I have a curious question regarding on musics used in music rhythm game. In Guitar Hero for example, they used all different music albums in one program. Then, each album requires to ask permission to the owner, composer of the music, or the copyright owner of the music. Let's say, if you used 15 albums for the music rhythm game, then you have to contact 15 copyright owners and it might be that, for the game developer, that the profit earned goes to the copyright owner or owner of this music. For the independent game developers, was it okay if either used the copyright music by just mentioning the name of the singer included in the credits and in the music select screen or use the non-popular/old music that about 50 years ago? And, does still earn money for the indie game developers by making free downloadable game?