Posted by Goro on 12/08/05 15:53

Found myself researching HD and ended up reading wikipedia's BluRay
entry (http://en.wikipedia.org/wiki/Blu-ray_disc), whch was quite
interesting and contained some items that i wasn't (quite) aware of.

Granted (Allan), that since there's product there's certainly room for
change from the "facts" of now, but this is all still quite interesting
and food fro thought.

==

the introduction of a clear polymer that gives Blu-ray discs
unprecedented scratch resistance. The coating, developed by TDK
Corporation under the name "Durabis," allows BDs to be cleaned safely
with only a tissue-a procedure that can damage CDs, DVDs, and
(presumably) HD DVDs, which are manufactured by the same process as
these older optical media. Bare BDs with the coating are reportedly
able to withstand attack by a screwdriver

- I don't believe the screwdriver part. And i'm still wary of the
notion of "scratch resistant" as it's in Sony's interest for the discs
to be somewhat delicate. Still, it's an interesting statement if true.

==

The BD-ROM format specifies at least three video codecs: MPEG-2, the
standard used for DVDs; MPEG-4's H.264/AVC codec; and VC-1, a codec
based on Microsoft's Windows Media 9. The first of these only allows
for about two hours of high-definition content on a single-layer
BD-ROM, but the addition of the two more advanced codecs allows up to
four hours per layer.

- This is interesting to me. THere's an inherent TIME limitation
independent of video disc size? It's not quite clear why this should
be true and I'm concerned about it. a 4hr/25GB layer seems
questionable. No, i'm not wanting to see any 4+ hr long movies crammed
onto one layer, but I AM thinking about SD tv shows that would
inevitably be put on BR. currently you canput (say) 2 1/2 hrs on a
DVD9, sometimes more. So on nearly 3x the capacity, being restricted
to 4hrs isn't quite convenient.

==

At the 2005 JavaOne trade show, it was announced that Sun Microsystems'
Java cross-platform software environment would be included in all
Blu-ray players as a mandatory part of the standard. Java will be used
to implement interactive menus on Blu-ray discs, as opposed to the
method used on DVD video discs, which uses pre-rendered MPEG segments
and selectable subtitle pictures and is considerably more primitive.
Java creator James Gosling, at the conference, suggested that the
inclusion of a Java virtual machine as well as network connectivity in
BD devices will allow updates to Blu-ray discs via the Internet, adding
content such as additional subtitle languages and promotional features
that are not included on the disc at pressing time. This Java Version
will be called BD-J and will be a subset of the GEM (Globally
Executable MHP) standard. GEM is the world-wide version of the
Multimedia Home Platform standard.

- Maybe this is where all the talk about the updates via permanent
internet connection is coming from. not from Sony proper but from
ancillary (but associated) persons like James Gosling. On the one
hand, I really like the idea of having something like Java to render
the menus (just not FLASH for God's sake! :) ) and in pariticular,
hopefully, to have a true (unicode) text stream for subtitles (with
scalable fonts) instead of the poor looking current image streams.
I'd also be somewhat worried about exploits and virii for my BR player,
esp. if required to be connected to the internet.

-goro-

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