DigiDesign Digidesign Pro Tools 8.0, Reference Manual

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Chapter 29: MIDI Editing 603
You can measure the latency for a MIDI device
assigned to a MIDI track by recording its audio
output back into Pro Tools. Compare the sample
locations for the recorded audio events against
the original MIDI notes to calculate the latency.
To configure a MIDI or Instrument track offset for
a track:
1
Choose
Event > MIDI Track Offsets
.
2
Click in the Sample Offset column for the
MIDI or Instrument track and enter the number
of samples (–10,000 to 10,000) for the offset. A
negative value causes the MIDI or Instrument
tracks to play back earlier than the audio tracks;
a positive value causes the MIDI or Instrument
tracks to play back later.
The equivalent offset in milliseconds is dis-
played in the msec Offset column. This value
cannot be edited, but updates when a new value
is entered in the Sample Offset column.
3
Press Enter (Windows) or Return (Mac) to ac-
cept the entered offset value.
To reset all offsets for all MIDI and Instrument
tracks, click the
Reset
button in the upper left of
the window.
Stuck Notes
If you encounter stuck notes with any of your
MIDI devices, you can silence them with the
All
MIDI Notes Off
command.
To turn off all stuck notes:
„
Choose
Event > All MIDI Notes Off
.
Remove Duplicate Notes
The
Remove Duplicate Notes
command is used to
remove duplicate MIDI notes. If a note starts
within the first 25% of the duration of a note of
the same pitch which is already sounding (or
within an eighth-note, whichever is shorter), it
is considered a duplicate and is combined with
the previous note. If it starts later than that, the
first note is shortened so that it ends at the same
tick at which the new one starts.
To remove duplicate notes:
1
Make an Edit selection including the duplicate
notes you want to remove.
2
Choose Event > Remove Duplicate Notes .
Measuring MIDI latency
MIDI Track Offsets window
MIDI Note On
Audio Transient recorded
from MIDI device
Approximate offset
in samples
Press Shift+Period (.) (Windows)
or Shift+Period (.) (Mac) for the
All MIDI Notes Off command.