I’m honestly not sure which stock music library these came from; they were included on the CD-ROM for the Broderbund MovieShop video editing software I used in my early days of home movie production.
The “Furby in the Big City” theme is simply called “Jazz1”, the “Furby Goes Back To School” blues theme is called “Blues2”, and the hip-hop theme from the same short is called “Light Hip Hop Intro”. The CD-ROM copyright info said they were licensed from ArtBeats, but I’ve never known ArtBeats to also have stock music; they generally just produce stock footage (and the CD-ROM did include some of their stock footage clips). I’m guessing these tracks could actually be from the Valentino Production Music Library, since the CD-ROM also had some sound effects from Valentino’s sound library, and the Furby Cliffhanger cartoons also used sound effects from that library. Or maybe they’re Sound Ideas stock music tracks. I’m pretty sure they are royalty-free tracks, given they were included in a PC video editing application.
