Need help to encode difficult video to compress

[mr.muscade]

Hello, I encode with x264 since many years, I know well its parameters. Recently, I get some videos difficult to encode, because there are many artifacts, crispy image, and when I try to encode these videos, these artifacts are still present and the result is ugly. Bellow a sample uncompressed with the artifacts at the top of the image.

Please, could you help me to set the x264 parameters in order to smooth these area of artifacts? I wish result in almost HD@1Mbps. Thanks in advance!

Original video : LINK
Compressed video : LINK
The sample @1Mbps is encoded with the following x264 parameters:

cabac=1 / ref=9 / deblock=1:0:0 / analyse=0x3:0x133 / me=umh / subme=9 / psy=1 / psy_rd=1,00:0,00 / mixed_ref=1 / me_range=32 / chroma_me=1 / trellis=2 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=0 / chroma_qp_offset=-2 / threads=6 / lookahead_threads=1 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=3 / b_pyramid=2 / b_adapt=2 / b_bias=0 / direct=3 / weightb=1 / open_gop=0 / weightp=2 / keyint=300 / keyint_min=30 / scenecut=40 / intra_refresh=0 / rc_lookahead=40 / rc=2pass / mbtree=1 / bitrate=1000 / ratetol=1,0 / qcomp=0,60 / qpmin=0 / qpmax=69 / qpstep=4 / cplxblur=20,0 / qblur=0,5 / vbv_maxrate=62500 / vbv_bufsize=78125 / nal_hrd=none / filler=0 / ip_ratio=1,40 / aq=1:1,00