Kari — pitch & speed for music

Key and speed of music on youtube.com and soundcloud.com. Slide for speed, tap for pitch. By YGG HOMME, powered by Cantum.

Kari changes the key and the speed of music on YouTube and SoundCloud while it plays, loops a bar of it, and keeps a small animated character on the player. How it works • Slide left to slow the song down, right to speed it up. The pitch rides the speed, like a record, until you turn on key lock. • Tap Pitch − or + to change the key a semitone at a time, from −12 to +12. • Tap ½, 1, 1 bar or 2 bars to loop that much of the song. Tap it again and the song carries on where it would have been. • Tap Rec for a practice take: what Kari plays, at your key and speed, saved to your computer as a WAV file with every move you made as a marker. Tap it again to stop. • Kari reads the tempo herself after about six seconds. Tap tempo, or type a bpm, to override her. • Everything starts at zero, and one tap resets it. • Hide Kari on YouTube or on SoundCloud from her settings or the gear on her panel. Her toolbar icon brings her back. Measured, not promised The pitch engine is Rubber Band Library R3 in an audio worklet. On the audio that 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, a typed bpm, MIDI pads for the loops, and a live readout of how far the sound runs behind the picture. Kari remembers the key and speed you chose for each video or track, on your own device. SoundCloud Optional. Click Kari's icon on a SoundCloud tab and allow her once; she then sits above the player bar. A tab that was open before needs one reload. Go+ tracks are speed only. Free and private Kari is free, with no paid tier and no account. She never sends your data to us or anyone else: no analytics, no servers, no network requests. The code is open source under the GPL-2.0 at https://github.com/cantum-io/kari. Works in desktop Chrome on youtube.com video pages and on soundcloud.com. Screenshots show "Ritual Fire Dance" performed by the Illinois Brass Band (Creative Commons Attribution) and music by AMAI on SoundCloud, used with permission. YouTube is a trademark of Google LLC. SoundCloud is a trademark of SoundCloud Global Limited & Co. KG. Kari is not affiliated with or endorsed by YouTube, Google or SoundCloud. YGG HOMME · powered by Cantum · Rubber Band Library (GPL)