PMS: Random Freezes on Mac OS

Plex Media Server Desktops & Laptops
1

Server Version#: 1.13.8.5395 on a MacMini7,1
PHT Player#: 1.4.1.469-47a90f01
OPEN PHT Player #: v1.8.0.148-573b6
Mac OS Mojave (10.14), High Sierra (10.13)

For over a year on multiple Mac OS versions, PHT and OPEN PHT, on separate Mac Minis including the one that hosts PMS, all sharing the same PMS and GBe wired home network over Cat 6 cabling via both an old and a new NetGear unmanaged switch:

Multiple times during a movie, video will randomly freeze for a few seconds while the audio plays on, uninterrupted. Some viewings we have no problems. Other times we experience 3-4 freezes. Freezes can’t be re-created (i.e. the freezes are not embedded in the video, or the result of a poor recording), which indicates to me that the freezes are randomly being produced by PMS during playback.

Then the video fast-forwards (captioning too), and catches up with the audio. Plex and the movie continue on, like nothing happened, no errors indicated. Until the next time it randomly happens.

The common denominator seems to be the PMS server on a MacMini7,1. Any ideas what’s going on? Thank you in advance.

2

Do you have this issue with PMP?

It seems to me the common denominator might be the PHT/OpenPHT players…

3

Good question. I believe so, but honestly we stopped using PMP b/c of the UI interface. I will attempt to cause my underlings to use PMP and report if any freezes. Even so, how can both PHT and OPEN PHT (newest version) have identical, unresolved problems for over a year?

4

Another suspicion I have is that the Mac Mini’s GPU just can’t keep up with the processing. Although other Mac Mini owners would have reported the same thing (and in my brief search I didn’t see that issue).

5

The other avenue to pursue would be to take a look at the PMS logs when the freezing is happening.

6

Good idea. Might you be able to point me to the URL that describes how to retrieve PMS logs on Mac OS?

7

Maybe not, PMS performance also depends on if there’s any transcoding going on or not and if so, how cpu intensive it is.

8

Will the logs indicate if the CPUs are being outmatched? Or if I’m transcoding (please forgive my ignorance - I don’t know what that means). I found how to retrieve logs on PMS. I’ll post them soonest.

9

Given my house setup, do you recommend I turn transcoding on? Keep it off? I have Blu-Ray as well as DVDs if that matters.

10

You cannot enable/disable transcoding. It is always enabled.

By default, PMS uses the CPU to transcode media. Since you have a Plex Pass, you can enable hardware accelerated transcoding, which uses the internal GPU. This will reduce the load on the server CPU when transcoding is required Note: Only video transcoding is hardware accelerated. Audio transcoding uses the CPU.

See Using Hardware-Accelerated Streaming for system requirements and additional information.

How to tell if you’re transcoding:

When playing a movie, login to your Plex server using a web browser. Go to Status -> Now Playing. It will show you what is playing. Mouse over the movie. It will show you if the movie is direct playing, direct streaming, or transcoding.

You can use the Activity Monitor on a Mac to view the CPU utilization.

Direct Play vs Direct Stream vs Transcoding

See How are Direct Play, Direct Stream, and Transcoding different?

Short version:
Direct Play: The player supports the movie container (MKV, MP4, M4V), video format (h.264, h.265), and audio format (AC3, dts, etc). The server simply streams the movie to the client w/o modification. This takes very little CPU.

Direct Stream: The player does not support the movie container (MKV/MP4/etc) but does support the audio & video formats. Plex Server will remux the audio & video to a supported container then stream the movie to the player. Direct Stream does not require much CPU.

Transcode: The player does not support either the video or the audio formats, or both. It has to transcode it to a compatible format.

Example 1: Play a movie with a DTS audio track, but the player does not support DTS audio. The Plex server will transcode DTS to a supported format such as Dolby Digital, AAC, PCM, etc.

Example 2: Play a HEVC encoded movie to a player that does not support HEVC video. The Plex Server must transcode HEVC to AVC before streaming the video to the player.

Video transcodes are very compute intensive. If the system cannot transcode in real time, you will see buffering and maybe warning messages on-screen. Audio transcodes are moderately CPU intensive.

11

PMS server log. Redacted repetitive items in the beginning, realized it was feudal. Turned on verbose logging too.com.plexapp.system.log (147.0 KB)
Plex Media Server.log (2.1 MB)

12

I too have this issue on High Sierra. I have two PleX media servers however, Server (1) being on a Windows box and Server (2) on the Mac Mini. I originally intended on Migrating to the Mac solely however found that keeping the two gave me room to update and manage without interrupting the entire house in that one server is always available. I generally watch media from the Windows box using OpenPHT on the Mac Mini and still suffer from the Video freeze, audio maintain and then quick catch-up and continues normally. I’m honestly afraid to upgrade to Mojave, although I’d really like to, for fear that things may get worse. Recently, the house had a power outage in the wee hours of the early morning and my Synology never came back on so I have both PleX servers shutdown to preserve the Libraries until my replacement unit arrives and I’m back up. I cannot provide logs however I’m sure whatever is happening to @MRY is revealed in the logs he provided. I’ve not really done any digging as I just sort of deal with it however, I’m at a point where I want to upgrade and I need to know what’s causing this issue.

Thanks in advance,

Kuzama

13

Oh, sorry, I do have the issue no matter if it’s OpenPHT or PMP. I will tell you that if I’m forced to transcode, I do NOT believe it happens but I’m not positive regarding that. I’ve been too busy to care and just finished a big project so now I have some time to look. I will figure this out if it isn’t resolved (or already resolved) in the next few weeks.

Thanks again,

K

14

so I’m curious. One thing for certain that I’m seeing from your provided logs is Safari over and over. I know that running Mojave on my other MacBooks that whenever I play a YouTube video, I get a little freeze right before I starts playing but this behavior is only happening in Safari. If I use Chrome, no such behavior exists. I wonder if this could be as simple as changing the default browser in settings to Google Chrome? Again, my server(s) are down until my Synology is replaced and I have surgery the day before it’s supposed to arrive. I’m not sure I’m going to give a damn about much that day and more than likely will not be in a hurry to get everything set back up. It’s just a thought. If we tell the Mac to use Chrome as the default I wonder if the log files would reflect it attempting to use Chrome instead of Safari? Again, Just stabbing into the wind here.

Thanks,

K

15

I use Multibrowser and keep my desired default for Web surfing and mail.

16

So for this device, I truly don’t care since it’s only used for playback and PMS. If changing it to Chrome fixes the freeze issue, then I’m done. It’s just annoying. Every great once in a while the sudden freeze will result in the app closing unexpectedly but it’s rare. The quick freezes, not so much, that happens all the time.

-K

17

The browser is independent of Plex, hence the word Browser to Browse.

18

I realized that about two minutes after I wrote it. Sorry… I had surgery so I’m in recovery mode and maybe a few too many pain killers…

Thanks,

-K

19

I guess I need to have one more question answered before I upgrade to Mojave. Does PMP and/or OpenPHT work with Mojave? Has anyone heard any buzz? I figure at best, the freezes go away, At worst, it no longer works at all at which time I fire up a Chromecast and buy the Hard wired adapter.

Thanks in advance,

K

20

I have no issues with PMP on my iMac with Mojave.