I just found that there is a huge difference for avcsource and directshowsource. Sample clip is here:
Code:
http://rapidshare.com/files/288791896/Flag.rar
In this case, avcsource screwed the clip while directshowsource handled it well. I used DGAVCDec Version 1.0.9.
Code:
LoadCplugin("C:\Program Files\AviSynth 2.5\plugins\yadif.dll")
directshowsource("Flag.ts").AssumeTFF
#avcsource("Flag.dga").AssumeTFF
#avcsource("Flag.dga", deblock=false).AssumeTFF
Yadif (order=1)
crop(4,4,706,572).BicubicResize(704,528)
Edited: so either DGAVCDec or avcsource has a bug.