The Wall Street Journal’s Joanna Stern has a deep look at Sora, OpenAI’s new text-to-video generator — and with it, an interview with CTO Mira Murati, who steadfastly refuses to clarify what data was used to train the system. No wonder, since the explosion of copyright lawsuits against AI companies is quickly becoming an existential risk to them all. 4:25 in the video below: