MediaSonic MS9000, Руководство пользователя

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HD Player Index
110 Rev. 6.4
Y matrix values and filter characteristics. It does not actually define the electro-
mechanical interface-see ITU-R BT.656. ITU-R 601 is normally taken to refer to
color difference component digital video (rather than RGB), for which it defines
4:2:2 sampling at 13.5 MHz with 720 luminance samples per active line and 8 or
10-bit digitizing. Some headroom is allowed with black at level 16 (not 0) and
white at level 235 (not 255)-to minimize clipping of noise and overshoots. Using
8-bit digitizing approximately 16 million unique colors are possible: 28 each for
Y (luminance), Cr and Cb (the digitized color difference signals) = 224 =
16,777,216 possible combinations. The sampling frequency of 13.5 MHz was
chosen to provide a politically acceptable common sampling standard between
525/60 and 625/50 systems, being a multiple of 2.25 MHz, the lowest common
frequency to provide a static sampling pattern for both.
JPEG Joint Photographic Experts Group. ISO/ITU-T. JPEG is a standard for the data
compression of still pictures (intrafield). In particular its work has been involved
with pictures coded to the ITU-R 601 standard. JPEG uses DCT and offers data
compression of between two and 100 times and three levels of processing are
defined: the baseline, extended and "lossless" encoding.
S
ee also: Motion-JPEG .
Letterbox Image of a widescreen picture on a standard 4:3 aspect ratio television screen,
typically with black bars above and below. Used to maintain the original aspect
ratio of the source material.
S
ee also: Side panels and pillarbox.
Lossless
compression Reducing the bandwidth required for transmission of a given data rate without
loss of any data.
Lossy
compression Reducing the total data rate by discarding data that is not critical. Both the video
and audio for DTV transmission will use lossy compression.
Luminance
The component of a video signal that includes information about its brightness. .
Macroblock In the typical 4:2:0 picture representation used by MPEG-2, a macroblock
consists of four eight by eight blocks of luminance data (arranged in a 16 by 16
sample array) and two eight by eight blocks of color difference data which
correspond to the area covered by the 16 by 16 section luminance component of
the picture. The macroblock is the basic unit used for motion compensated
prediction.
S
ee also: Block, Slice.
Megabyte
(Mbyte) One million bytes (actually 1,048,576); one thousand kilobytes
Motion-JPEG Using JPEG compressed images as individual frames for motion. For example,
30 Motion-JPEG frames viewed in one second will approximate 30-frame per
second video.
MPEG Compression standards for moving images conceived by the Motion Pictures
Expert Group, an international group of industry experts set up to standardize
compressed moving pictures and audio. MPEG-2 is the basis for ATSC digital
television transmission.
Its work follows on from that of JPEG to add interfield compression, the extra
compression potentially available through similarities between successive
frames of moving pictures. Four MPEG standards were originally planned, but
the accommodation of HDTV within MPEG-2 has meant that MPEG-3 is now
redundant. MPEG-4 is intended for unrelated applications, however, can be used
to display ATSC formats on a PC. The main interest for the television industry is