TEN years ago DVDs rejuvenated the film business, encouraging people to own films rather than simply watch them. But sales, which began declining gradually in 2006, are now falling more steeply. Around a third of the drop in the first quarter was counteracted by rising sales of high-definition Blu-ray discs, which are more profitable. Meanwhile, rentals are booming. Redbox, which rents films cheaply from self-service kiosks, has been adding machines at the rate of more than 500 per month. For the studios it is much more profitable to stream a film digitally or sell it through a cable operator as a video-on-demand (VOD).

Shutterstock