Some films are unrated, meaning they have not been given an official rating by a film rating board. Indie films are usually independently produced and distributed, often with a lower budget than mainstream films. NOIR films are a genre of crime dramas that typically feature dark themes and morally ambiguous characters. REMADE films are those that have been adapted from an earlier work, such as a novel or play. Erotic films are those that contain explicit sexual content. X-rated films are those that have been given the highest rating by a film rating board, indicating that the content is suitable only for adults. InThreeD films are those that have been shot in 3D, giving viewers a more immersive experience.