Video to be played on traditional NTSC or PAL televisions is encoded using an interlaced frame rate. Each frame is actually made up of two half-frames called fields. Each field contains half the frame lines; the odd (or upper) field contains lines 1, 3, 5, 7, 9 and so on, and the even (or lower) field contains lines 2, 4, 6, 8, 10, and so on. When the video is played back, the TV displays the fields in an alternating pattern, which creates an effective illusion of smooth movement. Viewing interlaced video on a computer screen that displays both fields simultaneously may reveal a combing effect.
You can deinterlace, or remove the fields from an interlaced video clip, by converting it to a progressive frame rate. The video settings provided in Compressor contain a “Field order” pop-up menu in the Video inspector that you can use to turn interlacing on or off for the transcoded file. For more information, see the topic that covers the format you’re using for transcoding, for example, QuickTime Movie or MPEG-2.