Apple Logic Pro X - Manual (Page 818)

Chapter 23 Work in the Environment 818
Use meta events to control condition and operation values
You can control the values of any transformer conditions or operations by using meta events.
Meta events are internal Logic Pro messages—their form is similar to MIDI controller events,
but they have no MIDI meaning, they never leave Logic Pro, and they control internal Logic Pro
parameters.
Like MIDI controller events, meta events have two data values: the first one indicates the type of
meta event (49 to 127, but not all are used), and the second one is the event value (0 to 127).
Meta events 122 to 127 affect transformer parameters.
•
Meta event #127 sets the first (top) operation value.
•
Meta event #126 sets the second (bottom) operation value (if available).
•
Meta event #125 sets the first (top) condition value.
•
Meta event #124 sets the second (bottom) condition value (if available).
Note: Transformers can also process meta events, as long as they are not the meta events listed
above.
Note that all numerical condition and operation parameters used (conditions not set to All and
operations not set to Thru) will be affected by the same meta event. The status condition and
operation are not affected by meta events.
If you want to set numerical parameters individually, or leave some fixed, use separate
transformers in series.
•
Meta event #123 sets the transformer map position.
•
Meta event #122 sets the transformer map value for the current map position. (Use meta event
#123 to set the position first.)
Note: You can use a transformer’s Map Set operation to create these two meta events
simultaneously. When the operation status is set to Map Set, the Data Byte 1 parameter specifies
the map position, and the Data Byte 2 parameter specifies the map value at that position. (A
meta event #122 is sent with the Data Byte 1 value, followed by a meta event #123 with the Data
Byte 2 value.)
You can create meta events with a fader object, you can transform MIDI events into meta events
with a transformer, and you can add meta events to a MIDI region from the Event List. When you
use a fader, set the Output definition to meta, then set the Data Byte 1 value to the meta event
number.
You can remotely control any fader by changing its Input definition, allowing you to use faders
(as well as other transformers) to convert MIDI events to meta events for the remote control
of transformers.