On 2/15/07, Dieter <[EMAIL PROTECTED]> wrote:

> Yes I've heard that "type A HDMI is backward-compatible with the
> single-link Digital Visual Interface carrying digital video (DVI-D or
> DVI-I, but not DVI-A) ".

But not dual link DVI?
I don't know and I would have to read through both specifications to
give you an honest answer.

> > I think HDMI requires HDCP?  HDCP is optional on DVI.

> So just say that you have dvi with some but not all of hdmi 1.3
> features as a bonus.
> Plus does anyone know if monitors/tvs would refuse to display if you
> didn't encrypt?

I believe it is the other way around.  The source (Blu-Ray, HD-DVD,
cable/satelite box, whatever) will not play unless the display supports
HDCP and the secret handshake succeeds.
Yes thats for the encrypted(HDCP) scenario, both made a handshake
using a 40 key vector  and some addition rules. Each key is only
56bits . There is  a master matrix involved. It has been shown that
techniques from linear algebra suffice to recover this master matrix.
Furthermore once one has this master matrix you can fabricate whatever
per device keys that you need. The whole hdcp scheme was designed to
fit into less than 10,000 gates IIRC.

http://citeseer.ist.psu.edu/cache/papers/cs/25911/http:zSzzSzwww.cs.berkeley.eduzSz~dawzSzpaperszSzhdcp-drm01.pdf/a-cryptanalysis-of-the.pdf
and a few other places talk about it's weaknesses.

However since this project is making not displays, but video cards; we
can choose the behavior of the video cards but not the monitors or the
Operating System or a TPM type chip or the video player software.
If a monitor/display receives an unencrypted signal will it display it
correctly? I believe the answer is yes. So we can still use the
features of HDMI that are better than just DVI .

Another question is whether this project can be used to display
movies(HD-DVD, Blu-Ray) protected by AACS runing on Windows Vista with
it's "Protected Media Path", especially with AMD and Intel having TPM
type stuff in their CPUs.

http://en.wikipedia.org/wiki/Advanced_Access_Content_System
http://www.aacskeys.com/
http://en.wikipedia.org/wiki/Trusted_Platform_Module

http://it.slashdot.org/article.pl?sid=06/12/25/2034238
http://www.theinquirer.net/default.aspx?article=36570
http://www.cs.auckland.ac.nz/~pgut001/
http://www.cs.auckland.ac.nz/~pgut001/pubs/vista_cost.txt

"Output Content Protection and Windows Vista",
http://www.microsoft.com/whdc/device/stream/output_protect.mspx, from WHDC.

"Windows Longhorn Output Content Protection",
http://download.microsoft.com/download/9/8/f/98f3fe47-dfc3-4e74-92a3-088782200fe7/TWEN05006_WinHEC05.ppt,
from WinHEC.

"How to Implement Windows Vista Content Output Protection",
http://download.microsoft.com/download/5/b/9/5b97017b-e28a-4bae-ba48-174cf47d23cd/MED038_WH06.ppt,
from WinHEC.

"Protected Media Path and Driver Interoperability Requirements",
http://download.microsoft.com/download/9/8/f/98f3fe47-dfc3-4e74-92a3-088782200fe7/TWEN05005_WinHEC05.ppt,
from WinHEC.

http://en.wikipedia.org/wiki/Protected_Media_Path

Given the "open" nature of this project -- I think that the most you
could do is put in the hdcp stuff in and allow the driver to load a
secret hdcp vector in. However I don't think that situation is likely
to make the code signers happy.

Word is that the early disks
don't require this, but it is expected to be turned on at some point
down the road.  Some cable boxes do already have it turned on, and of
course there are stories of bugs that prevent this from working properly.
So even if you are a good little consumer and buy a HDCP display you
still might not get to watch the movie or whatever.  Or maybe it plays
at low resolution, I forget.

http://en.wikipedia.org/wiki/Image_Constraint_Token most of the
HD-DVDs and BluRays have not set this yet. and yes the specifications
say they can downsample instead of refusing to play whatsoever. Yes I
know these drm schemes have caused lots of issues. I strongly dislike
them and won't buy any products which require the use of drm.

> >  Is there a standard/specification somewhere for how
> > large the hole for connectors is supposed to be?

> I would assume the standard gives pin out and size information.

Sorry, I wasn't clear.  Not the hole in the card's bracket.
The rectangular hole in the case that the connectors stick out of
when you install a PCI/PCIe card.  On some cases the hole isn't
quite large enough for some cards.

I am sorry I have been working on other things and have not had time
to read the relevant specifications.

--
http://dmoz.org/profiles/pollei.html
http://sourceforge.net/users/stephen_pollei/
http://www.orkut.com/Profile.aspx?uid=2455954990164098214
http://stephen_pollei.home.comcast.net/
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