Grass Valley PDR v.2.2 - Manual (Page 63)

Analog Composite Video Input Advanced Control
Profile Family 45
• Enable Quiet Line acts as a noise reference. If the Quiet line is noise-free,
the rest of the signal should also be noise-free. This allows the decoder to not
mistake noise for motion. If the Quiet Line is enabled, the line values for
Field 1 and Field 2 are used. Use the sliders to set the line values for each
field. Click on
Default Lines to return to the default values.
• Enable Impulse Noise Reduction automatically filters out noise spikes,
such as amplifier crackling.
NOTE: If reduction of impulse noise is selected, the disk recorder
automatically switches the clamp speed to slow. It is recommended
that you use the spatial adaptive decode option, although it does not
automatically switch.
Clamp Speed
Clamp speed sets the reaction to changing DC levels of the input signal. Speed
can be Adaptive, Slow, Medium, or Fast. The faster the clamp the more reactive
it is to small DC variations.
Slow ignores short-term DC level changes but gradually changes the clamping
level to track the input. Adaptive uses the best clamp for the current video input.
The Clamp Speed also helps with white noise reduction. Adaptive is the best
choice for white noise reduction. Do not use Adaptive for impulse noise, use
Slow and the Impulse Noise Detection option from the Noise Reduction group.
NOTE: If you set AGC (audio gain control) to automatic on the main
screen, clamp speed cannot be selected.