Now, this is my just theory, but it would seem that the Imagineers spliced the beginning of "Intro/Stardust" from Benny Goodman's "Camel Caravan Broadcasts November 16, 1937 - January 3, 1939" with a live recording of Artie Shaw's "Stardust" from "The Uncollected Artie Shaw And His Orchestra Vol. 2, 1938." At least, that's what Shazam is telling me. The Album is on Apple Music. Edit: Yeah, it's definitely from "Uncollected V2." The telltale murmuring in the background gives it away.