TANDBERG EN8000, Справочное руководство

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Glossary
Reference Guide: EN8000 MPEG-4 Part 10 (H.264/AVC) Encoders Page A-3
ST.RE.E10233.1
BW Bandwidth: The transmission capacity of an electronic line such as (among others) a
communications network, computer bus, or broadcast link. It is expressed in bits per second,
bytes per second or in Hertz (cycles per second). When expressed in Hertz, the frequency
may be a greater number than the actual bits per second, because the bandwidth is the
difference between the lowest and highest frequencies transmitted. High bandwidth allows
fast transmission or high-volume transmission.
Byte-mode Each byte is delivered separately in the ASI Transport Stream, with stuffing data added
between the Bytes to increase the data rate to 270 Mbit/s. See DVB Document A010 rev. 1,
Section B3.3, (ASI) Layer-2 Transport Protocol.
CA Conditional Access: The technology used to control the access to viewing services to
authorised subscribers through the transmission of encrypted signals and the programmable
regulation of their decryption by a system such as viewing cards.
CABAC Context Adaptive Binary Arithmetic Coding is a form of entropy coding used in H.264 that
has greater coding efficiency than CAVLC but is more computationally expensive.
CAT Conditional Access Table: Part of the MPEG-2 Program Specific Information (PSI) data.
Mandatory for MPEG-2 compliance if CA is in use.
CAVLC Context Adaptive Variable Length Coding is a form of entropy coding used in H.264 that
has lower coding efficiency than CABAC but is less computationally expensive.
C-Band The portion of the electromagnetic spectrum, which spans the frequency range of
approximately 4 GHz to 6 GHz. Used by communications satellites. Preferred in tropical
climates because it is not susceptible to fading.
CBR Constant Bit-rate where the bit-rate of the bit-stream out of the encoder remains constant
over an extended period of time within the buffer limits of the decoder.
CCIR See: ITU-R.
CCITT See: ITU-T.
Channel A narrow range of frequencies, part of a frequency band, for the transmission of radio and
television signals without interference from other channels.
In the case of OFDM, a large number of carriers spaced apart at precise frequencies are
allocated to a channel.
Channel Coding A way of encoding data in a communications channel that adds patterns of redundancy into
the transmission path in order to improve the error rate. Such methods are widely used in
wireless communications.
Chrominance The colour part of a TV picture signal, relating to the hue and saturation but not to the
luminance (brightness) of the signal. In a composite-coded colour system, the colour
information (chrominance, often referred to as chroma) is modulated onto a high frequency
carrier and added to the monochrome-format video signal carrying the luminance (Y). In a
component-coded colour system, the two colour-difference signals (R-Y)(B-Y) usually
referred to as C
R
C
B
(digital) or P
R
P
B
(analogue), are used to convey colour information. When
C
R
C
B
(P
R
P
B
) is added to the luminance (Y), the complete picture information is conveyed as
YC
R
C
B
(YP
R
P
B
).
Closed Captioning A TV picture subtitling system used with 525-line analogue transmissions.
CODE Create Once Distribute Everywhere.
Codec The combination of an Encoder and a complementary Decoder located respectively at the
input and output of a transmission path.
COFDM Coded OFDM: COFDM adds forward error correction to the OFDM transmission consisting of
Reed-Solomon (RS) coding followed by convolutional coding to add extra bits to the
transmitted signal. This allows a large number of errors at the receive end to be corrected by
convolutional (Viterbi) decoding followed by RS decoding.