anytools

Video tools

Change video speed

Speed a video up or down by rescaling the timestamp on every packet. A packet-level copy, no decoding, so this runs in Node, the CLI and MCP as well as the browser. Audio speeds up with the video and its pitch shifts along with it, the same trade-off most simple speed-change tools make; correcting pitch back to normal needs decoding and resampling the audio, which this tool deliberately does not do.

Runs on your device. The file is never uploaded.

Change video speed divides every packet timestamp and duration by a factor you set, 1.5 by default, and writes MP4 with a -speed.mp4 ending. Above 1 shortens the clip, below 1 stretches it. A factor of 1 exactly is turned away, and audio rides the same rescale, so voices change pitch.

Input

Options

Questions

How does it speed the video up?

By rescaling every packet timestamp and duration, not by dropping or generating frames. A factor of 2 divides each timestamp by two, so the same frames play in half the time. Nothing is decoded or re-encoded, so the picture quality is untouched and the tool runs in Node, on the command line and through MCP as well as in the browser.

Does the audio go squeaky?

Yes. Audio is rescaled with the video, so its pitch shifts along with the speed, the same trade-off most simple speed tools make. Correcting the pitch back to normal would need the audio decoded, resampled and re-encoded, which this tool deliberately does not do. Mute the video first if the chipmunk effect is a problem.

What values can factor take?

Any positive number, entered as text, with 1.5 as the default. Above 1 is faster and shorter, below 1 is slower and longer. A factor of exactly 1 is refused with "factor of 1 would leave the video unchanged" rather than writing a pointless copy, and a zero or negative value gets "factor must be a positive number".

What comes out?

Always an MP4, named after your input with -speed.mp4 on the end, whatever container went in. Audio is included and rescaled when the source has an audio track. Rotation metadata from the source video track is carried across, so a sideways recording stays upright.

Why does it say no video track found?

Because the file has no readable video track. This tool works on video containers. For an audio only file, use Trim or merge audio, though note that tool changes duration by cutting rather than by rescaling speed. Video and audio are rescaled by the same factor, so a file that opens correctly keeps its tracks in step.

Is my file uploaded?

No. Everything happens on your device, in memory. Nothing is sent to a server, there are no accounts, and the page keeps working offline after the first visit. Both the source and the new file are held in memory at once, so a long recording can still be limited by your device rather than by any rule in the tool.

Related Video tools

n→nConvert videoChange videos between MP4 and WebM, in the browser only. It encodes with WebCodecs, which Node has no equivalent of, so the CLI and MCP surfaces refuse it.Runs on each file you dropn→nCompress videoShrink a video by re-encoding it at a lower quality, in the browser only, like video-convert (src/tools/video-convert.ts), because mediabunny encodes through WebCodecs, which Node has no equivalent of. Always outputs MP4.Runs on each file you dropn→nTrim / cut videoCut a video down to a start-to-end range without decoding a single frame. Packets are copied straight from the source into a new MP4, so this runs in Node, the CLI and MCP as well as the browser. The cut snaps back to the nearest keyframe before the start you asked for, the same trade-off ffmpeg -c copy makes.Runs on each file you dropn→1Merge videosConcatenate two or more videos, one after another, into a single MP4. A packet-level copy with no decoding, so this runs in Node, the CLI and MCP as well. Every input must share the same video codec (and audio codec, if present); mixed-codec inputs need re-encoding first, which this tool deliberately does not do.Combines the files you dropn→nResize / crop videoResize and/or crop a video, in the browser only, like video-convert (src/tools/video-convert.ts), because mediabunny decodes and re-encodes through WebCodecs, which Node has no equivalent of. Always outputs MP4.Runs on each file you dropn→nRotate videoRotate a video by a multiple of 90° by writing rotation metadata into the container, the same trick phones use for orientation, rather than re-encoding every frame. A packet-level copy, no decoding, so this runs in Node, the CLI and MCP as well as the browser. Most players honour this metadata; a player that ignores it will show the original orientation.Runs on each file you drop