Help... Combing artifacts only on TV!

[mp3dom]

Hi to all.
I'm going crazy for this problem that I can't resolve.
I have a PAL 16/9 interlaced top field film (sure of this because i've checked all the settings with VirtualDub MOD and "AssumeTFF" command in AviSynth) that i've encoded with CCE. In every software dvd player (WinDVD, PowerDVD, TheaterTek, CinePlayer etc.) the play is perfect. On my 4/3 TV in VERY dynamic scenes i got combing/scanlines artifacts. This is VERY strange to me because the TV is interlaced (the movie also) so.. how can it be possibile?
For test I've made an AviSynth script with AssumeTFF().SeparateFields() and loaded the AVS in VirtualDubMOD. The SAME scenes with this script are pretty perfect in VDubMOD.
My "standalone dvd player" is an XBOX... Could be this the problem? (but never had a similar problem before)

[moon1234]

I have noticed this on some DVD players as well. I never saw this on APEX players, but I have seen it on Norcent and almost all players based on any MediaTek processor. I have not seen this effect on players based upon the ESS chipset.

I don't have an Xbox so I can not say for sure why you see this on that player. Most of my content is progressive with pulldown applied. This only thing I was able to surmise is that the chipset does not do pulldown correctly when duplicating the frames.