Good afternoon!
I have the following configuration:
NAS Synology DS118
Inside installed HDD Seagate ST6000NM0115
DSM version: 6.2.2-24922 Update 2
PMS version: 1.18.3.2156-349e9837e
Panasonic TV 40DXR600
NAS and TV are connected in the 1GBit router
When playing a movie, buffering periodically occurs, playback stops and after time a while falls with a message on the screen such as “Playback did not start on time…”.
The problem arises in different films and at random times.
XML is one of the problematic films: LastVegasXML.zip (1.9 KB)
Logs in the attachment. The problem was somewhere around 16.01 in 19:59: Logs_16-01-2020.zip (1.6 MB)
The system is burning subtitles into your video which is very CPU intensive.
I realize your video had a lot of SRT subs which are generally the best, but I’m not sure well it’s going to work on that Synology. Another user who has one might be able to provide more information. There’s probably an optimal format of tracks for that player, maybe AAC, maybe another video encoding. Sorry I don’t know offhand.
Have you read the website articles on buffering and subtitles? There’s also a Synology FAQ here that’s a good resource in general.
but I failed to read the actual decision which was to only transcode the audio to 6ch AAC.
Jan 16, 2020 19:55:57.725 [0x7f7111f1d0] DEBUG - Streaming Resource: Reached Decision id=893 codes=(General=1001,Direct play not available; Conversion OK. Direct Play=3000,App cannot direct play this item. Direct play is disabled. Transcode=1001,Direct play not available; Conversion OK.) media=(id=2344 part=(id=2344 decision=transcode container=mpegts protocol=hls streams=(Video=(id=5439 decision=copy width=1920 height=800) Audio=(id=5440 decision=transcode bitrate=768 encoder=aac channels=6 rate=48000))))
Because I wrongly deduced it was subtitle lag, I didn’t mention the client broken pipes:
Jan 16, 2020 19:56:00.464 [0x7f88d101d0] DEBUG - Failed to stream media, client probably disconnected after 763096 bytes: 32 - Broken pipe
Jan 16, 2020 20:00:04.549 [0x7f88d101d0] DEBUG - Failed to stream media, client probably disconnected after 3011840 bytes: 32 - Broken pipe
Jan 16, 2020 20:00:05.726 [0x7f88ffe1d0] DEBUG - Failed to stream media, client probably disconnected after 794952 bytes: 32 - Broken pipe
Jan 16, 2020 20:03:58.954 [0x7f88ffe1d0] DEBUG - Failed to stream media, client probably disconnected after 731240 bytes: 32 - Broken pipe
That would indicate the TV closed the connection for whatever reason. There might be Plex app logs off the TV you can gather. If I read your OP correctly, the TV is wired to the switch, not wireless.
It’s a known limitation of certain TVs the amount of memory and cpu power they provide. If you put too much load on a TV app through very high bit rates or from multiple tracks, they have been known to lag. A workaround is to put an AppleTV4K or a Shield before the TV and let those professional appliances take all the load like they were designed to do. Another workaround is to test your video with all the extra tracks muxed out of it. You could also try to find an encode with a lower bitrate if that helps it.
The “client broken pipes” error is related to problems at the network level. I analyzed the logs on the switch and saw that there is a buffer overflow on the port where the NAS is connected.
I switched the port from 1Gbit to 100Mbit and the errors on the port disappeared, as did the error “client broken pipes” in the Plex logs.
Movie playback is no longer interrupted!
P.S. As an experiment, I returned the speed on the port to 1 Gbit and turned on flow control on the same port. After that, in the magazines, I saw that the Tx Paused indicator is growing. This suggests that Plex (Synology) sends too much data to the port of the TV and he does not have time to process them, which is why the brocken occurs and an error “client broken pipes” occurs.
Honestly, I don’t know whose problem it is - Plex or Synology…
What is being described here is an apparent lack of flow control in the TV’s TCP/IP stack.
Are the ethernet frames set to the default MTU of 1500 or are they Jumbo?
If set to Jumbo Frames, this type overload will always happen.
Where did you set flow control on the Synology? I find no such option.
Plex sends data through the Syno’s TCP/IP stack and the TV app receives it.
Now, where the root problem actually is , or if it’s in another device, is the challenge.
Jumbo Frame disable on Synology, set in standard size MTU = 1500.
I set flow control on Mikrotik switch.
Prior to installing Plex, I used the standard application DLNA at Synology - a mediaserver. The hardware configuration was identical. There were no problems with viewing and no errors on the ports.
No, in my case the opposite is true - as soon as I turn off auto-negotiation on the TV port, a stream of errors and collisions begins. Everything works for me in the auto-negotiation mode - NAS (and Plex) at a speed of 1Gbit, a TV - 100Mbit.
In order to finally resolve the issue of stack overflow when transmitting a stream to a TV and eliminating client broken pipes errors in the Plex log, I configured Mikrotik switch bandwidth shaping to 90Mbps by IP addresses of NAS and TV.
After that, playback goes without interruption and periodic buffering.
