Patent ID: 8502921

Claim:
A digital broadcast receiver which receives a digital broadcast signal in which a video signal and either of an audio signal including a main audio signal or an audio signal including a main audio signal and a sub-audio signal are multiplexed, and which informs a viewer by a visual display whether the received digital broadcast signal includes the sub-audio signal, and the digital broadcast receiver comprising: a receiving section that receives the digital broadcast signal and decodes the received digital broadcast signal to output a decoded digital broadcast signal; a signal separating section that separates the main audio signal and the video signal from the decoded digital broadcast signal inputted thereto, and when the audio signal consists of the main audio signal and the sub-audio signal, further separates the sub-audio signal from the inputted decoded digital broadcast signal; an audio generating section that decodes the main audio signal inputted thereto, which has been separated by the signal separating section to generate a decoded main audio signal that can be reproduced, and when the signal separating section has further separated the sub-audio signal, decodes the sub-audio signal inputted thereto, which has been separated by the signal separating section to further generate a decoded sub-audio signal that can be reproduced; a video generating section that decodes the video signal inputted thereto, which has been separated by the signal separating section to generate a decoded video signal that can be displayed; a detecting section that, by monitoring an input side of the audio generating section and directly detecting a presence of the sub-audio signal, detects an input to the audio generating section of the sub-audio signal having been separated by the signal separating section; and a control section that, when the detecting section has detected an input of the sub-audio signal to the audio generating section, controls the video generating section so as to further generate a sub-audio image signal to display a sub-audio image indicating the presence of the sub-audio signal, wherein the detecting section further detects whether or not the level of the decoded sub-audio signal is greater than or equal to a predetermined value, and the control section, when the detecting section has detected an input of the sub-audio signal to the audio generating section by directly detecting a presence of the sub-audio signal and also has detected that the level of the decoded sub-audio signal is greater than or equal to the predetermined value, controls the video generating section so as to further generate the sub-audio image signal.