AV1 is the king of ultra-low bitrates, but as you go higher — and not even that much higher — HEVC becomes just as good, if not more. Publicly-available AV1 encoders (still) have a tendency to over-flatten anything that is low-contrast enough, while x265 is much better at preserving visual energy.
This problem is only just now starting to get solved in SVT-AV1 with the addition of community-created psychovisual optimizations... features that x264 had over 15 years ago!
This problem is only just now starting to get solved in SVT-AV1 with the addition of community-created psychovisual optimizations... features that x264 had over 15 years ago!