8.0

Synchronization
Timecode (positional references)
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• The “timecode slave” is any device receiving the timecode and synchronizing
or “locking” to it.
Timecode (positional references)
The position of any device is most often described using timecode. Timecode
represents time using hours, minutes, seconds, and frames to provide a location for
each device. Each frame represents a visual film or video frame.
Timecode can be communicated in several ways:
• LTC (Longitudinal Timecode) is an analog signal that can be recorded on
tape. It should be used for positional information primarily. It can also be used
for speed and phase information as a last resort if no other clock source is
available.
• VITC (Vertical Interval Timecode) is contained within a composite video
signal. It is recorded onto video tape and is physically tied to each video frame.
• MTC (MIDI Timecode) is identical to LTC except that it is a digital signal
transmitted via MIDI.
Timecode standards
Timecode has several standards. The subject of the various timecode formats can
be very confusing due to the use and misuse of the shorthand names for specific
timecode standards and frame rates. The reasons for this confusion are described
in detail below. The timecode format can be divided into two variables: frame count
and frame rate.
Frame count (frames per second)
The frame count of timecode defines the standard with which it is labeled. There are
four timecode standards:
24 fps Film (F)
This frame count is the traditional count for film. It is also used for HD video
formats and commonly referred to as “24 p”. However, with HD video, the
actual frame rate or speed of the video sync reference is slower, 23.976
frames per second, so timecode does not reflect the actual realtime on the
clock for 24p HD video.
25 fps PAL (P)
This is the broadcast video standard frame count for European (and other PAL
countries) television broadcast.