TLDR: Explain how the V4L2 M2M API works through the use-case of implementing hardware video encoding on the Raspberry Pi. This knowledge is generally useful as V4L2 is the de-facto generic API for hardware decoding and encoding on Linux. Background My journey started at this video on the excellent Craft Computing YouTube channel which showed how to setup TinyPilot, a Python app for KVM over IP which runs on a Raspberry Pi. Behind the scenes, TinyPilot uses ustreamer to read frames from a HDMI c...