There is no need to split the video. If you use 2pass encodes, the difficult scenes will be allocated with more bits.
Interestingly, tomsmocomp() works quite well on this clip after mpeg2source()'s deblock is applied. mvbob() works great too. tdeint() improves a bit too but it still leaves residual combs.
mpeg2source("railing.d2v",cpu=4)
colormatrix(d2v="railing.d2v")
tomsmocomp(1,5,0)
degrainMedian(mode=3)
Sample:
http://dump.ru/files/7/749008459/
[Teegedeck's Quality Preset Level 45 at 3000kbps]
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It's strange that I fail to reproduce this result again.