Plex buffers when playing some MKVs

[csh8428]

I'm pretty much a newb when it comes to *.nix systems and plex, so please pardon my ignorance.
There's a certain set of MKV files the client starts playing, then freezes after a 10-30 seconds, then plays, then freezes and sometimes crashes. It seems to happen more often with larger files(greater than 15GB), but it also happens from time to time with smaller files. It happens with all clients(web wireless, web wired, Amazon Firetv Gen 2 wired, Vizio P65 wired). I'm pretty sure my rig and network are more than sufficient to play these files. I did notice that Freenas dashboard shows the CPU jumps to 125% when trying to play those files. I've tried Transcoder Default throttle value buffers as high as 120 and that made no difference.

All my clients can direct play all my files, I don't need a transcoder. The same files play fine over the network(both Wifi and wired) if I play them directly from the SMB share via VLC on my PC. I just need a GUI media library.

Plex was installed using the GUI in an iocage jail.

I think I set up permissions correctly. Freenas has user csh84285 that is set to read/write/execute. The owner of the MKV files, jail, and Transcoder temporary directory is csh84285. My Plex login user is csh84285.

System specs
Intel Pentrium dual core G630 2.7Ghz 3Mb cache
16GB GDDR3 RAM
WD red HDs
FreeNAS-11.2-RELEASE-U1 installed to an SSD

I have all the logs from the "Download Logs" in Plex and can upload them, but there are hundres of them. I can upload them if somebody can tell me which ones to upload.

Thanks for any help!

 

[dlavigne]

Were you able to resolve this?

 

[nojohnny101]

This sounds like the transcoding choking due to not being powerful enough. What I would do is to setup a client to play the file then head over to the "dashboard" view that Plex gives in the web client. There you should see the stream playing on the client you are testing and it should tell you whether it is transcoding the file or not.

Often I think people assume the client can direct play but I have found numerous times where even when you think it should, plex chooses to trasncode for whatever reason. If it is indeed transcoding on those files that you are having problems with, and you do see CPU spikes, then that would point to your CPU not being powerful enough.

Looking up your CPUs passmark score (only 2370), it is very low for what plex requires. See this page for plex recommendations and general guidelines for passmark scores and how that translates to the ability to transcode files.

Here is the relevant section:

The Guideline
Very roughly speaking, for a single full-transcode of a video, the following PassMark score requirements are a good guideline for the following average source file:

• 4K HDR (50Mbps, 10-bit HEVC) file: 17000 PassMark score (being transcoded to 10Mbps 1080p)
• 4K SDR (40Mbps, 8-bit HEVC) file: 12000 PassMark score (being transcoded to 10Mbps 1080p)
• 1080p (10Mbps, H.264) file: 2000 PassMark score
• 720p (4Mbps, H.264) file: 1500 PassMark score

The CPU Benchmark website is a good resource to see what sort of PassMark score a particular processor received.

You should read this page as there are sooo many factors that go into determining this and can even choke a CPU that "technically" has a sufficient passmark score but still struggles.
Plex CPU guide

 

[csh8428]

Were you able to resolve this?

Not yet.

 

[csh8428]

This sounds like the transcoding choking due to not being powerful enough. What I would do is to setup a client to play the file then head over to the "dashboard" view that Plex gives in the web client. There you should see the stream playing on the client you are testing and it should tell you whether it is transcoding the file or not.

Often I think people assume the client can direct play but I have found numerous times where even when you think it should, plex chooses to trasncode for whatever reason. If it is indeed transcoding on those files that you are having problems with, and you do see CPU spikes, then that would point to your CPU not being powerful enough.

Looking up your CPUs passmark score (only 2370), it is very low for what plex requires. See this page for plex recommendations and general guidelines for passmark scores and how that translates to the ability to transcode files.

Here is the relevant section:


You should read this page as there are sooo many factors that go into determining this and can even choke a CPU that "technically" has a sufficient passmark score but still struggles.
Plex CPU guide

Thanks!! I will give this a try later today

 

[csh8428]

This sounds like the transcoding choking due to not being powerful enough. What I would do is to setup a client to play the file then head over to the "dashboard" view that Plex gives in the web client. There you should see the stream playing on the client you are testing and it should tell you whether it is transcoding the file or not.

Yep.. This was it!!

Looking up your CPUs passmark score (only 2370), it is very low for what plex requires. See this page for plex recommendations and general guidelines for passmark scores and how that translates to the ability to transcode files.

This was SUPER helpful!! I didn't realize to look at that. I looked at the passmarks for my chipset and apparently there isn't any processor capable of over 9700.