Flashing Light Effect
This effect adds a flashing color to your clips. Set the Color, Blend Mode, and Speed.
Modify with Wave Shape and Phase.
Wave Shape provides Sine, Square, Sawtooth and Triangle wave forms that drive the opacity of the light color.
Phase allows you to add more than one Flashing Light effect to a clip and synchronize the flashing into alternating flashes.
Use 3.1416 to offset alternating flashes for two Flashing Light effects.
Use the built in Effects Masks to limit the areas where the color flashes in your clip. In general, Shape Masks are recommended, however, the Color Mask can also be used to great effect.