How do I blend/average N amount of frames as opposed to only 2?
Solution 1:
You can use the tmix filter, available since ffmpeg v4.1
Basic syntax is
tmix=frames=5:weights="1 1 1 1 1",select='not(mod(n\,5))'
The tmix blends each frame with 4 following frames. The select filter then keeps only the first out of every 5 frames.
See docs.