Switcher Basics
A switcher works by routing video signals
through the various boards and cards in the
frame and feeding them out of the assigned
output BNC. The boards and cards that the video
signal passes through depends on the video
manipulation that is required, and which ME
the source is selected on.
Video Sources
The switcher has access to two basic types of
video sources, external and internal. All video
sources can be assigned to video source buttons.
By pressing a video source button on a bus, the
video source assigned to that button is selected
on that bus.
• External — External video sources come
from cameras, video servers, character
generators, or other external devices into the
switcher.
• Internal — Internal video sources come from
internally generated video, such as
Media-Stores, matte color, and black.
Video Layering
Video layering depends on the ME re-entry and
Keyers that make up the output video. If we
assume that each ME has all keyers on-air and
is re-entered into the ME below, the layering
will start with ME 1 Background and progress
to ME 4, Key 8.
The priority of the MEs on the switcher, or how
they are layered, can be altered by changing
how the MEs are re-entered on the switcher. For
example, if ME 3 is re-entered into ME 1, then
ME 3 will appear behind ME 1 in the video
layering.
As with MEs, the priority of keys can be altered.
The priority of keys can be changed using a Key
Over transition.
ME Re-Entry
Re-entry is the term used to describe the process
of selecting another ME on an ME. For example,
if you select ME 1 on ME 2, ME 1 is said to be
re-entered onto ME 2. Re-entry takes the output
of an ME and uses it as the background or key
on the other ME. If you select an ME on the
background bus, the ME becomes background
video source of the other ME. If you select an
ME on a Key Bus, the ME becomes the key
source of the other ME.
Keep the following in mind:
Keep the following in mind when working with
re-entries:
• You cannot re-enter an ME onto an ME that
is re-entered into the first ME unless Re-entry
Loops is turned on. For example, ME 1 cannot
be re-entered into ME 3 when ME 3 is already
re-entered into ME 1.
• You cannot re-enter an ME into itself.
To Re-Enter an ME
This procedure explains how to re-enter ME 1
into ME 2, but any MEs can be used, as well as
multiple re-entries.
1.
Set up ME 1 with a background and a key.
2.
Set up ME 2 with a key.
28 • Switcher Basics — Ultrix Acuity Operation Manual (v10.1)