TMC22191 CADEKA [Cadeka Microcircuits LLC.], TMC22191 Datasheet - Page 41

• Manufacturer Part Number: TMC22191
• Description: Digital Video Encoders/Layering Engine
• Manufacturer: CADEKA [Cadeka Microcircuits LLC.]

PRODUCT SPECIFICATION
A DOWNSTREAM KEY image comprises the white alpha
characters "HAPPY FACE", and black alpha characters
"Time". This is to be superimposed over the previous 3-layer
composite image. The key signal needed for superimposing
DOWNSTREAM KEY image over the other composite
images is shown to the right. This represents a single bit sig-
nal mapped over the image. When the signal is black (logic
LOW), the DOWNSTREAM KEY image is active, when it
is white (logic HIGH), the previous composite image is
active.
The final 4-layer composite image, DOWNSTREAM KEY
over FOREGROUND over MIDGROUND over BACK-
GROUND, is shown in Figure 21.
HAPPY
3-LAYER COMPOSITE
2-LAYER COMPOSITE
DOWNSTREAM KEY
HI KIDS !
HI KIDS !
FOREGROUND
FACE
TIME
Figure 20. Adding a 3rd Layer
Figure 21. Adding a 4th Layer
HAPPY
HI KIDS !
FACE
TIME
In this illustration, all four source images are static (not mov-
ing). The images input to the TMC22191 can just as well be
"live" (from video camera or VCR sources) as long as:
• Data from those sources is in an input format that the
• The sources either synchronize the TMC22191
Key signals may be generated external to the TMC22191
(Hardware Keying) and use the KEY input pin for control.
Key signals may also be generated within the TMC22191
(Data Keying) by the comparison of input color data with
color data stored in the TMC22191.
KEY
KEY
TMC22191 can accept, and
(Genlock mode) or are synchronized by the TMC22191
(Master or Slave mode).
HAPPY
4-LAYER COMPOSITE
3-LAYER COMPOSITE
HI KIDS !
HI KIDS !
FACE
27037A
TIME
27038A
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