How to change a video's speed and keep the pitch

Use the speed filter in Cut by Zaweba. It changes a video's speed anywhere from 0.25 times (four times slower) to 4 times faster, and the sound keeps its pitch, so a sped up voice doesn't turn into a squeak and a slowed down one doesn't become a growl. Set the speed in the Filters tab, then save through a preset.

Cut is free software under the EULA, works offline and needs no account.

Why pitch matters

Play a recording faster in the simplest way and every sound rises in pitch along with it, which is where the cartoon chipmunk effect comes from. Slow it down and voices drop and drag. Keeping the pitch means the speed changes but voices and music stay in their natural key. It's the difference between a quick tour of a house that sounds like the person who filmed it and one that sounds like a toy.

Setting the speed

Open the video in Cut by dragging it onto the window or using Open. If only part of the clip should be included, mark in with I and out with O, or mark the parts you don't want and press Delete. Every kept part shows on the scrub bar, and undo and redo work if you change your mind.

Go to the Filters tab and set the speed. Above 1 speeds the video up; below 1 slows it down. Two times is a good start for a long job you want to show briefly. Half speed is plenty for picking out a moment, and 0.25 times suits something very quick, like a splash or a ball leaving a bat.

Then open the Convert tab and pick what the video is for. For WhatsApp, For YouTube 1080p, Small file and Best quality are all there, along with For email, which works to stay under 25 MB. Before you start, Cut shows the estimated size and which encoder it will use. Only the kept parts are converted, in one frame-exact pass, with the speed change applied.

Choosing a speed

Speeding up suits the long and steady: assembling furniture, painting a fence, a drive along a coast road, a cake rising in the oven. At 4 times, ten minutes becomes two and a half. If that's still too long, trim the duller stretches first and speed up what remains.

Slowing down suits the short and sudden: a dive, a goal, a dog catching a ball, a child blowing out candles. A slow clip only looks smooth when there were enough frames to begin with, so footage shot at a high frame rate slows down more gracefully than ordinary video. The Details tab tells you the frame rate of the clip you have.

Making speed changes look natural

Keep the slow part short. Slow motion is striking for a few seconds and tiring after that. Mark tightly around the moment and let the rest go.

Listen through before you send it. Pitch is kept, but speech at 4 times speed is still very fast and hard to follow. For a fast clip with talking in it, a lower speed such as 1.5 or 2 often works better, or remove the sound and let the picture tell the story.

Add a fade. A fast clip that stops dead feels unfinished, and a short fade in and out on picture and sound, from the same Filters tab, rounds it off nicely.

Doing it for several clips

If you have a batch of clips that all want the same speed, set the filter once and add the files from the Batch tab. The current filters are applied to every file, the jobs run in the background with progress bars, and the queue carries on even if the PC restarts. On a modest computer Cut's low-spec mode takes care of itself, running one job at a time so the machine stays usable.

Changing speed is one of the jobs that usually sends people looking for a big editor. In Cut by Zaweba it's a single setting.