I only have that problem with one TV show I’m trying to watch, and it’s only on the Mac Plex app. It works fine in the browser and on my other devices, but for some reason, it stutters on the Mac app.
CPU usage also ramps up to 100%. I couldn’t reproduce the same issue with any other file.
It’s a 4K HDR10+ Profile A MKV file.
Can you get the desktop player logs after it happened with that file. Hopefully it has the events same time frame as your logs from server. Is the server transcoding or direct play.
Do you have low power mode enabled in macOS?
No it’s disabled.
Direct play audio and video.
UPDATE
It also stutters on the Windows Plex app, also direct play.
yep same here I thought it was just me, I’m on an old mac
iMac (Retina 5K, 27-inch, Late 2015), OS: 11.7.10
From my testing, the current build: 1.109.0.329-ea562b95
is like the laggiest interface ever when playing video files, direct or not direct, like I can hear the audio play for a good 5-10s before the video even starts & trying to open UI elements like the settings to change the subs or audio lang takes soo long to respond. even pausing feels like cancer..
purging $HOME/Library/Caches/Plex & $HOME/Library/"Application Support"/Plex
& re-initlise Plex build 1.104.0.241-2164c90a from scratch its all good.
& if I initlise Plex build 1.109.0.329-ea562b95 & just switch back to the older Build before purging those 2 folders it still a laggy mess.
But something happens within those 2 folders on the latest build, it breaks/corrupts something & the UI is non-responsive..
& this does not matter what video file I play, it can even be a low rest 480p 30s clip & it still lags so hard.
here is the old build for mac if anyone wants/needs till plex fixes their broken build.
@BigWheel, here are my log files if it helps.
Plex App Logs (1.109.0.329-ea562b95).zip (2.3 MB)
However, I think I found the issue, it’s to do with the UI windowHeight, windowWidth etc found in.
$HOME/Library/Application Support/Plex/plex.ini
deleting everything within the [ui] category & restoring to default window size & it doesn’t seem to lag but as soon as the user resizes the window or goes to full screen its over.
Also on initial setup as in no Plex Folder in app support or caches (for the Mac app, not server)
there is no lag on any video file but as soon as you restart the app & resize window its over, lag city here we come.
This is the metadata of the video file I tested with normal home video lib in plex
Video
ID : 1
Format : VP9
Format profile : 0
Codec ID : V_VP9
Duration : 40 min 45 s
Bit rate : 26.2 kb/s
Width : 256 pixels
Height : 144 pixels
Display aspect ratio : 16:9
Frame rate mode : Variable
Frame rate : 15.019 FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Bits/(Pixel*Frame) : 0.047
Stream size : 7.63 MiB (35%)
Default : Yes
Forced : No
Color range : Limited
Matrix coefficients : BT.709
Audio
ID : 2
Format : AAC LC SBR
Format/Info : Advanced Audio Codec Low Complexity with Spectral Band Replication
Commercial name : HE-AAC
Format settings : Implicit
Codec ID : A_AAC-2
Duration : 40 min 45 s
Bit rate : 48.0 kb/s
Channel(s) : 2 channels
Channel layout : L R
Sampling rate : 44.1 kHz
Frame rate : 21.533 FPS (2048 SPF)
Compression mode : Lossy
Stream size : 14.0 MiB (63%)
Default : Yes
Forced : No
I used yt-dlp to DL the lowest quality 76kbps video file: https://www.youtube.com/watch?v=Ee4oHnkXRnM
144P video file UI still lags so it don’t matter how big or how bad the video file is quality does not matter.
Thanks for the logs and details @XxUnkn0wnxX
I have the same problem actually. v. 1.109.0, Macbook Pro M1 Pro
This has not been fixed with ver: Plex-1.110.0.351-4e48eb83
I’m still using ver 1.104.0.241-2164c90a 
ok thanks. bug report shows that is the one it should have been fixed in. I’ll let folks know.
I know you downgraded but since the QA folks could not reproduce anymore is it possible to get fresh logs from 1.110 version
Plex App (1.110.0.351-4e48eb83).zip (96.4 KB)
here are fresh logs, but I suspect diagnosing this will be hard, unless you have an ancient mac like I do.
it feels like my whole system lags when video playback starts, like the whole windowserver is about to crash every UI element on the system lags even finder etc..
I get a similar issues when trying to playback 4k video on youtube or trying to render HDR video knowing that my system cannot handle it.
strangely CPU or memory did not spike but still unsure whats causing this lag.
Thanks. Just wanted to double check as well. is this only when the window resizes or all the time? only in windowed mode?
It doesn’t matter; it lags whether in full-screen or windowed mode.
even resetting the plex.ini file doesn’t help much anymore..
it feels like my whole system lags when video playback starts, like the whole windowserver is about to crash every UI element on the system lags even finder etc..
I don’t see the videos stuttering, but there is definitely still a serious performance issue. On my 2019 16” MacBook Pro, the playback lags, the audio and video sometimes get out of sync and the fans systematically run full blast.
On the same Mac, the AppleTV app doesn’t break a sweat playing 4k content…
I just wanted to comment that I am seeing the same behavior. On my M2 Mac mini (15.7.1) connected via gigabit ethernet, the web player works perfectly, but the desktop app (1.110.0.351-4e48eb83) has stuttery playback and a laggy UI. It didn’t used to be this way, but I haven’t used plex on my Mac in a few months.
I tried downloading the 104 build linked above, but it doesn’t play at all, I get 1008 codec errors.
I should also note, I see the same stutters at the same locations in videos on both my iPad and iPhone, both have the latest Plex app installed. I don’t seem to notice the stutters on my Apple TVs, and it doesn’t stutter at all on my Windows desktop (which is a 13yr old i5-3570k, no where near the horsepower of my M2 Mac mini).
I’m running the latest plex server (1.42.2.10156) on my Synology DS918+ (7.2.1-69057 Update 8). Let me know if there are any logs that would be helpful.
if you’re getting codec errors, especially if you’re just switching out the app version. its recommended you purge the cache & any codecs already downloaded in “$HOME/Library/Application Support/Plex/Plex Media Server/”
I’ve had issues when jumping between the latest build & back again when I was testing stuff.
and for good measure, I also delete the codecs folder in the server as well
“$HOME/Library/Application Support/Plex Media Server/”
ensure both the server & app are fully closed.
also if your running the server on synology, the recently removed support for x265 hardware decoding on their systems due to high licence fees they don’t want to pay for.
so try to test with x264 video file.
also try toggling “Direct Play“, “Direct Stream“ In debug settings & “Use Hardware Decoding“ in Player settings. with it on/off I do get some media that refuse to play based on the video codec with some of these on/off or choppy video with it off.
I just wish they kept the plex player app on their git repo: GitHub - plexinc/plex-media-player: Next generation Plex Desktop/Embedded Client up to date & not leave it archived.
having access to their latest builds would have allowed me to diagnose the issue myself if could build from source like with different MPV versions & flags etc..
there is also the Plex HTPC app that could also be tested, but not a fan of the UI.
