Grass Valley 1200 Operation Manual - Manual (Page 28)

2-10
Section 2— Startup
Shaped Video
Shaped video is video that has been multiplied by a key signal to
create a partial-raster image that is matted over black. A good
example of shaped video is the fill video output of some character
generators, which consists of characters on a black matte.
Typically, the shaped fill video is also accompanied by a matching
key signal that may be used in a keyer to cut a hole in background
video into which the already-shaped fill video may be inserted.
The 1200 configuration menus ask you to identify video inputs as
shaped or unshaped because the switcher handles those two types
of fill video signals differently. For keying with shaped fill video,
the keyer multiplies only the background video with the key
signal to cut a hole in the background, and then adds the already-
shaped fill video into the hole. For fill video that is not already
shaped, the keyer first multiplies both the background and the fill
video with the key to cut a hole in the background and shape the
fill to match the hole. Then the background video and the fill
video are added together to create the finished key.
If you incorrectly identify the type of fill video in the Define
Inputs configuration menu, selecting shaped when you should
select unshaped or vice versa, your keys will have dark lines at the
edges or other artifacts. Changing the video type in the Define
Inputs configuration menu will correct the problem.
Effects Send
Effects Send provides a close interface between the switcher and a
digital picture manipulator (DPM). Effects Send takes the key and
fill video outputs of an effects keyer and sends them to the DPM
for manipulation. The manipulated key and fill outputs from the
DPM then re-enter the switcher’s mixers via the aux buses.
The Effects Send advantage lets you transform a switcher key
effect, such as a chroma key or a preset pattern, as though the
DPM circuitry were built into the middle of the switcher: The
transformed key can be layered over a switcher background and
additional keys can be layered on top of the transformed key.