VBrick Systems 7000 Series, Руководство администратора

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Video/Audio Configuration
VBrick H.264 Appliance Admin Guide 41
Audio Template Settings
The lower area of the Audio page has a set of parameters that can be controlled by pre-
configured templates. Use the
Load Template
button to populate the Audio Template Settings
with pre-configured audio values. The audio templates vary depending on the selected
Audio
Source
(Stereo, Mono, or Dual).
Med Fidelity
is the
default template. All audio encoder
parameters defaults will match these values.
Table 6. Audio Template Settings
Automatic Volume
Control
The volume is continually monitored and automatically adjusted to
normalize audio levels as follows. Default = Standard.
• Standard – Default. Use for general content which may already be
companded (compressed and expanded).
• Light – Peak limiting. Best dynamic range.
• Moderate – Peak limiting with expansion. Reduced dynamic range.
• Aggressive – strong normalization, low dynamic range, most
noticeable.
• User-Defined – Advanced users only. User Defined values employ
two thresholds (high level limit and low level boost) which define
db threshold levels to which volume changes are applied. The low
level boost threshold defines the threshold whereby lower signals
lower will be amplified by gain. The gain is applied gradually until
the audio level is higher than the configured threshold. The high
level limit threshold defines the threshold whereby signals higher
than this value will be attenuated until the audio level is reduced to
a lower value than the threshold.
Minimum Level – the minimum (boosted) audio level you wish to
achieve after reaching the threshold.
Noise Gate Used to suppress unwanted audio noises that are continuous and
predictable (for example air conditioning equipment or traffic sounds).
A a noise gate allows a signal to pass through only when it is above a
certain threshold. If the signal falls below the threshold no signal is
allowed to pass.
Note: The noise gate is particularly useful in AVC (automatic volume
control) configurations to keep ambient, low-level noise from
propagating with gain (i.e. being amplified).
Noise Gate Level Displayed only if Noise Gate is enabled. Range: -34 to -82 dB.
Name Stereo as Mono? AAC-HE Sample Freq Bit Rate †
Stereo/Dual Mono
Best Fidelity Off 48k 256k 84k
High Fidelity Off 48k 160k 84k
High Fidelity – AAC-HE Off Enable 48k 64k 32k
Med Fidelity †† Off 32k 72k 40k
Med Fidelity - AAC-HE Off Enable 32k 40k 24k