The conventions of a music video include showing the artist or band through close ups, mid shots, and long shots. The mise-en-scene and outfits vary by music genre from crisp looks in R&B videos to all black clothing in metalcore videos. Music videos use techniques like jump cuts, dissolves, and parallel narratives. The purpose is to promote the artist's song and CD sales while sometimes helping audiences understand the song's meaning. There are three main types: concept-based videos around an idea, performance-based videos focused on the artist playing, and narrative-based videos that tell a story.