FFmpeg 6.1 Downmixing issues

Plex Media Server
,
1

Server Version#:1.43.3.10896
Player Version#:roku - latest and preview
The latest version - atmos - 7.1 downmixing ends with server not fast enough issues

same movies had no problems before, now most of them I can’t watch without trying to find a 2.0 mixdown in the file or 5.1, but even that has issues.. what about this release changed with how downmixes are handled… cpu usage is like 30-60% where before it would average 10-15%

2

It seems like this fix introduced the problem for me

  1. The TrueHD to EAC3 Transcoding Fix (Version 1.41.7)

If you track back slightly into the 1.41 cycle, Plex explicitly patch-fixed an aggressive audio bug. [1]

  • The Note: Fixes for playback failures specifically when transcoding TrueHD into EAC3.
  • The Impact: Prior to this patch, users on Roku and LG TV devices would experience complete stream crashes or continuous buffering when Plex tried to convert heavy TrueHD tracks into Dolby Digital Plus (EAC3). The hotfix restored proper transcoding functionality, but it forced a lot of users to realize that their setups were transcoding the audio in the first place
3

**This fixed it

  1. Clear the Server’s Corrupted Codec Cache (Most Successful Fix)**

Often, when Plex updates the transcoder logic, the old EAC3 encoder files stored in your server’s directory become corrupted or fail to update properly. [1]

  1. Shut down your Plex Media Server completely.
  2. Navigate to your Plex AppData directory (e.g., %LOCALAPPDATA%\Plex Media Server\ on Windows, or the shared app data path on Linux/Docker).
  3. Locate the folder named Codecs.
  4. Delete everything inside the Codecs folder. (Don’t worry, Plex will automatically download clean, updated versions of the encoders the next time you play a file).
  5. Restart your Plex Server and try streaming the file to your Roku again
4

Nope, fixed it on a couple movies, still an issue on others

5

Installed the latest beta, issue seems to be fixed in that release..

6

nope - still not working on some …

Testing the same set of movies, all w/ TrueHD 7.1 + Atmos, deleting the codec cache fixed one not the rest, upgrading to the beta, fixed another, but not all

what is it about these audio tracks and the new the changes around ffmegeg is so different from before.

also, doesn’t plex have a couple of rooms full of devices you test against before these releases… why do I keep on running into updates that break things SO consistantly