Add bloom to a clip: lights, reflections, and bright skin spread a soft halo into their surroundings, the way they do through a diffusion filter or a slightly dirty lens.
Threshold, radius, and strength
Threshold picks the light sources. Radius sets how far the light spreads, and Strength how much is added back. Small radius with high strength gives a tight halo around each light; large radius with low strength gives a wide, soft wash.
Glow in motion
The glow is computed from each frame, so moving lights carry their halo with them. Night footage, concerts, and backlit shots bloom well. Bright daylight scenes pass the threshold almost everywhere and wash out; raise Threshold toward 60% for those.
For a softer, lens-like veil that also lifts the shadows, use the black mist video filter.