I use VLC for watching IPTV (multicast MPEG2), which means practically all the material is interlaced. The only full frame rate deinterlacer VLC currently offers is the bobbing deinterlacer, meaning the vertical resolution is halved. The "X" deinterlacer seems to be the only adaptive one, however, it is too aggressive (stationary parts get deinterlaced as if they were moving very easily) and it only produces half the possible frame rate.
MPlayer currently has an awesome deinterlacer called yadif. I've tried it on material recorded with VLC (from IPTV) and I've yet to see any deinterlacing artifacts. It works in real-time (on standard definition MPEG-2 decoded by a 2400+ AMD Athlon CPU) and seems to work great on pure interlaced as well as hybrid or film-based material.
Could it be ported to VLC?
Source code:
http://svn.mplayerhq.hu/mplayer/trunk/l ... vf_yadif.c
AviSynth Yadif port:
http://avisynth.org.ru/yadif/yadif.html
Michael Niedermayer's deinterlacer comparison:
http://guru.multimedia.cx/deinterlacing-filters