Acronym Definition
DITV Defence Information Television
DITV Direct Internet TV
DITV Digital TV
DITV Dig It TV
DITV Digitally Imported TV
DITV Digital Intermediate TV
DITV Defense Information TV
DITV Document Imaging TV
DITV Design Interface TV
DITV Data Interchange TV
DITV Digital Interface TV
DITV Discovery Internet TV
DITV Detective Inspector TV
DITV Direct Instruction TV
DITV Digital Imagery TV
DITV Dance Instruction TV
DITV Disabled Individual TV
DITV Dental Internet TV
Digital television (DTV) is a telecommunication system for broadcasting and
receiving moving pictures and sound by means of digital signals, in contrast to
analog signals used by analog (traditional) TV. DTV uses digital modulation
data, which is digitally compressed and requires decoding by a specially
designed television set, or a standard receiver with a set-top box, or a PC
fitted with a television card. Introduced in the late 1990s, this technology
appealed to the television broadcasting business and consumer electronics
industries as offering new financial opportunities.
Technical information
Formats and bandwidth
In current practice, high-definition television (HDTV), which is usually used
over DTV, uses one of two formats: 1280 × 720 pixels in progressive scan mode
(abbreviated 720p) or 1920 × 1080 pixels in interlace mode (1080i). Each of
these utilizes a aspect ratio. (Some televisions are capable of receiving an HD
resolution of 1920 × 1080 at a 60Hz progressive scan frame rate — known as
1080p60 — but this format is not standard and no broadcaster is able to transmit
these signals over the air at acceptable quality yet.)
Standard definition TV, by comparison, may use one of several different formats
taking the form of various aspect ratios, depending on the technology used in
the country of broadcast. For aspect-ratio broadcasts, the 640 × 480 format is
used in NTSC countries, while 704 × 576 (rescaled to 768 × 576) is used in PAL
countries. For broadcasts, the 704 × 480 (rescaled to 848 × 480) format is used
in NTSC countries, while 704 × 576 (rescaled to 1024 × 576) is used in PAL
countries. A broadcaster may opt to use a standard-definition digital signal
instead of an HDTV signal, because current convention allows the bandwidth of a
DTV channel (or "multiplex") to be subdivided into multiple subchannels,
providing multiple feeds of entirely different programming on the same channel.
This ability to provide either a single HDTV feed or multiple lower-resolution
feeds is often referred to as distributing one's "bit budget" or multicasting.
This can sometimes be arranged automatically, using a statistical multiplexer
(or "stat-mux"). With some implementations, image resolution may be less
directly limited by bandwidth; for in DVB-T, broadcasters can choose from
several different modulation schemes, giving them the option to reduce the
transmission bitrate and make reception easier for more distant or mobile
viewers.
Reception
There are a number of different ways to receive digital television. One of the
oldest means of receiving DTV (and TV in general) is using an antenna (known as
an aerial in some countries). This way is known as Digital Terrestrial
Television (DTT). With DTT, viewers are limited to whatever channels the antenna
picks up. Signal quality will also vary.
Other ways have been devised to receive digital television. Among the most
familiar to people are digital cable and digital satellite. In some countries
where transmissions of TV signals are normally achieved by microwaves, digital
MMDS is used. Other standards, such as DMB and DVB-H, have been devised to allow
handheld devices such as mobile phones to receive TV signals. Another way is
IPTV, that is receiving TV via Internet Protocol with guaranteed quality of
service (QoS). Finally, an alternative way is to receive TV signals via the open
Internet infra-structure, usually referred to as Internet TV.
Today, regardless of how viewers receive DTV, most will pick up digital
television via a set-top box, which decodes the digital signals into signals
that analog televisions can understand — thus using the television purely as a
monitor. However, a growing number of TV sets with integrated receivers are
available — these are known as iDTVs.
Some signals carry encryption and specify use conditions (such as "may not be
recorded" or "may not be viewed on displays larger than 1m in diagonal measure")
backed up with the force of law under the WIPO Copyright Treaty and national
legislation implementing it, such as the U.S. Digital Millennium Copyright Act.
Access to encrypted channels can be controlled by a removable smart card, for
example via the Common Interface (DVB-CI) standard for Europe and via Point Of
Deployment (POD) for IS or named differently CableCard.
Protection parameters for terrestrial DTV broadcasting
System Parameters
(protection ratios) Canada USA EBU [9, 12]
ITU-mode M3 Japan [36, 37]
C/N for AWGN Channel +19.5 dB
(16.5 dB ) +15.19 dB +19.3 dB +19.2 dB
Co-Channel DTV into Analog TV +33.8 dB +34.44 dB +34 ~ 37 dB +38 dB
Co-Channel Analog TV into DTV +7.2 dB +1.81 dB +4 dB +4 dB
Co-Channel DTV into DTV +19.5 dB
(16.5 dB<ref name="protection_parameters_table_note_a" />) +15.27 dB +19 dB +19
dB
Lower Adjacent Channel DTV into Analog TV ?16 dB ?17.43 dB ?5 ~ ?11 dB ?6 dB
Upper Adjacent Channel DTV into Analog TV ?12 dB ?11.95 dB ?1 ~ ?10<ref
name="protection_parameters_table_note_c" /> ?5 dB
Lower Adjacent Channel Analog TV into DTV ?48 dB ?47.33 dB ?34 ~ ?37 dB<ref
name="protection_parameters_table_note_c" /> ?35 dB
Upper Adjacent Channel Analog TV into DTV ?49 dB ?48.71 dB ?38 ~ ?36 dB<ref
name="protection_parameters_table_note_c" /> ?37 dB
Lower Adjacent Channel DTV into DTV ?27 dB ?28 dB ?30 dB ?28 dB
Upper Adjacent Channel DTV into DTV ?27 dB ?26 dB ?30 dB ?29 dB
1. ^ ISDB-T (6MHz, 64QAM, R=2/3), Analog TV (M/NTSC).
2. ^ The Canadian parameter, C/(N+I) of noise plus co-channel DTV interface
should be 16.5 dB.
3. ^ Depending on analog TV systems used.
4. ^ Digi-tv esill? ymp?ri maata. Finnish Ministry of Communications. Retrieved
on 2007-08-12.
5. ^ Andorra fa el salt a la TDT. Vilaweb.
6. ^ Teracom (October 15, 2007). Historisk ?verg?ng till digital-tv. Press
release.
7. ^ First UK homes go digital TV only. BBC News (2007-03-15). Retrieved on
2007-09-28.
8. ^ First digital TV switch date set. BBC News (2007-03-15). Retrieved on
2007-04-24.
9. ^
10. ^ Digital TV. Government of Hong Kong. Retrieved on 2007-06-04.
11. ^ Daily Nation, October 5, 2007: Kenyans to switch to digital TVs
12. ^ Section 3002 of the Deficit Reduction Act of 2005, Pub. L. No. 109-171,
120 Stat. 4 (Feb. 8, 2006), amending the Communications Act of 1934, section
309(j)(14), codified at .
13. ^ Bray, Hiawatha (2007-02-26). FCC rule requires all new TVs to be digital.
The Boston Globe. Retrieved on 2007-04-24.
14. ^ FCC: Wireless Services: Lower 700 MHz. Federal Communications Commission
(2004-10-28). Retrieved on 2007-05-09.
15. ^ Converters Signal a New Era for TVs.
16. ^ National Telecommunications and Information Administration - U.S.
Department of Commerce (April 2007). Preparing for the Digital Television
Transition (PDF). Retrieved on 2007-05-12.
Interaction
Interaction happens between the TV watcher and the DTV system. It can be
understood in different ways, depending on which part of the DTV system is
concerned. It can be an interaction with the STB only (to tune to another TV
channel or to browse the EPG).
Modern DTV systems are able to provide interaction between the end-user and the
broadcaster through the use of a return path. With the exceptions of coaxial and
fiber optic cable, which can be bidirectional, a dialup modem, Internet
connection, or other method is typically used for the return path with
unidirectional networks such as satellite or antenna broadcast.
In addition to not needing a separate return path, cable also has the advantage
of a communication channel localized to a neighborhood rather than a city
(terrestrial) or an even larger area (satellite). This provides enough
customizable bandwidth to allow true video on demand.
Analog switch-off
Many countries around the world currently operate a simulcast service where a
broadcast is made available to viewers in both analog and digital at the same
time. As digital becomes more popular it is likely that the existing analog
services will be removed. In some cases this has already happened where a
broadcaster has offered incentives to viewers to encourage them to switch to
digital or simply switched their service regardless of whether they want to
switch. In other cases government policies have been introduced to encourage the
switch-over process, especially with regard to terrestrial broadcasts.
Government intervention usually involves providing some funding for broadcasters
to enable a switch-over to happen by a given deadline.
Switch-off completed
* Luxembourg was the first country to complete the move to digital broadcasting,
on September 1, 2006.
* The Netherlands moved to digital broadcasting on December 11, 2006. The
switch-off was helped greatly by the fact that about 90 percent of the
households have cable that continues to use analogue broadcasts.
* In Finland, terrestrial analogue transmissions were terminated nationwide at
4am, September 1, 2007 (switch-off was previously planned for the midnight after
August 31 but a few extra hours were added for technical reasons). Cable-TV
viewers will continue to receive analogue broadcasts till the end of February
2008.
* Andorra completed its switch-off on September 25, 2007.
Switch-off in progress
* Austria began analog switch-off on March 5, 2007, progressing from the west to
the east.
* The Czech Republic started the switch-off in September 2007 and should finish
by September 2010. A broadcast law amendment which would change this is awaiting
approval. The areas of Brno, Doma?lice and ústí nad Labem have already switched
off.
* Germany started the switch-off at different times in different regions. The
first was the Berlin area, where the switch-off began on November 1, 2002 and
was completed on August 4, 2003. Most other regions have followed, and in most
populous areas the switch-off is completed, but a number of regions have not yet
started. The switch-off is planned to be completed by the end of 2008.
* Switzerland began with the switch-off on July 24, 2006 (Tessin) and continued
with Engadin on November 13, 2006. The switch-off is planned to be completed on
November 26, 2007.
* In Sweden, the switch-off of the analog terrestrial network progressed
region–by–region. It started on the island of Gotland on September 15, 2005 and
will be completed on October 29, 2007 when the last analogue SVT1 transmitters
in Scania and Blekinge are shut down. Cable distributors are allowed to continue
broadcasting analogue television.
* In the United Kingdom, the first switchoff of analogue television was on 30
March 2005, in the villages of Llansteffan and Ferryside in Wales. However, it
was partially unsuccessful as residents insisted that BBC Two Wales be left
broadcasting in analogue as they felt that the digital replacement, BBC 2W,
which opts out from BBC Two from 20:30 to 22:00 on weekdays, shows too much
Welsh programming The switch-off of all analogue terrestrial TV broadcasts
resumed again on October 17 2007 with Whitehaven in Cumbria and will now proceed
region by region. The last regions will be switched off in 2012. Freeview is now
available to its fullest pre-switch off coverage. A set top box can be used with
an analogue television and tuners are integrated into new sets. Freeview is a
DTT system complying to the DVB-T standard.
Switch-off time announced
* In Australia, the government originally planned a switch-off in 2008. This has
now been delayed to a "to be determined" date in 2010-2012. Until that time,
free-to-air stations will be simulcast, along with digital only channels like
ABC2. Since 1999, regulations have required that all locally-made free-to-air
television shows be in 16:9 widescreen format. Cable Television Networks began
broadcasting in simulcast from 2004 and analogue cable services were
switched-off in June 2007.
* In Belgium, the situation is rather complex, as media regulations are under
regional legislation. The Flemish region has announced that it will switch
analogue television off on December 31, 2008, because coverage is already at 99
percent. The Wallonian Region has not yet announced a date and is expected to
follow the European dates because the geographic difficulties to cover the whole
region. In Wallonia there is already an 80 percent DTT coverage.
* In Brazil, the free-to-air digital transmissions will start on December 2,
2007 in S?o Paulo, but broadcasting companies must transmit signals in both
analogue and digital formats until June 2016.
* In Bulgaria, the switch-off will be completed in December 2012.
* In Canada, the main free-to-air broadcasters (Canadian Broadcasting
Corporation, CTV, and Global) have launched HD streams of their programming.
Originally, unlike in the other countries, Canada was allowing the market to
determine when the analogue switch-off begins. As a result, currently analogue
and digital broadcasts co-exist, with virtually the only way to receive digital
TV in much of the country via cable or satellite TV. However, in some urban
areas like Toronto, it's also possible to pick up DTV over-the-air, though as of
May 2007 there are less than 20 digital television stations in Canada. On May 17
2007, the Canadian Radio-television and Telecommunications Commission (CRTC,
Canada's broadcasting authority) ruled that television stations would indeed be
forced to switch to ATSC digital broadcasting by the end of August 2011, and
that analogue NTSC channels must then be dropped, except in remote and northern
regions where analogue transmission may continue for an undetermined period.
* In China, the switch-off is scheduled to be in 2015.
* In Denmark, digital transmission has started and the analogue net will be
closed at the end of October 2009.
* In Greece, the switch-off will completed after the end of 2010.
http://ec.europa.eu/information_society/policy/ecomm/doc/todays_framework/digital_broadcasting/switchover/el_152_el.doc.
* In Hong Kong, analogue broadcasting is planned to be switched off by 2012.
* In Ireland, the government aims to complete the digital switchover by/in 2012.
* In Italy, the government aims to complete the digital switchover by 2012.
* In Japan, analogue transmissions will be terminated nationwide in July 24,
2011.
* In Kenya , The Communications Commission of Kenya (CCK) announced that the
country will start digital broadcasting by 2012 and analogue transmissions will
be stopped in June 17, 2015 .
* In Malaysia, Information Ministry was planning to shut down the country's
analogue television system in phases beginning from 2009 and set to convert to
full digital TV in 2015.
* In New Zealand, shutting down of analogue TV transmissions is planned to
happen between 2013 and 2017
* In Norway, the switch-off will start in late 2007 and finish by 2009.
* In the Philippines, the National Telecommunications Commission will terminate
all analog television transmission on December 31, 2015.
* In Slovenia, the switch-off will be completed in 2012.
* In South Africa, the switch-off will start in November 2008 in preparation for
the 2010 Soccer World Cup and should be completed by mid 2011.
* In Spain, the switch-off will be completed on April 3, 2010.
* In Ukraine, analogue transmissions will be terminated on July 17,
2015.http://comments.com.ua/?spec=1173973950&sart=1173974411
* In the United States, all U.S. television broadcasts will be exclusively
digital as of February 17, 2009, by order of the Federal Communications
Commission. This deadline was signed into law in early 2006. Furthermore, as of
March 1, 2007, all new television sets that can receive signals over-the-air,
including pocket-sized portable televisions, must include digital or HDTV tuners
so they can receive digital broadcasts. Currently, most U.S. broadcasters are
transmitting their signals in both analog and digital formats; a few are
digital-only. Citing the bandwidth efficiency of digital TV, after the analog
switch-off, the FCC will auction off channels 52–59 (the lower half of the 700
MHz band) for other communications traffic, completing the reallocation of
broadcast channels 52–69 that began in the late 1990s.
The analog switch-off ruling, which so far has met with little opposition from
consumers or manufacturers, would render all non-digital televisions dark and
obsolete on the switch-off date, unless connected to an external off-the-air
tuner, analog or digital cable, or a satellite system. The FCC has determined
that an external tuning device can simply be added to non-digital televisions to
lengthen their useful lifespan. Several of these devices have already been
shown, and it is expected that low-cost units will be available in January 2008.
At that same time, the U.S. government will take requests from households for up
to two coupons to reduce the price of some converter boxes by $40. Currently,
even the earliest televisions continue to work with present broadcast standards.
This mandate was designed to help provide a painless transition to the new
standard.
Pros and cons
DTV has several advantages over traditional, analog TV, the most significant
being that digital channels take up less bandwidth (and the bandwidth needs are
continuously variable, at a corresponding cost in image quality depending on the
level of compression). This means that digital broadcasters can provide more
digital channels in the same space, provide High-definition television service,
or provide other non-television services such as multimedia or interactivity.
DTV also permits special services such as multiplexing (more than one program on
the same channel), electronic program guides and additional languages, spoken or
subtitled. The sale of non-television services may provide an additional revenue
source. In many cases, viewers perceive DTV to have superior picture quality,
improved audio quality, and easier reception than analog.
However, DTV picture technology is still in its early stages. DTV images have
some picture defects that are not present on analog television or motion picture
cinema, due to present-day limitations of bandwidth and compression algorithms
such as MPEG-2.
When a compressed digital image is compared with the original program source,
some hard-to-compress image sequences may have digital distortion or
degradation. For example:
* quantization noise,
* incorrect color,
* blockiness,
* a blurred, shimmering haze.
Broadcasters attempt to balance their needs to show high quality pictures and to
generate revenue by using a fixed bandwidth allocation for more services.
High-definition television (HDTV) is a digital television broadcasting system
with a significantly higher resolution than traditional formats (NTSC, SECAM,
PAL). While some early analog HDTV formats were broadcast in Europe and Japan,
HDTV is usually broadcast digitally, because digital television (DTV)
broadcasting requires much less bandwidth if it uses enough video compression.
HDTV technology was first introduced in the US during the 1990s by a group of
electronics companies called the Digital HDTV Grand Alliance.
History
The first television system capable of 1125 lines was created in Soviet Union in
1958. The system was dubbed "Трансформатор" (in Russian) meaning "Transformer".
The original purpose of the system was teleconferencing between high-ranked
military command offices. This system was not intended for commercial use and
was not implemented at the large scale.
Commercial High-Definition television was first developed by Nippon Hōsō Kyōkai,
and was unveiled in 1969. However, the system did not become mainstream until
the late 1990s.
In the early 2000s, a number of high-definition television standards were
competing for the still-developing niche markets.
Three HDTV standards are currently defined by the International
Telecommunication Union (ITU-R BT.709). They include 1080i (1,080 actively
interlaced lines), 1080p (1,080 progressively scanned lines), and 720p (720
progressively scanned lines). All standards use a 16:9 aspect ratio, leading
many consumers to the incorrect conclusion of equating widescreen television
with HDTV. All current HDTV broadcasting standards are encompassed within the
ATSC and DVB specifications.
Enlarge picture
Projection screen in a home theater, displaying a high-definition television
image.
HDTV is also capable of "theater-quality" audio because it uses the Dolby
Digital (AC-3) format to support "5.1" surround sound. It should be noted that
while HDTV is more like a theater in quality than conventional television, 35 mm
and 70 mm film projectors used in theaters still have the highest resolution and
best viewing quality on very large screens. Many HDTV programs are produced from
movies on film as well as content shot in HD video.
The term "high-definition" can refer to the resolution specifications
themselves, or more loosely to media capable of similar sharpness, such as
photographic film and digital video. As of July 2007, HDTV saturation in the US
has reached 30 percent – in other words, three out of every ten American
households own at least one HDTV. However, only 44 percent of those that do own
an HDTV are actually receiving HDTV programming, as many consumers are not aware
that they must obtain special receivers to receive HDTV from cable or satellite,
or use ATSC tuners to receive over-the-air broadcasts; others may not even know
what HDTV is.
HDTV sources
The rise in popularity of large screens and projectors has made the limitations
of conventional Standard Definition TV (SDTV) increasingly evident. An HDTV
compatible television set will not improve the quality of SDTV channels. To get
a better picture HDTV televisions require a High Definition (HD) signal. Typical
sources of HD signals are as follows:
* Over the air with an antenna. Most cities in the US with major network
affiliates broadcast over the air in HD. To receive this signal an HD tuner is
required. Most newer HDTV televisions have an HD tuner built in. For HDTV
televisions without a built in HD tuner, a separate set-top HD tuner box can be
rented from a cable or satellite company or purchased.
* Cable television companies often offer HDTV broadcasts as part of their
digital broadcast service. This is usually done with a set-top box or CableCARD
issued by the cable company. Alternatively one can usually get the network HDTV
channels for free with basic cable by using a QAM tuner built into their HDTV or
set-top box. Some cable carriers also offer HDTV on-demand playback of movies
and commonly viewed shows.
* Satellite-based TV companies, such as Optimum, DirecTV, Sky Digital (in the UK
and Ireland), Bell ExpressVu and Dish Network, offer HDTV to customers as an
upgrade. New satellite receiver boxes and a new satellite dish are often
required to receive HD content.
* Video game systems, such as the Xbox (NTSC only), Xbox 360, and Playstation 3,
can output an HD signal. The Xbox Live Marketplace service offers HD movies, TV
shows, movie trailers, and clips for download to Xbox 360 consoles.
* Two optical disc standards, Blu-ray and HD DVD, can provide enough digital
storage to store hours of HD video content.
Notation
In the context of HDTV, the formats of the broadcasts are referred to using a
notation describing:
* The number of lines in the vertical display resolution.
* Whether progressive scan (p) or interlaced scan (i) are used. Progressive scan
redraws all the lines (a frame) of a picture in each refresh. Interlaced scan
redraws every second line (a field) in one refresh and the remaining lines in a
second refresh. Interlaced scan increases picture resolution while saving
bandwidth but at the expense of some flicker or other artifacts.
* The number of frames or fields per second.
The format 720p60 is 1280 × 720 pixels, progressive encoding with 60 frames per
second (60 Hz). The format 1080i50 is 1920 × 1080 pixels, interlaced encoding
with 50 fields (25 frames) per second. Often the frame or field rate is left
out, indicating only the resolution and type of the frames or fields, and
leading to confusion. Sometimes the rate is to be inferred from the context, in
which case it can usually be assumed to be either 50 or 60, except for 1080p
which is often used to denote either 1080p24, 1080p25 or 1080p30 at present but
will also denote 1080p50 and 1080p60 in the future.
A frame or field rate can also be specified without a resolution. For example
24p means 24 progressive scan frames per second and 50i means 25 interlaced
frames per second, consisting of 50 interlaced fields per second. Most HDTV
systems support some standard resolutions and frame or field rates. The most
common are noted below.
Changes in notation
The terminology described above was invented for digital systems in the 1990s. A
digital signal encodes the color of each pixel, or dot on the screen as a series
of numbers. Before that, analog TV signals encoded values for one monochrome, or
three-color signals as they scanned a screen continuously from line to line. By
comparison, radio encodes an analog signal of the sound to be sent to an
amplified speaker, typically up to 20 kHz, but video signals are in the MHz
range, which is why they are much higher in the broadcast spectrum than audio
radio. Analog video signals have no true "pixels" to measure horizontal
resolution. The vertical scan-line count included off-screen scan lines with no
picture information while the CRT beam returned to the top of the screen to
begin another field. Thus NTSC was considered to have "525 lines" even though
only 486 of them had a picture (625/576 for PAL). Similarly the Japanese MUSE
system was called "1125 line", but is only 1035i by today's measuring standards.
This change was made because digital systems have no need of blank retrace lines
unless the signal was converted to analog to drive a CRT.
Standard resolutions
Enlarge picture
Visual comparison of common TV display resolutions.
When resolution is considered, both the resolution of the transmitted signal and
the (native) displayed resolution of a TV set are taken into account. Digital
NTSC- and PAL/SECAM-like signals (480i60 and 576i50 respectively) are
transmitted at a horizontal resolution of 720 or 704 "pixels". However these
transmitted DTV "pixels" are not square, and have to be stretched for correct
viewing. PAL TV sets with an aspect ratio of 4:3 use a fixed pixel grid of 768 ×
576 or 720 × 540; with an aspect ratio of 16:9 they use 1440 x 768, 1024 × 576
or 960 × 540; NTSC ones use 640 × 480 and 852 × 480 or, seldom, 720 × 540. High
Definition usually refers to one million pixels or more.
In Australia, the 576p50 format is also considered a HDTV format, as it has
doubled temporal resolution though the use of progressive scanning. Thus, a
number of Australian networks broadcast a 576p signal as their High-definition
DVB-T signal, while others use the more conventional 720p and 1080i formats.
Technically, however, the 576p format is defined as Enhanced-definition
television.
Standard frame or field rates
* 23.977p (allow easy conversion to NTSC)
* 24p (cinematic film)
* 25p (PAL, SECAM DTV progressive material)
* 30p (NTSC DTV progressive material)
* 50p (PAL, SECAM DTV progressive material)
* 60p (NTSC DTV progressive material)
* 50i (PAL & SECAM)
* 60i (NTSC, PAL-M)
Comparison with SDTV
Close-up view
HDTV resolution SDTV resolution
HDTV has at least twice the linear resolution of standard-definition television
(SDTV), thus allowing much more detail to be shown compared with analog
television or regular DVD. In addition, the technical standards for broadcasting
HDTV are also able to handle 16:9 aspect ratio pictures without using
letterboxing or anamorphic stretching, thus further increasing the effective
resolution for such content.
Format considerations
The optimum formats for a broadcast depends on the type of media used for the
recording and the characteristics of the content. The field and frame rate
should match the source, as should the resolution. On the other hand, a very
high resolution source may require more bandwidth than is available in order to
be transmitted without loss of fidelity. The lossy compression that is used in
all digital HDTV storage/transmission systems will then cause the received
picture to appear distorted when compared to the uncompressed source.
Photographic film destined for the theater typically has a high resolution and
is photographed at 24 frames per second. Depending on the available bandwidth
and the amount of detail and movement in the picture, the optimum format for
video transfer is thus either 720p24 or 1080p24. When shown on television in
countries using PAL, film must be converted to 25 frames per second by speeding
it up by 4.1 percent. In countries using the NTSC standard, 30 frames per
second, a technique called 3:2 pulldown is used. One film frame is held for
three video fields, (1/20 of a second) and then the next is held for two video
fields (1/30 of a second) and then the process repeats, thus achieving the
correct film rate with two film frames shown in 1/12 of a second.
See also: Telecine
Older (pre-HDTV) recordings on video tape such as Betacam SP are often either in
the form 480i60 or 576i50. These may be upconverted to a higher resolution
format (720i), but removing the interlace to match the common 720p format may
distort the picture or require filtering which actually reduces the resolution
of the final output.
See also: Deinterlacing
Non-cinematic HDTV video recordings are recorded in either 720p or 1080i format.
The format used depends on the broadcast company (if destined for television
broadcast); however, in other scenarios the format choice will vary depending on
a variety of factors. In general, 720p is more appropriate for fast action as it
uses progressive scan frames, as opposed to 1080i which uses interlaced fields
and thus can have a degradation of image quality with fast motion.
In addition, 720p is used more often with Internet distribution of HD video, as
all computer monitors are progressive, and most graphics cards do a poor job of
de-interlacing video in real time. 720p video also has lower storage and
decoding requirements than 1080i or 1080p.
In North America, Fox, My Network TV (also owned by Fox), ABC, and ESPN (ABC and
ESPN are both owned by Disney) currently broadcast 720p content. NBC, Universal
HD (both owned by General Electric), CBS, PBS, The CW, HBO, Showtime, Starz!,
MOJO HD, HDNet ,TNT, and Discovery HD Theater currently broadcast 1080i content.
In the United Kingdom on Sky Digital, there are BBC HD, Sky One HD, Sky Arts HD,
Sky Movies HD1 & 2, Sky Sports HD1,2 & X, Discovery HD, National Geographic
Channel HD, The History Channel HD & Sky Box Office HD1 & 2. With MTV HD, FX HD,
Living HD Rush HD, Ultra HD & Eurosport HD to come in the near future. BBC HD is
also available on Virgin Media. The BBC Trust has given provisional approval for
a BBC HD channel, which would be broadcast satellite, cable and DTT.
* Public consultation on the Trust's provisional conclusions on the proposed BBC
HD service is open until 23 October 2007.
Technical details
Enlarge picture
One of the first DVB-S2 tuner cards.
MPEG-2 is most commonly used as the compression codec for digital HDTV
broadcasts. Although MPEG-2 supports up to YCbCr chroma subsampling and 10-bit
quantization, HD broadcasts use and 8-bit quantization to save bandwidth. Some
broadcasters also plan to use MPEG-4 AVC, such as the BBC which is trialing such
a system via satellite broadcast, which will save considerable bandwidth
compared to MPEG-2 systems. Some German broadcasters already use MPEG-4 AVC
together with DVB-S2 (Pro 7, Sat.1 and Premiere). Although MPEG-2 is more widely
used at present, it seems likely that in the future all European HDTV may be
MPEG-4 AVC, and Ireland and Norway, which have not yet begun any digital
television broadcasts, are considering MPEG-4 AVC for SD Digital as well as HDTV
on terrestrial broadcasts.
HDTV is capable of "theater-quality" audio because it uses the Dolby Digital
(AC-3) format to support "5.1" surround sound. The pixel aspect ratio of native
HD signals is a "square" 1.0, in which each pixel's height equals its width. New
HD compression and recording formats such as HDV use rectangular pixels to save
bandwidth and to open HDTV acquisition for the consumer market. For more
technical details see the articles on HDV, ATSC, DVB, and ISDB.
Television studios as well as production and distribution facilities, use HD-SDI
SMPTE 292M interconnect standard (a nominally 1.485 Gbit/s, 75-ohm serial
digital interface) to route uncompressed HDTV signals. The native bitrate of
HDTV formats cannot be supported by 6-8 MHz standard-definition television
channels for over-the-air broadcast and consumer distribution media, hence the
widespread use of compression in consumer applications. SMPTE 292M interconnects
are generally unavailable in consumer equipment, partially due to the expense
involved in supporting this format, and partially because consumer electronics
manufacturers are required (typically by licensing agreements) to provide
encrypted digital outputs on consumer video equipment, for fear that this would
aggravate the issue of video piracy.
Newer dual-link HD-SDI signals are needed for the latest 4:4:4 camera systems
(Sony HDC-F950 & Thomson Viper), where one link/coax cable contains the 4:2:2
YCbCr info and the other link/coax cable contains the additional 0:2:2 CbCr
information.
Advantages of HDTV expressed in non-engineering terms
High-definition television (HDTV) potentially offers a much better picture
quality than standard television. HD's greater clarity means the picture on
screen can be less blurred and less fuzzy. HD also brings other benefits such as
smoother motion, richer and more natural colors, and the ability to allow a
variety of input devices to work together.
Almost all commercially available HD is digital, so the system cannot produce a
snowy or washed out image from a weak signal, effects from signal interference,
such as herringbone patterns, or vertical rolling.
With HDTV the lack of imperfections in the television screen often seen on
traditional television is another reason why many prefer high definition to
analog. As mentioned, problems such as snow caused from a weak signal, double
images from ghosting or multi-path and picture sparkles from electromagnetic
interference do not occur with HDTV digital broadcasts.
The colors will generally look more realistic, due to greater bandwidth. The
visual information is about 2-5 times more detailed overall. The gaps between
scanning lines are smaller or invisible. Legacy TV content that was shot and
preserved on 35 mm film can now be viewed at nearly the same resolution at which
it was originally photographed. A good analogy for television quality is looking
through a window. HDTV offers a degree of clarity that is much closer to this.
The "i" in these numbers stands for "interlaced" while the "p" stands for
"progressive". With interlaced scan, the 1,080 lines are split into two, the
first 540 being painted on a frame, followed by the second 540 painted on
another frame. This method reduces the bandwidth and raises the frame rate to
50-60 frames per second. A progressive scan displays all 1,080 lines at the same
time at 60 frames per second, using more bandwidth. (See: An explanation of HDTV
numbers and laymen's glossary)
Dolby Digital 5.1 surround sound is broadcast along with standard HDTV video
signals, allowing full surround sound capabilities. (Standard broadcast
television signals usually only include monophonic or stereophonic audio. Stereo
broadcasts can be encoded with Dolby Surround, an early home video surround
format.) Both designs make more efficient use of electricity than SDTV designs
of equivalent size, which can mean lower operating costs. LCD is a leader in
energy conservation.
Disadvantages of HDTV expressed in non-engineering terms
However, there are a variety of reasons why the best HD quality is not usually
achieved. The main problem is a lack of HD input. Many cable and satellite
channels and even some "high definition" channels are not broadcast in true HD.
Also, image quality may be lost if the television is not properly connected to
the input device or not properly configured for the input's optimal
performance.HD digital signals will either deliver an excellent picture, a
picture with noticeable pixelation, a series of still pictures, or no picture at
all. Any interference will render the signal unwatchable. As opposed to a
lower-quality signal one gets from interference in an analogue television
broadcast, interference in a digital television broadcast will freeze, skip, or
display "garbage" information.
HDTV is the answer to a question few consumers were asking. Viewers will have to
upgrade their TVs in order to see HDTV broadcasts, incurring household expense
in the process. Adding a new aspect ratio makes for consumer confusion if their
display is capable of one or more ratios but must be switched to the correct one
by the user. Traditional standard definition TV shows and feature films (mostly
movies from before 1953) originally filmed in the standard 4:3 ratio, when
displayed correctly on an HDTV monitor, will have empty display areas to the
left and right of the image. Many consumers aren't satisfied with this unused
display area and choose instead to distort their standard definition shows by
stretching them horizontally to fill the screen, giving everything a too-wide or
not-tall-enough appearance. Alternately, they'll choose to zoom the image which
removes content that was on the top and bottom of the original TV show.
As of 2007, broadcasters may demand, or cable-television operators may elect, to
place HD signals in a premium band that requires higher cable fees. That some
satellite companies offer the local HD channels as a service at additional cost
(transmission comes from satellite) suggests to some broadcasters that on-air
broadcasts of local HD signals must be a premium service to subscribers. Viewers
may be denied some television channels that they expected, be allowed only
access to the non-digital, and obviously sub-standard non-digital signal, or to
install an antenna to receive the digital broadcasts. Such issues more entail
economic and legal disputes than they entail technology.
Some viewers of HDTV will notice a type of distortion during faster scene
movement or total scene change. This "pixelation" or "blockiness" distortion is
caused by aggressive video compression in the source material. Technically this
is not a fault of HDTV, which is generally just displaying what is provided by
the tuner or source (like a cable tv or satellite tv decoder box). The higher
the compression used on the video, the more pronounced the pixelation. Since
each content provider can choose bitrate (hence, the amount of bandwidth) used
for the video, providers who devote more bandwidth will have higher video
quality HDTV content and less distortion. This type of pixelation did not occur
using traditional, broadcast, analog TV.
Another disadvantage of HDTV compared to traditional television has been
consumer confusion stemming from the different standards and resolutions, such
as 1080i, 1080p, and 720p. Complicating the matter have been the changes in
television connections from component video, to DVI, then to HDMI. Finally, the
HD-DVD vs. Blu-ray Disc high definition storage format war engenders even more
animosity for consumers. The confusion has led to slower uptake of the
technology as many people wait to see what becomes the "ultimate" de-facto
standard.
Early systems
Analog high-definition television systems
The term "high definition" was used to describe the electronic television
systems of the late 1930s and 1940s beginning with the former British 405-line
black-and-white system, introduced in 1936; however, this and the subsequent
525-line U.S. NTSC system, established in 1941, were high definition only in
comparison with previous mechanical and electronic television systems, and NTSC,
along with the later European 625-line PAL and SECAMs, is described as standard
definition today.
On the other hand, the 819-line French black-and-white television system
introduced after World War II arguably was high definition in the modern sense,
as it had a line count and theoretical maximum resolution considerably higher
than those of the 625-line systems introduced across most of postwar Europe.
However, it required far more bandwidth than other systems, and was switched off
in 1986, a year after the final British 405-line broadcasts.
Japan was the only country where commercial analog HDTV was launched and had
some success. In other places, such as Europe, analog (HD-MAC) HDTV failed.
Finally, although the United States experimented with analog HDTV (there were
about 10 proposed formats), it soon moved towards a digital approach.
Contemporary systems
Large-screen television technology
In addition to an HD Ready television, other equipment is often needed for the
home user to view High Definition Television. Cable Ready TV sets can display HD
content without the use of an external box. They provide a card slot that
accepts a CableCARD. There are several sources of high definition content and
the equipment used to control each of these must be HD compatible.
High Definition picture sources include terrestrial broadcast, direct broadcast
satellite, digital cable, high definition discs (BD and HD DVD), internet
downloads and the latest generation of games consoles. The availability of
television pictures broadcast in the HD format varies by region and country.
HDTV can be recorded to D-VHS (Data-VHS), W-VHS (analog only), to a HDTV-capable
digital video recorder (for example DirecTV's high-definition Digital video
recorder, Sky HD's set-top box, or TiVo's Series 3 or HD recorders), or an
HDTV-ready HTPC. Some cable boxes are capable of receiving or recording two
broadcasts at a time in HDTV format, and HDTV programming, some free, some for a
fee, can be played back with the cable company's on-demand feature. The massive
amount of data storage required to archive uncompressed streams make it unlikely
that an uncompressed storage option will appear in the consumer market soon.
Realtime MPEG-2 compression of an uncompressed digital HDTV signal is also
prohibitively expensive for the consumer market at this time, but should become
inexpensive within several years (although this is more relevant for consumer HD
camcorders than recording HDTV). Analog tape recorders with bandwidth capable of
recording analog HD signals such as W-VHS recorders are no longer produced for
the consumer market and are both expensive and scarce in the secondary market.
In the United States, as part of the FCC's "plug and play" agreement, cable
companies are required to provide customers that rent HD set-top boxes with a
set-top box with "functional" Firewire (IEEE 1394) upon request. None of the
direct broadcast satellite providers have offered this feature on any of their
supported boxes, but some cable TV companies have. As of July 2004, boxes are
not included in the FCC mandate. This content is protected by encryption known
as 5C. This encryption can prevent duplication of content or simply limit the
number of copies permitted, thus effectively denying most if not any fair use of
the content.
We have links for many of
the best free online TV:
YouTube
We had to
start with the big one.
Google paid billions of
dollar for YouTube. This is
user uploaded videos. The
presidential debate even
used YouTube.
Joost
Another much-hyped favorite from the authors
of
Skype is still in beta
stage. Good amounts of good content, great GUI,
almost glitch-free work, quality video.
Babelgum
Babelgum
is
similar
to
Joost
in
two
ways:
P2P-based
content
delivery,
and
free
but
ad-supported
content.
Zattoo
For
Europe
based
FreeTube (completely free
alternative to cable television that lets you watch
and TV shows online using just your browser.)
Hiveproductions (lists shoutcast tv
streams.)
Tape
it of the Internet (Over 2,000+
or 90,000+ episodes etc)
Streamic (More then 300 real TV
channels to choose from including NBC, ESPN,
BBC1 and many more, organized in categories and
ranked by the site users)
TVlinks (A directory that amalgamates
the most popular tv shows, cartoon & anime series.)
BabelgumBabelgum is P2P-based content delivery,
and free but ad-supported content. Channels include
news, music, documentaries, sports, animation, and
others. It takes some time to buffer it and there’s no
visible indication that it’s happening.
Zattoo
A p2p-based online television with a downloadable
client focused on European (over 50) channels.
Unfortunately, it won’t work if you’re not from one of
the supported countries.
Veoh
Veoh has a slightly different concept than other
services on this list. Their downloadable player acts
like a VCR: you can save movies to it for later viewing.
Although it’s possible to watch videos online on the
Flash version of the Veoh player, the focus is on
offline (or at least desktop) viewing, and videos longer
than 45 minutes can be viewed only on the desktop
player. Available videos include both user generated
content as well as professionally produced, sometimes
copyrighted stuff.
NGTV
NGTV, which is short for No Good TV. it’s similar to what kids see on TV everyday: lots of
music & entertainment, lots of foul language, and long,
long intros for every episode
PPStream (Sports, movies - all in one please.
Just choose a show from the list of available
channels)
ABC (Watch popular shows like Lost, Desperate
Housewives, Alias etc online)
PeekVid (Over 700 episodes of popular shows such
as 24, Buffy, Desperate Housewives, Family Guy.
Shows can be downloaded)
PPlive
(a popular service for watching many foreign
channels)
TV-Video (All the latest TV shows as they aired
including 24, Smallville, Prison Break, Lost etc)
TVU Player (TVU is a nifty little player that
offers users a variety of channels that can be used
to watch normal TV or Sport. US channels are also
found on this player.)
Chooseandwatch
(It’s a free TV portal where you can watch more than
250 online TV channels. Some of them have to be
good.)
Channelking (Channel King provides the
best selection of free Internet TV channels. Free
broadband TV channels from around the world enable
you to watch TV from anywhere with broadband.)
IPTV (Internet Protocol Television) is a system
where a digital television service is delivered by
using Internet Protocol over a network
infrastructure, which may include delivery by a
broadband connection. A general definition of IPTV
is television content that, instead of being
delivered through traditional broadcast and cable
formats, is received by the viewer through the
technologies used for computer networks.
For residential users, IPTV is often provided in
conjunction with Video on Demand and may be bundled
with Internet services such as Web access and VoIP.
The commercial bundling of IPTV, VoIP and Internet
access is referred to as "Triple Play" service
(adding mobility is called "Quadruple Play"). IPTV
is typically supplied by a service provider using a
closed network infrastructure. This closed network
approach is in competition with the delivery of TV
content over the public Internet, called Internet
Television. In businesses, IPTV may be used to
deliver television content over corporate LANs.
History
In 1994, ABC's World News Now was the first
television show to be broadcast over the Internet,
using the CU-SeeMe videoconferencing software.
Internet radio company AudioNet started the first
continuous live webcasts with content from WFAA-TV
in January, 1998 and KCTU-LP on January 10, 1998.[1]
Kingston Communications, a regional
telecommunications operator in UK, launched KIT
(Kingston Interactive Television), a DSL-based
broadband interactive TV service in September 1999
after conducting various TV and VoD trials. The
operator re-launched its VoD service in October 2001
via Yes TV, a provider of IP-based VoD service and
solutions. Kingston was one of the first companies
in the world to introduce IPTV and IP VOD over ADSL.
In the past, this technology has been restricted by
low broadband penetration. In the coming years,
however, residential IPTV is expected to grow at a
brisk pace as broadband was available to more than
200 million households worldwide in the year 2005,
projected to grow to 400 million by the year 2010.
Many of the world's major telecommunications
providers are exploring IPTV as a new revenue
opportunity from their existing markets and as a
defensive measure against encroachment from more
conventional Cable Television services. In the mean
time, there are thousands of IPTV installations
within schools, corporations, and other institutions
that do not require the use of wide area
connectivity.
It is important to note that there has historically
been many different definitions of "IPTV" including
elementary streams over IP networks, transport
streams over IP networks and a number of proprietary
systems. Although (in Mid 2007) it is premature to
say that there is a full consensus of exactly what
IPTV should mean, there is no doubt that the most
widely used definition today is for single or
multiple program transport streams which are sourced
by the same network operator that owns or directly
controls the "Final Mile" to the consumer's
premises. This control over delivery enables a
guaranteed quality of service, and also allows the
service provider to offer an enhanced user
experience such as better program guide, interactive
services etc.
By contrast "Internet TV" generally refers to
transport streams sent over IP networks (normally
the Internet)from outside the network that connects
to the users premises. An Internet TV provider has
no control over the final delivery and so broadcasts
on a "best effort" basis. Elementary streams over IP
networks and proprietary variants as used by
websites such as YouTube are now rarely considered
to be IPTV services.
Architecture
Broadcast IPTV has two major architecture forms:
free and fee based. As of June 2006, there are over
1,300 free IPTV channels available. This sector is
growing rapidly and major television broadcasters
worldwide are transmitting their broadcast signal
over the Internet. These free IPTV channels require
only an Internet connection and an Internet enabled
device such as a personal computer, HDTV connected
to a computer or even a 3G cell/mobile phone to
watch the IPTV broadcasts. See also: Internet
television Mobile TV
In December 2005, independently produced mariposaHD
became the first original IPTV broadcast available
in an HDTV format. Various Web portals offer access
to these free IPTV channels. Some cite the
ad-sponsored availability of TV series such as Lost
and Desperate Housewives as indicators that IPTV
will become more prevalent.
Because IPTV uses standard networking protocols, it
promises lower costs for operators and lower prices
for users. Using set-top boxes with broadband
Internet connections, video can be streamed to
households more efficiently than current coaxial
cable. ISPs are upgrading their networks to bring
higher speeds and to allow multiple High Definition
TV channels.
In 2006, AT&T launched its U-Verse IPTV service.
Comprised of a national head end and regional video
serving offices, AT&T offered over 300 channels in
11 cities with more to be added in 2007 and beyond.
While using IP protocols, AT&T has built a private
IP network exclusively for video transport.
Local IPTV, as used by businesses for Audio Visual
AV distribution on their company networks is
typically based on a mixture of: a) Conventional TV
reception equipment and IPTV encoders b) IPTV
Gateways that take broadcast MPEG channels and IP
wrap them to create multicast streams.
IPTV uses a two-way digital broadcast signal sent
through a switched telephone or cable network by way
of a broadband connection and a set-top box
programmed with software (much like a cable or DSS
box) that can handle viewer requests to access to
many available media sources.
Protocols
IPTV covers both live TV (multicasting) as well as
stored video (Video on Demand VOD). The playback of
IPTV requires either a personal computer or a
set-top box connected to a TV. Video content is
typically compressed using either a MPEG-2 or a
MPEG-4 codec and then sent in an MPEG transport
stream delivered via IP Multicast in case of live TV
or via IP Unicast in case of Video on Demand. IP
Multicast is a method in which information can be
sent to multiple computers at the same time. The
newly released (MPEG-4) H.264 codec is increasingly
used to replace the older MPEG-2 codec.
In standards-based IPTV systems, the primary
underlying protocols used for:
Live TV is using IGMP version 2 for connecting to a
multicast stream (TV channel) and for changing from
one multicast stream to another (TV channel change).
VOD is using the Real Time Streaming Protocol
(RTSP).
Currently, the only alternatives to IPTV are
traditional TV distribution technologies such as
terrestrial, satellite and cable. However, cable can
be upgraded to two-way capability and can thus also
carry IPTV.
NPVR (network-based Personal Video Recorder)
Network Personal Video Recording is a consumer
service where real-time broadcast television is
captured in the network on a server allowing the end
user to access the recorded programs on the schedule
of their choice, rather than being tied to the
broadcast schedule. The NPVR system provides
time-shifted viewing of broadcast programs, allowing
subscribers to record and watch programs at their
convenience, without the requirement of a truly
personal PVR device. It could be compared as a "PVR
that is built into the network" -- however that
would be slightly misleading unless the word
"Personal" is, of course, changed to "Public" for
this context.
Subscribers can choose from the programmes available
in the network-based library, when they want,
without needing yet another device or remote
control. However, many people would still prefer to
have their own PVR device, as it would allow them to
choose exactly what they want to record. This
bypasses the strict copyright and licensing
regulations, as well as other limitations, that
often prevent the network itself from providing "on
demand" access to certain programmes (see Heroes,
below).
In the UK, Virgin Media (the current near-monopoly
cable TV brand which also provides telephone,
Internet and cellular services) has such an NPVR
service called "Virgin On Demand". It currently
provides access to a limited-but-growing volume of
documentaries, films, drama series and music videos
"on cue"; however it is important to take into
account the technological limitations which can
result in noticeable delays during playback, and in
response to the "pause", "rewind" and "fast forward"
features that it shares in common with VCRs and DVD
Players. There is a smaller library of selected
programmes that is available to all customers of the
cable TV service for no additional fee, but it is
more limited in variety and is intended as a "Catch
Up" archive consisting only of programmes that aired
within the last seven days.
Advantages
The IP-based platform offers significant advantages,
including the ability to integrate television with
other IP-based services like high speed Internet
access and VoIP.
A switched IP network also allows for the delivery
of significantly more content and functionality. In
a typical TV or satellite network, using broadcast
video technology, all the content constantly flows
downstream to each customer, and the customer
switches the content at the set-top box. The
customer can select from as many choices as the
telecomms, cable or satellite company can stuff into
the “pipe” flowing into the home. A switched IP
network works differently. Content remains in the
network, and only the content the customer selects
is sent into the customer’s home. That frees up
bandwidth, and the customer’s choice is less
restricted by the size of the “pipe” into the home.
This also implies that the customer's privacy could
be compromised to a greater extent than is possible
with traditional TV or satellite networks. It may
also provide a means to hack into, or at least
disrupt (see Denial of Service) the private network.
Interactivity
An IP-based platform also allows significant
opportunities to make the TV viewing experience more
interactive and personalized. The supplier may, for
example, include an interactive program guide that
allows viewers to search for content by title or
actor’s name, or a picture-in-picture functionality
that allows them to “channel surf” without leaving
the program they’re watching. Viewers may be able to
look up a player’s stats while watching a sports
game, or control the camera angle. They also may be
able to access photos or music from their PC on
their television, use a wireless phone to schedule a
recording of their favorite show, or even adjust
parental controls so their child can watch a
documentary for a school report, while they’re away
from home.
Note that this is all possible, to some degree, with
existing digital terrestrial, satellite and cable
networks in tandem with modern set top boxes.
VoD
VoD stands for Video on Demand. VoD permits a
customer to browse an online programme or film
catalogue, to watch trailers and to then select a
selected recording for playback. The playout of the
selected movie starts nearly instantaneously on the
customer's TV or PC.
Technically, when the customer selects the movie, a
point-to-point unicast connection is set up between
the customer's decoder (SetTopBox or PC) and the
delivering streaming server. The signalling for the
trick play functionality (pause, slow-motion,
wind/rewind etc.) is assured by RTSP (Real Time
Streaming Protocol).
The most common codecs used for VoD are MPEG-2,
MPEG-4 and VC-1.
In an attempt to avoid content piracy, the VoD
content is usually encrypted. Whilst encryption of
satellite and cable TV broadcasts is an old
practice, with IPTV technology it can effectively be
thought of as a form of Digital Rights Management. A
film that is chosen, for example, may be playable
for 24 hours following payment, after which time it
becomes unavailable.
Triple Play
Traditionally, TV has come down one wire cable TV or
a terrestrial antenna, the telephone has used
another (the Plain Old Telephone Service - POTS),
and the Internet has been available on either. Both
cable operators and telco operators are starting to
offer all three on one wire, which is more cost
effective. Triple play is an expression used by
service operators describing a bundle of telephony,
data and video via a single connection. Triple play
also refers to the combination of three services
(typically Video, Voice and Internet) bundled
together to entice customers to purchase all three
products at a reduced rate. A quadruple play bundle
usually includes a wireless component. Triple Play
has nothing to do with IPTV in its pure meaning but
deserves mention as a potential video element.
IPTV based Converged Services
Another advantage of an IP-based network is the
opportunity for integration and convergence.
Converged services implies interaction of existing
services in a seamless manner to create new value
added services. One good example is On-Screen Caller
ID, getting Caller ID on your TV and the ability to
handle it (send it to voice mail, etc). IP-based
services will help to enable efforts to provide
consumers anytime-anywhere access to content over
their televisions, PCs and cell phones, and to
integrate services and content to tie them together.
Within businesses and institutions, IPTV eliminates
the need to run a parallel infrastructure to deliver
live and stored video services.
Limitations
Because IPTV requires real-time data transmission
and uses the Internet Protocol, it is sensitive to
packet loss and delays if the IPTV connection is not
fast enough or picture break-up or loss if the
streamed data is unreliable. This latter problem has
proved particularly troublesome when attempting to
stream IPTV across wireless links. Improvements in
wireless technology are now starting to provide
equipment to solve the problem.
Are you interested in mult-player
online internet games? Such as runescape and neopets?Internet
Game Online-games, tips, cheats and kids forumsAnother good forum is
the Internet Junction For Gamers IJFG.COM Internet
Junction For Gamers, Runescape Market and More IJFG.COM Jokes, Pranks,
Runescape and other cool games at IJFG.COM. RuneScape is set in a medieval
fantasy world, similar to "Guild Wars" or "EverQuest", where players control
character representations of themselves. As with most massive multiplayer online
roleplaying games (MMORPG), there is no overall objective or end to the game.
Players explore, form alliances, perform optional tasks, and complete quests for
rewards and to build character's skills.
RuneScape has often been one of
the top massive online role playing games. It is a unique game. But, with a
unique game, comes unique players. Players get bored, and then try to develop
cheats....autos or bots that will help them achieve success in their beloved
games of Runescape 2.
RuneScape is a virtual world which
is divided into two part: Members Areas and Non-Members areas. People who pay to
play (p2p), receive access to the special areas. They also have access to the
free areas. The members' places are much larger, offer "better" items for the
gameplay of rs2, and much, much more. The character that you create when you
first start playing runescape, moves around the game on foot; either by running,
or walking. Players are challenged to their utmost skills by fighting new
monsters, completing difficult quests, and manipulating marketing. As Runescape
2 is an RPG (Role playing game), there is no set path a person must take to play
rs. They can choose what to do, and when, whether it be training their
money-making skills, or fighting another player. Players usually interact with
each other by chatting through public chat, or private chat.Internet
Junction For Gamers, Runescape Market and More IJFG.COM IJFG.com was a
runescape 2 based site. They have now, however, taken another look....
Of course the king of all game
cheating websites is
trick
the trik (otherwise known as RPG Cheats Site), where you can find cheat
forums, mmorpg topsite, arcade games and any mmo game related topics.
The master of massive multiplayer
online role-playing games (MMORPG) cheats can be found at Trik.com
Trik.com; this site is one of the best today. The forum section,
Trik.com forum, originally came from IJFG.com (Internet Junction For
Gamers) , which was one of the best websites that discussed various gamers'
issues. The full name was Internet Junction For Gamers, Runescape Market and
More. This site had Jokes, Pranks, RuneScape and other cool games. RuneScape is
set in a medieval fantasy world, similar to "Guild Wars" or "EverQuest," where
players control character representations of themselves. As with most MMORPG,
there is no overall objective or end to the game. Players explore, form
alliances, perform optional tasks, and complete quests for rewards and to build
characters' skills.
With the rising popularity of
commercial MMORPG games came the desire from ardent players of these games to
run their own servers beside the ones run by the game's creator. Since the
original server software is not usually available, the behavior of the server
has to be re-engineered. This can be done by analyzing the data stream with the
original server, or by disassembling and analyzing the client which is
available.
Ultima Online was one of the first
large MMORPGs. Due to its openness in implementation, server emulators arose
very quickly, even during the beta stage of development. The destination to
which the client connects was changeable by simply editing a text file. In beta
stage the client-server data stream was not encrypted yet. The term server
emulator became known through Ultima Online server reimplementation such as UOX,
which was the pioneer. Many forks and reimplementations followed UOX, because
its source code was released under the GNU General Public License relatively
early. RunUO is today the most widely used UO-server emulator. After RuneScape
implemented anti-cheating measures, many gamers left and started their own
private servers. The best place to discuss the private server is at
Trik- The Master of Private Server.
Another useful site is
Rune
Web ruwb.com . This site is about more serious RuneScape gold trading,
account exchange, gold for real life cash and many services. It includes tips on
how to avoid getting lured/scammed while using the marketplace. For programming,
visual basics, java, C/C++, scar and all other languages such as PHP, HTML, ASP,
Delphi. There are also sections for graphics talents, plus many cool videos and
fun stuff.
A defining moment in internet
gaming history was when a group of gamers called (hygo 7) decided to start an
ultimate game forum, which they named
hygo.com. It has the best financial backing, the friendliest game community,
and the highest quality of information. Currently Hygo.com has entered a new
phase...Hygo.com is offering the best private server game. With thousands of
members, Hygo.com is your next place to visit, as they have an amazing game with
a community and economy.
Hygo.com - The Online Adventure Game. is definitely one of the top sites you
want to join right now!
Ezud.com is now the powerhouse of
Runescape bugs and glitches. All and any rs2 bugs that anyone could ever
want are now found at the
Ezud forum. From a range of infinite running in runescape, to rs item
duping, ezud truly is an amazing glitching site.
Ezud has an excellent administration, and a great
moderating team. When everyone strives to make ezud.com a better place….it
becomes just that: a better place. Everyone contributes, and helps
Ezud strive.
So come on down to the new type of runescape 2 cheating:
runescape bugging. This is Ezud…this is
RuneScape 2 Bug Abuse.
Contact Information
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