Optional
Maximum concurrent jobs. Defaults to 1.
One is the right default for an encode queue: a single ffmpeg already saturates the machine it runs on, so serialising is faster than thrashing.
Refuse a job once this many are waiting. Defaults to unbounded.
Back-pressure as a number: with a queue that accepts work forever, an overloaded service converts a slowdown into an out-of-memory crash.
Maximum concurrent jobs. Defaults to 1.
One is the right default for an encode queue: a single ffmpeg already saturates the machine it runs on, so serialising is faster than thrashing.