| T.R | Title | User | Personal
Name | Date | Lines |
|---|
| 1210.1 | DVD 500 lines - LD 400 | COPS02::FRIES | Hi-NRG sitebyte (Gary at Postal) | Thu Feb 27 1997 10:04 | 11 |
| Hi Jason,
The standard resolution of a LD player is 400 lines. With DVD I would
expect a sharper image depending on the display device and add-ons.
Since I'm an avid LD collector my main concern would be the
availability of movies in DVD format.
Later,
Gary
|
| 1210.2 | DVD uses lossy compression | CADSYS::SHEPARD | Overwhelmed by trivialities | Thu Feb 27 1997 10:27 | 10 |
|
My understanding of DVD is that it uses a lossy compression algorithm.
Therefore, although there may be a higher resolution, there will be
artifacts as a result of the compression. LD is therefore expected to
be the videophile's first choice with DVD becoming the average consumers
choice. I expect availability of DVD's to slowly solve itself as more
players become available. JMHO.
Cheers,
--Dave
|
| 1210.3 | LD resolution | CADSYS::SHEPARD | Overwhelmed by trivialities | Thu Feb 27 1997 10:28 | 6 |
|
One more thing. I believe the resolution of an LD player is actually
in the 425 - 450 range.
Cheers,
--Dave
|
| 1210.4 | | QUARK::LIONEL | Free advice is worth every cent | Thu Feb 27 1997 11:15 | 10 |
| "500 lines" is the theoretical peak resolution of DVD - the actual resolution
will vary depending on what the on-screen images are. For static shots, DVD
should look better than laserdisc, but for fast-moving images, it could look
worse as compression artifacts appear. DVD will have less color noise than
laserdisc.
Nonetheless, laserdisc will continue to be the superior format for the
movie collector, unless all you're interested in is the latest mega-hits.
Steve
|
| 1210.5 | | LABC::RU | | Thu Feb 27 1997 13:56 | 5 |
|
DVD does have the advantage of compact size. Easy to carry.
The LD probably will cost more to produce than laserdisc.
The player certainly cost more(almost double). On computer,
I believe DVD will take over CD in the future.
|
| 1210.6 | Pioneer CLD is 425 lines | COPS02::FRIES | Hi-NRG sitebyte (Gary at Postal) | Fri Feb 28 1997 08:20 | 8 |
| Hi,
To noter from .3 (Dave) - I stand corrected ... My Pioneer doc lists
CLD704 at 425 lines.
Regards,
Gary
|
| 1210.7 | | LABC::RU | | Fri Feb 28 1997 15:41 | 2 |
|
Fry has the Panasonic DVD selling for $599 now.
|
| 1210.8 | | QUARK::LIONEL | Free advice is worth every cent | Fri Feb 28 1997 21:31 | 3 |
| Anything to watch on it other than a demo disc?
Steve
|
| 1210.9 | | 42376::BARKER | Careful with that AXP Eugene | Mon Mar 03 1997 05:08 | 27 |
| re .0
> Sony is coming out with DVD player soon. It claims
> 500 lines resolution. Is this an improvement from laser
> disk player?
Not only Sony but all the other companies too. They see DVD as the next big
thing for home entertainment. It's theoretical resolution is a little better
than laserdisk (about 450 lines) although motion artifacts from MPEG
encoding/decoding may also be introduced.
The problem with DVD for the next few years is lack of software. The number of
titles planned for the next year is only in the low hundreds (2-300 I think).
Compare this to laserdisk which has been around for 10 years & has 8000+ titles
in print.
There are to be combined DVD & laserdisk players which looks like it might be a
good futureproofing route. I am a recent convert to laserdisk which has always
been far less popular here in the UK than in the US. I bought a nice cheap
second-hand player & have been really impressed with the quality & performance
of laserdisk. I wish that I had bought one years ago. As one who enjoys movies
very much the opportunity to watch them at home with good surround sound, in
their original cinema ratio & with better than broadcast picture quality is not
to be missed.
Nigel
|
| 1210.10 | | SOLVIT::SNORAT::OLOUGHLIN | The fun begins at 80! | Mon Mar 24 1997 11:26 | 59 |
|
A question if I may. Can you please describe what you
mean by "artifacts" as a result of the compression?
Deb and I checked out the DVD display yesterday while at
a mall. I looked pretty good. Streamlined deck that will
double as a CD player, cool.
I currently have a laser disk player, a pretty good one.
I admit to being spoiled since I have not rented a VHS tape
in over three years but I don't think I'll be as militant,
(for lack of a better word) towards holding on to the LD
player. It belongs in some sort of perspective.
For the sake of a measuring stick consider a VHS tape
rated at 1 and a LD rated at 100. Everyone who has made the
leap from VHS to laser would never go back, because of the
quality of both the video and audio, but how bad, (if at all)
is DVD to the LD anyway?
The general opinion is that the DVD has a better image
on static or slow shots but the compression method creates
artifacts on action shots. How bad or noticable are these
artifacts? If you have to sit back and search these out then
is it *that* bad?
If the VHS is 1 and LD 100, then maybe the DVD is a 90?
If that is the case, then the lesser performance of the DVD
may not be enough of an issue for me, and maybe you, to not
go with DVD.
As far a titles go, true there may be 8000 titles out
there on LD, but there were only 1-300 available, (or less)
when LD was introduced. It seems to be an unfair comparison
to say that there are thousands more however true the statement
may be. After all, it *has* been TEN years time to build that
library.
If, (a giant "if") the DVD is accepted, then it will
replace the VHS deck and rental industry. This is a win win
for us. My guess is that the DVD will be so much better than
the VHS that people will flock to it. Also as a guess is that
the performance of the DVD will be so close to that of a LD,
that apathy will become the rule towards LD's in the future and
the industry will slowly turn its back on LDs.
The above will be a true statement when Blockbuster rents
DVDs instead of tape.
Anyway, those are my guesses. I'd still like to hear more
about the artifacts seen during action shots.
Best regards.
-Rick.
|
| 1210.11 | Blockbuster to carry DVD. | SUBPAC::TADRY | | Tue Mar 25 1997 12:55 | 4 |
| Blockbuster video is supposed to start with 45 rental titles by May '97.
RT
|
| 1210.12 | | SOLVIT::SNORAT::OLOUGHLIN | The fun begins at 80! | Tue Mar 25 1997 13:22 | 32 |
|
There you have it.
This all seems to remind me of CD players when they first
came out. Again, for the sake of comparison, I'll use a 1 to
100 scale. 1 being a turntable, 100 being the best in terms
of audio quality.
For low cost (100 to 200) you can get a CD that provides
a rating of 90. Mid cost, 3 to 5, you get something like a
92-94. Huge cost you get a rating of 96-98.
Q: Who can really hear the difference between the three?
A: The same people who used green highlighters on their CD's.
The point being the DVDs may have some flaws but they
provide such a higher viewer experiance in both audio and
video that they will quickly become the norm.
However, I am still not sure of what the "artifacts"
are. Anyone care to expand on it? Or is it one of those
things that has to be shown and can not be described?
-Rick.
PS: I am going to hold off buying a DVD until they
offer a 5 disk carousel deck that will replace
the Sony. I do hope they make it someday.
|
| 1210.13 | | JAMIN::WASSER | John A. Wasser | Tue Mar 25 1997 15:08 | 31 |
| > However, I am still not sure of what the "artifacts" are.
artifact: n. An object, esp. a tool, produced by human
workmanship. In the case of DVD it is a noticable error
in the picture due to losses in compression.
There are two forms of compression:
1) Lossless
2) Lossy
Lossless compression will guarantee that the output is identical to
the input. For most computer files you can get about a 50% reduction
in size. It works fine for downloading EMail but to get the larger
reductions necessary to fit two hours of video onto a CD-ROM you have
use lossy compression.
In lossy compression the goal is to throw out only those
picture elements that the viewer will not miss. In still
photographs you can divide the picture into rectangles of
a very similar colors and store only the rectangles instead
of each pixel. In video you can update only the parts of the
picture that changed since the last frame. If many pixels
change between frames and there aren't large areas of a single
color, you may not be able to store all of the data necesary
to reproduce the picture closely enough to fool the eye.
When the user notices that an area of subtile colors looks blocky
(colors that are too different have been grouped as one) or that
parts of the picture aren't moving when they should be (a
stutter on a quick pan, for example) you have an "artifact".
|
| 1210.14 | | SOLVIT::SNORAT::OLOUGHLIN | The fun begins at 80! | Tue Mar 25 1997 16:34 | 20 |
|
smarta_s : adj, american slang, term meaning...
8^)
Thanks John.
I have seen quick pans that have had a stutter in
them and have wondered just what the hell was causing
it. It would seem that the networks have been using
this compression method for a while for their broad-
cast and storage needs. Regardless, I have indeed
seen it and don't care for it either.
For a higher quality disk or version of a release,
can they bypass this? Meaning two disks for a release
vs one disk that has noticable stutter/artifacts?
-Rick.
|
| 1210.15 | | TAPE::PETERS | | Tue Mar 25 1997 18:42 | 16 |
| re .14
Uncompressed NTSC video takes about 20-25 MBytes/sec . A DVD player
plays at 1 - 1.5 MBytes/sec. So, DVD must compress at ~20:1 . If someone
made a 2x ( or 4x,8x,12x,... ) speed DVD you have a player that could play
a better picture. The bad news is the data ( i.e. quality ) is lost in the
compression process. You would need movies compressed for a 2x player.
We have DVD players running in the lab here in Shrewsbury MA.
( Storage Systems ). The picture is better than VHS, I can't say if
it is better or worse than my laser disk player, it's just different.
Steve Peters
|
| 1210.16 | | LEFTY::CWILLIAMS | CD or not CD, that's the question | Wed Mar 26 1997 10:36 | 12 |
| Also, the compression technology is still evolving... As the
compressors learn to take advantage of buffering in the drives, they
will be able to vary the data rate somewhat to compensate for fast
movement by throwing a little bandwidth at it. This does not work for
continous movement, but can help on fast scene changes.
I'd agree with Steve. It's different. It's also probably good enough
for 95%+ of the consumer market, given that it does give generally
better picture quality than std VHS.
Chris
|
| 1210.17 | | JAMIN::WASSER | John A. Wasser | Wed Mar 26 1997 13:35 | 13 |
| > For a higher quality disk or version of a release, can they [eliminate
> compression artifacts]? Meaning two disks for a release vs one disk
> that has noticable stutter/artifacts?
The quality can be improved, up to a point, by going to multiple
disks. The compression not only reduces the space needed to store
the data but also the rate at which you have to transfer data
in order to keep the video and audio buffers filled.
Going to multiple disks will relieve the space limit but at some
point you may hit the data rate limit of the drive and have to
start throwing away data.
|
| 1210.18 | | LEFTY::CWILLIAMS | CD or not CD, that's the question | Wed Mar 26 1997 17:05 | 12 |
| The places where you see the artifacts are the fast movement times,
which is exactly when you need the highest bandwidth... 2 disks won't
help there - it's drive bandwidth limited. If DVD movies are mastered
for 2x read players, and 2x read players exist, then a 2 disk solution
would help more. I don't expect that to happen for a long while.
Also, DVD supports dual layer disks, so you can get a little under 2x
the data on one of those... which can help some, but not enough to
solve the problem completely.
Chris
|
| 1210.19 | Artifacts are only one factor to consider | NPSS::NEWTON | Thomas Newton | Tue Apr 08 1997 23:50 | 42 |
|
Keep in mind that aside from picture quality, DVD has a number of big
strikes against it, including
o No recordability today (and the likelihood that studios will
fight future recordability tooth and nail)
o Copy protection on the digital outputs - possibly even worse
than with CDs/(DAT, DCC, MD), which allow one generation.
o Macrovision on the analog output. We all know what a joy(!)
this can be even when playing an original VHS tape on a good
TV that is directly connected to the VCR.
o Copy protection / encryption of DVD video signals when being
transported around inside a personal computer. Forget using
a short fair-use video clip in Johnny's multimedia report!
o Attempts to get the Congress to mandate all this crud, using
language so vague the HRRC says it would require every piece
of equipment to enforce every type of copy perversion either
known now or ever invented.
o Regional codes so that a title made in one part of the world
WILL NOT PLAY in another (NTSC/PAL differences aside). Thus
things like Japanese imports would become unavailable.
o Rumors that studios like Disney will not support DVD unless/
until they can get some sort of modem/pay per view junk into
the players. So you might go and buy a title, take it home,
and find that you have to pay AGAIN each time you play it!!!
o No clear provision for HDTV.
Don't get me wrong - the increased storage capacity will be greatly
useful (once there are DVD-RAM drives, or once there's enough of an
installed base that vendors start churning out DVD-ROMs).
But as a home video medium, it's deader than a doornail at my house.
I'd rather stick with VHS, or pick up a LaserDisc player/discs, even
as the powers-that-be orchestrate LaserDisc's LP-like end.
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