User`s guide

Pro Tools Reference Guide152
Tick-Based Timing
Pro Tools is a sample-based program with
an internal 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 oc-
cur when placing events at certain loca-
tions (see “Sample-Rounding and Edit Op-
erations” on page 152).
When working in Bars:Beats, you’ll often
want to specify tick values for a number of
operations, including:
• Placing and spotting regions
• Setting lengths for regions or MIDI notes
• Locating and setting play and record
ranges (including pre/post-roll)
• Specifying parameters in the Quantize
and Change Duration windows
• Setting the Grid and Nudge values
The Following table lists the number of
ticks for each of the main note sizes:
Ticks vs. Samples
Audio material in Pro Tools is sample-
based. This means that if an audio region is
located at a particular sample (or SMPTE)
location, it will not move from this loca-
tion if the tempo changes in the session
(though the audio region’s bar and beat lo-
cation will change).
MIDI data in Pro Tools is bar- and beat-
based. This means that if a MIDI region is
located at a particular bar and beat loca-
tion, it will not move from that location if
the tempo changes in the session—though
its sample location will change, thereby ad-
justing its relationship to audio.
When creating Markers and Selection
Memory Locations, you can specify
whether they have an Absolute (sample-
based) or Bar|Beat (tick-based) reference.
For more information, see “Bar|Beat and
Absolute Reference” on page 236.
Sample-Rounding and Edit Operations
Because audio material in Pro Tools is sam-
ple-based, some amount of sample-round-
ing may occur with some edits when the
Main Time Scale is set to Bars:Beats. This is
most evident when you need audio regions
to fall cleanly on the beat (as when loop-
ing) and notice that the material is some-
times a tick or two off. With a few simple
precautions, this can be avoided.
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