How does Jellyfin live transcoding?

[TheDreadPirate]

The transcode files stay in the transcode directory until the client that requested the transcode ends their playback session. At which point Jellyfin immediately cleans up just the transcode files associated with that session.

If Jellyfin happens to crash hard, there is a job in the Scheduled Tasks dashboard that will clean up the transcode directory of any files older than 24 hours. This job runs on startup and every 24 hours after.

As for the "best" specs, it depends on your budget and needs. And whether it will be a dedicated server or mixed use. A lot of people run Jellyfin on their gaming PC. In that situation, I'd recommend an Nvidia GPU for transcoding. For a dedicated server, I'd recommend an Intel dedicated GPU or Intel CPU with an iGPU (this excludes most Xeons and F SKU desktop chips).