Adding subtitles changes the Quality type and slows down everything on Synology SD720+

Plex Media Server NAS & Devices
1

Server Version#: Version 1.19.5.3112
Player Version#:
Synology SD720+

For some strange reason when I play Plex from my Android Plex app, I don’t have any issue, and the quality and speed look great when I enable the subtitles. But as soon as I try to run the same file from my Fire TV Cube or Android TV Sony, or Desktop connected directly to NAS I start seeing the spin and it comes very slowly the video all pixelated.

If I switch back to no subtitles, I get the original quality and things go back to running smoothly.

This is definitely something new that was introduced in the last month os so because I have been using plex for more than 2 years having no problem.

What could be the issue?

Thanks,
_Petar

2

Burning subtitles is always slow and hard to do on any Synology unit.

Check the subtitle type. SRT, ASS, and SSA are text and can be overlayed
PGS, VOBSUB, and DVDRIP are images. These must be burned.

In most cases, we find the player app settings changed -OR- the media has changed.

3

I just installed Plex on my PC and pointed to the same shared files that are o the synology and the video is running smoothly, change to synology and updated to latest DSM 6+ and still having this issue.

I have watched videos on my synology for a while and this was not an issue before. Saying that its slow on Synology is not right, something else must be going on, this is a Plex issue not a synology issue.

What else can I do? Finding subtitles in different formats is not possible either

4

I just tried a movie with ASS subtitles and the same issue happens, the issue is the transcoding, it goes directly to converting x quality and that just keeps on spinning the wheel. Even if I chose the lowest quality of 160p, its still not moving

5

I just cleaned up old plex files from synology (32K files within Plex Application Support folder?) and reinstalled the latest version specifically for Synilogy and the same issue is happening while watching on Fire TV, ANdroid TV and Desktop.

BUT, its perfect on Android Galaxy S20 Ultra App. It has issues on Android Mobile Web as well.

I don;t think its synology, why its working great in the App? is the transcoding happening on the client side? must be

Plex Mobile App Version: 8.3.1.19108

Thank you for your help

6

Any update? Saying that Synology is not good is unacceptable for a product you pay for. Especially when it used to work great, please do some deep dive and fix the issue

7

I don’t mean to seem like I’m sidestepping but I can’t do anything about the apps other than report the issues (which I have).

My expertise and responsibility is Linux (which includes the NAS boxes).

I own 2 Synology and 2 QNAP. I am painfully aware of their processing limitations.

As for the performance on Android – I cannot speak to it. I have an Nvidia Shield Pro 19, Apple TV 4k, iPhones and iPads.

8

Looking closely at the settings, I noticed that only in Android you can still have original quality without transcoding and in top of that add subtitles. That’s why it’s working. Why is that? Why on all other platforms adding the subtitles charges automatically the video quality from original to transcoding which is where Synology/plex chokes. Also, the 720+ can have additional caching installed, if I do that, would that help?

9

Can you please do the following so we remove the theoretical aspects?

  1. Verify DEBUG logging enabled, VERBOSE logging disabled
  2. Recreate (start and play for 30 seconds) one of the videos which causes the problem
  3. Wait 30 seconds after stopping it
  4. Settings -Server - Troublehooting - Download Logs
  5. Attach the ZIP file.

with that info, we can see exactly what it happening and can proceed from there.

10

I will do this later today, meanwhile,

here is a year old video where transcoding is helping to get the best quality depending on the network.

Here is a video a year later showing the issue with transcoding

11

Those don’t do any good, I’m afraid.

They are very content-type and usage case specific.

Transcoding is abysmal on Synology if Subtitles are burned. It’s ALWAYS been that way. The CPU just isn’t strong enough.

SRT / ASS / SSA (Text based) , with the player in Automatic mode, is the best you can hope for UNLESS you want to pre-burn the subtitles into the video.

That’s the nature of the beast, I’m afraid.

12

FYI:

There’s a reason why this thread is way too long to read:

The reasons 4K Transcodes are almost limitless and the best advice given in that thread is:
“Make sure your 4K Direct Plays - or don’t bother with 4K.”

On a system that can’t transcode - that would seem like sage advice.

13

[Transcode 1080p - 8Mbps with ASS subtitles]Plex Media Server Logs_2020-08-07_18-42-03.zip (5.5 MB) [Transcode to 480p with no subtitles, nothing showing]Plex Media Server Logs_2020-08-07_18-46-25.zip (5.7 MB)

14

I am transcoding 1080p 8 Mbps with subtitles and its moving like 1 frame per 2 sec

15

Any update? Meanwhile, where can I get previous versions of the synology 64bit? Early June version was working great.

16

OK, I got it working perfectly with an older synology version: https://downloads.plex.tv/plex-media-server-new/1.16.3.1433-359b06978/synology/PlexMediaServer-1.16.3.1433-359b06978-x86_64.spk

Here is the debug file running exactly the same 1080p video as above with Transcoding and subtitles: Plex Media Server Logs_2020-08-11_22-26-41.zip (3.9 MB)

Then I updated to the version Version 1.18.5.2309, which was suggested automatically by Synology and the issue was there, here are the logsPlex Media Server Logs_2020-08-11_22-32-48.zip (3.3 MB)

Then I updated manually as suggested by plex to the latest version 1.19.5.3112 and having the same issues as it goes to Converting Maximum Quality and English PGS Subs.

As you can see, Synology has nothing to do with your Server having a bug. Please reproduce it yourself and fix it instead of blaming Synology. Also, I would expect that you guys can do this basic testing.

1 Like
17

Any comments? ticket to devs created? solution? timelines to fix this? I am still using the 1.6 version

18

This topic was automatically closed 90 days after the last reply. New replies are no longer allowed.