Few bar of lines shown moving downwards on my PC when I am recording using the cam recorder?

Question

I noticed that when I was recording using a cam corder , the image projected from the computer shows signs of straight bar lines moving downwards but when I try it on the TV , it does not happen. Any way to elimate the straight lines when recording from a cam recorder. Many thks

Answer 1

This is because pcs are progressive scan while tvs are interlaced scan. In normal person talk, tv and computer screens (the big crt kind, not lcds) can only show one little square of picture information at a time. But the scan these pixels in lines so fast that you cant tell. On computer screens, every line is followed by the next (line 2 is scanned after line 1). But on tvs, it scans all the even lines, then goes back and scans all the odd lines to form a picture. This coincidentally, is what your camcorder uses, which is why when you play something back on your tv, it looks normal, because it matches, and the same reason when you record a tv screen. However, when you record a computer screen, the lines dont match, and you see the line. The only thing I can tell you is try adjusting the shutter speeds, or if your camera has a clearscan option, adjust that, otherwise, its just something that youll have to get used to :-(. Hope this helps!