Patent ID: 7631339

Claim:
A method for correcting a frequency used in a system including a broadcasting apparatus, a receiving apparatus and a reproducing apparatus, the broadcasting apparatus generating a plurality of pieces of broadcasting data by encoding content based on an encoding standard clock, and broadcasting the plurality of the pieces of broadcasting data, the receiving apparatus receiving the plurality of the pieces of broadcasting data in an order, and the reproducing apparatus receiving the plurality of the pieces of broadcasting data from the receiving apparatus via a first path, decoding the plurality of the pieces of broadcasting data based on a decoding standard clock, and for reproducing the content, the method comprising: a time information broadcasting step for broadcasting broadcasting-side time information, the broadcasting-side time information indicating broadcasting-side time measured in accordance with the encoding standard clock and being contained in at least one of the pieces of broadcasting data; a judging step for judging whether the broadcasting-side time information is contained in the broadcasting data received by the receiving apparatus; a transmitting step including a first transmitting substep for transmitting a status change signal from a status change signal output unit in the receiving apparatus to a status change signal receiving unit in the reproducing apparatus via a second path different from the first path immediately after a result in the judging step is affirmative, the status change signal indicating timing that the affirmative result was returned in the judging step and at least one of a plurality of status changes occurred in the receiving apparatus, one of the plurality of status changes being a status that the broadcasting-side time information is contained in the broadcasting data, and a second transmitting substep for transmitting information about a type of status change that occurred in the receiving apparatus to the reproducing apparatus via the first path upon the transmission of the status change signal in the first transmitting substep; and a correcting step for correcting, by using the broadcasting-side time information and reproducing-side time information, a frequency of the decoding standard clock to be closer to a frequency of the encoding standard clock, the broadcasting-side time information being received via the first path, the reproducing-side time information being stored in a reproducing-side time information holding unit in the reproducing apparatus and indicating reproducing-side time measured in accordance with the decoding standard clock when the timing information is received in the status change signal receiving unit in the reproducing apparatus.