Outlier is a youtuber that has a passion for deep learning by making explanatory videos for theory and code implementations.
At this video he gives a detailed explanation of how Diffusion Models work. At first he explains the fundamental idea of these models and later he dives deep into the math part. He tries to explain all of this on a really easy & intuitive level. After the math derivation, he took a look at the results from different papers and how they compare to other methods.