The problem you're having is called the soap opera effect, it sounds like you're using a 120 hz or higher TV. Most have a setting to disable this as it does make filmic sources look off as the motion is smoother than we're used to seeing. Play around with your settings and see if you can find a "Movie" mode, most manufacturers include something like this. Hope this helps!
I've tried to search this forum (and others) in regards to the issue I have, but I haven't found any answers. I think it may be due to the language I am using, as I find it hard to describe. I have a Samsung HDTV model LN46C630 and I've had this issue with both a DVD player and my DTV antenna. While the quality of the screen looks clear, it appears to be shot with a low quality camera, almost as if I am watching a home movie. I've uploaded a sample I took with my phone here. You can see it a bit, but the quality looks off. To me, it looks like some of the old british shows they used to show on PBS. My girlfriend describes it as being 'too smooth.' I've tried to play with my TV settings but I haven't had any luck. Does anyone have any guidance? I sure hope you can see what I mean in that video. Thank you!