I was going to run some Compressor tests (part of Final Cut Pro, Compressor 4.1.1), but it has several bugs including the one shown below.
It runs reliably as long as I don’t try to enable multiple instances , otherwise it likes to fail as shown, or stall/wait. Also, quitting it leaves orphaned daemons around still computing heavily. Multiple reboots show that it sometimes works and sometimes does not (several successful runs with multiple instances enabled). This is on the 2013 Mac Pro, a fresh install. But between the flaky behavior and mdworker kicking in while testing, I’ll likely defer any efforts around Compressor.
As an FYI/context, shown below is a 4K video clip set up for batch processing a 4K video clip to 1080P.