CPU runs at 100% when Assisted (ASS) subtitles in MKV file are enabled on TV

[davids3906_gmail_com]

Server Version#: 4.63.0 running beta
Player Version#: 8.23.2.28987 (9f2ee47b)
Plex Media Server Logs_2021-10-19_12-11-37.zip (1.6 MB)

I run my server off a laptop running:
AMD Ryzen 7 3700U with Radeon Vega Mobile Gfx 2.30 GHz
8GB RAM
500GB SSD
with 2TB external HDD (which is where I store my media)
Windows 10 version 21H1 64bit

I have tested it with automatic burn in and always burn in subtitles, and have also tested server as public and beta with the exact same issue, my laptop sounds like a rocket ship. I have about 250 files with this format and don’t see the practicality of extracting every ASS file and converting to srt for each file. I have seen previous that this was an issue which got fixed but it doesn’t seem to be fixed for my situation.

I’ve included logs from when I play an episode directly streamed to my smart TV using internal WIFI, usually my CPU runs at around 10-15% but as soon as ASS subtitles are switched on it jumps to 100% and stays there. Included in the logs I switch off ASS subtitles halfway through and it jumps right back down to 10%.

Any ideas with a solution would be really appreciated as I really want to get into this show.

Thanks

[FordGuy61]

FYI, you are running Plex Media Server v1.24.4.5081. 4.63.0 is the Plex Web client version. The PMS version is displayed at Settings → Server_Name → General.

Your logs show you are using an Amazon FireStick 4K.
Oct 19, 2021 12:10:20.850 [12040] DEBUG - [Now] Device is Android (AFTMM).

The Plex Android TV app uses the ExoPlayer video player, which is part of Android. ExoPlayer has poor support for ASS subtitles.

When ASS subtitles are enabled, Plex Media Server must transcode the video and burn the subtitles into the video stream. Video transcoding is compute intensive, and spikes your CPU to 100%.

Oct 19, 2021 12:10:15.098 [6912] DEBUG - [Transcode] MDE: E1 - Episode 1: selected subtitle cannot be converted to a compatible format, burning into video stream

Unfortunately, you don’t have a lot of options to avoid the video transcode.

You can change Burn Subtitles to Image Formats Only. However, you will most likely lose formatting, color, etc information.

You might try enabling hardware accelerated transcoding. AMD GPUs are not officially supported, but you might get some help offloading the video transcode from the CPU (it won’t hurt to try). Burning subtitles will still use the CPU, so your CPU will still spike, just maybe not as high.

FWIW, the Plex app on LG webOS and Samsung Tizen TVs have the same limitation as Android devices when it comes to ASS subtitles. They don’t use ExoPlayer, since they’re not Android based, but Plex still has to burn in the subtitles. I’m not sure about other clients such as Roku and AppleTV. Others can help fill in the blanks.

[davids3906_gmail_com]

Thanks, sorry first post missed some details. Yeah I was wrong I am using Amazon firestick not android TV. I tried your suggestions, changing subtitles to image only doesn’t do much and I already had hardware acceleration turned on. Ah well worth a shot. Might have to remove ASS somehow, the most annoying part is no other subtitles come up on the Plex search so I can’t even switch to using online subs. Bloomin pain in the ASS.

Thanks for looking into for me though appreciate your time.

[davids3906_gmail_com]

I think I’ve fixed the issue now. I only had use hardware-accelerared video encoding checked. I also now checked use hardware acceleration where available aswell and now my CPU is back to normal when playing ASS videos.