What Is a Speed Ramp?
A speed ramp changes the speed of the action inside one shot. The action builds in real time, slows at its most important moment, and then returns to real time. The contrast between the speeds is what gives the peak its weight.
In this Short the ramp is directed through the prompt, so the speed changes have to be described, not applied afterwards in an editor.
Define the Phases, Hold the Peak, Snap Back
The directing principle is to script distinct phases around the action peak. If the whole clip is slowed down, the contrast disappears. Describe the build-up, the held peak, and the clean return as separate parts of the prompt.
In the selected output for this Short, a martial artist travels sideways into an extended kick. The airborne moment is held for several seconds, and the landing returns to real-time speed. The review of the vertical crop also noted the action reads larger on mobile, with the face and kicking foot readable.
For another way of stretching a moment, see the Bullet Time Short.
Example Directing Pattern for a Speed Ramp
This is an example directing pattern, not the exact production prompt.
Continuous tracking shot following [subject].
Phase 1, real time: [subject] [build-up action].
Phase 2, extreme slow motion: at the peak of [action], time slows dramatically while [detail to hold].
Phase 3, snap back: speed returns to real time as [subject] [resolving action].Giving each phase its own line, ideally with approximate timing, keeps the three speeds from blurring together.
Quality Checks for Speed Ramp Generations
- Phase Contrast: The held peak should look clearly slower than the real-time action before and after it.
- Peak Placement: At normal speed, check that the slowdown lands on the intended action and not on the build-up.
- Clean Return: Check that the snap back to real time is clear and that the subject does not drift between phases.
Part of the AI Cinematic Effects playlist.
