Grass Valley PROFILE FAMILY v.2.5 - Manual (Page 57)

Analog Composite Video Input Advanced Control
Profile Family 57
- ² Spatial Adaptive . Decoding uses either the comb or notch decoder, on a
pixel by pixel basis, depending on which gives the best results. For
horizontal lines, notch is used; for vertical lines, comb is used.
NOTE: Spatial adaptive and temporal/spatial adaptive decoding uses
the high or low threshold setting.
- ² Temporal/Spatial Adaptive . This is for earlier analog composite cards
only. Decoding uses both the next line and the same line in the alternate
field in the calculations. This decoder uses all of the properties of the
Spatial Adaptive decoder, plus it uses Temporal (interfield changes)
information. The phase change (or lack of) from field to field helps
determine whether high frequency should be decoded as chrominance or
luminance. The threshold determines the amount of motion allowed
between alternate fields to still have the Temporal decoder recognize the
pixel. High allows more motion than Low.
3. For the current analog composite card, click Enable Clamp Speed to enable
it. Clamp speed sets the reaction to changing DC levels of the input signal.
Speed can be either slow or fast. The fast clamp speed is more reactive to
small DC variations. The slow speed ignores short-term DC level changes
but gradually changes the clamping level to track the input.
For clamp speed on earlier cards, click Adaptive , Slow , Medium , or Fast
under the Clamp Speed group. Fast and Slow settings are the same for both
the earlier and current cards, while Medium is a compromise between Fast
and Slow . Adaptive uses the best clamp for the current video input. 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.
4. For current analog composite cards, the Vertical Interval controls set how
vertical interval signals are handled. Move the Group Definition slider to set
how many lines are in Groups 1 and 2. In Group 1, Notch and Pass are
available while Blank and Pass are available in Group 2:
- Notch applies notch filtering to the vertical interval video line. This
means that chrominance information and any luminance around the
chroma subcarrier are removed.