Plex Playback Buffering on Roku Devices

roku

#1

Cross posting from the Windows forum where I got no response.

I have a large collection of anime in which some titles play just fine and other titles stop to buffer every few minutes.

Interestingly this appears to be the only library that seems to have the problem. I have two movie libraries, one for grown-ups & one for kids. Plus three TV show libraries, Adults, Kids, and Anime. None of the movies or normal TV shows I have watched produce the previously mentioned behavior.

Plex is running on a devoted Windows Server 2012 media server (it actually hosts DNS and the domain as well but those are a negligible resource demand). Specs below.

Asus M5A97 R2.0 System Board
AMD FX-6300 3.50 GHz six core processor
12 GB DDR3 RAM
OS Drive 512GB SSD
Library Drive 4TB Western Digital HDD
No video card

Some of the .MKVs and .MP4s play normally. But a few .MKVs and .MP4s suffer from the problem described above. All .AVIs I have tested appear to be fine.

I've pulled up the resource manager and watched the usage in real time while transcoding problem file as the only stream, and it is barely touching the system resources. The thing that gets closest is disk IO and it is less than 50% of max.

After some digging I discovered that the library drive on my Plex server was at 51% fragmentation and the OS drive was at 84%. Defragging the drives, has cleared the behavior for most of the titles.

However I still can't get a coupe of titles in my test group to play correctly. It is still pausing every few of minutes to buffer. Though it now gets through the buffering every time and no longer produces the "server not powerful enough" error.

I've attached the server logs for the last play attempt one of the remaining test files. I interrupted the playback while it was buffering. So that should be the last few entries in the logs.

Anyone see anything I'm missing here?


#2

No Logs attached…


#3

@NewPlaza said:
No Logs attached…

They are attached. The file title is “Plex Media Server Logs_2018_04_29_07-13-03.zip”


#4

New information has come to light. My wife turned on subtitles for Game of Thrones so she could understand the Dothraki and the episode started doing the same thing as the anime collection (which I always watch with subtitles).

Turning off the subtitles on the affected anime titles resolves the buffering problem. However it now means that I am unable to understand the dialogue in the episodes.

Anyone know if there is a fix or work-around for this issue?


#5

I had seen this as well. Here is what I observed. With sub-titles off I could direct play with no transcoding and no issues. WIth subtitles on a transcode occurred. This caused buffering when I had hardware decoding checked (I have Plex Pass). Once I unchecked hardware decoding I could have sub-titles and transcoding occurred without buffering. For the record, I use the PGS files that come on the blu-ray or dvd for sub-titles. Additionally, I encode my videos using handbrake and usually encode the video with H.264 with QSV. Not sure if using the hardware encoding messes with the hardware decoding or not. I have not run an experiment with “normal” encoding and hardware decoding.

Thus, if you have hardware decode or hardware assist or whatever it is called checked then I recommend unchecking it and seeing if your problems go away.


#6

I hear most client players can play plain text (.srt) without transcoding. All others including .ass/.ssa will most likely need transcoding.

so, I think if it buffers on transcoding then maybe your server is not powerful enough to transcode.


#7

Thanks for the input!

After some diagnostics, it looks like the cause is that the drive that Plex is running on is degrading. I have ordered a replacement. But I will try turning off hardware transcoding in the meantime.