User manual

652
Synchronization
Timecode (positional references)
• 30 fps non-drop SMPTE (N)
This is the frame count of NTSC broadcast video. However, the actual frame rate
or speed of the video format runs at 29.97
fps. This timecode clock does not run in
realtime. It is slightly slower by 0.1
%.
• 30 fps drop-frame SMPTE (D)
The 30 fps drop-frame count is an adaptation that allows a timecode display
running at 29.97
fps to actually show the clock-on-the-wall-time of the timeline by
“dropping” or skipping specific frame numbers in order to “catch the clock up” to
realtime.
Confused? Just remember to keep the timecode standard (or frame count) and frame
rate (or speed) separate.
Frame rate (speed)
Regardless of the frame counting system, the actual speed at which frames of video
go by in realtime is the true frame rate.
In Cubase the following frame rates are available:
• 23.9 fps (Cubase only)
This frame rate is used for film that is being transferred to NTSC video and must be
slowed down for a 2-3 pull-down telecine transfer. It is also used for the type of
HD video referred to as “24
p”.
• 24 fps
This is the true speed of standard film cameras.
• 24.9 fps (Cubase only)
This frame rate is commonly used to facilitate transfers between PAL and NTSC
video and film sources. It is mostly used to correct for some error.
• 25 fps
This is the frame rate of PAL video.
• 29.97 fps
This is the frame rate of NTSC video. The count can be either non-drop or drop-
frame.
• 30 fps
This frame rate is not a video standard anymore but has been commonly used in
music recording. Many years ago it was the black and white NTSC broadcast
standard. It is equal to NTSC video being pulled up to film speed after a 2-3
telecine transfer.
• 59.98 fps (Cubase only)
This rate is also referred to as “60 p”. Many professional HD cameras record at
59.98
fps. While 60 fps could theoretically exist as a frame rate, no current HD
video camera records at a full 60
fps as a standard rate.
Frame count vs. frame rate
Part of the confusion in timecode stems from the use of “frames per second” in both
the timecode standard and the actual frame rate. When used to describe a timecode
standard, frames per second defines how many frames of timecode are counted
before one second on the counter increments. When describing frame rates, frames
per second define how many frames are played back during the span of one second
of realtime. In other words: Regardless of how many frames of video there are per
second of timecode (frame count), those frames can be moving at different rates
depending on the speed (frame rate) of the video format. For example, NTSC
timecode (SMPTE) has a frame count of 30
fps. However, NTSC video runs at a rate
of 29.97
fps. So the NTSC timecode standard known as SMPTE is a 30 fps standard
that runs at 29.97 realtime.