Used ISOBuster but ISOB said there were unreadable sectors.

Is this DVD just SOL?

In article <F9ednXSHG9IFSX7anZ2dnUVZ_o_inZ2d@comcast.com>,
Rick Merrill <rick0.merrill@NOSPAM.gmail.com> wrote:
If you're talking abut error-free recovery; good chance.

If you're talking about salvaging something playable; another utility like
CDRoller or BadCopyPro may do a better job of extraction.

Mike S. wrote:

Well, our smart (but not "tech savy") gal called the company that made
the DVD and got a 2nd copy which (natch) had the same problem so she
called again (love that persistance), and this time she was told the
following that I (for one) would NEVER have suspected:

The DVD has 7 'chapters'. The first 4 chapters (which play on any
player) was made with single layer technology and chapters 5,6,7
were made with double layer technology!!!! That is why ch 567 would
not play on older players (including the reader on the PC).

Is this what tools like Nero do when they promise to "compress" the DVD
"if needed???"

In article <LcadnRQGH5qbl3HanZ2dnUVZ_gednZ2d@comcast.com>,
Rick Merrill <rick0.merrill@NOTgmail.com> wrote:
Everything on a double-layer disc has to reside on one layer or the other.
If chapters 5-7 are unplayable, and they are the only ones that reside on
the second layer, then there may be a problem with the disc fabrication
process involved in that release.

Double layer compatibility is part of the DVD specification which dates to
the late 1990's. Some older players have trouble with _seamless_ layer
changing (i.e. not pausing significantly when a video stream transitions
from layer 1 to layer 2 right in the middle). Being _unable_ to play the
second layer of a properly manufactured, pressed commercial DVD is not
something you'd expect because of the age of the player. Either the disc
or the player is defective.

(On the other hand, double-layer RECORDABLE (DVD-R or DVD+R) discs are
fraught with compatibility issues, especially with older players).

Yes. The copy program knows (or is told) the capacity of the blank that
the video is to be copied to. If the data won't fit, then the video must
be reprocessed to fit.

Mike S. wrote:
Could you express that differently? (It sounds as if using only one
layer (or the other) would not increase capacity!)

Do you mean that a disk sector is on only one layer, and the next sector
could be on the other layer?

Thanks for the info.

He means each data sector is on one layer or the other - no sector is
on both layers.

AFAIK, the first half of the content of any DL DVD is on layer 0 and
the second half is on layer two, almost exactly evenly divided.

On 3/28/2008, Rick Merrill posted this:
--
Gene E. Bloch (Gino) letters617blochg3251
(replace the numbers by "at" and "dotcom")

In article <hcCdnSoKWqPKu3DanZ2dnUVZ_u_inZ2d@comcast.com>,
Rick Merrill <rick0.merrill@gmail.com> wrote:
Gee, the meaning (or perhaps the irony) was obvious to me when I typed it
:-)

Quoting what your employee was told by the publisher, a disc cannot have
"single layer technology" for some of the data and "dual layer technology"
for the rest. A dual-layer disc is a dual-layer disc through and through.
Some of the data are on layer 1, some on layer 2, and some may be on both.

In article <mn.e2ad7d836524c129.1980@nobody.invalid>,
Gene E. Bloch <hamburger@NOT_SPAM.invalid> wrote:
Thanks for untying my tongue :-)

I was also trying to refute the publisher's rep assertion that different
parts of the disc can use different "technology" (single or dual). The
disc is what it is, through and through ... the only difference is what
part of it a given piece of data resides on.

In article <fsjjq6$ntl$1@reader2.panix.com>,
Mike S. <retsuhcs@xinap.moc> wrote:
(Well, not a single sector, as Gino points out. But a given program on a
video DVD; i.e. a VOB file, can begin on one layer and end on the next;
hence the file itself exists on both).

Mike S. wrote:

So the burner writes onto layer 1 until the layer is full, then the
burner writes onto layer 2. The older players read layer1 just fine,
but crap out because they don't know how to read layer 2 - is that it?

In article <-7Gdnb4Rs6uG43DanZ2dnUVZ_o_inZ2d@comcast.com>,
Rick Merrill <rick0.merrill@gmail.com> wrote:
That's what doesn't make sense to me. The requirement to read the second
layer goes back into the original DVD standard in the 1990's. The OP has
several pieces of equipment that can't read these discs. They can't all be
bad. Surely he has played other double layer discs before (without
explicitly knowing it) as most commercial movie releases have been pressed
that wya for ages and ages.

"Mike S." <retsuhcs@xinap.moc> wrote in message
news:fsk3q6$eff$1@reader2.panix.com...
Commercial discs are different to recordable discs though in that even
single layer recordable discs have lower reflectivity.

In a dual layer disc the upper layer has similar reflectivity to a normal
recordable disc but the lower layer has even lower reflectivity again.

It's quite possible therefore that older players can't read the lower layer
as they weren't designed to be this sensitive.

It was the same in the early days of car CD players which quite commonly
couldn't play CD-Rs due to their lower reflectivity.

Good media is even more important with dual layer than single layer DVDs due
to the tighter sensitivity requirements for reading the lower layer.


Stephen

Stephen Stewart wrote:
Thanks for clearing that up!

Are those reflectivity numbers publicized or are they company
confidential info?

In article <oqidnUGEWPTZw3LanZ2dnUVZ8rednZ2d@bt.com>,
Stephen Stewart <a.nonymous@no.spam> wrote:
Nowhere in the OP's problem report did I see anything about problems with
recordable discs. The DVD's he is having trouble reading are, by his
account, commercial, pressed discs.

For commercial discs, they HAVE to be "this sensitive" to use the DVD
logo; it's part of the sandard.

True; but we aren't talking about recordable discs.

"Mike S." <retsuhcs@xinap.moc> wrote in message
news:fso5d2$5dc$1@reader2.panix.com...
The OP mightn't have but the query that Mike S raised related to the
previous post concerning DL recordable discs.

The point I'm making is that that dual layer recordable discs weren't
invented when standards were originally made.

To read dual layer recordable media the machines have to be more sensitive
than the original spec.

Well the others are and I was just replying in that context.

If you read back a few posts and you'll see this.

">So the burner writes onto layer 1 until the layer is full, then the
HTH.


Stephen

"Rick Merrill" <rick0.merrill@gmail.com> wrote in message
news:QdCdnfIB0NgnC3LanZ2dnUVZ_tHinZ2d@comcast.com. ..
Don't know if actual figures as such are available but I'd be surprised if
they're not.

According to this site only half the laser's power reaches the lower layer
but I'm sure if you search you'll find more detail.

http://www.misco.co.uk/CONTENT/MODUL...ERDVD.HTM?bp=1


Stephen

"Stephen Stewart" <a.nonymous@no.spam> wrote in message
news:0fGdnT4eifGxXXLanZ2dnUVZ8vWdnZ2d@bt.com...
Sorry Mike I got the posters names mixed up but the context still applies.


Stephen