Random stops when playing 4K videos after DSM upgrading to 6.1.5-15254



recently I've updated Synology DSM to the latest version 6.1.5-15254 released on 2018/01/26 and now I experience random stops for about 4-5 seconds when streaming 4K movies (e.g. data bitrate 61980kbps) via PLEX. It seems that the issue I'm facing with might be related to updating DSM, since I was able to watch all 4K videos without any problems before the update. I've tried to reinstall PLEX on Synology NAS, reinstall PLEX app on my TV Sony XE9005, nothing is helping. Synology NAS is not overloaded: CPU usage is less than 3%, RAM about 25% when playing 4K videos. PLEX version is, Synology NAS is DS716+, no changes has been made on the home network side.
Any clue how can I solve this issue? Does anybody facing with the same issue after installing the latest Synology DSM? Maybe the issue I'm facing with and DSM updating might be coincidence?


If you would:

  1. Verify you have DEBUG logging , not VERBOSE logging, enabled in Settings - server - General
  2. Recreate what your seeing (two occurrances)
  3. Stop playback
  4. Settings - Server - Help - Download Logs and attach the ZIP here
  5. With the ZIP, also please attach the media info or the XML of that file.


Thank you for your quick reply. I’ve attached collected log files and media information as a screenshots. When I started to play video, it was playing fine for 20 minutes and then started to freeze time to time. Freeze time was about 22:04 , 22:06 and 22:07 in local time. The same time zone is set on Synology too and maybe that will be visible in the logs.


Thanks for the logs.

Unfortunately, there’s nothing I can do for you here other than point you to the Android/Player forum section. The problem you’re having is either

A. player itself
B. network can’t keep up during extreme peak bit rate moments.

When pushing 60 Mbps of ‘average’ video, you will have peaks well over 100 Mbps. With peaks over 100 Mbps, the TCP/IP traffic demand will be over 120 Mbps.

Wired or wireless?

What’s the ethernet adapter limit of the TV? Most are 100 Mbps.


Than you for your reply. It would be pretty strange, that this might be somehow related to the network setup. I haven’t changed anything in the network setup (firmware, settings, etc.). I’m using TP-LINK Archer C7 AC router (only 5Ghz band and AC protocol) for connecting TV to my home network environment. WiFi router itself is hidden behind the TV, so there are no walls or long distances between TV and access point. Both WiFi access point and Synology NAS are connected via gygabit ports on Mikrotik router.
When I took a look how does the network traffic looks like, I saw drops to 0 bps every 2 minutes. Is this some kind of buffer? And where is that buffer: on TV itself, Synology NAS or there is some Plex media server buffer configuration? I’ve attached two movies for comparison: The Martian (average is about 60-65 Mbps from the router perspective) and Passengers (average is about 65-70Mbps). The Martian movie doesn’t stuck at all and plays smoothly.
By the way, I found very similar issue in the forum https://forums.plex.tv/discussion/35109/movies-stop-every-2-3-minutes-buffer , but the discussion ended without any solution.


Anybody experience the same issue as I?