YouTube players won't run from a file opened straight off disk. Serve this folder instead, for example npx serve ., and open the localhost address. Audio files work either way.
ACrossfaderB
Mashup: set one deck to Instrumental, the other to Acapella, then play both in sync.
Set list
Your set is emptyAdd YouTube links or audio files, then pick how each track mixes into the next. For an Oasis-over-Blur style mashup, add the Song 2 instrumental, then the Supersonic acapella, and set the first track's transition to Mashup.
Ready. Load a track on each deck, or build a set below.
What works with YouTube and what needs audio files
YouTube's player lets a page play, pause, seek and change volume, but never hands over the audio. YouTube decks get crossfades, cuts and timed transitions. They can't be beat-synced, EQ'd, filtered, or split into vocal and instrumental.
Audio files get everything: BPM detection, beat grids, tempo sync with key lock, 3-band EQ, filter, echo, brake, and the Instrumental/Acapella modes.
Instrumental and Acapella modes are quick in-browser tricks (centre-channel cancelling and a vocal band filter). They're rough. For clean mashups, use real acapella and instrumental versions, or split stems first with a tool like Ultimate Vocal Remover or Demucs.
Set each track's In point where you want it to start (the drop, or where the vocal begins for an acapella). Out is where the mix starts; leave it blank to use the track length setting.
Tracks within about 8% BPM of each other blend best. Bigger gaps get a warning; use ½ or ×2 on a deck if a BPM was detected at double or half speed.
Some YouTube videos block embedding. The set skips them and logs which one.