Changing a video’s speed opens up two effects from the same control. Slow it down and you get slow-motion, good for catching a moment that flies past at normal speed. Speed it up and you get a time-lapse, which compresses a long, slow event into a few quick seconds. Both come from setting a playback multiplier.
The short version: load the video, pick a speed, and download the re-timed clip. The video speed changer does it on your device, with the audio kept in sync and nothing uploaded.
Speeds below and above normal
The multiplier is the whole story. Normal speed is 1x. Anything lower slows the clip, anything higher speeds it up.
- 0.25x to 0.75x gives slow-motion, with 0.5x being a natural half-speed look.
- 1.5x to 2x is a gentle speed-up, handy for trimming dead time out of a talk without it feeling rushed.
- 4x to 8x is time-lapse territory, turning minutes into seconds.
Pick the effect you want and the tool sets both the picture and the audio to match.
What slowing down can and cannot do
Slow-motion looks best when the footage was shot at a high frame rate to begin with. Slowing a normal clip stretches the existing frames over more time, and because no new frames are invented, very low speeds can look a little choppy. For smooth slow-motion, start from the highest-frame-rate version you have, and avoid pushing standard footage below a quarter speed.
Speeding up has the opposite trait: it drops frames you do not miss, so a time-lapse from a long static shot tends to look clean even at high multipliers.
Keep the audio sensible
The sound is re-timed with the picture so the two stay in sync. Within a reasonable range the pitch is handled, so a 2x speech clip does not turn squeaky and a 0.5x one does not turn into a drone. At extreme speeds the audio will sound unusual no matter what, which is often fine for a time-lapse where you would drop or replace the sound anyway.
How to change a video’s speed
Step 1: Add your video
Drop in the clip you want to re-time.
Step 2: Set the speed
Pick a preset, from slow-motion below 1x to a fast time-lapse above it.
Step 3: Download the result
Apply the new speed, check the preview, and save the clip. Nothing was uploaded to get there.
The short version
To get slow-motion or a time-lapse, change the playback speed rather than reaching for a separate app. Go below 1x to slow the clip and above it to speed up, and the audio is re-timed to match. It all runs in your browser, so the file stays on your device and comes back without a watermark. To turn a long clip into a short time-lapse, trim the dead time first, then speed up what is left.
