Video Speed Changer & Pitch Shifter by Lacuna

Change the speed and the pitch of any video or audio in your browser — independently.
Slow a solo down to 0.25× without it dropping an octave, transpose a backing track up 3 semitones without it speeding up, or push a lecture to 2× and still understand it.

Works on the media playing in your tab, and on local files you drop in.

WHAT YOU GET
• Speed from 0.125× to 8×, pitch preserved — no chipmunk, no slow-motion growl
• Key shift up to ±12 semitones, speed untouched
• Both at once, controlled separately
• Local file mode: process a file and export the result as WAV (up to 20 minutes)
• Reopen the popup on a tab you've already adjusted and the sliders show its live values

WHAT IT'S FOR
• Learning a part by ear — slow the solo down until you can hear every note
• Practising along — transpose the track to a key that fits your voice or instrument
• Singing — move a backing track into your range without re-recording it
• Transcribing — half speed, same pitch, actual note names
• Watching faster — 1.5× or 2× without the pitch going cartoonish

FREQUENTLY ASKED

How do I slow down a song without changing the pitch?
Open the extension while the track is playing and drag the speed slider down. Pitch correction is on by default — the tempo changes, the key doesn't.

Can I change the key of a song without changing its speed?
Yes. The pitch slider moves the key in semitones and leaves the tempo alone. ±12 semitones is a full octave in either direction.

Does the pitch shift work on every site?
Speed control does. Pitch shifting needs direct access to the audio stream, which DRM-protected and some cross-origin players don't allow — on those the extension tells you pitch is unavailable and speed keeps working. Local files always support both.

Can I save the result?
Drop a local audio file into the extension and export the processed audio as WAV. Media playing on a webpage is changed for playback only, not re-encoded.

Is it free?
Yes, and it works without an account.