AT&T says it will offer 1-gigabit, fiber-to-the-home Internet service in the city of St. Louis, probably beginning next year, the latest strike in a speed contest with Charter Communications.

The very-high-speed service should become available to homes and businesses in parts of the city in mid-2015, said John Sondag, president of AT&T Missouri.

The formal announcement is expected today.

A gigabit is enough speed to download 25 songs in one second, AT&T said. At that speed, users can download a TV show in less than three seconds and an HD movie in 36 seconds. Customers could watch five Internet-streaming HD movies at once.

The company didn’t announce a price for the service in St. Louis. AT&T began the same “U-verse with AT&T GigaPower” service in Dallas in August with a price of $90 for 100 megabits and $120 for a gigabit of speed.