Scrambling Levels; Elementary Stream Level Scrambling - Cisco RF Gateway 1 Configuration Manual

Scrambling Levels

Scrambling can be done on an elementary stream level or service level. The
following list describes these scrambling levels.

Elementary Stream Level Scrambling

Each component of a service may be scrambled by a separate CW. For example,
video and audio may be scrambled with a separate CW. This is useful in
multilingual systems where a premium is charged for a second audio in a different
language. In this case, each component or elementary stream is associated with its
own stream of ECM messages.
When scrambling at the elementary stream level, all elementary streams within the
service are scrambled using different CWs. One ECM is required for each
elementary stream. The CA descriptors are inserted after each elementary stream
within the Program Map Table (PMT).
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Scrambling Levels

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