It seems to be a paper for 2023 conference: "Under review as a conference paper at ICLR 2023" So I would say it looks pretty advanced, however they don't use

It seems to be a paper for 2023 conference: "Under review as a conference paper at ICLR 2023" So I would say it looks pretty advanced, however they don't use a Diffusion model to generate the images, but an "image conditional video generation", another different approach.