Installation and Operation, cont’d
Technical Points for Digital Video and Content Protection Encryption
•Digital Visual Interface (DVI) is a digital video format that was created by the computer industry in 1999.
•High Definition Multimedia Interface (HDMI™) is a multimedia format that was created by the consumer video industry in 2003.
The HDMI format is built onto the DVI format, adding digital audio and control while reducing the size of the connector.
The HDMI format is likely to replace the DVI format in the near future.
With passive adapters, the HDMI format is backward compatible with the DVI format.
•With Extron adapters and/or cables, the DVI 201 fully supports either format, regardless of the connector type on the video source and display. See appendix A, "Reference Information," for part numbers.
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HDCP is generated by video player hardware, enabled by the video content.
The HDCP key is transmitted with the Display Data Channel (DDC).
The DDC signal line was designed for the DDC’s low data rate; the HDCP key rate is much higher.
♦Without active buffering, an HDCP key signal can travel only a short distance. The display may properly receive the digital video signal, but not the HDCP key. Without the key, the display cannot decrypt the video signal. Symptoms of undecrypted video may include a flashing black or blue screen or “snow”.
♦With active buffering, an HDCP key signal can travel as far as other signals to ensure proper decryption.
♦The DVI 201 actively buffers the HDCP key.
Troubleshooting
DVI signals run at a very high frequency and are especially susceptible to bad video connections, too many adapters, or cables that are too long. To avoid the loss of an image or introduction of image jitter, follow these guidelines:
•The DVI cable on the input to the transmitter or
the output of the receiver should not exceed 10' (3 m).
•Use only cable designed for DVI signals.
•Limit or avoid the use of adapters.
•If the display exhibits a flashing black or blue screen, snow, or other distortion, a
Check for an HDCP problem by ejecting the DVD from the player. If the display distortion stops and the DVD menu or screen saver image is clear, the problem is
•Always power the display before the DVI video source in order for the source to retrieve the DDC from the display.
| DVI 201 Tx/Rx • Installation and Operation |
