| Video Noise October 2007
 Hi-Def Movies by Mail: Great Idea, But You May Have Problems
The Netflix and Blockbuster rent-DVDs-by-mail plans are
sheer genius in conception and, mostly, in execution. A plethora of regional distribution
centers means that it takes only a day or two for you to receive a disc, or for the
service to receive a disc you’ve returned. If you limit yourself to DVDs, problems
are few and far between. But if you’ve joined to rent high-definition HD DVD or
Blu-ray (BD) discs, you may encounter an occasional problem.
A single-layer HD DVD can contain 21 times more data
than a CD, and 3.3 times more than a single-layer DVD. A single-layer BD disc can contain
35 times more data than a CD, and 5.5 times more than a single-layer DVD. Lay a hair on
the surface of any of these discs to represent a scratch. If the hair runs from the center
hole to the outer edge, it doesn’t affect many data. Every player in every format
will be able reconstruct any data that can’t be read. But if you turn the hair so
that it follows the curve of the disc, it now covers many more data. Chances are a CD will
still be read without problem, but more of a DVD’s data will be obscured, 3.3 times
more than that on an HD DVD, and 5.5 times more on a BD. The player might freeze the
frame until it can find a readable part of the disc, or give up altogether and eject the
disc -- in the latter case, too many data have been destroyed for the player’s
error-correction algorithm to be able to accurately reconstruct them. Collectively, these
freezes can last longer than the film’s playing time -- for each block of data the
player makes an error in trying to read, it re-tries numerous times before giving up.
Both disc-by-mail programs ship movies in mailers in which
nothing but two or three layers of paper or paper-like material protect each side of the
disc. As a disc works its way through the US mail, there’s nothing in the packaging
to protect it from being squeezed or bent. The paper sleeves touch the disc, grinding into
its surfaces any dirt on the disc or in the sleeve. This isn’t too bad for DVDs, but
the scratches pose a serious challenge to the hi-def formats’ data density and error
correction.
I have received an HD DVD and a BD, each with so many
scratches that the discs either refused to play from the beginning, or failed to play past
some point in the film. These scratches, easy to see but very fine, were mostly 1/8"
to 2" long and ran in random directions, often crossing each other. I’ve gotten
two BDs that appeared to be new but refused to play in a Sony BD player, which displayed
the error message "invalid region code." I saw no scratches or fingerprints, so
I gave up and returned them for other copies, which played fine.
Recently, I tried bending a brand-new BD to see how much
flexure it could take before it stopped playing. Any amount of bending with the clear side
on the inside of the bend did nothing -- the disc continued to play even after I’d
bent it more than 90 degrees. But the first bending with the label on the inside
produced the "invalid region code" error and the disc failed to play. The disc
was no longer quite flat when placed on a flat surface, so I bent it back several times
until it again looked flat -- and it played as if nothing had happened to it. From this I
conclude that the bending the discs get in the mail probably won’t hurt them; all the
problems seem to be related to scratches, fingerprints, or other dirt on the surface. So
far, of the 60 or so titles I’ve received by mail, four have failed partway through
or refused to be read at all. In each case, a second copy of the movie played fine.
For the reasons mentioned above, fingerprints on hi-def
discs tend to be more trouble than fingerprints on DVDs -- you might want to clean rented
or mailed discs with mild soap and water before playing them. I like to take the disc to a
sink, wet it and my hands, apply a little liquid soap to the fingertips of one hand, clean
both disc surfaces with soapy fingers and more water, rinse the disc to remove all the
soap, and dry it with a clean cotton towel. The hard coating applied to hi-def discs
protects them nicely during this process.
All of this means that you sure don’t want to judge
the performance of any disc player based on how it handles discs received by mail. When I
receive bad discs, both Netflix and Blockbuster ship replacements as soon as I’ve
notified them by e-mail. If you’re using or plan to use either program for hi-def
disc rentals, that’s fine -- don’t expect every disc to be perfect, and
you’ll still get your money’s worth out. The disc-by-mail programs are now so
efficient that you’ll be amazed by how many movies you can see for such a small cost.
Through Blockbuster, I average 12 mail-order movies a month for $18, and get five more
free rentals from their retail outlet -- any combination of DVDs, hi-def movies, or games.
It’s a deal that’s hard to beat.
...Doug Blackburn
db@hometheatersound.com |
