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HD TECHNOLOGY - Pullingfocus's Blog

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HD TECHNOLOGY
Juan Carlos Rosero
HISTORY
? The term high definition once described a
series of television systems originating
from the late 1930s; however, these
systems were only high definition when
compared to earlier systems that were
based on mechanical systems with as few
as 30 lines of resolution.
Great Britain
? The British high definition TV service
started trials in August 1936 and a regular
service in November 1936 using both the
(mechanical) Baird 240 line and
(electronic) Marconi-EMI 405 line (377i)
systems. The Baird system was
discontinued in February 1937.
France
? In 1938 France followed with their own
441 line system, variants of which were
also used by a number of other countries.
The US NTSC system joined in 1941. In
1949 France introduced an even higher
resolution standard at 819 lines (768i), a
system that would be high definition even
by today's standards, but it was
monochrome only.
Main differences
? All of these systems used interlacing and a
4:3 aspect ratio except the 240 line system
which was progressive (actually described
at the time by the technically correct term
'sequential') and the 405 line system which
started as 5:4 and later changed to 4:3.
The 405 line system adopted the (at that
time) revolutionary idea of interlaced
scanning to overcome the flicker problem
of the 240 line with its 25 Hz frame rate.
Color TV
? Color broadcasts started at similarly higher
resolutions, first with the US NTSC color
system in 1953, which was compatible
with the earlier B&W systems and
therefore had the same 525 lines (480i) of
resolution. European standards did not
follow until the 1960s, when the PAL and
SECAM colour systems were added to the
monochrome 625 line (576i) broadcasts.
Analog HD Systems (France)
? French 819 lines system (768i) was used
only on VHF for the first French TV
channel. It first started transmission in
1949 and was discontinued in 1985.
Analog HD Systems (URSS)
? In 1958, the Soviet Union developed
Тransformator (Russian: Трансформатор,
Transformer), the first high-resolution
(definition) television system capable of
producing an image composed of 1,125
lines of resolution aimed at providing
teleconferencing for military command. It
was a research project and the system
was never deployed in the military or
broadcasting.
Analog Systems (Japan)
? In 1969, the Japanese state broadcaster NHK
first developed consumer high-definition
television Hi-Vision or MUSE with a 5:3 aspect
ratio, a rather wider screen format than the
usual 4:3 standard. The system required about
twice the bandwidth of the existing NTSC
system but provided about four times the
resolution (1080i/1125 lines). Satellite test
broadcasts started in 1989, with regular testing
starting in 1991 and regular broadcasting of BS9ch commenced on 25 November 1994, which
featured commercial and NHK programming.
Analog Systems (USA)
? In 1981, the MUSE system was
demonstrated for the first time in the
United States, using the same 5:3 aspect
ratio as the Japanese system. Upon
visiting a demonstration of MUSE in
Washington, US President Ronald Reagan
was most impressed and officially
declared it "a matter of national interest" to
introduce HDTV to the USA.
Analog Systems (USA)
? Several systems were proposed as the
new standard for the USA, including the
Japanese MUSE system, but all were
rejected by the FCC because of their
higher bandwidth requirements. At this
time, the number of television channels
was growing rapidly and bandwidth was
already a problem. A new standard had to
be more efficient, needing less bandwidth
for HDTV than the existing NTSC.
Analog HD Unification
? In 1983, the International Telecommunication
Union's radio telecommunications sector (ITUR) set up a working party (IWP11/6) with the
aim of setting a single international HDTV
standard. One of the thornier issues concerned
a suitable frame/field refresh rate, the world
already having split into two camps, 25/50Hz
and 30/60Hz, related by reasons of picture
stability to the frequency of their main electrical
supplies.
Analog HD Unification
? The IWP11/6 working party considered many
views and through the 1980s served to
encourage development in a number of video
digital processing areas, not least conversion
between the two main frame/field rates using
motion vectors, which led to further
developments in other areas. While a
comprehensive HDTV standard was not in the
end established, agreement on the aspect ratio
was achieved.
Analog HD Unification
? Initially the existing 5:3 aspect ratio had been
the main candidate but, due to the influence of
widescreen cinema, the aspect ratio 16:9 (1.78)
eventually emerged as being a reasonable
compromise between 5:3 (1.67) and the
common 1.85 widescreen cinema format. The
16:9 ratio was chosen as being the geometric
mean of 4:3, Academy ratio, and 2.4:1, the
widest cinema format in common use, in order
to minimize wasted screen space when
displaying content with a variety of aspect
ratios.
Analog HD Unification
? An aspect ratio of 16:9 was duly agreed at the
first meeting of the IWP11/6 working party at
the BBC's Research and Development
establishment in Kingswood Warren. The
resulting ITU-R Recommendation ITU-R
BT.709-2 ("Rec. 709") includes the 16:9 aspect
ratio, a specified colorimetry, and the scan
modes 1080i (1,080 actively interlaced lines of
resolution) and 1080p (1,080 progressively
scanned lines). The current Freeview HD trials
use MBAFF, which contains both progressive
and interlaced content in the same encoding.
Analog HD Unification
? It also includes the alternative 1440?1152
HDMAC scan format. According to some reports,
a mooted 750line (720p) format (720
progressively scanned lines) was viewed by
some at the ITU as an enhanced television
format rather than a true HDTV format, and so
was not included, although 1920?1080i and
1280?720p systems for a range of frame and
field rates were defined by several US SMPTE
standards.)
Demise of analog HD Systems
? This limited standarization of HDTV did not lead
to its adoption, principally for technical and
economic reasons. NHK's MUSE required over
four times the bandwidth of a standarddefinition broadcast, and despite efforts made
to reduce it to about twice that of SDTV, it was
still only distributable by satellite with one
channel shared on a daily basis between seven
broadcasters. Japan remained the only country
with successful public broadcast analog HDTV,
starting in 2000 in Japan, and ended in October
2007.
New Standards
? Since the formal adoption of Digital Video
Broadcasting's (DVB) widescreen HDTV
transmission modes in the early 2000s the
525-line NTSC (and PAL-M) systems as
well as the European 625-line PAL and
SECAM systems are now regarded as
standard definition television systems. In
Australia, the 625-line digital progressive
system (with 576 active lines) is officially
recognized as high definition.
Digital Video Broadcasting
? DVB is a suite of internationally accepted open
standards for digital television. DVB standards
are maintained by the DVB Project, an
international industry consortium with more than
270 members, and they are published by a
Joint Technical Committee (JTC) of European
Telecommunications Standards Institute (ETSI),
European Committee for Electrotechnical
Standardization (CENELEC) and European
Broadcasting Union (EBU).
DVB Transmission
? DVB systems distribute data using a variety of
approaches, including:
? satellite: DVB-S, DVB-S2 and DVB-SH
? DVB-SMATV for distribution via SMATV
? cable: DVB-C, DVB-C2
? terrestrial television: DVB-T, DVB-T2
? digital terrestrial television for handhelds:
DVB-H, DVB-SH
? microwave: using DTT (DVB-MT), the MMDS
(DVB-MC), and/or MVDS standards (DVB-MS)
ATSC Standards
? The ATSC standard was developed in the
early 1990s by the Grand Alliance, a
consortium of electronics and
telecommunications companies that
assembled to develop a specification for
what is now known as HDTV. ATSC
formats also include standard-definition
formats, although initially only HDTV
services were launched in the digital
format.
ATSC RANGE
? The high definition television standards
defined by the ATSC produce wide screen
16:9 images up to 1920?1080 pixels in
size ? more than six times the display
resolution of the earlier standard.
However, many different image sizes are
also supported.
Rise of digital compression
? Both ATSC and DVB were based on the
MPEG-2 standard. The DVB-S2 standard
is based on the newer and more efficient
H.264/MPEG-4 AVC compression
standards. Common for all DVB standards
is the use of highly efficient modulation
techniques for further reducing bandwidth,
and foremost for reducing receiverhardware and antenna requirements.
Digital HD (USA)
? HDTV technology was introduced in the
United States in the 1990s by the Digital
HDTV Grand Alliance. The first public
HDTV broadcast in the United States
occurred on July 23, 1996. The American
Advanced Television Systems Committee
(ATSC) HDTV system had its public
launch on October 29, 1998, during the
live coverage of astronaut John Glenn's
return mission to space on board the
Space Shuttle Discovery.
Digital HD (Europe)
? Although HDTV broadcasts had been
demonstrated in Europe since the early
1990s, the first regular broadcasts started
on January 1, 2004 when the Belgian
company Euro1080 launched the HD1
channel with the traditional Vienna New
Year's Concert.
Digital HD (Europe)
? These first European HDTV broadcasts
used the 1080i format with MPEG-2
compression on a DVB-S signal from SES
Astra's 1H satellite at Europe's main DTH
Astra 19.2°E position. Euro1080
transmissions later changed to MPEG4/AVC compression on a DVB-S2 signal in
line with subsequent broadcast channels
in Europe.
WQHD (1440p)
? The Wide Quad High Definition, display
standard is a resolution of 2560 x 1440 pixels in
a 16:9 aspect ratio. It is four times the
resolution of the 720p display standard, hence
the name. Their high pixel counts and heavy
display hardware requirements mean that there
are currently few LCD monitors which have
pixel counts at these levels. It is a non-standard
resolution found in some displays, such as the
Dell UltraSharp U2711 and the 27" iMac.
QFHD (2160p)
? Quad Full High Definition) is a non-standard
display resolution of 3840 x 2160 pixels
arranged in a 16:9 aspect ratio. It is four times
the resolution of the 1080p display standard,
hence the name.
? In early 2008, Samsung revealed a proof-ofconcept 82-inch LCD TV set capable of this
resolution and LG has demonstrated an 84-inch
displayEyevis produces a 56" LCD named
EYELCD 56 QHD HD while Toshiba makes the
P56QHD, and Sony the SRM-L560, all which
can deliver a resolution of 3840 x 2160.
Super Hi-Vision
? Super Hi-Vision (also known as 4320p,
8K, Ultra High Definition Television
(UHDTV), and Ultra High Definition
Video (UHDV)) is an experimental digital
video format, currently proposed by NHK
of Japan, the BBC, and RAI.
Super Hi-Vision
? Sky also appears to be interested in the
technology. During IBC 2008 Japan's NHK,
Italy's RAI, the BBC, RTE, Sony, Samsung, and
Panasonic (with various partners) demonstrated
the first ever public live transmission of Super
Hi-Vision, from London to the conference site in
Amsterdam.
? In addition, it was demonstrated at the BBC's
Media Centre in West London in early October
2008. The BBC has been looking into the use of
its Dirac codec with Super Hi-Vision.
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