Blackmagicdesign ATEM - Page 217

Developer Information
128: signed 5.11fixed point Data elements are signed 16 bit integers representing a real
number with
5 bits for the integer component and 11 bits for the fractional
component.
The fixed point representation is equal to the real value
multiplied by 2^11.
The representable range is from -16.0 to 15.9995 (15 + 2047/2048).
Data types 129 through 255 are available for device specific purposes.
Operation type (uint8) The operation type specifies what action to perform on the specified
parameter. Currently defined values are:
0: assign value The supplied values are assigned to the specified parameter. Each
element will be clamped according to its valid range.
A void parameter may only be “assigned” an empty list of boolean type.
This operation will trigger the action associated with that parameter.
A boolean value may be assigned the value zero for false, and any other
value for true.
1: offset / toggle value Each value specifies signed offsets of the same type to be added to the
current parameter values. The resulting parameter value will be
clamped according to their valid range.
It is not valid to apply an offset to a void value.
Applying any offset other than zero to a boolean value will invert
that value.
Operation types 2 through 127 are reserved. Operation types
128through 255 are available for device specific purposes.
Data (void) The data field is 0 or more bytes as determined by the data type and
number of elements.
The category, parameter, data type and operation type partition a 24 bit operation space.
Group ID Parameter Type Index Minimum Maximum Interpretation
Lens
0.0 Focus fixed16 0.0 1.0 0.0=near, 1.0=far
0.1
Instantaneous
autofocus
void
trigger
instantaneous
autofocus
0.2 Aperture (f-stop) fixed16 -1.0 16.0
Aperture Value
(where fnumber =
sqrt(2^AV))
0.3
Aperture
(normalised)
fixed16 0.0 1.0
0.0=smallest,
1.0=largest
0.4 Aperture (ordinal) int16 0 n
Steps through
available aperture
values from
minimum (0) to
maximum (n)
0.5
Instantaneous
auto aperture
void
trigger
instantaneous
auto aperture
0.6
Optical image
stabilisation
boolean
true=enabled,
false=disabled
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