What is the highest-grossing film worldwide?

Context: With a worldwide box-office gross of over $2.9 billion, Avatar is proclaimed to be the "highest-grossing" film, but such claims usually refer to theatrical revenues only and do not take into account home video and television income, which can form a significant portion of a film's earnings. Once revenue from home entertainment is factored in it is not immediately clear which film is the most successful. Titanic earned $1.2 billion from video and DVD sales and rentals, in addition to the $2.2 billion it grossed in theatres. While complete sales data are not available for Avatar, it earned $345 million from the sale of sixteen million DVD and Blu-ray units in North America, and ultimately sold a total of thirty million DVD and Blu-ray units worldwide. After home video income is accounted for, both films have earned over $3 billion each. Television broadcast rights will also substantially add to a film's earnings, with a film often earning as much as 20–25% of its theatrical box office for a couple of television runs on top of pay-per-view revenues; Titanic earned a further $55 million from the NBC and HBO broadcast rights, equating to about 9% of its North American gross.

Answer: Avatar is the highest-grossing film worldwide, grossing over $2.9B. It was written and directed by James Cameron, and was released in 2009.