This could be a big step toward ultra low latency streaming with an rpi.

I tried to do this (low latency streaming) circa 2016 and ran into two issues, one of which was the high framerate or subframe capture and the other was subframe encoding.

With high framerate capture you can fake the subframe capture by capturing a whole frame and encoding just a subset.

Now to get the h264 drivers to do subframe encoding…