I'm curious about grain encoding - did you work on that at all? My friend heard they were doing a grain extraction layer that was re-added client side. Feel free to contact devin@techcrunch if you have any interesting insight.
I used to do a poor-mans version of that with low-bitrate mpeg4 (ASF or divX) movie downloads back in the day; the resolution would be low, and the MS MP4 codec tended to blur as well (plus noise killed the quality so much that there was often a denoiser in the encode pipeline), so adding any noise to the playback significantly improved the look of the movie.
Removing Grain and then re-adding it after encoding isn't specific to Netflix or even AV1 as some have suggested. I believe a recent part of H.265 HEVC, or H.266 VVC or MPEG-5 has something similar.
