When AI subtitles are made, and Start now

On the Subtitles screen, under Make subtitles with AI, choose When to make subtitles:

• When the computer is quiet (the first choice): only while nobody is watching anything on Jellyfin and, on a PC or Mac, nobody has used the keyboard or mouse for the minutes you chose. In Docker there's no keyboard, so only playback counts.
• Anytime, at low priority: for a server that's never quiet. Reelhost doesn't wait: it makes one video at a time at the lowest processor and disk priority, so everything else comes first. It still pauses while Jellyfin is converting (transcoding) a video for someone, and while a laptop runs on battery, so playback never stutters. Someone watching a video as it is, without converting, doesn't make it pause.
• Use at most half of the processor: slower, but leaves more room for everything else.

When it's waiting, the screen says why, for example "Waiting for a quiet moment: Jellyfin is playing on 2 devices."

Start now runs the queue straight away at the lowest priority, quiet or not, until every video is done (it still pauses for a conversion or battery). Pause stops it. On Windows the task runs while you're signed in; on a Mac its LaunchAgent; in Docker the server's own loop, which notices within 20 seconds. Both choices and Start now also work from your phone.

Whatever you choose, a video someone starts playing without subtitles in their language goes first, made from where they are.