Slow down part of a video
Mark the part that matters and say how long it should take, or draw a curve and let the clip ease into slow motion and back out again.
- Free
- Runs on your device
- No account
- No limits
One file at a time. The video is edited on your own device, so nothing is uploaded and there's no size limit beyond what your browser can hold.
How to slow down part of a video
- Drop a video in the box above. MP4, MOV, WebM, MKV and AVI all work.
- Pick section and length to mark one part and give it a running time, or speed curve to draw the pace across the whole clip.
- Drag the marks or the curve until the preview reads right, then download. The file keeps its name, with -slowed added.
- The first video also fetches the video engine, about 7MB, which your browser then keeps. After that it starts straight away.
About slowing part of a video down here
The other speed page changes the pace of the whole clip. This one changes a section of it and leaves the rest alone, which is what you want when the thing worth looking at is four seconds in the middle of a two minute recording. Say how long the section should take rather than how many times slower it should go, since a length is usually what you actually know.
The frames aren't repeated to fill the new running time. A section stretched fourteen times over holds exactly the frames it always did, spread out, so it steps rather than glides. That's what slowing footage down looks like unless it was shot at a high frame rate to begin with, and inventing the frames in between would mean encoding fourteen times as many of them for a picture that changes at the same moments anyway.
The sound is stretched along with the picture so it stays in step. A gentle slowdown still sounds like a voice, and a large one sounds like a large one. If the result is unusable, the mute page drops the track entirely and copies the picture untouched.
The speed curve is the other way in. Instead of one section at one pace it takes a graph of how fast the clip runs at each moment, so the footage can ease down into slow motion, hold there, and ease back to its own speed. Everything between two points on the curve is eased rather than switched, which is the difference between a ramp that looks deliberate and one that looks like a dropped frame. The preview plays the curve as you drag it, so you can see the shape before spending a single second encoding.
This edit changes the picture, so every frame has to be decoded and encoded again. Your own machine does that work, which is what keeps the file off anybody's server, and it's why a long clip takes longer than a short one. Trimming and removing the sound are the two things here that skip it entirely.
Common questions
Is the slow down part of a video free?
Yes, properly free. No paid tier, no trial, no watermark on the result and nothing to sign up for. Put as many files through it as you like, as often as you like.
Are my files uploaded to a server?
No. The slow down part of a video runs inside your browser, on your own machine, so your files never go anywhere. Big ones are fine too, up to whatever your browser can hold.
How do I slow down only one part of a video?
Mark where the section starts and stops, then say how long it should take. Everything before and after it is kept at its original pace and joined back on, so you get one file rather than three pieces to stitch together yourself. A two minute clip with ten seconds stretched to sixty comes out two minutes and fifty seconds long.
Why does heavily slowed footage look jerky?
Because the camera only recorded so many pictures a second, and slowing the clip down spreads those same pictures over more time rather than finding new ones. At fourteen times slower each frame is held for about half a second. Footage shot at 120 or 240 frames a second has the extra pictures already and slows down smoothly, which is what a phone's slow motion mode is doing.
How do I make a video get slower and then speed back up?
Switch to the speed curve and drag the line down where you want the slow part and back up where you want it to end. The curve eases between the points you place rather than jumping between them, so the clip slides into slow motion, holds as long as the line stays flat, and slides back out to its own pace. There are buttons for the usual shapes if you would rather not draw one.