DigiDesign Pro Tools, Справочное руководство

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Chapter 35: Working with Synchronization 803
Extended Pull Up and Pull Down
Preference and Session Setup Controls The Au-
dio Rate Pull Up and Down menu offers all pos-
sible combinations of pull ups and pull downs
for the audio sample rate, regardless of the ses-
sion frame rate.
In addition, if there is a QuickTime movie in the
timeline, the video rate can be pulled up or
down by 0.1%, regardless of the session frame
rate. Though not an approved workflow, earlier
versions of Pro Tools also enabled pull down of
QuickTime video clips when audio was pulled
down, so this option is included in Pro Tools
5.3.1 and higher to maintain compatibility with
earlier sessions.
Auto Match Pull Factors
Auto Match Pull Factors is available from the
session Time Code Rate menu in the Session
Setup window. When Auto Match Pull Factors is
enabled, Pro Tools adjusts audio and video play-
back rates as needed to match any changes to
the current session Time Code Rate.
Auto Match Pull is applied relative to the cur-
rent pull up setting. While enabled, if the ses-
sion frame rate is changed in such a way that the
video would have to be pulled by an unsup-
ported amount, the video remains unaffected.
This setting is latching, is not enabled by de-
fault, and its state is stored with the session.
Example of Auto Match Pull Factors
Auto Match Pull Factors links audio and video
pull factors when changing session frame rate.
For example, assume a Pro Tools session is set to
a frame rate of 25 fps, the audio and video are
both playing with no pull ups, and Auto Match
Pull Factors is enabled.
If you then change the session Frame Rate to
24 fps, both the Audio and Video Rate Pull set-
tings would change by –4.0% (the appropriate
pull setting required by the change in frame
rate).
Auto Match-enabled pull factors are applied to
any existing Audio Rate Pull Up/Down or Video
Rate Pull Up/Down settings. For example, if au-
dio was already being pulled –0.1% when you
changed the session Frame Rate from 29.97 to
24 fps, then the Audio Rate Pull Up/Down
menu would switch to None.
Audio Sample Rate Pull Up and
Down
The Audio Rate Pull Up/Down menu applies
pull up or down factors to session audio record
and playback. All pull rates are available, regard-
less of session frame rate.
Audio Rate Pull Up/Down menu in Session Setup
See also “Auto Match Pull Factors” on
page 803.