Are you familiar with avisynth and what it can do? I'm dealing with 10-bit HDR video here. It's not as simple as throwing it in mencoder or ffmpeg. Regardless, wine and an install of avisynth IS the easiest route to serve frames to an encoder. There are other avisynth-like things for Linux, but it's not worth my time, and I doubt they deal with higher bit depths well.
Comment on Re^4: figuring out Parallel::ForkManager slots
Anyway, I have fixed the stupid mistake in the example earlier, so it should at least run now, if I read the Parallel::ForkManager documentation correctly.