An information delivery system, an information delivery method, an information processing apparatus, and an information processing method is used advantageously to deliver content stream data easily, reliably and inexpensively to the general users. A personal computer prepares a content file and an order form file using software provided by a center system, and transmits the prepared files to the center system over the Internet. Given the order form file from a customer device, the center system encodes a content file accordingly to generate content stream data and causes a moving picture delivery server to deliver the generated stream data to user terminals. This invention can be applied, among others, to systems for delivering content data over the Internet.