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Speed change

Change speed

Pick a rate between half and double speed. Audio stays in sync.

Runs in your browser. Media is processed with FFmpeg WASM in this tab — nothing is uploaded to BrowserSpaces. The engine preloads in the background while you set up the tool.

0.5–2×

Practical browser range.

Audio sync

atempo + setpts.

MP4 out

H.264 + AAC.

Use the tool

Range 0.5×–2×. Audio uses atempo when a track is present.

How it works

How speed change works

Video timestamps scale with setpts; audio uses atempo within FFmpeg’s 0.5–2 window.

Three steps

  1. 1

    Load clip

    Keep length reasonable.

  2. 2

    Set rate

    Slider 0.5–2.

  3. 3

    Export

    Download sped clip.