Specifications

Chapter 34: Synchronization Concepts 545
If we use the black and white NTSC video stan-
dard (30 fps) instead of 29.97 fps, the process of
converting film frames to video frames is greatly
simplified. Now instead of any fractional
frames, we have 24,000 film frames going into
30,000 video frames (60,000 video fields). In the
Telecine process (for NTSC color video), each
odd film frame is copied to two video fields, and
each even film frame is copied to three video
fields, creating what is called a 3:2 Pulldown.
The speed of the film is also “pulled down” to
23.976 fps in order to accommodate the slower
speed of NTSC color video compared to NTSC
black and white video (29.97 fps compared to
30 fps).
Film Speed Differs from NTSC
Video Speed
When spotting audio to video that was trans-
ferred from film to NTSC video, there are two
important terms to keep in mind: film speed
and video speed.
Film Speed Film speed refers to audio that was
recorded and plays back in synchronization
with the original film material. This audio often
comes from production reels recorded on a Na-
gra® recorder or a field DAT recorder, and is usu-
ally striped with 30 Non-Drop time code. Film
must be pulled down 0.1% when being trans-
ferred to 29.97 NTSC. Film must be pulled up by
4.16667% when film is being transferred to PAL.
Video Speed Video speed refers to audio that is
running at the NTSC color standard of
29.97 fps. Video speed is 0.1% slower than film
speed, so audio that is still at film speed will be
out of sync with the video.
In Figure 47, note the following:
• The vertical arrow at the left (“faster”
“slower”) represents program speed or rate.
•Telecine is a frame count conversion (for ex-
ample, 24 to 30).
• The speed you play the result back is a frame
rate conversion (for example, 30 to 29.97).
The following table lists the applications for
each of the frame rates and counts shown in
Figure 47 on page 546.
How film frames translate to video fields and frames in
a Telecine transfer
Film frames
Video fields
1 1 2 2 2 3 3 4 4 4
Video frames
12345
Frame Rates and their Applications
Frame Rate Applications
25 fps PAL
24 fps Film, and 24P HD
23.976 fps 24P pull down, for NTSC broad-
cast, and HD digital video
30 fps 30 frame music production, and
30 frame recording for film
29.97 fps Broadcast NTSC video