Related-art product advertisement methods include not only a direct advertisement method which directly provides an advertisement through newspaper, radio, and a TV broadcast, but also a method which advertises a product indirectly by applying a product to be advertised to a prop which appears in a content such as a movie, a drama, a radio broadcast, or the like, or a product which is naturally mentioned as a part of the content (hereinafter, a product indirect advertisement or an indirect advertisement). In particular, in the case of the product indirect advertisement, a powerful advertisement effect can be provided to viewers and listeners, and its importance increases. However, the related-art indirect advertisement simply exposures products on a screen or merely mentions as a sound. Therefore, there is a problem that viewers or listeners should separately search for relevant information and retailers on the products, and then purchase the products based on the searched information when they desire to purchase the products. Various technologies for solving this problem have been suggested. For example, Korean Patent Registration No. 10-1310943 (Sep. 11, 2013) (System and Method for Providing Content-Related Information Related to Broadcast Content), Korean Patent Registration No. 10-1313293 (Sep. 24, 2013) (System and Method for Providing Additional Information of Broadcast Content), and Korean Patent Registration No. 10-0893671 (Apr. 9, 2009) (Generation and Matching of Hashes of Multimedia Content) disclose methods for providing a related content on a product indirect advertisement included in a content that a viewer or a listener views or listens to through their mobile receivers, using a sound characteristic of the broadcasted or played content. In another example, Korean Patent Registration No. 10-1363454 (Feb. 10, 2014) (System for Providing User-Customized Advertisement Based On Sound Signal Outputted from TV, Method for Providing User-Customized Advertisement, and Computer Readable Recording Medium Having MIM Service Program Recorded Therein) discloses a method for providing a related content on a product indirect advertisement included in a content that a viewer or a listener views or listens to through their mobile receivers by inserting a non-audible sound wave into the broadcasted or played content.
However, the above-explained technologies still have a problem that the viewer or listener should actively request the related content using their own mobile receivers. That is, when a content is played, the user should execute an application of the mobile receiver to receive a related content, or should instruct the application of the mobile receiver which provides the related content to recognize the content. Requiring the user to make an extra effort to receive the related content is contrary to the behavior pattern of the viewer or the listener who passively enjoys the content, or making the extra effort may interfere with viewer's or listener's immersion. Therefore, the efficiency of the related content may be reduced.
This problem may be overcome by continuously extracting a sound characteristic or a non-audible sound wave in the mobile receiver. However, this may cause power shortage in the mobile receiver which operates by a limited battery.