Integrator's Manual

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Figure 63 – Streaming Video from a COM24 Card
10.2 Preventing Pro:Idiom key loss
Each commercial TV that supports Pro:Idiom decryption must contain a copy of the secret
Pro:Idiom decryption keys. These keys can be corrupted which will prevent the TVs from
decrypting Pro:Idiom encrypted video until the TV is re-keyed. The main way that Pro:Idiom
TVs lose their keys is as follows:
A Pro:Idiom encrypted channel is being watched. The Pro:Idiom keys are sent on a different
PID for each video channel. The TV is asked to change channels to a different QAM carrier
which causes the TV‟s tuner to receive a different transport stream. This new transport stream
contains non-Pro:Idiom key packet on the same PID that previously contained Pro:Idiom key
packets. These are normally audio packets. The Pro:Idiom chip incorrectly interprets these
audio packets as Pro:Idiom key packets. This confuses the Pro:Idiom chip and causes it to lose
its keys.
The QAM24 modulator solves this problem by automatically moving only the Pro:Idiom key
packets to a high PID range that is only used for Pro:Idiom key packets. If a non-Technicolor
piece of equipment is sending packets in the high PID range that overlaps the Pro:Idiom key
PIDs then contact Technicolor for how to modify the QAM24‟s Pro:Idiom key PIDs.
To minimize the possibility of Pro:Idiom key loss when using other QAM modulators, the
COM24 will only output a single audio stream. To enable a second audio stream set the
Stream_ID to 54000.