I've been using Plex flawlessly on small files for my kids (I make 720p rips of kids movies). In the long run, I'd like to put my entire Blu-ray collection on my Synology in untouched format, so I figured I'd experiment with playing some Blu-ray remuxes.
Whenever I have a high bitrate file (say over 20 mbps) AND PMS has to transcode the audio, I run into constant buffering (as in, every few seconds). This happens on my 2016 Samsung Tizen TV and when using Plex Web in Firefox (both of which require transcoding audio). There are zero problems when using the Plex app in Windows, because it's direct play all the way.
I have tried multiple files, so it's not a single file problem. It's not a network issue, as direct play works. I have used both WiFi and hardwired (all of this is internal in my house). It's not the TV as the PC with Firefox has the same issue.
To reproduce the issue, I can take any 20+mbps file with DTS, DTS-ES, DTS-MA, etc audio that requires transcoding, and I will see buffering within seconds of playing it. The video is never being transcoded, and my Synology 1815+ will show 25% CPU and 25% RAM usage, so it's not being overloaded. If I transcode the audio myself before putting it on my NAS (untouched video, downmix to 2 channel AC3), I have zero problems.
Where can I look for more clues?
In my Plex Media Server.log I see a few of these from today when I was testing:
May 04, 2017 12:35:21.414 [0xecd11b40] ERROR - [Transcoder] [mp4 @ 0x92b76c0] Application provided duration: -16 / timestamp: 4518872 is out of range for mov/mp4 format
May 04, 2017 12:35:37.403 [0xe7559b40] ERROR - [Transcoder] [mp4 @ 0x92b76c0] Application provided duration: -16 / timestamp: 8134616 is out of range for mov/mp4 format
etc.
Also of note, unless I'm just not waiting long enough, I can never resume on the files I have trouble with. I can only do "Play from Beginning". If I try to resume, it loads forever with playback never starting. Resume works just fine on the other files that work flawlessly, of course. I don't know if those error messages above are related to the resume problem, the buffering problem, or neither.
Thanks for any tips.
Synology DS1815+
DSM 6.1 (been doing it for months though, in DSM 5 too)
PMS 1.5.5 (but been doing it for months prior, starting with 0.93).