CTV, which scored big ratings with the finale of “American Idol,” will produce “Canadian Idol” based on the same concept, it announced Wednesday.CTV acquired rights to the format from FremantleMedia and 19TV. The “American Idol” finale Sept. 4 was summer’s top-rated show in Canada, drawing 2.1 million viewers. CTV also has acquired the rights to the second season of “American Idol,” which it will air this winter. Rival Global network has its own musical reality show contest, “Popstars,” which will return in February for its third edition. “Popstars: The One” will focus on solo acts.