For 60hz video content at least I recommend AI interpolating to 180hz, you can usually only do an integer multiple if not doing pure motion vector interpolation, and then dropping or merging every other frame to bring it to 90hz. Now that youtube is doing 3d conversion they should also add this in, playing back 60hz video at 72hz or 90hz is very juddery. Also hopefully the youtube app or browser with fullscreened video will switch to 90hz when playing 30hz content, but to save battery life they may not.