Panasonic AG-HMC150 User Manual page 25

(cinemascope), widescreen video is 1.78:1 (16x9),
standard video and 16mm lm is 1.33:1 (4x3).
ATV. Advanced Television. An acronym for the new
digital television standards. See HDTV.
ATSC. Advanced Television Systems Committee. e
standards organization that recommended the new
digital television standards to the FCC.
Automatic Gain Control (AGC). An audio circuit
that in which the signal level is adjusted to an
appropriate level to prevent clipping (and thus
distortion). e disadvantage of AGC is that when
recording a mix of quiet and loud signals, the AGC
will tend to make the quiet passages louder and the
loud passages quieter, compressing the dynamic range
as well as recording an audible pumping up and
down of the noise level (higher with quiet signals and
softer with louder signals). erefore, professionals
prefer to set audio levels manually using a peak-
reading meter and use a limiter for those unexpected
peaks. is is how audio is set with the DVX100,
which offers a limiter, but not AGC. See Limiter.
Automatic white balance. A circuit in a video
camera that attempts to adjust the white balance
automatically. See White Balance.
AVCHD (Advanced Video Coding, HD). An inter-
frame video codec widely used among HD consumer
cameras that shoot to some variation of tapeless
media ( ash card, hard drive, etc). In most cases it
has to be transcoded to an intermediate format for
editing (e.g. Apple Intermediate Codec or ProRes
422) since it's very difficult to edit directly. See H.
264, Codec, Compression, Inter-frame compression.
B-roll. Shots in a documentary that are used to
illustrate what an interviewee is talking about or to
cover breaks in an interview. Often used to refer to
the footage that is shot for the purpose of using later
as cut-away shots. See Cut-away shot.
Balanced signal. An audio circuit with 3 wires, two
carry the signal, and the third provides the ground.
Compared to unbalanced circuit using a single signal
wire and a ground, balanced signals are much less
susceptible to picking up interference. erefore,
professional sound recording equipment is usually
designed to work with balanced wiring. While XLRs
are the most widely used connectors with balanced
wiring, a particular connector does not guarantee the
existence of balanced wiring. Better camcorders
provided balanced XLR connectors for audio input
and offer a choice of Line or Microphone level input.
Introduction to the Panasonic AG-HMC150 AVCHD camcorder (rough draft)
Bandwidth. e amount of information that can be
passed through a system at a given time. Typically, the
greater the bandwidth the better the image or audio
quality, however, the compression techniques (if any)
used also in uence this, since some compression
formats allow for a reduction of bandwidth while
maintaining very similar image quality, for example,
H.264 vs. MPEG-2.
Bayer pattern (a.k.a. Bayer mosaic). A color lter
array for arranging RGB color lters on a square grid
of CMOS or CCD photo sensors used in most
single-chip digital image sensors in digital still and
video cameras. e lter pattern is 50% green, 25%
red and 25% blue and is sometimes referred to as
GRGB or RGGB.
Bird's eye view. See Overhead shot.
Bit. 1. A single element (1 or 0) of digital
representation of information. 2. A minor role in
which an actor may speak only a few lines of dialog.
Also known as a bit part.
Bit rate. e amount of data transported in a given
amount of time, usually de ned in Mega (Million)
bits per second (Mbps). Bit rate is one way to de ne
the amount of compression used on a video signal.
Uncompressed standard de nition video has a bit rate
of 270 Mbps. e DV and HDV video standards
have a bit rate to 25 Mbps.
Broadcast quality. An nebulous term used by
marketing people to describe video products in a
manner that's more appealing.
Camera angle. e position of the camera in
relation to the subject during lming. It may be
straight (eye-level shot), tilted up at the subject (low-
angle shot), tilted down at the subject (high-angle
shot), or tilted off the vertical axis to either side
(Dutch-angle shot).
Camera movement. Any movement of the camera
during a shot, such as panning, tilting, dollying,
tracking, etc.
Camera log. A sheet used to keep track of
information about scenes or shots on a particular tape
or memory card.
Camera speed. e rate at which lm is run
through a motion picture camera in frames per
second (fps). e normal speed for sound lm
recording is 24 fps. Video cameras that simulate lm
shooting at 24 fps use the same terms as lm cameras
to describe the camera speed. See also Overcrank and
Undercrank.
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