HDCP Question
Dear Gary:
I understand a bit about HDCP, HDMI, and the Image Constraint Token (ICT) flag. My understanding is that if the ICT flag is set by a source playing back over an HDMI link, and the receiving device does not support HDCP, then the video resolution will be down-sampled by the playback device to 960 x 540. Non-HDCP compliant receiving devices connected by an HDMI-to-DVI cable will not see any picture at all. (I’m quoting from the Wikipedia entry for HDCP.)
I have also figured out that the studios producing HD DVD and Blu-ray Discs are not turning on the ICT flag on their discs until at least 2011 or later.
My question is this: Is there a demonstration disc for home theatre enthusiasts (and system installers) that turns on the ICT flag so that equipment can be tested for HDCP compliance? Or is there some other test procedure that can test for compliance, so that when the movie studios start turning on the ICT flag on newly manufactured discs, we will know for sure that our home theatres will work properly?
Thank you for any insight you can shed on this subject.
Michael A. Barnstijn, Guelph, Ontario, Canada,
Editor-In-Chief and Publisher Gary Reber Comments:
I asked Richard Doherty, Director of the Technology Strategy Consumer Media Technology Group at Microsoft, to answer your question:
“First off, please note that the ICT flag has no effect on content flowing out an HDMI connection that uses HDCP––ICT only affects analog outputs, such as HD component and VGA outputs. So if you are hooking up your gear using HDMI/HDCP, you never have to worry.
You asked also about the effect ICT has on HDMI connections that do not use HDCP. The question is actually moot, since NO content at all should flow out of an HD DVD [or Blu-ray Disc] player over unprotected HDMI. AACS does not allow for unprotected digital connections at any resolution.
The studios do not necessarily have anything preventing them from turning on the ICT flag today, though some have made public statements that they do not intend to do so. Note that any movie with the ICT flag set is required to make it clear on the packaging, so you can find out ahead of buying the title.
While there are professional testing discs that test for ICT (I believe), I’m not aware of any consumer-available disc that does so. But the easiest test is simply to play a regular DVD––per DVD rules, analog outputs are normally restricted to 480, while the HDMI output allows upconversion to HD. So the effect on your home system should be similar for testing (though obviously the original source is not HD).”
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