About Deinterlacing

You can use the Frame Controls feature in Compressor to deinterlace your video media.

NTSC and PAL video is interlaced. This means that each frame of video consists of two fields (1/60 of a second apart), one with the odd broadcast lines and one with the even lines of the image. The differences between these two fields create the impression of motion. Our eyes combine these two images into one whole frame of smooth, realistic motion at 30 fps in standard definition television, and because of the high field-refresh speeds (1/60 of a second), the interlacing is invisible.

Because interlacing creates two fields for each frame, areas with fast movement within the field become separated into alternating jagged lines. You can view your source media one frame at a time and check for horizontal stripes along the leading and trailing edges of moving objects. If you find these, you need to deinterlace your source media to convert it to a frame-based format.

Figure. Illustration showing interlacing "comb" effect.

If your source media file needs to be converted to a frame-based format, you must deinterlace it to remove the effects of interlacing. Interlacing on computer displays can cause high-motion parts of your video to look fuzzy, so this is especially important if you’re outputting a QuickTime movie for desktop or web playback. You can remove the upper (odd) or lower (even) field from an interlaced video file, although smooth motion may be compromised within the clip. This filter can also be used to eliminate flickering caused by interlacing in still frames that have thin vertical lines, such as title pages with small text. The remaining fields are interpolated to create a whole image, resulting in an overall softening of the image.