Film grain synthesis in AV1, what's being discussed here, is about preserving the appearance of grain from the input but still reaping the compression benefits

Film grain synthesis in AV1, what's being discussed here, is about preserving the appearance of grain from the input but still reaping the compression benefits of denoising. This isn't a "make movie more film-y" layer they're just slapping over a pristine source. Now the filmmakers may have done that in the first place, depending on how the movie was made. So for say, things made by Netflix themselves I'm sure they sometimes use fake digital film grain, but that's coming in at an earlier step in the process.