Cisco Headend Digital Broadband Delivery System 用户指南
2-8
Audio Options
4002178 Rev C
Select the Best Audio Range for TV Viewing or
Connection to Theater Systems
Introduction
The Audio Range option affects how the Dolby Digital decoder in the set-top
presents the audio to the subscriber. When the original program encoder sends the
audio level information to the set-top, the decoder in the set-top uses this
information to compress the dynamic range of the audio in varying degrees.
What Audio Compression Works Best?
The amount of compression that is applied to the audio affects the output that your
subscribers will hear. You can apply either a narrow, normal, or wide range of
compression to the audio. You can select the best audio range for your subscribers,
or allow your subscribers to select the range. Read the following information to
determine the best range for your subscribers.
Narrow
With a narrow setting, the set-top performs the most extensive dynamic range
Narrow
With a narrow setting, the set-top performs the most extensive dynamic range
compression available. The narrow setting boosts the dialog levels to more closely
match analog channels. Most subscribers prefer the narrow setting for channel
surfing and program viewing because it minimizes the difference in volume levels
from channel to channel. The Narrow setting also works well for programs that have
lots of loud and soft passages.
Normal
With a normal setting, the set-top preserves a large dynamic range with only a
Normal
With a normal setting, the set-top preserves a large dynamic range with only a
moderate amount of compression. The dialog level may be noticeably quieter on
some channels, while the loudest passages will be noticeably louder. Most
subscribers will not like the normal setting while channel surfing because the
volume level can differ significantly from channel to channel. If your subscribers are
using a home theater system that does not support a digital input, they may find that
the Normal setting provides more of a movie-theater experience, but subscribers
may have to adjust the volume more frequently.
Wide
The wide setting disables dynamic range compression. For multichannel sources,
Wide
The wide setting disables dynamic range compression. For multichannel sources,
this setting reduces average signal levels to be significantly quieter than those for the
normal setting.
Important: The wide setting is not recommended for subscriber use; this setting has
Important: The wide setting is not recommended for subscriber use; this setting has
been provided for testing purposes only.
Recommended Setting
Enable this option to allow subscribers to select the audio range. We recommend that
you select narrow as the default.