>From [EMAIL PROTECTED] Fri Nov 8 15:52:46 2002
>> High frequency wobbling does not help to make the DVD recording better
>> in case of buffer underruns. You always use the pre-groove only to find
>> the course place where to resume recording. The exact position is found
>> by reading the already recorded data and switching from read to write.
>Well, explain following then. I can take *virgin* DVD+RW media,
>partially format it so that only lead-in gets written out as well as
>probably a small tail after it gets de-iced. This takes ~40 seconds.
>Then I can immediately seek to say 4GB, write some data and immediately
>eject the media. Another 10-20-30 seconds passed depending on how much
>I've chosen to write. I can flip the disc and note that media between
>lead-in and written data remained *virgin*. Now if exact positioning
>could be determined only by playing earlier written data how come it
>went so fast and surface in between remained virgin? If it weren't
>accurate enough how can they guarantee that I'll be able to squeeze 4GB
>in between lead-in and data written at 4GB offset?
This seems to be contradicting the official developer information
for the DVD+RW drives. It includes a state diagram that states that you
need to detect an interrupted de-ice and continue it before the media
becomes usable.
On the other side: Pioneer introduced background formatting for DVD-RW
about 2 weeks ago. Let us wait if there is a difference when the A05 is
available.
>> Call it ho you like, it _is_ some kind of packet writing.
>Well, yet the fact is that whatever we call it, the result is
>*indistinguishable* from whatever that might appear as TAO/SAO/DAO.
If you did format a DVD-RW, then you have the same behavior as with DVD+RW.
The fact that you may distinguish this from other write modes by looking at the
media parameters, does not make it worse than DVD+RW. DVD+RW just does not
support the other write modes.
>MMC specifications mention "link data" in DVD-R[W] context as well as
>border-in/-out in DVD-R incremental recording context. Does either hold
>true? If yes, what's role of border-in/-out? Most importantly. Is
>explicit support by DSP [performing the actual decoding of user data]
>required for playback of DVD-R[W] recorded in packet mode?
I have to ask Pioneer. I have not yet been able to write a DVD-R in packet mode
but the MntFuji mailing list tells me that it should work.
>Then I fail to understand why did you bring up packet writing at all?
>cdrecord[-ProDVD] doesn't support it so that those willing to perform
>say live NFS backups have to solely rely on buffer underrun protection,
>don't they? Is there reason to believe that recovery is so much more
>accurate than in CD [where it's off by default] that you're ready to bet
>your backup on it?
Because it is the only write method that is supported by DVD+RW.
Cdrecord-ProDVD will support multi border DVD-R writing if this is possible.
What I currently know to do does not makes to be integrated into cdrecord-ProDVD
because it does not help the users.
>As already mentioned. DVD+RW supports write of randomly addressed 2KB
>blocks even to *virgin* media (well, when you write 2KB, 32KB gets
>naturally written/de-iced], and naturally rewrite in random order at
>later occasion. Randomly written DVD+RW disc is *indistinguishable* from
>one written progressively/streamed. DVD+R media can be written
... because the drive does not support other write modes.
>progressively in 32KB ECC blocks, *but* uninterrupted streaming is not a
>requirement [you can even eject media between writes]. DVD+R media
>written progressively with interrupts is *indistinguishable* from one
>written streamed/in one single take. All this thanks to "high [spatial]
>frequency wobbled [pre-]groove with addressing information modulated
>into it."
As there is no good information from either DVD group, we may only guess :-(
J�rg
EMail:[EMAIL PROTECTED] (home) J�rg Schilling D-13353 Berlin
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