NETWORK AUDIO-VIDEO CONTENTS PLAYBACK TERMINAL, SERVER, AND SYSTEM

摘要

Methods to set a viewing and/or listening term are classified into two types, which are a fixed-time-length type to limit time length and a fixed-expiration-time type to limit expiration time. And the timings of license acquisition are classified into two types which are an immediate-acquisition type and a point-of-use type. The type of the timing of license acquisition is written to a meta data which is to be sent to a terminal before initiating download. The terminal determines the timing of license acquisition according to the meta data. When contents are point-of-use type, the terminal doesn't acquire a key and an expiration time information until a time of initiating playback. On the other hand, when contents are immediate-acquisition type, the terminal acquires the key and the expiration time information at any point of time. Since the key is acquired at the early timing such as download completion timing, a reaction velocity in response to a playback instruction can be heighten.