I have to remove aliasing from this anime, is it possible?

[mirkosp]

Yeah, looks good now, though I think 0.8 should still be fine, as Mister Hatt says. Lower aq-strength = more compression, at the cost of over-quantizing blocks that x264 perceives as flat. At 0.8 you should still have a good balance without hitting quality, at least not visibily. Going too high will just inflate the filesize for no reason.

[Mister Hatt]

Actually the reason for dropping AQ has little to do with compression and more to do with taking bits that aren't helping on flat places and putting them in more detailed places. It's a bit redistribution scheme. It was rather useful before mbtree came along if you had microdetail in places and large flat sections elsewhere, like in space anime with lots of bg detail but flat foreground textures.