x264 vs x265 shimmering

[valnar]

I've noticed that with sensible parameters, I seem to gain more shimmering or grain in x265 encoded videos vs x264.

Original source

x264 example

x265 example

Right after the video starts, look at the barn redwood. It has a bit of flicker on the x265 video. The x264 example is more like the original source, which is more "stable".

Yes there is some slight handheld camera movement going on, but nevertheless x264 handles it better.

I've played with many smoothing/non-smoothing parameters in the x265 lexicon and cannot seem to stop this. Any ideas?

edit: I just realized my source cut is slightly longer than the encode examples, so sizes are slightly off.