Problem with Transcoding

Plex Media Server NAS & Devices
1

Hello,

I am setting up my new QNAP TS-251D as a server, with Plex Pass.

I have a problem when transcodding. The film sounds good but the image it is pixelated (nothing is recognized) and is jerking.

In the server everything looks correct: Video Transcode (hw) and also Sound Transcode.

The Bandwidth looks wavy, with starts and idle times of about 3 seconds.

CPU shows about 20% of system and 8% Plex Media Server.

RAM continous at 23% System and 2.24% Server.

I made trials with 4K UHD 66Mbs and SD (720Kbps) and allways the same.

In the case of Direct Play, the movies are fluid, without problem.

What is the problem??

Thank you.

Regards

Server Version#:4.30.2
Player Version#: Android 8.0.1.17410

2

According to the NAS compatibility list linked in this support article… your NAS can only hw decode 4K media if it’s encoded as h265. It can deal with 4K h264 media only if it’s SDR.
So what you experience could be a case of bad hw-accelerated transcoding where you pushed beyond what the CPU can properly handle.

https://support.plex.tv/articles/201373803-nas-compatibility-list/.

3

If I may add,

There is a known issue with all QNAP J4xxx CPUs.

We have just received a test unit in our lab from QNAP and are starting our investigation.

One option to try, as a temporary mitigation, is to add VaapiDriver="i965" to the Preferences.xml file in /share/*/.qpkg/PlexMediaServer/Library/Plex Media Server/Preferences.xml

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4

I bougth this because I saw that table details for Nimbustor 4 are the same tthan for this one; I saw Nimbustor 4 transcodding 4KUHD and aldo videos 120 Mbps.

I tested again the trascodding with a film h264, 1080x804; 23.98 fps; 6Mbps transcodding it to SD (H264), 1 Mbps (Transcode hw) and the result is the same than when using a 4K UHD film.

About adding this code… what are the term of mitigation since a trascodding posiblity point of view? I would know it before change anything. Is it better to wait until a solution arrives?

5

Adding the preference VaapiDriver="i965" is a way to help diagnose if the problem is with the iHD_drv_video.so QSV driver and the J4xxx CPU or if it is a bigger problem.

This preference instructs the transcoder to stay with the long-established transcoding method.

We just received a NAS to test with from QNAP to test with.

6

OK, and how can I access to the folder? I did not see share nor Plex folder in the root of the NAS.

Are there any tuto?

Thank you

Edit: I got to change this document via SSH (with the help of an user - thank you [umanand_xp_gmail_com) but I am in the same situation thn before. Nothing has changed.

Captura
Captura958Ă—522 19.7 KB

Is this the file to edit? Is it ok?

7

Dude I have the EXACT same problem!!! Got this NAS cause I thought with the iGPU I can transcode without having a super expensive PLEX server. Turns out hardware transcoding doesn’t work at all… Hope this will get fixed soon! I guess it’s a problem on Plex’s end??

8

From the ssh terminal session window: ( My Plex installation is on CACHEDEV2; most will be on CACHEDEV1 )

[~] # cd /share/*/.qpkg/PlexMediaServer/Library  
[/share/CACHEDEV2_DATA/.qpkg/PlexMediaServer/Library] # 
[/share/CACHEDEV2_DATA/.qpkg/PlexMediaServer/Library] # cd Plex\ Media\ Server/
[/share/CACHEDEV2_DATA/.qpkg/PlexMediaServer/Library/Plex Media Server] # 
[/share/CACHEDEV2_DATA/.qpkg/PlexMediaServer/Library/Plex Media Server] # vi Preferences.xml

Now add the VaapiDriver="i965" preference to the last line, just before the closing /> of Preferences.xml

This is a temporary workaround while we figure out what’s happening with the J4xxx CPUs.

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9

DEBUG logs please.

Let me see what is going on. You might have another, unrelated, problem.

10

This causes for me to have the CPU spike to 100% while the transcoding still won’t work. At least when I use software transcoding with the same CPU load it works.

11

debug.txt (62.9 KB)

12

Works!!

I did not find the correct file. With above instructions I found the correct document.

Thank you very much for your support.

Only one doubt. I understooth that with Vaapi we run old engine? When current or new engine is available… we have to remoove vaapi instruction??

Thank you very Much, really.

13

So, any news update? Considering the x53 series coming out will have those CPUs as quadcore variant plus the new Synology from the x20+ series as well this issue is something that REALLY needs to be adressed. Not to mention right now there’s a lot of false advertising as QNAP is promoting something like the 251D as Plex machine where it clearly has its issues currently!

14

Has there been any progress on this issue? Can we use the current transcoding method?

15

There is a lot going on at QNAP, none of which I understand.
I clearly am not fully briefed on what they are doing.

We are trying to resolve problems with their new J4xxx series CPU-based NAS units.

Beyond this, there is nothing I am aware of or can advise on.

All I can advise is to experiment, watching CPU utilization for the specific media, and see if you’re getting the results you expect.

16

Hi everyone,
My 2 cents on this. Setting up my brand new QNAP TS-251D with latest PMS server (plex pass). Had the exact same problem : everything was running perfectly from LAN, but i was unable to stream from outside my home if using hadware transcoding/encoding, until i discovered this thread. Setting VaapiDriver="i965" has solved the problem for now. Thanks for this (temporary ?) solution.

Have a nice day all,

17

I am glad I found this thread as I was at wits end trying to diagnose my transcoding issues. Adding VaapiDriver=“i965” fixed my TS-251D transcoding issues.

18

I recently bought a TS-653D, and had the same issue. Adding VaapiDriver=“i965” resolved the problem. I’m just wondering whether there has been any progress with a permanent resolution?

19

Yes would really like to know that too. It’s working fine on my TS-453D but some clarification from the Plex team would be appreciated.
(also yes, switched from my 251D, wanted a bit more power xD)

20

The fix and solution for the Intel Media Driver (iHD) and given to Intel to implement and release.

The transcoder team is waiting for those corrections to be released to public.

You may follow along with the discussion on github.

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