Somewhere in a comment it says that this is "salzburg, mozart-jahr , uchida, muti, bartoli." They are performing "Ch'io mi scordi di te," K 505, the great Mozart concert aria.
My flagging memory tells me that Salzburg wanted a performance of this specific aria and had asked Renée Fleming to sing it. She replied that it did not suit her voice. She offered to sing something else, but the pianist Mitsuko Uchida was the featured soloist. And thus occurred this performance. Cecilia Bartoli is still my favorite Mozart singer, and she is very much in form here.
Why am I posting this? Because I wish I was going to Zurich for Rossini.