Compressor 4 - About Deinterlacing

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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.


Chapter 23

Working with Frame Controls

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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.

Interlacing creates
a “comb” effect that
should be removed.

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.