Glossary of Video Terms and Acronyms - Isotest

Video Terms and Acronyms
Glossary
waveforms in the parade mode. The first signal is a 500 kHz sinewave
packet which is fed to video channel 1. The other two signals are identical
502 kHz. The three sinewave packets are generated to be precisely in
phase at their centers. Because of their 2 kHz offset, the color difference
channels become increasingly out of phase with the luminance channel on
either side of center. If the three signals are properly timed, their sum
results in the bowtie waveform shown below.
Box House – A slang term for a mail-order business for audio and video
components. Box houses frequently offer little or no consumer support or
equipment repair.
BPF – See Bandpass Filter.
22 www.tektronix.com/video_audio
BPI – Bits per linear inch down a recorded track.
B-Picture (Bidirectionally Predictive-Coded Picture) – An MPEG picture
that is coded using motion compensated prediction from past and/or
future reference pictures. Motion vectors pointing forwards and backwards
are used, and they may point at either I-pictures or P-pictures. The B-pictures
provide the highest compression, but demand knowledge of several
pictures. Consequently, B-pictures give a higher delay and call for a larger
picture memory. B-pictures are never used as a reference in a prediction.
When B-pictures are part of a sequence, the pictures are not sent in
chronological order owing to the fact that future P-pictures and/or
I-pictures are needed (and therefore must be decoded) for the decoding of
B-pictures. The P- and I-pictures have to be sent earlier than the actual
point of time to which they relate.
BPS – Bits Per Second.
BPSK – Binary Phase Shift Keying.
BR – Radiocommunication Bureau.
BRA – Basic Rate Access.
Branch – See Jump.
Break Elongation – The relative elongation of a specimen of magnetic
tape or base film at the instant of breaking when it has been stretched at a
given rate.
Breakdown – A written accounting of the shooting schedule and production
resources.
Breakpoint – a) A break in the smoothness of a curve. b) Software or
hardware device that stops the program and saves the current machine
status, under user-specified conditions.
Breakup – Disturbance in the picture or sound signal caused by loss of
sync or by videotape damage.
Breathing – Amplitude variations similar to “bounce” but at a slow, regular
rate.
Breezeway – The portion of the video signal which lies between the trailing
edge of the horizontal sync pulse and start of burst. The Breezeway is
part of the back porch. Also refer to the Horizontal Timing discussion.
Bridge – Bridges are devices that connect similar and dissimilar LANs at
the data link layer (OSI layer 2), regardless of the physical layer protocols
or media being used. Bridges require that the networks have consistent
addressing schemes and packet frame sizes. Current introductions have
been termed learning bridges since they are capable of updating node
address (tracking) tables as well as overseeing the transmission of data
between two Ethernet LANs.
Brightness – a) Overall DC voltage level of the video signal. The brightness
control is an adjustment of setup (black level, black reference).
b) Attribute of a visual sensation according to which an area appears to
emit more or less light. The subjective counterpart of objective luminance.
c) The value of a pixel along the black-white axis.
Brightness Signal – Same as the luminance signal (Y). This signal carries
information about the amount of light at each point in the image.