Strange transcoding behavior on Plex apps

[Matutanos]

Server Version#: 1.32.7.7621 Ubuntu/Linux VM
Player Version 1: Plex HTPC for Windows 1.50.0.19045
Player Version 2: Plex Desktop for Windows 1.81.0.4012-a9d3f098
Player Version 3: PlexWeb 4.108.0 from Server mentioned above

After searching the forums, found no other reports of this kind of behavior, so decided to open a new thread.

Not sure why this is, tried several different settings, even tried to copy every setting from the HTPC app into the Desktop app, but always end up with similar results:

The same file, with same audio and subtitles, being played on the same machine gets:

• Direct play on HTPC
• Video transcoding from 1080p to 1080p on Plex Web
• Audio and Video transcoding (this time down to 480p) on the Plex for Windows Desktop App. (the thing I can’t fix)

Since this is a desktop, the HTPC app is kind of clunky to be used with mouse and scaled up doesn’t look good from 2 feet (60cm) away.

Not sure what logs to upload since 3 different apps are all behaving in a different way, and don’t know if it’s the app or the Server causing this

The desktop is has fairly decent HW and should support H264 and AAC.
Ryzen 7 5800X3D, 64GB of RAM and Radeon RX6800XT connected over 1GB Ethernet

Any help or hint that could solve this issue would be kindly appreciated.

[JaysPlex]

The first thing that stands out is the (ass) subs. Disable those and see what happens. I convert all my (ass) subs to srt because it causes problems with a lot of devices

Usually Plex for Windows is better than Plex Web so that’s a bit puzzling

Are these your quality settings?

Since the other two players are doing what I might expect just focus on Plex for Windows.

Recreate that stream by itself and upload a set of logs after you get another transcode

[Matutanos]

I could swear I tried that before, and ended up with not the recommended, but Video quality set to Maximum.

Setting it to Recommended fixed the issue, but even more puzzling, reverting it to Maximum no longer triggers transcoding. I cannot reproduce the issue anymore.

As for the ASS subtitles, they are packaged inside the .mkv container, any suggestion on how to convert them, if something similar happens again?

Thanks for the fast and easy solution to an issue that was driving me bananas.

[JaysPlex]

Yeah, I’ve had my share of problems that I fixed by mistake using this app lol

If you want to convert them it’s not exactly easy but I had to do it because some of my remote Roku users just couldn’t watch anything

Unfortunately, it’s a multistep process that takes a few different apps usually

Install MkvToolNix. Alongside that you install Inviska MKV Extract.

Then I use Subtitle Edit to convert them

You can leave them as external but I always remux them back into the video using MkvToolNix

I’m sure there’s an easier way. You might even be able to do the entire process using Subtitle edit but I’m too lazy to find out

[Matutanos]

Noice. I got the MKV toolset, thanks for the Subtitle Edit suggestion.

Since all my users are on Desktop/HTPC app, Plex web or Firestick, if no further issues happen, I’ll leave them for the time being. Still nice to know a workaround in case the situation changes.

Thanks again for the help provided.

[Matutanos]

For some reason, as soon as the next episode started, the issue manifested itself again.

Toggling the Quality option back an forth and restarting the app didn’t fix it this time.

Attaching the Server and Player logs shortly after the last try.

Plex Media Server Logs_2023-11-19_02-52-38.zip (5.5 MB)
WinAppLog.txt (267.9 KB)

[JaysPlex]

Ok, this doesn’t make sense to me

MDE: Gunslinger Girl - S2 E3 - Simulacra: selected media 0 / 122747
Nov 19, 2023 02:46:31.038 [139837498882872] DEBUG - [Req#db5489/Transcode] Streaming Resource: Calculated bandwidth of 5294kbps exceeds bandwidth limit. Changing decision parameters provided by client to fit bandwidth limit of 3000kbps

To me, it looks like Plex for Windows isn’t honoring the setting of “Maximum” in the quality settings

I don’t know if there’s some kind of bug or I’m just worse at reading logs than I thought lol

Same file, same device, same app and you’re getting different results from one play to the next

I tested a similar file and added an external (ASS) to see if I could duplicate it, but it plays fine for me

In the short term, the only thing I can suggest is to uninstall then reinstall the Plex for Windows app and see if starts behaving
https://support.plex.tv/articles/windows-and-macos-intro-installation/

As I said, I don’t read logs well and I may be way off base. Leave your logs here so a Ninja or employee can take a look when they come around

[Matutanos]

Well, tried to reinstall Plex twice (one quick and dirty way, one as recommended in the support page), no joy.

It starts off with Direct Play and then falls back to SD transcode after a couple seconds.

ASS was never an issue before (even with heavily stylized subs), but thanks for testing it out as well.

Guess I’ll stick to HTPC app until some wizard comes along, although I suspect it’s a bug, rather have someone who knows the ins and outs take a look at it before making any conclusions.

Once again thanks for time and effort taken.

[Matutanos]

A bit more testing and tweaking.

It looked like it was following the limit for remote bandwidth, although the player is on the same LAN as the server. (Network Settings → LAN Networks → 192.168.178.0/24)

Another weird effect was the “BANDWIDTH” monitor on the server Dashboard was showing no traffic (local or remote) when playing the transcoded video, maybe the server was “confused” about the type of traffic/bandwidth to enforce. But was showing “Local” and the proper address in the “Now playing” section.

Guessing those few Kbps are the web interface traffic, since they are always a few even when no playback is underway.

So I tried changing the server config “Limit remote stream bitrate” to unlimited and the issue disappeared.
Changing it back to 3Mbps 720p didn’t revert to the buggy transcoding scenario. (for now)

Now am at a loss if it’s the Player or the Server acting up…

I will try out a couple more episodes this evening to see if the bug reappears and report accordingly.

[Matutanos]

Well, after some more testing, looks like the issue might be gone.

Toggling server-side the “Limit remote stream bitrate” to unlimited and then back to 3Mbps seems to have fixed it.

Still would be nice to know what the root cause was.