I think she is using Real Tracks.

Does anyone know which set this is in.

Also, is this AI?

Ha! Not AI. At least it's interesting...

They need to turn up the bass and drums in the mix.

Some of the camera angles were interesting. There needed to be about 4 to 6 cameras in the room to simultaneously capture this from so many angles, yet no other camera was seen. Alternatively, this was performed multiple times and cuts made to combine the separate clips. I couldn't really guess. But the skill and talent is 'up there', for sure.

Think you've got it right. Believe this is a single take with multiple cameras. There's a stray lock of hair curling past her right earring that is the same from every angle. And with zooms and booms, they could certainly keep the multiple cameras out of the edited shot. So with the copyright on this video being a pre-AI (as we know it) 2018, I'm voting for Hollywood magic on behalf of the videographer and not evil AI. (Digital manipulation in post is certainly a possibility though)

Her playing is breathtaking...

This is all one take stuff.

She is an absolute goddess. Her playing simply takes my breath away and has made me become obsessed with trying to learn some of these pieces on the classical guitar but they're fiendishly difficult.

I have a boxed set of her CDs and it's pretty much the most remarkable stuff I've ever heard.

There's no way on God's green earth that she would allow cutting and splicing on anything that she did of this fashion.

She plays numerous pieces like this in concert all the time back to back. Some of these scores are like 30 pages long.

It's mind boggling.

I agree.
Seemingly effortless, phenomenal talent.

Went down an extended YouTube wormhole of Hilary's stuff after watching the OP video. Her playing is so otherworldly, it just breaks me down...