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Real-world Application of HDCP. CPTWG May 28, 2003. The problem. DVI sensitive to capacitance and noise Marginal installation – cable or connector out of spec, nearly out of spec, or loose If HDCP turned on in such conditions, interface can fall into “perpetual snow” state Scope of problem
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Real-world Application of HDCP CPTWG May 28, 2003
The problem • DVI sensitive to capacitance and noise • Marginal installation – cable or connector out of spec, nearly out of spec, or loose • If HDCP turned on in such conditions, interface can fall into “perpetual snow” state • Scope of problem • Legacy installed base of HDCP 1.0 transmitter/receiver pairs • Could be 1/1 billion, 1/1 million, 1/ten thousand of those installations
Ways to address problem • Reauthenticate periodically • Changes to specifications • Proposed HDCP changes for 1.1 may help • HDMI AV_MUTE state may address problem • Reset HDCP state on consumer actions • Make it likely that any consumer action will display a useful picture and reset/reauthenticate HDCP • Provide positive visual feedback to consumers
Possible Solution • Assuming full screen video should be usually protected, • Unencrypted video could be allowed for a short time during “mode changes”