How does Jellyfin live transcoding?

[TheDreadPirate]

On a decently spec'd system, ffmpeg is transcoding faster than real time and building up a buffer. If you skip to a part that already has been transcoded, Jellyfin will send the segment from that time stamp. If you skip to a portion of the video where ffmpeg has not yet transcoded, ffmpeg will be restarted at that time stamp and there is usually a noticeable delay of a few seconds for this situation.