Kari — pitch & speed for music

Change the key and speed of music on youtube.com in real time. Slide for speed, tap for pitch. By YGG HOMME, powered by Cantum.

Kari changes the key and the speed of music on youtube.com while it plays, with studio accuracy, and a small animated character to keep you company. How it works • Slide left to slow a song down, right to speed it up. By default the pitch moves with the speed, like a record (vinyl mode), using only Chrome's own resampler. • Tap Pitch − or + to change the key without changing the speed. • Turn on key lock and the pitch stays put while the speed changes. • Everything starts at zero, and one tap resets it. Studio accuracy The pitch engine is Rubber Band Library R3, running in an audio worklet. Measured on the audio that actually reaches your speakers, every step from −12 to +12 semitones lands within 0.02 cents, and key lock holds 440.00 Hz at ±16 % speed. The engine runs only when the key changes and never stacks a second pass. If it ever stalls, you hear the original sound, never silence. Full control Vinyl or key lock, a ±8, ±16 or ±50 % speed range, hold-to-compare against the untouched sound (level- and delay-matched), key names, and a live readout of how far the sound runs behind the picture. Kari remembers the key and speed you chose for each song, on your own device. Free and private Kari is free, with no paid tier and no account. It never sends your data to us or anyone else: no analytics, no servers. The code is open source under the GPL-2.0 at https://github.com/cantum-io/kari. Works on youtube.com video pages in desktop Chrome. Screenshots show "Ritual Fire Dance" performed by the Illinois Brass Band, shared under a Creative Commons Attribution licence. YouTube is a trademark of Google LLC. Use of this trademark is subject to Google Permissions. Kari is not affiliated with or endorsed by YouTube or Google. YGG HOMME · powered by Cantum · Rubber Band Library (GPL)