There are systems for carrying out transmission/reception of data of audio and video (hereinafter referred to as A/V) (hereinafter referred to as A/V data) between equipments linked by digital network to reproduce such data on the real time basis. The system for manipulating A/V equipment existing at a remote place to receive contents by monitor or speaker near at hand to reproduce it is an example of the systems as described above. As an equipment which manipulates such A/V equipment existing at a remote place (hereinafter referred to as remote output equipment), remote controller having speaker or earphone, etc. is mentioned. It should be noted that there are cases of only audio data, or cases of only video data as data caused to undergo transmission/reception.
In the case where packet communication is utilized for communication, the transmitting side encodes A/V data to divide it into frames. Further, the transmitting side supplements headers for exchanging data on network to divided individual frames to transmit them as communication packet. In correspondence therewith, the receiving side removes the headers from the received communication packet to decode the removed remaining data portion to reproduce it. By such a series of processing, at the receiving side, it is possible to reproduce audio and video data on the basis of A/V data reproduced at the transmitting side.
Meanwhile, in such system, there are instances where information except for A/V data is also caused to undergo transmission/reception together. For example, there is the case where user desires to recognize the state of player by remote output equipment at a remote position while reproducing music by player.
Here, as the player, there is mentioned a disc recording and/or reproducing apparatus having a function to reproduce recording medium, e.g., so-called CD (Compact Disc), DVD (Digital Versatile Disc) or MD (Mini Disc), etc. In addition, as the state that user desires to know, there are mentioned title of tune that player is reproducing, playing remaining time of tune and/or internal state of player (e.g., playback (reproduction), double speed playback (reproduction), stop, temporary stop, etc.).
However, ordinarily, this function is available only in the system where communication except for A/V data can be carried out in parallel. In this case, mechanism for carrying out transmission/reception of information except for A/V data is independently defined to carry out communication in accordance with the mechanism. Further, it is necessary to mount two communication protocols into the equipment.
For this reason, players designed in correspondence with only communication protocol of A/V data in which such a definition is not carried out in advance cannot send, on the real time basis, information such as title of tune being reproduced, playing remaining time of tune and/or internal state of player, etc. to remote output equipment.