A server device includes a communicating portion that sends content data through a communication network to a client machine and a controlling portion that acquires processing capability information of the client machine that plays back the content data, and generates a playback format list that includes playback format information corresponding to the content data, based on, at least, the processing capability information acquired for the client machine. The content data is converted into a playback format based on playback format information selected by the client machine side from the playback format list, and is sent through the communicating portion to the client machine.