You can also crop and deinterlace your movie in the Export Movie Options.
Television systems use a technique called interlacing to paint a picture on the TV screen.
The television raster puts every other picture line on the screen. Then it goes back and inserts lines between the first set. In the early days of television, interlacing was pretty handy. If the raster painted the image down the lines of phosphors of the TV screen, the top pixels would begin to fade before the raster painted the bottom pixels. The result was a kind of flicker.