Change the speed of a video: slow motion or fast forward

Overview

Pick a video and choose a speed: 0.25×, 0.5× or 0.75× to slow it down, 1.5×, 2×, 3× or 4× to speed it up. Then choose how the frames should be made. Sharp drops or repeats frames, which keeps every frame crisp and suits footage with little motion. Smooth blends neighbouring frames, which gives slow motion a softer, more fluid look at the cost of some sharpness in fast movement.

Sound is handled separately. Keep it, and iEdit stretches the audio to the new speed while holding its original pitch, so voices stay recognisable at 2× or 0.5×. Or mute it and add music later in the video editor. The video is re-encoded with the phone's hardware encoder in H.264 or HEVC; location, device and date metadata are kept, and HDR footage is saved as SDR. The job runs in the background and a notification tells you when it is finished.

Speed is the quickest way to turn a long process into a watchable clip: a 4× sunset, a 2× walk-through of a flat, a 0.25× look at a golf swing or a dog catching a ball. Because the tool runs on your device, it works wherever you are and nothing is uploaded; the result lands in My files, and the original is left as it was.