Multi-track timeline
Video, audio, text and image tracks, trimming, splitting, stacking and frame-accurate navigation.
Speed ramps, slow motion and timelapse
Change speed across a single clip instead of switching between two of them. Clip Smasher's ramp lane runs from 0.05x to 8x, eases in and out, and rewrites the clip's length on the timeline as you drag.
What a speed ramp is
A plain speed change is one number for the whole clip: this shot plays at half speed. A speed ramp changes speed during the shot: normal speed, easing down into slow motion, holding there, then easing back up. The audience reads it as the moment slowing down rather than as an effect being switched on.
It is the transition most often used to land on an action: the board leaves the ground at normal speed, the trick happens at a fifth of it, and the landing is back at normal.
How the ramp lane works
A ramp in Clip Smasher is four keyframes in a lane under the clip, and the shape is always the same: start at normal speed, arrive at the speed you asked for, hold, return to normal.
The three things you set
- Where. Dragging the outer keyframes moves the start and end of the whole ramp along the clip.
- Speed. One slider, reading out as a multiplier (
0.20x,2.00x, and so on) across the full 0.05x to 8x range. - Ease. How long the acceleration takes at each end. A short ease snaps into the new speed; a long one glides into it. The two ends are set separately, so you can drop into slow motion hard and drift back out.
Why the clip changes length
Playing a second of footage at a fifth speed produces five seconds of video, so the clip's bar on the timeline grows to match. This is not a side effect to work around: the timeline shows the running time of the finished piece, so the length of the bar is always the length of the result. Speed a clip up and it shortens.
The consequence worth knowing is that the ramp is what sets the clip's duration, so build the ramp first and cut around it afterwards.
Building one, step by step
Put the clip on the timeline and find the moment
Scrub the ruler until the playhead is on the frame where the interesting thing starts. Use the chevrons under the preview to land on it exactly.
Open the ramp lane
Hold the clip and let go without moving it. Its menu opens; pick Speed ramp. A lane appears under the clip with the four keyframes on it.
Ramps are video-only, so this entry does not appear on an audio clip.
Drag the outer keyframes to bracket the action
Put the ramp start slightly before the moment and the ramp end slightly after it. The preview follows the keyframe you are dragging, so you are looking at the frame you are setting.
Set the speed
Tap a keyframe to open its controls and drag the Speed slider. Around
0.20xis a convincing slow motion; below that starts to look like a freeze unless the source was shot at a high frame rate.Set the ease at each end
The Ease slider decides how much of the ramp is spent accelerating. Long eases suit gentle moves; for an impact, use a short ease going in and a longer one coming out.
Nudge to the frame
The keyframe controls have frame nudge buttons. Use them for the last few frames rather than dragging, with the preview showing you exactly where the ramp begins.
Cut around the new length
The clip is now longer or shorter than it was. Trim the surrounding clips, and if you have music, check the beat still lands where you wanted it.
Plain speed changes, without a ramp
Not everything needs a ramp. A whole clip at one speed is a normal slow motion or timelapse, and that one you can simply ask for:
- put clipA.mp4 in slow motion
- speed up clipA.mp4 by 2x
- make it a timelapse
- speed everything up by 1.5x
- put clipA.mp4 back to normal speed
Typed instructions cover fixed speed changes across a clip or across the whole timeline. How natural-language editing works. Building a ramp inside a clip is a timeline job, done by dragging the keyframes in the ramp lane.
Getting a slow motion that holds up
- Shoot high frame rate if you can. Slowing 60fps or 120fps footage gives real frames to play back. Slowing 30fps footage a long way has nothing extra to show.
- Ramp on movement, not on a static shot. The effect is only visible where something is moving fast enough for the change of rate to read.
- Mind the audio. Ramps are video-only. Unlink the audio if you want the sound to run at normal speed under a slowed picture. That is usually what you want, since slowed dialogue rarely helps.
- Ramp, then cut. Splitting a clip that already has a ramp is not allowed; remove the ramp, split, and re-ramp the piece you meant.
Speed and slow motion questions
What is a speed ramp?
A speed ramp is a speed change that happens gradually inside one clip rather than switching between two fixed speeds. The shot eases from normal speed into slow motion, holds there, and eases back out, so the change reads as part of the movement rather than as an edit.
How slow and how fast can Clip Smasher go?
Playback runs from 0.05x to 8x. At the slow end a second of footage stretches to twenty seconds of timeline; at the fast end twenty seconds compress into two and a half.
Does changing the speed change the clip's length on the timeline?
Yes, and that is the point. Speeding a clip up shortens the bar it occupies and slowing it down lengthens it, so what you see on the timeline is the running time of the finished video rather than the length of the source file. The app recalculates the clip's length as you drag the speed.
Can I put a speed ramp on audio?
No. Ramps are video-only. If a clip has linked audio, unlink it first if you need the sound to keep running at normal speed underneath.
Can I split a clip that has a speed ramp?
Not while the ramp is on it. Remove the speed ramp, split the clip, and apply ramps to the pieces. The app tells you this in the clip menu rather than letting you make a cut it would then have to interpret.
Can I ask for a speed change in words?
You can ask for a speed change, such as “put clipA.mp4 in slow motion”, “speed everything up by 1.5x” or “make it a timelapse”. Building a ramp inside a clip is done on the timeline, by dragging the keyframes in the ramp lane.
Read next
Video effects
Every colour, blur, texture and transform effect in the app, and which of them keyframe.
Natural-language editing
Type or dictate an editing instruction and Clip Smasher carries it out on your own footage.
Ramp your own footage
Clip Smasher is free to download for iPhone and Android, and speed ramps are in the free version.
Free to download · iPhone and Android · No account · Works offline