Specifications

Pro Tools Reference Guide 546
Frame Rates and Relative Playback Speeds
The following diagram illustrates the relative playback speeds of SMPTE formats.
Pull Up and Pull Down
Pull Up and Pull Down are terms used to refer to
the deliberate recalibration of the audio sample
rate clock (speed, or musical pitch) in order to
compensate for a speed change. Pro Tools can be
used to pull down or pull up audio or video
playback rates. Pro Tools 5.3.1 and higher sup-
port pull rates known as “4% factors” (4.0%
down, or 4.167% up to be exact), applicable to
audio and video playback, to support
PAL/film/NTSC conversion requirements.
Pull Down allows you to play back film-origi-
nated material at video speed (–0.1%). Pull Up
allows you to play back video speed material at
film speed (+0.1%).
Using Pro Tools in Pull Up or Pull Down modes
requires a SYNC I/O, USD, or third party syn-
chronizer.
When to Pull Up or Pull Down
There are many ways to get audio into Pro Tools
for post production. Consider your source audio
and your final destination format carefully. In
some cases, audio will already be pulled down
for you. In other cases, audio will have to be
temporarily pulled down. In still other cases,
you may choose to pull down your audio
source, like a DAT deck, then use a a D-A-D (dig-
ital-to-analog-to-digital) process, or the Sample
Figure 47. Frame rates, telecine transfers, and relative playback speeds
faster
slower
25 fps
24 fps
23.976 fps
30 fps
29.97 fps
same speed,
less frames
more frames
same speed,
x104.1667% up x96.0% down
(“4%” pull up) (“4%” pull down)
x100.1% up
(0.1% pull up)
(0.1% pull down)
x99.9% down
Telecine
Telecine
(0.1% pull down)
x99.9% down
x100.1% up
(0.1% pull up)