Chapter 1

concerns. Panasonic also released a progressive-scan player (DVD-H1000,
$3000) in the fall of 1999. Many manufacturers have released progressive
models since then at progressively cheaper prices (pun intended). It’s also
possible to buy an external line multiplier to convert the output of a standard
DVD player to progressive scanning. All DVD computers are progressive
players, because computer monitors are progressive-scan, but quality
varies. (See Chapter 4’s “Can I Play DVD Movies on My Computer?” and
Chapter 2’s “Will High-Definition DVDs or 720p DVDs Make Current Players
and Discs Obsolete?”)
Converting interlaced DVD-Video to progressive video involves much
more than putting film frames back together. This conversion can be done
in essentially four ways:
• Reinterleaving (also called weave) If the original video is from a
progressive source, such as film, the two fields can be recombined
into a single frame.
• Line doubling (also called bob) If the original video is from an interlaced
source, simply combining two fields will cause motion artifacts
(the effect is reminiscent of a zipper), so each line of a single field is
repeated twice to form a frame. The best line doublers use interpolation
to produce new lines that are a combination of the lines above and
below. The term line doubler is vague, because cheap line doublers
only bob, whereas expensive line doublers (those that contain digital
signal processors) can also weave.
• Field-adaptive deinterlacing This examines individual pixels across
three or more fields and selectively weaves or bobs regions of the picture
as appropriate. These chips used to cost $10,000 and up, but the
feature is now appearing in consumer DVD players.
• Motion-adaptive deinterlacing This examines MPEG-2 motion
vectors or does massive image processing to identify moving objects
in order to selectively weave or bob regions of the picture as appropriate.
Most systems that do this well cost $50,000 and up (aside from
the cool but defunct Chromatic Mpact2 chip).
Three common kinds of deinterlacing systems are available:
General DVD 47
• Integrated This is usually the best, where the deinterlacer is integrated
with the MPEG-2 decoder so that it can read MPEG-2 flags and
analyze the encoded video to determine when to bob and weave.
Most DVD computers use this method.
• Internal The digital video from the MPEG-2 decoder is passed to a
separate deinterlacing chip. The disadvantage is that MPEG-2 flags