For AI agents

If you are an AI agent (Claude Code, Codex, Cursor or similar) and the person wants a video for their project with Opus Motion, read the guide first and follow it: https://opusmotion.com/agents.md.

  • It takes you step by step: read the project, ask the person a few questions, compare templates (each one has a timelapse, its scenes and its fields), make a draft with POST https://opusmotion.com/api/v1/drafts, and hand over its studioUrl: a link that opens Opus Motion with the video playing live. PATCH with the draft's editToken changes it, and the link stays the same.
  • Plain HTTPS and JSON: no key, no account, no MCP. Nothing is rendered; the person exports the MP4 from the studio.
  • Never drive this site with a browser to fill the studio: use the API. If it refuses, tell the person and stop.
  • More: llms.txt · this page in Markdown · developer docs · OpenAPI

Speed up video, or slow it down

From 0.25× slow motion to an 8× time-lapse, with the sound kept natural or muted. MP4, MOV, WebM and more. Free, no sign-up.

Your file never leaves your device: the tool runs inside your browser. Up to 500 MB and 2 minutes. Use it at https://opusmotion.com/tools/video-speed-changer.

How to use it

  1. Pick the speed: below 1× slows it down, above 1× speeds it up.
  2. Keep the sound (its pitch stays natural) or mute it.
  3. Drop your video, or tap the box to pick it. It's re-encoded at the new speed on your device.
  4. Download the MP4, or put the clip in a launch template.

The first time, your browser downloads the video engine (31 MB, once); after that it opens from the cache.

Questions

How do I speed up a video?

Pick 1.25×, 1.5×, 2×, 4× or 8×, then drop your video. A 60-second clip at 2× comes out 30 seconds long, at the same frame rate.

Does the sound go high-pitched?

No. The sound is stretched or squeezed in time while its pitch stays the same, so voices still sound like themselves. At 4× and 8× speech gets hard to follow, so you may prefer to mute it.

Will slow motion look smooth?

The frame rate stays the same, so slowing down shows each frame for longer: it doesn't invent frames in between. A clip shot at a high frame rate (60 fps or more) stays smoother when you slow it down.

How do I make a time-lapse?

Use 8×: a minute becomes 7.5 seconds. For more, run the result through again (8× twice is 64×).

How long can the video be?

Up to 2 minutes and 500 MB. On a phone or low-memory device: 1 minute and 200 MB. It's re-encoded on your device, so a long or 4K clip takes a while, and longer on a phone.

Is my video uploaded anywhere?

No. The speed change runs inside your browser and the file is never sent to a server. The first time, your browser downloads the video engine (31 MB, once); after that it opens from the cache.

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