Runway, a startup developing generative AI models for media production, has raised $308 million in a Series D funding round.General Atlantic led the round, with participation from Fidelity Management & Research Company, Baillie Gifford, Nvidia, SoftBank, and others.The funding will be used for AI research, hiring, and expanding Runway Studios film and animation production arm.Runway released Gen-4, a video-generating model that can create consistent characters, locations, and objects across scenes.