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PALsite
Glossary O-T
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http://www.PALsite.com
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The home of the PAL system
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Off-Line Editor
- A low resolution, usually computer and disk based edit
system in which the creative editing decisions can be made at lower
cost and often with greater flexibility than in an expensive fully
equipped on-line suite. See also Non-Linear Editor
- On-Line Editor
- An editing system where the actual video master is
created. An on-line bay usually consists of an editing computer, video
switcher, audio mixer, 1 or more channels of DVE, character generator,
and several video tape machines.
- Oxide tape
- Magnetic tape coated with microscopic particles of ferric oxide
dispersed in a liquid binder.
- PAL
- Phase Alternate Line. The television and video standard in use in
most of Europe, Hong Kond and the Middle East. Consists of 625
horizontal lines at a field rate of 50 fields per second. (Two fields
equals one complete Frame). Only 576 of these lines are used for
picture. The rest are used for sync or extra information such as VITC
and Closed Captioning.
- PALplus
- A widescreen (16x9) television standard in use in Europe that
is compatible with existing 4x3 TV sets. Non-16x9 TVs show the picture
in a letterboxed form.
- Perfect Pause
- This refers to
a perfect picture in pause mode. I.e. no noise bars across the screen.
It was a feature of the more up-market machines.
- PCM
- Stands for Pulse Code Modulation and is a way of digitally encoding data.
Specifically it is a system used to record high quality digital audio
on to the Betamax video format. The picture if viewed on a television would show black and white
dancing around in an almost static interference type pattern. When connected to a PCM unit, this image
is converted to a digital audio stream. A number of Betamax units came with a switch at the rear
to allow the unit to work more efficiently when recording a digital audio "picture", the
switch is used to remove the drop out compensator circuitry on playback to allow the PCM unit
to carry out its own error correction on the signal without the player altering the signal. For
normal video playback, the should not be switched on.
See also the PCM feature for further information.
- Phono Connector
- Also known as an RCA connector this is the standard audio connector on
most Betamax VCRs.
- Piano Key
- This refers to VCRs
where the deck operations are carried out by old fashioned mechanical
buttons and levers.
- Pinch Roller
- The is the
rubber roller which pulls the tape through the VCR. It operates in a
similar fashion to an audio deck. For reliable operation the Pinch
Roller must be clean and free from oxide build up. See also the
pinch roller page.
- Pixel
- Short for Picture Element. The basic unit from which a video or
computer picture is made. Essentially a dot with a given colour and
brightness value. D1 images are 720 pixels wide by 486 high. NTSC
images are 640 by 480 pixels.
- Portable
- A portable VCR is
one which could be used outdoors from an internal battery source and
connected to a camera. E.g. SL-F1.
- Pre-recorded Tapes
- These are
tapes which come ready to watch. Usually sell-through films or
ex-rental tapes. See also the for sale page.
- Pre-Roll
- This refers to the sequence of events before and edit begins during which
the plyer and recording VTRs are synchronised.
- R-Y signal
- A chrominance signal determined by subtracting the Y (luminance)
signal from the R (red) signal. One of the component signals.
- Reference video signal
- A video signal consisting of a sync signal or sync and burst signals,
used as a reference.
- Resolution
- The amount of detail in an image. Higher resolution equals
more detail. Generally expressed in "lines". It is the number of
VERTICAL line pairs that the system can distinguish, and has no
relationship to the number of horizontal scan lines. Also used to
describe the size of a computer image, usually in pixels.
- Resolution Independent
- A term to describe equipment that can work in
more than resolution. For example, most equipment can do film
resolution or video resolution, but not both. Resolution independent
equipment can work in both.
- RGB
- Red, Green, Blue. The primary colours of light. Computers and some
analogue component devices use separate red, green, and blue colour
channels to keep the full bandwidth and therefore the highest quality
picture.
- Reels
- These are the two teethed gears that turn the spools of the cassette.
- Remote Control
- The ability to
operate the VCR from afar. Usually using a infra-red handset, although
early models employed a wired system. See also the remote control
gallery.
- Remote connector
- This is either the 36-pin parallel or 9-pin serial connector on the
back of a U-matic VTR through which the machine is controlled by an external device.
See also the U-matic
RX-707 the
RM-440 and the
RX-303.
- Reverse Play
- The ability to
play the tape backwards. See also speed controls.
- RS-422C
- Standard serial data transmission format. It uses a
9 pin serial
control port superceeding the older 36-pin interface.
- Sampling Frequency
- The number of sample measurements taken from an
analogue signal in a second, generally expressed in megahertz. These
samples are then converted into digital numeric values to create the
digital signal.
- SECAM
- French T.V. Standard (Sequentiel Couleur a Memoire).
Compare with NTSC and PAL.
- Servo
- This is a term used to describe the electronic control systems of the VCR
which keep the head and capstan motors running in correct synchronisation.
- Shell
- This is the plastic case which comprises the housing of a video cassette.
See also the tapes page.
- SIN ratio
- Abbreviation of Signal-to-Noise ratio. The higher the S/N ratio, the
less noise and higher the picture quality.
- Search mode
- A VTR mode used when searching for specific scenes, by viewing the
video output or time codes while playing back the tape at various
speeds in forward or reverse direction.
- Servo lock
- Synchronising the drum rotation phase and tape transport phase with a
reference signal during playback and recording so that the video heads
scan the tape in the same pattern during playback and recording.
- Skew
- This refers to a tape tracking adjustment. If the playback
pictures suffers from 'hooking' then the SKEW setting is incorrect
will need to be adjusted.
- Slave
- The VTR used as a player in an edit suite. Usually a play only
(VO series) machine.
- Slow Speed Playback
- The ability to playback pictures at slow speeds.
See also speed controls.
- SMPTE
- Society of Motion Picture and Television Engineer. A major
standards-setting organisation for the motion picture and television
industries. Established the standards for time code and for all the
major video tape formats.
- Sub-carrier
- The signal on which the video colour information is carried. Equal to
6.85991MHz Lo-Band/9.83803MHz Hi-Band.
- Super Betamax
- This was an
improved Betamax format. Both chromiance and luminance of the format
were improved by extending the dynamic range. The mode required
special formulation Pro-X tapes. An example of a super betamax is the SL-HF950.
- Superimpose
- To put a picture (or a set of characters) onto another so that both
can be seen at the same time.
- SP
- Superior Performance. U-matic format variant using chrome tape
offering improved colour and black and white detail (resolution) and
better separation of colours.
- Standard U-matic
- Recording in which the luminance FM deviation is from 3.8 to 5.4 MHz and the colour under frequency is 685 kHz.
Also known as Low band. See also PALsite's U-matic site.
- S-video Input connector
- A connector that inputs Y (luminance) and C (chrominance) signals
separately to reduce interference between Y and C signals, and to help
reproduce noiseless images.
- Sync signal
- A reference signal consisting of vertical and horizontal sync signals
used for synchronising the scanning patterns of the video camera and
the monitor.
- Tape Guides
- This refers to
the rollers and other items which guide the tape through its way
inside the VCR. See also the shuttle block assembly.
- Tape Path
- This is the path
the takes as it passes through the VCR. Typically the tape will pass
the full-track erase head, video drum, audio head and pinch roller.
Because the tape passes over many components there is potential for
wear and tear. This is especially true when inserting and ejecting the
tape. Beta tape path,
U-matic tape path,
Betacam tape path.
- TBC
- Abbreviation of Time Base Corrector. Electronic circuits to
electrically stabilise the playback signals by removing colour
variation and roll in the playback picture caused by irregularity in
drum rotation and tape movement. Time base correction reduces
deterioration of picture quality when transmitting or copying playback
signals.
- Telecine
- A device that creates video from motion picture film.
- Terabyte
- 1 trillion bytes.
- Time Base Corrector
- A device for removing jitter (time base errors) from the signal played back by a VTR (essential if using a special effects generator/vision mixer).
- Time Code
- A time reference recorded on tape to identify each frame.
Longitudinal Time Code (LTC). Absolute address for each frame in
hours, minutes, seconds and frames recorded on a dedicated (address)
track used by BVU. Vertical Interval Time Code (VITC). The same as
above but recorded in the vertical interval on lines 17 and 18 by the
video heads.
- Timer
- This is the clock unit inside the VCR which is used to make recodrings
automatically. A multi-event timer is simply a timer which can be set
for several occasions.
- Tracking
- Electrically controlling the video head so that the playback phase
matches the recording phase of the tape. Especially when playing back
the tape with a VTR other than the one used for recording, adjusting
the tracking prevents noise from appearing on the picture.
- Trick Modes
- This is a generic name for the variable speed playback modes on a VCR.
See also speed controls.
- Tuner
- This is the receiver part of the video which decodes off-air broadcast
signals.