Plex “Transcoder stopped / conversion failed” when using hardware transcoding (GTX 1080 Ti, Ubuntu 2

Plex Media Server Desktops & Laptops
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1

Server Version#: 1.43.0.10492
Player Version#: NA (all Plex players give same issue)

Hi everyone,

I’m running into a recurring “Playback error: conversion failed. The transcoder failed due to an error” issue when hardware transcoding is enabled. I’m hoping someone has seen something similar.

System Information

  • OS: Ubuntu 24.04.3 LTS (noble)

  • GPU: NVIDIA GeForce GTX 1080 Ti (Pascal)

  • NVIDIA Driver: 535.274.02 (Ubuntu recommended driver)

  • CUDA Version: 12.6

The Problem

When hardware transcoding is enabled:

  • Certain episodes fail to play on all Plex player apps (browser, TV-apps, Apple TV, mobile,…)

  • Error shown:

    “Playback error: conversion failed. The transcoder failed due to an error.”

  • In the logs, the Plex Transcoder process gets killed (signal 9).

If I disable hardware transcoding, everything works fine using software transcoding.

Important Detail

If I restart the server (or reboot the machine), the issue mostly disappears and hardware transcoding works again for a while.

However, after some time (mostly days, sometimes hours), the problem returns and hardware transcoding starts failing again until I reboot.

So it feels like something becomes unstable over time rather than being broken immediately.

Observations

  • NVDEC/NVENC starts correctly.

  • GPU usage looks normal in nvidia-smi.

  • The transcoder runs briefly and then gets killed.

  • Logs mention “Client stopped playback.”

  • Exit code shows signal 9 (Killed).

My Questions

  1. Is anyone else experiencing similar hardware transcoding instability (on Ubuntu 24.04 with NVIDIA drivers and Pascal GPUs)?

  2. What is the proper way to permanently solve this without having to reboot the server every time it starts happening?

I’d like to keep hardware transcoding enabled for performance reasons, but I need it to remain stable long-term.

Otherwise, I’m in doubt about buying a new Mac Mini to launch as a Plex server. Is that a good solution in terms of maintenance (not a real Linux guy) and stability/performance?

Any insights, similar experiences, or known fixes would be greatly appreciated.

Thanks in advance!

2

I’m experiencing experiencing similar hardware transcoding instability, but on MacOS (Server Version#: 1.43.0.10492). I’ve disabled hardware transcoding for now.

If I had to make a guess, I’d say it’s FFMPEG 6.1 introduced in 1.43.x.