In April, a New York start-up called Runway AI unveiled technology that let people generate videos, like a cow at a birthday party or a dog chatting on a smartphone, simply by typing a sentence into a box

The four-second videos were blurry, choppy, distorted and disturbing. But they were a clear sign that artificial intelligence technologies would generate increasingly convincing videos in the months and years to come.

Just 10 months later, the San Francisco start-up OpenAI has unveiled a similar system that creates videos that look as if they were lifted from a Hollywood movie. A demonstration included short videos — created in minutes — of woolly mammoths trotting through a snowy meadow, a monster gazing at a melting candle and a Tokyo street scene seemingly shot by a camera swooping across the city.

OpenAI, the company behind the ChatGPT chatbot and the still-image generator DALL-E, is among the many companies racing to improve this kind of instant video generator, including start-ups like Runway and tech giants like Google and Meta, the owner of Facebook and Instagram. The technology could speed the work of seasoned moviemakers, while replacing less experienced digital artists entirely.

It could also become a quick and inexpensive way of creating online disinformation, making it even harder to tell what’s real on the internet.