 18 to work better.
This is a remarkably confusing:
The first part leads us to believe Plex now supports 4k transcoding and tone-mapping with any CPU. However it then explicitly states that 4k transcoding relies on Intel Quick Sync which again is only offered by some Intel processors.
PS: The plex “cpu support article” listed prior is also utter garbage as it lists an i7 with X GHz speed. Now depending on the generation that can be a 4 core 8 thread, or even 4 core 4 thread if you count mobile, product. So all in all it’s utterly worthless.
tone mapping at the server/transcoder has only been added recently (and can be disabled for performance reasons)
client color mapping was available prior to server tone mapping, and that happens on the client, not the server.
as far as the cpu article, I agree, without a specified generation, the difference between i3/i5/i7 is mostly irrelevant, but I didn’t write it.
the main thing about cpu transcoding is how many ‘passmarks’ it takes to transcode the content you want to transcode, and the single core performance for processing audio/subtitles/anything else that runs on a single core/process.
Yeah. The CPU support section should if anything list something like: “Minimum 8 Intel threads at 3.2 GHz or an AMD equivalent processor”. After all the only reason to ask for an i7 is to avoid a 4 core 4 thread part from Intel. As far as I know any i3 would probably end up sporting far to few threads for 4k transcoding.
The first two rules of 4K Trans codings are Do not Transcode 4K, the lession here is to collect Titles that do not require 4K Transcoding. That does not mean don’t collect 4K titles. 
I understand that the rule is not to transcode 4k. However, I could have sworn I saw a post on another, non-plex forum (but I can’t find it now) that someone was able to transcode 4k down to 1080p quite easily using QuickSync on an i5 CPU. It was so easy that they had multiple transcodes running. They may have been using Ubuntu. Now, it’s possible I’m remembering wrong, and they were only referring to 1080p transcodes (source is only 1080p). What say you? On modern (say, 10th-gen or higher i5 CPUs), is it possible to get 2 “4k-down-to-1080p” transcodes running quite easily?
Yes, with a modern Intel chip with QuickSync, it is fairly trivial to transcode 4K to 1080p. The best experience is on Linux, as on Windows the tone mapping is only partially supported in hardware.
Dave, thanks for the reply. OK, how about i7-8800K (8th-gen intel chip)? vs Nvidia 1070 Ti? My hardware has both (Running Windows 10), but doesn’t seem to perform that well. In fact, it can’t handle a single transcode from a 4k remux (blu-ray rip) to 1080p. It can handle taking it down to 720p, but not 1080p. The symptoms are: CPU usage isn’t that high (less than 50%), GPU usage isn’t that high (less than 20%), but the transcode keeps “buffering” (as reported by the plex server dashboard). Network is ruled out as I’m playing it back on the same machine.
Is the QuickSync transcode expected to work much better if I disable (remove) the 1070Ti GPU? Or is it just a more modern CPU that I need (newer silicon generation)?
