Speed up or slow down videos online

Speeding up or slowing down videos, simply explained

The tool re-encodes the clip at the speed you chose: the picture plays faster or slower, and the sound is stretched to match while keeping its pitch — a voice at 2× sounds fast but not high-pitched, and at 0.5× slow but not deep. Only the first audio track is kept, subtitles are not carried over, and chapters are dropped, while the clip's general file information — such as a title or location, where the file has any — is kept. The picture is re-encoded at the same quality as a conversion, with odd dimensions rounded down to even numbers, so the sped-up or slowed-down clip plays everywhere. A clip without sound speeds up or slows down the same way, with no audio track added. WebM runs accept mono sound only, since the sound is always re-encoded — save a clip with stereo or surround sound as MP4; a silent clip saves as WebM fine. The result is named after the original clip, with the speed added, like -2x or -0.5x. Everything runs on your device, which keeps your videos private but means speed depends on your device — short clips finish quickly, while long videos can take a very long time, so this tool is best for short clips.