An apparatus, method, and medium are provided for modifying a program. A selection of a category of program for which modification is to be performed is received, and a model object is stored in association with the category of program. An original signal is received, and it is determined whether the original signal includes a source signal of the category of program. When the original signal includes the source signal of the category of program, at least one portion of the source signal to be extracted is identified. The model object stored in association with the category of program is retrieved, and at least one portion of the model object is inserted into the original signal in correspondence with the portion of the source signal to be extracted. The original signal including the inserted portion of the model object is configured to be displayed at a user site.