Problem with dark thin lines in x264 at low bitrates

[Nozdrum]

Is it possible to allocate more bitrate to that kind of lines (in clothes/hairs), detracting it from the backgrounds?

x264 settings:

--chroma-qp-offset -4 --b-adapt 2 --ref 10 --qcomp 0.70 --qpmin 10 --qpmax 51 --me umh --crf 27 --tune Animation --preset veryslow --bframes 8 --deblock 1:2 --fade-compensate 0.35 --aq-mode 3 --subme 10 --trellis 2 --merange 24 --chroma-qp-offset -4 --threads 2 --keyint 250 --min-keyint 12 --scenecut 45 --aq-strength 0.75