Create smooth speed ramps with custom speed curves.
Speed is a curve, not a switch. Place points on a clip, ease from 1x to 2x to 0.5x and back to 1x, and keep the change continuous instead of a hard step.
Cubix interpolates between curve points. It does not use optical flow inside the ramp.
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Speed curve
What is a speed ramp?
A speed ramp changes playback rate over time inside one clip: faster through setup, slower through the moment that matters, then back to normal. A constant speed change sets one rate for the whole clip. A speed curve sets several rates and interpolates between them.
Speed is a curve, not a switch.
Typing 200% gives you a step. The join between 1x and 2x is visible because nothing eases. A ramp is the graph between those rates — which is why the same clip can rush in, hold, and settle without cutting.
- 0:001x
- 0:042x
- 0:080.5x
- 0:121x
What a Cubix speed ramp can do
- 01
Custom speed curve
Add, move, and ease points on a graph. Playback interpolates between them instead of jumping.
Points + easing
- 02
Constant rate when you need it
A single playback rate still exists. The UI clamps that rate between 0.1x and 16x.
0.1x–16x
- 03
Velocity presets
Start from Montage, Hero, Bullet, Flash In, Flash Out, Pulse, Heartbeat, or Whip, then edit the curve.
Hero · Bullet · Whip
- 04
Intensity on presets
Subtle, Standard, or Extreme scales how far a velocity preset pushes.
Subtle / Extreme
- 05
Audio follows time, pitch held on export
Export time-stretches audio along the curve and preserves pitch. Preview follows the clip’s playback rate. Mute the clip separately when you don’t want its original audio.
Pitch held
- 06
Slow motion without optical flow
Ramps do not generate in-between frames with optical flow. Slow sections hold source frames, capped so the freeze does not run away.
No optical flow
How to create a speed ramp
- 1
Select the clip
A ramp lives inside one shot. If only part of the take should change speed, you are still editing that clip’s curve — not a second timeline.
- 2
Open Speed and choose Curve
Start from a velocity preset if the shape is close, or build a custom curve. Intensity on a preset is Subtle, Standard, or Extreme.
- 3
Place the rates
A typical ramp is 1x → faster → slower on the action → 1x. Drag points; easing is linear, ease in/out, smooth, or step.
- 4
Preview the audio
Picture duration changes with the curve. On export, pitch is held rather than chipmunked. Preview uses the playback rate. Mute the clip separately when you don’t want its original audio.
Speed curve controls
The graph is the feature. Presets are starting shapes. Optical flow lives on a separate Smooth slow-mo path, not inside this ramp.
Shape
A starting velocity preset.
Intensity
How far a preset pushes.
Easing
How the curve interpolates between points.
On the curve
- 0.1x–16x rate range
- Add and move points
- Linear / ease / smooth
- Pitch-preserving export
Want speed hits placed on the music? → Open Make it a Banger
Speed ramp vs a constant speed change
Constant speed
“The whole clip is 2x, or it is 0.5x.”
- One playback rate
- A visible step if you cut between rates
- Useful for a process shot that should stay fast
Speed ramp
“1x → 2x → 0.5x → 1x on one clip.”
- Several rates on a curve
- Continuous interpolation between points
- Presets for common velocity shapes
- Pitch-preserving time-stretch on export
Where a ramp earns its place
Product demos
Rush the setup, slow the click that matters, return to 1x for the explanation.
Shorts & Reels
A brief slow on the action, then out. Pair with Beat Edit when the ramp should land on a hit.
You draw the pace. Cubix interpolates it.
No optical-flow frames are invented inside the ramp. Slow motion holds source frames. Export holds pitch.
Cubix provides
- A speed curve with continuous interpolation
- Velocity presets and Subtle / Standard / Extreme
- 0.1x–16x for a constant rate
- Pitch-preserving time-stretch on export
You decide
- Where the clip should be fast or slow
- How many points the curve needs
- Which easing sits between those points
- Whether to keep the original soundtrack — mute the clip separately if not
Speed ramp FAQs
A speed ramp is a playback-rate change over time inside one clip. You set several speeds on a curve and the editor interpolates between them, instead of switching the whole clip to one rate.
Constant speed is one number for the clip — 2x the whole way. A ramp is 1x, then 2x, then 0.5x, then 1x, with easing between those points. The ramp is for emphasis. The constant change is for retiming a whole take.
Yes. Points are interpolated with the selected easing, so speed changes along the clip rather than jumping from one keyframe to the next.
A constant playback rate can go from 0.1x to 16x. Curve editing uses that same neighborhood of slow-to-fast. Extreme slow motion still depends on the source frame rate.
No. The ramp does not generate optical-flow in-betweens. Slow sections hold source frames. Smooth slow-mo / interpolation is a separate panel, not this curve.
On export, audio is time-stretched along the curve with pitch preserved, so a voice does not rise and fall with the picture. Preview follows the clip’s playback rate. Mute the clip separately when you don’t want its original audio.
Yes. The curve belongs to the clip. Hold 1x on either side of the action and only move the middle points.
Montage, Hero, Bullet, Flash In, Flash Out, Pulse, Heartbeat, and Whip are starting curves. Intensity scales them. You can still edit the result.
Below the source frame rate you are watching held frames. It is usable on simple motion and less so on fast hands or hair. Shoot higher frame rate when you know you will slow the shot.
Make it a Banger is a whole-edit energy pass that can include speed hits. Speed Ramps is the manual curve on a clip when you want that 1x → 2x → 0.5x shape yourself.
Want zooms timed the same way, as a motion curve? Open Zoom Curves
Rush the setup.Slow the moment. Return to 1x.
Draw the curve, keep every point editable, and mute the clip separately if you don’t want its original audio.
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