I use FFMPEG as a thermostat to keep my apartment nice and warm :) I encode all of my videos (phone, DSLR, dash cameras) to h265 on my Ryzen workstation when it's not use. I have a primitive "PID-controller" script pulling temperatures from influxdb (data collected using a few esp8266 with ds18b20 sensors) and adjusting -threads parameter accordingly. It automatically adjusts presets (slow, veryslow, placebo, etc) depending on number of videos in the queue, so it never runs out of material to encode :) It saves me from using stinky baseboard heaters and reduces my HDD bills!