Why are most of my 4K video stream buffering?

Plex Media Server NAS & Devices
29

I am not very savy with how all this compression, transcoding etc works, but I have a DS918+ and use apple tv 4k with Plex.

I have been very happy with Plex and using this up until recently when I started trying out 4K HEVC files and Plex just doesn’t do the job at all. It rarely even get passed buffering. I have enabled hardware transcoding, but it doesn’t help.

Downloaded Infuse on the apple tv and with that the files play instantly without any buffering at all and I can forward/go backwards in the movie without holdups.

I have no idea why infuse seem to do the job and Plex can’t.

I use plex media center though and point to this in the infuse app.

31

Curious how is enabling hardware acceleration going to help if he did have a Plex Pass? There’s no dedicated gpu. It has quick sync but ultimately this is celeron cpu made for a file server. It’s not very powerful, which I understand would cause buffering if a file can’t be played natively but curious how enabling hardware transcoding would help in this scenario.

34

Thanks for the info.
To give you an example, I am able to play Mary Queen of Scots using Synology DS Player. It plays perfectly but as soon as I switch to Plex Player it buffers every 30 seconds with Plex Pass activated… So what could be wrong with PLEX that is not with Synology DS Player, a free alternative to Plex… Bad product?

36

Thanks Trumpy81,
Will it make a difference if I told you that I reset the NAS twice, installed the latest DiskStation Manager 6.2 version and updated the Plex Server to the latest version too… It has to be said that re-encoding the movie files work with Plex Player for those files that refuse to play in Plex. I am sorry I would appreciate if you could advise me how to get the logs taken one minute after I experience this issue and how to provide the View XML text of the file played? I really appreciate the assistance to break this status quo…

Many thanks,

38

I have always used direct stream on my home network and untill a few months ago, all my 4k files played just fine. This whole “buy the plex-pass” remark is BS. They release a patch some time ago, that messed upped the PMS, atleast for me. I’m unable to play any 4k file with the use of the plex app or X-play (use my lg tv most of the time). Useing the default LG player, works fine, but somehow the combination of PMS and plex app/xplay creates buffer issues.

39

Hi Rams3y, thanks for the message. I actually changed the settings to not encode movies so as to play the files in their native state and again although it should have improved the situation and once more I did not get lucky with that

40

Providing DEBUG (not VERBOSE) log files (ZIP), captured 30 seconds after that first stutter and the XML of the file which stutters will allow us to provide definitive guidance.

Until such time, there is nothing actionable here.

42

keep in mind, that with direct stream, the device that is encoding the file, is able to do so!

@ChuckPa, I havent changed anything since I bought my NAS and installed plex about 3 years ago. I had no problems playing any kind of 4k file, until a couple of months ago. I only use my lg tv to play these files, and as said, when I play a 4k file with the use of the default LG player, the movie plays fine! But, when I start using the plex or the x-play app, the buffer issue starts. It’s pretty clear, that one of the latest pms updates messed things up. I wish we could simple turn back patches :frowning:

43

Thanks Rams3y,
The settings in Plex are that files should be played in their original format. So Plex should not transcode them as it is meant to play the movies in their native form. Could that be the problem? It encoding the files while being played? My problem with the 4K movies, encoded as H.265, is that they used to work until I installed Plex Pass as a trial for a month several weeks ago and did not renew it at the end of the trial. Ever since that trial period ended most of my 4K movies started to buffer every 30 seconds. We thought that not renewing the pass was the problem so became a full member yet it has not changed anything. The work around has been to re-encode them again to H.264/H.265 to resolve the problem. However Synology DS Player can read the files that don’t work with Plex. So hopefully with the help of some of the Plex Tech Masters this will get sorted as it could have been experienced by so many other Plex customers up to now. I have about 400 movies in 2K and 4K so could you imaging the time it will take to re-encode those 4K movies for them to work with Plex? I love Plex but this issue is testing my patience lol As depending of the size of the files, It can take up to 48 hours for each movie to re-encode, and I have a MacBook Pro… Crasy!!!

44

Thank you Trumpy81, I will do that on Saturday next,

45

Hi Trumpy81, this is the logs zipped filePlex Media Server Logs_2019-04-27_11-14-33.zip (2.7 MB)
and will include soon the soon include the XML file

Thank you, Trevor

46

XML FILE.zip (16.4 KB)

49

If I may be of assistance here?

  1. The J3455 CPU, while good with HW transcoding of the video, is terrible with burning subtitles. The logs clearly show:
Apr 27, 2019 11:02:59.409 [0x7f605b735700] DEBUG - Scaled up video bitrate to 51331Kbps based on 4.500000x fudge factor.
Apr 27, 2019 11:02:59.410 [0x7f605b735700] DEBUG - MDE: Selected protocol dash; container: mp4
Apr 27, 2019 11:02:59.410 [0x7f605b735700] DEBUG - MDE: analyzing media item 23498
Apr 27, 2019 11:02:59.410 [0x7f605b735700] DEBUG - MDE: Bohemian Rhapsody (2018): Direct Play is disabled
Apr 27, 2019 11:02:59.410 [0x7f605b735700] DEBUG - MDE: Bohemian Rhapsody (2018): media must be transcoded in order to use the dash protocol
Apr 27, 2019 11:02:59.411 [0x7f608fa23700] VERBOSE - WebSocket: processed 1 frame(s)
Apr 27, 2019 11:02:59.411 [0x7f605b735700] DEBUG - MDE: Bohemian Rhapsody (2018): selected subtitle cannot be converted to a compatible format, burning into video stream
Apr 27, 2019 11:02:59.411 [0x7f605b735700] DEBUG - MDE: Bohemian Rhapsody (2018): avoiding video remux due to burned subtitle stream
Apr 27, 2019 11:02:59.411 [0x7f605b735700] DEBUG - MDE: Bohemian Rhapsody (2018): no remuxable profile found, so video stream will be transcoded
Apr 27, 2019 11:02:59.411 [0x7f605b735700] DEBUG - MDE: Cannot direct stream video stream due to profile or setting limitations
Apr 27, 2019 11:02:59.411 [0x7f605b735700] DEBUG - Codecs: hardware transcoding: testing API vaapi
  1. When it attempts to burn those subtitles into the stream, the CPU, which is only 2000 passmarks, behaves exactly as expected; overwhelmed Speed must be > 1.0 for smooth playback (1.0 = real time, 2.0 = 2x real time) .
Apr 27, 2019 11:03:06.448 [0x7f608cde2700] DEBUG - Request: [127.0.0.1:42570 (Loopback)] PUT /video/:/transcode/session/a9irx5lu88gaxlxrqcnxfpbm/55e1b3fd-535f-4660-9e88-a3f64982a4e8/progress?progress=0.0&size=-22&remaining=5932114&vdec_packets=53&vdec_hw_ok=47&speed=0.3&vdec_hw_status=1 (20 live) Signed-in Token (Sexy_Winnie)
Apr 27, 2019 11:03:06.448 [0x7f608cde2700] VERBOSE -  * User-Agent => Lavf/58.9.100
Apr 27, 2019 11:03:06.448 [0x7f608cde2700] VERBOSE -  * Accept => */*
Apr 27, 2019 11:03:06.448 [0x7f608cde2700] VERBOSE -  * Range => bytes=0-
Apr 27, 2019 11:03:06.448 [0x7f608cde2700] VERBOSE -  * Connection => keep-alive
Apr 27, 2019 11:03:06.448 [0x7f608cde2700] VERBOSE -  * Host => 127.0.0.1:32400
Apr 27, 2019 11:03:06.448 [0x7f608cde2700] VERBOSE -  * Icy-MetaData => 1
Apr 27, 2019 11:03:06.448 [0x7f608cde2700] VERBOSE -  * X-Plex-Token => xxxxxxxxxxxxxxxxxxxx
Apr 27, 2019 11:03:06.448 [0x7f608cde2700] VERBOSE -  * X-Plex-Http-Pipeline => infinite
Apr 27, 2019 11:03:06.448 [0x7f608cde2700] VERBOSE -  * progress => 0.0
Apr 27, 2019 11:03:06.448 [0x7f608cde2700] VERBOSE -  * size => -22
Apr 27, 2019 11:03:06.449 [0x7f608cde2700] VERBOSE -  * remaining => 5932114
Apr 27, 2019 11:03:06.449 [0x7f608cde2700] VERBOSE -  * vdec_packets => 53
Apr 27, 2019 11:03:06.449 [0x7f608cde2700] VERBOSE -  * vdec_hw_ok => 47
Apr 27, 2019 11:03:06.449 [0x7f608cde2700] VERBOSE -  * speed => 0.3
Apr 27, 2019 11:03:06.449 [0x7f608cde2700] VERBOSE -  * vdec_hw_status => 1
Apr 27, 2019 11:03:06.449 [0x7f608cde2700] VERBOSE - We want 60 seconds ahead, last returned was -1.000000 and max is -1.000000.
Apr 27, 2019 11:03:06.449 [0x7f608cde2700] VERBOSE - It took 0.0 sec to serialize a list with 0 elements.
Apr 27, 2019 11:03:06.449 [0x7f608fa23700] DEBUG - Completed: [127.0.0.1:42570] 206 PUT /video/:/transcode/s

In this case, it is not the fault of the player nor is it the fault of the software. causes here are:

  1. Source material has Image-based subtitles which must be burned
  2. There is no hardware-assist in the CPU to help with this task.
  3. The CPU attempts to burn at its best possible speed. Burning subtitles is a single-threaded task.
  4. The root cause here is improperly curated content / content not matched with server resource capabilites. (the machine is too small or the files need be properly remuxed)
1 Like
50

Really Plex does not want to admit that on Synology hardware it is not recommended to use Plex Player because it’s not compatible with Synology technologies.

Bad product, now I have to re-encode those half of 400 4K movies that are not playing on Plex ever since that trial of Plex Pass. So excuse me to say again that Plex is not recommended.

Thanks anyway,

51

To respond to this and provide the missing information:

Synology has embedded proprietary hardware in their products. They do no license access to that hardware therefore Plex cannot utilize it.

While they may have a hardware advantage, they do not have codec advantage. They limit themselves to freely-obtainable codecs only.

52

The hardware is fine. How it’s being used in this case is the problem. As the server owner, it is your responsibility to understand the limits of the hardware (which we freely and frequently instruct throughout these forums) and curate the media appropriately.

Synology is well known for using weak processors. It has been stated countless times. It is for this fundamental reason, QNAP is so popular. They build products with the same J3455 CPU through the i7-7700 CPU. Synology’s best processor is the J3455.

54

You seem to miss the point that until a month ago everything was working perfectly and I loved accessing my favourite 4K movies with Plex Player. So your analogy about the hardware limitations is nonsense… So thus far you failed to explain why half of my 4K movies stopped playing with Plex Player. Suddenly just like that and it used to play flawlessly

1 Like
55

Which Plex Player as there are several. PMP ? Player on a specific device? Web ?
I don’t know what you played before. Did you acquire new content?

I can only reply based on the log files I have been provided.

Those log files showed me

  1. Subtitles were active
  2. The processor was unable to keep up with real-time playback requirements because it was forced to burn-in those subtitles.

Please do the following:

  1. Turn off VERBOSE logging.
  2. Leave DEBUG logging on.
  3. Begin playback and play until the 2nd stutter.
  4. Stop Playback
  5. Download the ZIP log files from the server
  6. View the XML of the file played (Hover -> Get Info -> View XML)
  7. Attach the ZIP file
  8. Attach the XML

With this information, I can make a more accurate report.

2 Likes
56

Thanks Chuckle, I will this coming bank holiday weekend. I don’t know if it makes a difference but re-encoding the 4K movies using Handbrake fixes the problem of those files that won’t work with Plex Player for a Samsung TV. Even though those 4K movies played great a month ago with Plex Player for Samsung… So basically they work after handbrake does its magic. Which means that if a solution is not found I will have to re-encode about 150 4K movies… grrr Many thanks,

57

Hi ChuckPA
Thanks again for your help.
I watch my 4K movies on a Samsung TV UE65MU6120
Connected via an ethernet home network
Playing 4K movies always worked except until over a month ago subsequently to trying Plex Pass for a month. I did not renew the Plex Pass until I was told that it is required for Hardware Acceleration. Plex Media Server Logs_2019-05-02_10-11-19.zip (2.3 MB)
But even with the hardware acceleration Plex Player for Samsung TV is buffering every 30 second when this does not happen with Synology DS Player.
Many thanks
View XML - 02 May 2019.zip (12.1 KB)