What does “Strength” do on Modify Video?

The "Strength" setting controls how closely the modified video adheres to the source material. 

a) Adhere —  The output adheres very closely to the source video. This is ideal for subtle enhancements, minor retexturing, or applying a light stylistic filter without drastically altering the original content.
b) Flex —  The output flexibly adheres somewhat to the shapes, characters, and details of the source video. This range allows for more significant stylistic changes while still maintaining recognizable elements from the original footage.

c) Reimagine —  The output adheres much more loosely to the source video. This setting is best for fundamentally changing the world and style to something entirely new, even transforming the characters or objects into completely different forms.