It’s a pop / punk / rock band, like fall out boy, their music is very similar. The music video takes place in a church, all the band is dressed in white. They start to clap their hands, and claim WOOOHOOHOOHOOHO (A C A D E, A C A D E, A C A D C, A C A D C) and then the singer starts to sing . After that, another guy, also played by the singer and dressed in black appears in the church. I also remember a thing. They used to make a diamond sign with their fingers in live, their symbol maybe.
