Re: [Dvdrtools-users] DVD+R/+RW support

[Bryan J . Smith]

All of this "speculation" is 100 percent, factually and technically 
explained by the understanding of how "single-groove" media and 
"pie-slice" media differ physically.

CD-RW, DVD-RW and DVD+RW are "pie-slice" MO and DVD+R is a hybrid 
MO-WORM, but still "pie-slice" physically.

CD-R and DVD-R are "single-groove" WORM.  Physically, how the laser 
tracks is *no* different than CD-ROM or DVD-ROM.  I.e., literally like 
an analog record, a revolution does not return the laser where it 
started.

This is not true of MO.  When the disc does a revolution, the laser 
starts *exactly* back where it was.
So for "pie-slice" MO to emulate "single-groove" WORM, additional logic 
is required.

An additional issue in DVD+R/+RW v. DVD-RW/RAM is CAV v. CLV, 
respectively.
CLV MO always has the same, relative layout.
CAV MO requires "gap fill-in" that is not consistent.
It's much, much easier to accomodate MO CLV than MO CAV.

Which is why official CD-RW MO standards *never* introduced CAV, they 
were always CLV.
Even the 8x and higher Pioneer standards were CLV MO.
Sony/Philips introduced 10x and higher standards using CAV MO, which has 
been attributed to shortening of drive lifespans and reduced 
compatibility.
I used to refer to it as CD+RW.

At least there is no more confusion in the DVD arena.
But the issues with DVD+RW remain for non-DVD+RW consortium drives.
MO is already a support issue for players, but CAV MO is even worse.
Hence the problem with DVD+RW compatibility on even Sony/Philips 
consumer drives.

Again, I'll show this in the fact I'm writing.


> No I did mean computer dvdrom drives. If they're manufactured 2004 or
> later they should always be able to read everything. Many dvdrom drives
> manufactured in 2003 can also read everything, but there probably were
> still some sold who couldn't read DVD+R or DVD+RW. "Read everything"
> here means "meant to read everything", there are always some
> combinations of dvdrom drive and media brand which don't work. And the
> probability of some dvdrom drive failing to accept DVD+R media XYZ are
> not higher than a failure with DVD-R media XYZ, for drives of 2004 or
> later (and many earlier).
>
> Consumer video players can usually read DVD+R(W) since about 2004, but
> the packaging will say. Some players can also read some brands of media
> types for which they aren't specified, so it's worth trying.
>
> Burners aren't so much the issue, assuming you stick to the media
> varieties which the burner can actually burn. And obviously assuming the
> burner was designed to burn all formats.
>
> This all from my relatively small sample size.
--
Bryan J. Smith   mailto:address@hidden
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