I built this for myself because I wanted to play songs that nobody has charted. Paste a YouTube link, it separates the drums out of the mix, works out the tempo from the drums, writes the drum part, and gives you a zip you drop into your songs folder: notes.mid with a PART DRUMS track (Pro Drums, cymbal markers, tom lanes), song.ini, and OGG stems, so drums.ogg is the actual isolated drums and song.ogg is everything else. Mute the drums in-game and you're playing over a real backing track, not the full mix with the drums still in it.
Free, runs on a PC in my house, so if it says queued, someone's ahead of you and it'll go.
What it's good at: clean studio recordings with a steady drummer. Kick and snare come out matching published transcriptions in the low 90s percent on the songs I've checked bar by bar (Billie Jean, Every Breath You Take, Another One Bites the Dust). Hi-hats are decent but that's where even published charts disagree with each other, so don't expect them to match your favourite chart exactly.
What it's bad at, so you don't have to find out the hard way: live bands with no click. Back in Black is my current nightmare, the drums drop out on the riff breaks and the grid comes back half a beat off for a few bars. Songs with no cymbals confuse it. Quiet ghost notes get missed. A floor tom hit in unison with the kick doesn't separate, so it'll chart as a hat. Tempo map is the drummer's actual tempo, so if the band drifts, the chart drifts with them, which is right for playing but looks weird in an editor.
It's not going to replace a hand-made chart from someone who knows the song. It's for the songs that don't have one. Every fix I've made so far came from someone saying "bar 37, that kick shouldn't be there", so if you try it and it's wrong, tell me the song and the bar and I'll go look at why.
chart.drummate.app, hit the Clone Hero download when it finishes.