DVD Demystified

Essentials of DVD Production
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■ Make sure the video does not have burned-in subtitles. Use the DVD
subpicture feature instead, particularly for multilingual discs.
■ If you want to pack a large amount of video on a disc, don’t try to encode
to MPEG-2 under 2 Mbps. Use MPEG-1 between 1 and 1.86 Mbps; it will
look better than MPEG-2 at the same data rates. You could also use “half
D1” resolution (352�480) at rates of about 1.5 to 3 Mbps, which can look
surprisingly good. Be aware that although half D1 video is mandatory in
the DVD-Video specification, it will cause problems on a few players.
Before encoding the video, use heavy digital video noise reduction
(DVNR) and liberal application of blurring filters in video processing
programs. These steps reduce the high-frequency detail in the video
which makes MPEG encoding more efficient. Also try reducing the color
depth from 24 bits to something between 16 bits and 23 bits. Do not use
a dither process which increases high-frequency detail. This can help
with encoding efficiency and can reduce posterization artifacts.
■ If video quality is a top consideration, create or request your content in
progressive format if at all possible: shoot on film or use a progressive
digital video camera. If your video assets come from an interlaced
source, consider converting to progressive form before encoding.
Depending on the nature of the video, progressive conversion may
cause artifacts that unacceptably degrade the video. For some types of
interlaced content, however, a high-quality progressive conversion will
result in a DVD that looks significantly better when played on
progressive DVD players and computers. See Chapter 3 for more on
progressive video.
Preparing Animation and Composited Video
Video produced on a computer, or camera-source video that is composited
with computer graphics, has its own set of issues. The most important thing
to keep in mind is avoiding too much detail, especially vertical detail, which
wreaks havoc on interlaced TVs. Avoid thin horizontal lines; use the antialiasing
and motion blur features of your animation or editing software whenever
possible. Use a low-pass or blur filter, but don’t overdo it because too
much blurring reduces resolution on progressive-scan players and computers.
For 525-line (NTSC) video, render animations at 720�540 and scale
down to 720�480 before encoding. For 625-line (PAL) video, render animations
at 768�576 and scale down to 720�576 before encoding, or if your
software supports it, render with D1 or DV pixel geometry.