--threads
Usage: --threads <integer>
Parralell encoding using slices. If you have a multi CPU or multi core
CPU, this will allow you a speed gain. Due to how threading and video
coding works, using threads will lead to a very slight degredation of
quality, but with the extra speed you gain you can just crank up the
settings a bit and offset your loss and still have a speed gain. You
use 1 thread for each CPU and/or core, so for dual core it would be
--threads 2, or for a dual core dual CPU it would be --threads 4.
