Short stadium tunes like this have been part of baseball presentation for decades, played over public address systems to mark the moment a game is ready to begin. The play ball call itself comes from the umpire starting play, and the musical sting turned that call into a recognisable cue for broadcasts, games and films. Online it survives as a compact sound effect because it needs no explanation, works over silent footage, and instantly changes a generic sports clip into a baseball moment for viewers.