Twin format discussions

David Burg dburg at
Tue Aug 2 03:16:44 PDT 2005

* From the T10 Reflector (t10 at, posted by:
* "David Burg" <dburg at>
Dear all, Dear Henry, Bill and Katata-san,

There have being a couple of e-mails sent last night, I will try to react to
all of them in a single e-mail.

Regarding the proposal from Henry, I do appreciate to not need any new
command for format layer change, this would be really great. It seems to me
this will be fine for DVD as when inserted in a DVD only player, only the
DVD layer is visible thus stay consistent with the legacy specification. I
am more skeptical regarding the file system when inserted in a Twin Format
capable device. And when I think of BD, and that likely we will have
recordable layer in the future, I do think we would violate UDF:
"Multisession/Multiborder recording shall not be used with Pseudo OverWrite"
(UDF 2.60 '6.15.3 Requirements for UDF Implementations'). Also for BDMV and
BDAV, we have already the restriction "6. Multisession and VAT recording
shall not be used." (UDF 2.60 ' Requirements for BDAV and BDMV
Application usage'). I think we should still consider the idea from Henry
but try to address its problems.

I fully agree with Henry that we should really consider user interface and
command set issues as a whole to achieve a good user experience. I really
don't want to see OS design ignored while we do the command set, as
ultimately it will affect the software Nero is creating. For instance, we
would prefer to avoid to have to write a low-level software to enable our
playback software to work with twin format discs.

Yes, we need to try to make this work for legacy OS, because this is what
most user will experience. I doubt we want to wait for a new major OS
revision before the user can use our new discs, isn't it?

Best regards,

David Burg

David Burg
Software Development

Nero AG               phone: +49 (0)7248 928 327 (room line) Internal VoIP
Im Stoeckmaedle 18    fax:   +49 (0)7248 928 299
76307 Karlsbad        email: dburg at

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