QNAP HW transcoding stuttering

Plex Media Server
,
1

Server Version#: 1.19.1.2589
Player Version#:iOS, latest

so i just got my QNAP tbs-453DX and put PLEX on it. and i notice some quite bad transcoding artifacts (color blocks) and the picture freezes every like 30 seconds. when the movie freezes, it’s only the video, the audio will play smoothly like normal, and the video picture will then jump couple frames (~1 second worth) and the audio/video will still be in sync. so i’m sure there is not any network bottleneck as i’m under LAN with >500mbps speed. also the performance shouldn’t be a bottleneck as well, i’m using a intel J4105 with UHD600, and i’m only playing 1 1080p ~10mbps stream.
this only happens for hardware transcoding, software seems fine. and it’s more severe when i enable hardware encoding.

anyone having the same problem? or does anyone know how to troubleshoot and solve this problem?
thanks

2

I had another report of this.

I don’t know what QNAP is saying but the HS series haven’t been tested or approved for Plex use.

I will contact QNAP now and see what’s going on.

3

I think HS and my TBS453 has the same hardware, BTW, the QNAP official repo has the 1.16.6 version, seems to work better.

4

Please verify the processors.

The HS-series uses the J4105 CPU.
The TS-series (TS-453Be) uses the J3455 CPU.

There is considerable video ASIC difference between the two CPUs.

I’ve reached out to QNAP support, sales, and product management to see if we can quickly get this resolved.

5

mine is TBS-453DX, which is pretty much the same as HS-453DX, only difference is the hard drive configuration (23.5+2m.sata vs 4m.sata). and they both have J4105.

hopefully we can have this resolved soon

6

Thanks. That’s what I thought you’d find.

The QSV ASIC in the J4xxx CPUs is purportedly a dual path device. If this is true, and upstream FFMPEG isn’t handling it, there will be problems.

I’m working now to see how quickly we can get our hands on one to test, give to engineering, and resolve.

If it can be made to work properly, I’ll be more than happy to add it to the NAS Compatibility List.

7

I’m doing some test myself, it seems the problem is with encoding
if I only check ‘hw acceleration’, but not ‘hw encoding’, it seems to play fine, just with significant higher CPU usage.

8

The purpose of the ASIC is to offload the CPU. What you’re seeing shouldn’t be happening.

The J4105 should handle multiple HEVC streams concurrently.

9

to be fair, it does handle multiple streams, only with the stuttering problem.
I’m not worried about the GPU performance at all.
if we can solve the stuttering problem, those small units can be really perfect PLEX all-in-one client. QNAP offers native ‘rclone’ client which caches google drive and other cloud services, and it has native HDMI out for Plex media player on TV.

10

It’s precisely that ‘stuttering’ (CPU overloading) problem that I’m trying to solve for.

I need identify the cause. At this point, it appears to be CPU-specific.
I need more information , which I get from hands-on testing.

11

Do you have a device you can test on?
I just rolled back to QNAP official 1.16.6 version, everything seems fine

12

I reached out to QNAP to see if they can loan us one for the Lab (they’re always very accommodating). I don’t know the timing given the worldly events but QNAP support USA is also testing for us via VPN (work from their homes to their lab systems as well).

13

Would this possibly also causing my synced content to not work. Each time I sync content and try to play offline the video does not play (properly).

14

Are you using the “experimental player’ for your offline client? Try turning that off in the Plex client to see if that helps or not.

15

Yes, but turning it off does not solve the issue.

16

Try updating to newer client/server versions to see if that makes any difference.

17

Unfortunately not

18

I have the exact same problem with a different CPU, but from the same series (J4005) on my TS-251D. From what I see this problem has been known since around two months now at least. Is there any time frame where we can expect a beta that fixes this?

19

Would appreciate if the issue can be solved. Always used Plex as happy user who travels a lot. Always the correct series with me offline.

20

I have an interim workaround which works well provided the video bitrate is < 90 Mbps.

  1. PMS 1.19.5 for QNAP now provides direct access to Preferences.xml in the “PlexData” share in File Station.
    -or-

  2. Install / use PMSLibShare

  3. Using a Linux (not Windows) text editor (QNAP text editor is recommended), Add VaapiDriver="i965" before the closing /> at the end of Preferences.xml. Put a space before and after this setting.

It will appear as: VaapiDriver="i965" />

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