| Video Noise February 2005
Goodbye DVD-Video, DVD-Audio,
SACD -- Hello Hi-Def DVD
DVDs are big business. Often, a movie makes as much
or more money for its studio from DVD sales and rentals than it did in theaters. That
means people are out there buying and renting DVDs in huge numbers. But the DVD-Video disc
is about to be overtaken by the high-definition DVD.
If you’re a movie buff who appreciates watching movies
displayed at the highest quality possible, the DVD has been "it" since its US
launch in 1997. D-VHS/D-Theater movies on VHS-size cassettes provide
better-than-high-definition performance, but few want to deal with videotape after having
experienced the convenience of DVD. And movies on D-VHS/D-Theater are pretty steep --
between $35 and $40 each.
The HD-DVD and Blu-ray high-definition discs and
play/record hardware will arrive in the US sometime this year, and the two formats will
compete head-to-head. There is little to distinguish them technically, but consortiums of
movie studios have committed to support each format and the equipment needed to
manufacture the discs. Blu-ray’s 25GB capacity per recording surface requires
completely new disc-pressing equipment. The HD-DVD’s 15GB per surface can, after
minor retrofitting, be produced on the machines that currently make regular DVDs, at far
lower cost than by brand-new machines. Blu-ray seems to have the advantage among makers of
consumer equipment, but HD-DVD has signed up some big studio support.
The arrival of the hi-def DVD means that DVD-V, DVD-A, and
SACD are about to be made obsolete. Once the buyer knows that, eventually, all movies will
be available on hi-def discs, what’s the point in buying them on DVD? Why not wait
for the hi-def version? If you own all three Special Extended Editions of The
Lord of the Rings films, will you be happy about buying them again to get the HD
versions?
The video quality of DVD does not compare with that of
high-definition TV. Watch two hours of HDTV, then switch to DVD, and you’ll notice
immediately that the DVD lacks detail, and can’t reproduce some of the colors you see
from HDTV. DVD-Video sound is limited to Dolby Digital or DTS, both of which employ
audible compression. The uncompressed, or lossless, audio to be used on HD-DVD and Blu-ray
discs will likely sound as good as or better than DVD-Audio and SACD. If you have a DVD-A
player and have compared the sound of DVD-A to the same disc’s DTS or Dolby Digital
tracks, you’ve heard how much better DVD-A sounds -- the difference is not subtle. I
can hardly wait to watch movies at home with sound that is that much better.
Once HD-DVD and Blu-ray players arrive in numbers, the
DVD-A and SACD formats will probably disappear. The existing installed base of compatible
DVD-A players and SACD players won’t be able to sustain either format. If you own
DVD-As and/or SACDs, keep your fingers crossed that your new HD-DVD and/or Blu-ray player
will also be able to play the older format(s). If not, you won’t be able to get rid
of your DVD-A or SACD player.
New laser technology
When you’re trying to squeeze more data onto a disc
the same size (120mm) as today’s DVD/CD, as you must for a hi-def movie, you’re
limited to adding data layers and/or making the data pits smaller so you can fit more
revolutions of data spiral onto the disc. Both of the new hi-def DVD formats are based on
blue lasers; the shorter wavelength of blue light means that a blue laser’s minimum
beam spot size is much smaller than a red laser’s minimum beam spot. (The lasers in
CD and DVD players are often described as "infrared." However, infrared light
is, by definition, invisible to the human eye. CD and DVD lasers are deep ruby red, and
visible to all or most people with normal vision.)
However, there were some serious technical challenges in
getting lasers to emit blue light, and the greater capacity of hi-def discs won’t
come without drawbacks. Blue lasers are likely to be not nearly as foolproof as and far
more sensitive than the red lasers used in CD players and DVD players. Because blue
lasers are still relatively new, I expect that we will see more outright laser failures in
the new hi-def players than we did in the red-laser devices, and the blue lasers in the
first models will probably not last as long as the red lasers used in the first CD and DVD
players.
There are other problems. Because the data pits on the
hi-def formats are much smaller than DVD pits, and very much smaller than CD pits,
a scratch on a hi-def disc will be a much bigger problem. Also, the longer wavelength of
light used in the red lasers that read CDs and DVDs can pass through dust and fingerprints
almost as if they did not exist; blue light cannot pass through fingerprints or dust
nearly as easily. Because of these issues, there has been a lot of talk about enclosing
the hi-def discs in protective carriers or cartridges, much as very early CD-ROMs were.
Coming soon?
Recordable HD-DVD and Blu-ray media and hardware are
already being sold in Japan: over $2000 for the recorder, $23 for a blank disc. As with
all new technologies, expect prices to steeply and steadily decrease in the first few
years. (You can also expect Blu-ray and HD-DVD playback-only machines to be much less
expensive than their recorder versions.) JVC has already announced media with DVD and
hi-def layers on the same disc; hardware for playing such discs can’t be far behind.
Home theater evolves so quickly that it can be frustrating
to try to keep up. But the high-definition DVD promises so much that I suspect few people
will want to soldier on with DVD -- at least not after hi-def prices fall and the format
war is won by one side or the other.
...Doug Blackburn
db@hometheatersound.com |
