Another crazy idia, somehow capture frames rgb24 format and convert to yv12 format, make video from this frames and stream to lan computer.
This operation must be even less cpu usage then x264 ultrafast.
For 720p60fps need 79 megabytes per second(1000mbit network card is cheap)
For 1080p60fps need 177 megabytes per second, one adapter not enough. Maybe use two adapters, send even frames to first adapter, send uneven frames to second then show it in right order.
It's just crazy idia and sure have many problems to make it work properly.
Quick Sync compare to capture cards have 12bit color space vs 24bit (i guesse) for capture cards.
Don't know if it make any difference, x264 in most cases also have 12bit color space ?