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Glossary
A-14 Appendix
Appendix
Non-drop frame mode
In this mode, drop frame mode processing
is not performed. Since there is no frame
cutting, a discrepancy of about 86 seconds
occurs each day (in the case of a field
frequency of 59.94 Hz) which causes
problems when editing programs in units
of seconds using the number of frames as a
refernce.
See also Drop frame mode.
Preroll
The rewinding of a video tape in the player
or recorder VTR by a certain length before
an edit point, allowing the tape to attain a
stable speed at the edit point and
synchronization with the other video tape
during editing.
Reference video signal
A video signal containing a sync signal or
sync and burst signal, used as a reference
for synchronizing video equipment.
Servolocking
The locking of the phase and speed of a
VTR’s head drum rotation and tape
transport to a reference signal during
recording and playback.
Standby-off mode
A mode in which head drum rotation is
stopped and tape tension is released, and
thus the VTR is not ready for immediate
recording and playback. This mode
alleviates the tape and video heads from
wear or damage.
Standby-on mode
A mode in which the head drum rotates
with the tape wrapped around it, and thus
the VTR is ready for immediate recording
or playback. The VTR enters standby-off
mode after remaining in standby-on mode
for a specified length of time to prevent
wear or damage to the tape and video
heads.
Time code
A digital signal recorded on the video tape
that supplies information such as hour,
minute, second and frame number for each
frame to facilitate the setting of edit points
or searching for specific scenes on the
tape.
There are two types of time codes: SMPTE
(for the NTSC color system) and EBU (for
the PAL/SECAM color system); and two
time code recording formats: LTC
(longitudinal time codes) which are CTL
signals and audio signals simultaneously
recorded longitudinally on the tape and
VITC (vertical interval time codes) which
are recorded on the video signal track.
Tracking
The synchronizing of the head drum
rotation phase and tape transport phase
during playback and recording. Tracking
is adjusted to eliminate picture instability
when playing back material recorded on
another VTR.
User bits
A recordable 32-bit section in each time
code on a video tape for recording such
information as the recording year, month,
and day, and the tape or program ID
number.
Vertical interval time code
See VITC.
VITC
Abbreviation for Vertical Interval Time
Code. This is a time code recorded on a
video signal track during the vertical
blanking interval. This VTR writes this
time code in the AUX data area in the
video signals. It can be read correctly even
during slow or still picture playback. See
also LTC.