Communication system, communication device, program and communication method

A communication device that communicates with a reproduction device in which content data items are stored, comprising:

• a storage unit configured to store content data items;
• a communication unit configured to communicate with said reproduction device;
• a priority ranking determining unit configured to obtain a first list of content data items stored in said storage unit and additional priority ranking information associated with each item of content data in the first list via the communication unit, obtain a second list of content data items stored in a second storage unit of said reproduction device and additional priority ranking information associated with each item of content data in the second list, and determine an individual priority ranking of each item of content data in a content data group including both the content data items of the first list and the content data items of the second list, based on a priority ranking criteria and the additional priority ranking information associated with each item of content data in the first and second lists;
• and
• a difference extraction unit configured to extract content data items from said storage unit to be transferred to said reproduction device, based upon the individual priority ranking of each item of content data in the content data group.

A non-transitory computer-readable storage medium storing computer readable instructions thereon that, when executed by an arithmetic processor, directs the arithmetic processor to execute a communication method, comprising:

• obtaining a first list of content data items stored in a first storage unit of a communication device and additional priority ranking information associated with each item of content data in the first list;
• obtaining a second list of content data items stored in a second storage unit of a reproduction device and additional priority ranking information associated with each item of content data in the second list;
• determining an individual priority ranking of each item of content data in a content data group including both the content data items of the first list and the content data items of the second list based on a priority ranking criteria and the additional priority ranking information associated with each item of content data in the first and second lists;
• and
• extracting content data items from said first storage unit to be transferred to said reproduction device, based upon the individual priority ranking of each item of content data in the content data group.

A communication method to be adopted in a communication device capable of communicating with a reproduction device in which content data items are stored, comprising:

• obtaining a first list of content data items stored in a first storage unit of said communication device and additional priority ranking information associated with each item of content data in the first list;
• obtaining a second list of content data items stored in a second storage unit of said reproduction device and additional priority ranking information associated with each item of content data in the second list;
• determining, by a processor of said communication device, an individual priority ranking of each item of content data in a content data group including both the content data items of the first list and the content data items of the second list based on a priority ranking criteria and the additional priority ranking information associated with each item of content data in the first and second lists;
• and
• extracting content data items from said first storage unit to be transferred to said reproduction device, based upon the individual priority ranking of each item of content data in the content data group.