DigiDesign Pro Tools, Справочное руководство

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Pro Tools Reference Guide 350
Tick-Based Timing
Pro Tools is a sample-based program with an in-
ternal MIDI resolution of 960,000 pulses per
quarter note (ppq). However, when the Time
Scale is set to Bars|Beats, the display resolution
in Pro Tools is 960 ppq.
In Bars|Beats, Pro Tools is tick-based (960 ticks
to a quarter note), which means that some
amount of sample-rounding may occur when
placing events at certain locations (see “Sample
Rounding and Edit Operations” on page 352).
When working in Bars|Beats, you will often
want to specify tick values for a number of oper-
ations, including:
• Placing and spotting regions
• Setting lengths for regions or MIDI notes
• Locating and setting play and record
ranges (including pre- and post-roll)
• Specifying settings in the Grid/Groove
Quantize and Change Duration pages of
the MIDI Operations window
• Setting the Grid and Nudge values
The following table lists the number of ticks for
each of the main note sizes:
Tick- and Sample-Based
Timebases
Pro Tools lets you set any track timebase to ei-
ther sample-based or tick-based.
Audio in Pro Tools is sample-based by default.
This means that if an audio region is located at a
particular sample location, it will not move
from that location if the tempo changes in the
session—though its bar and beat location
will
change.
MIDI data in Pro Tools is tick-based by default.
This means that if a MIDI region is located at a
particular bar and beat location, it will not move
from that location if the tempo changes in the
session—though its sample location
will
change.
Sample-Based Audio and MIDI
With a sample-based audio track, all audio re-
gions in the track have an absolute location on
the Timeline. Audio stays fixed to the sample
time, regardless of where tempo or meter
changes occur in a session.
If you make a MIDI track sample-based, all MIDI
events in the track have an absolute location on
the timeline. MIDI events stay fixed to the sam-
ple time, regardless of where tempo or meter
changes occur in a session.
Note Value Normal Dotted Triplet
1/2 note 1920 2880 1280
1/4 note 960 1440 640
1/8 note 480 720 320
1/16 note 240 360 160
1/32 note 120 180 80
1/64 note 60 90 40