Datacasting

Datacasting (data broadcasting) is the broadcasting of data over a wide area via radio waves. It most often refers to supplemental information sent by television stations along with digital terrestrial television, but may also be applied to digital signals on analog TV or radio. It generally does not apply to data which is inherent to the medium, such as PSIP data which defines virtual channels for DTT or direct broadcast satellite systems; or to things like cable modem or satellite modem, which use a completely separate channel for data.[1]

Overview

Datacasting often provides news, weather, traffic, stock market, and other information which may or may not relate to the programs it is carried with. It may also be interactive, such as gaming, shopping, or education. An electronic program guide is usually included, although this stretches the definition somewhat, as this is often considered inherent to the digital broadcast standard.

The ATSC, DVB and ISDB standards allow for broadband datacasting via DTT, though they do not necessarily define how. The overscan and VBI are used for analog TV, for moderate and low bandwidths (including closed captioning in the VBI) respectively. DirectBand and RDS/RBDS are medium and narrow subcarriers used for analog FM radio. The EUREKA 147 and HD Radio standards both allow for datacasting on digital radio, defining a few basics but also allowing for later expansion.

The term IP Datacasting (IPDC) is used in DVB-H for the technical elements required to send IP packets over DVB-H broadband downstream channel combined with a return channel over a mobile communications network such as GPRS or UMTS. The set of specifications for IP Datacast (phase1) was approved by the DVB project in October 2005.

Datacasting services around the world

North America

Ambient Information Network

Ambient Information Network, a datacasting network owned by Ambient Devices presently hosted by U.S.A. Mobility, a U.S. paging service and focuses on information of interest to the local (or larger) area, such as weather and stock indices, and with a paid subscription Ambient will provide a particular device with more personalized information.WITH dish sat

RBDS

A slight variation of the European Radio Data System, RBDS is carried on a 57kHz subcarrier on FM radio stations. While originally intended for program-associated data, it can also be used for datacasting purposes including paging and dGPS.

DirectBand

DirectBand, owned by Microsoft, uses the 67.65 kHz subcarrier leased from FM radio stations. This subcarrier delivers about 12 kbit/s (net after error correction) of data per station, for over 100 MB per day per city. Data includes traffic, sports, weather, stocks, news, movie times, calendar appointments, and local time.

MovieBeam

The now-defunct MovieBeam service used dNTSC technology by Dotcast to transmit 720p HDTV movies in the lower vestigial sideband of NTSC analog TV. The set-top box stored the movies to be viewed on demand for a fee. This was distributed through PBS's National Datacast.

TV Guide On Screen

TV Guide On Screen is an advertising-supported datacast sent by one local station in each media market. It supplements or replaces the limited electronic program guide sent by each TV station, which is already mandated by the U.S. Federal Communications Commission (FCC).

ATSC-M/H

ATSC-M/H is yet another mobile TV standard, although it is transmitted and controlled by the broadcasters instead of a third party, and is therefore mostly free-to-air (although it can also be subscription-based). From a technical standpoint, it is an IP-encapsulated datacast of MPEG-4 streaming video, alongside the ATSC MPEG transport stream used for terrestrial television broadcasting. Heavy error correction, separate from that native to ATSC, compensates for ATSC's poor mobile (and often fixed) reception.

UpdateTV

UpdateTV is a service used by some brands of TV sets and other ATSC tuners to update their firmware via over-the-air programming. This is also transmitted on PBS stations via National Datacast.

Australia

Australian broadcast infrastructure company Broadcast Australia undertook a three-year trial in Sydney of a datacasting service using the DVB-T system for use in Australia.

The trial consisted of a number of services on one standard 7MHz multiplex, collectively known as Digital Forty Four.

The collection included:

  • A combined program guide for the free-to-air broadcasters (Channel 4)
  • ABC news, sport, and weather items (Channel 41)
  • Channel NSW (link) Government and Public Information, including real time traffic information and life surf webcam images (Channel 45)
  • Australian Christian Channel (Channel 46)
  • Expo Home Shopping (Channel 49) and
  • Federal parliamentary audio broadcasts.

More recently a near-Australia wide broadcast of a datacasting channel called MyTalk commenced on April 13, 2007. Broadcasting as part of the multiplex on Southern Cross and Southern Cross Ten stations, it provided news, weather and other information, available free to anyone able to tune in. The stream consisted of text applicable to the viewer's location and a 4:3 video window of terrestrial TV from the relevant Southern Cross/Southern Cross Ten station.

On February 25, 2008, MyTalk ceased broadcasting. Digital Forty Four was shut down at exactly midnight on the night of April 30, 2010.

Malaysia

Malaysian multi-channel pay-TV operator, MiTV Corporation Sdn Bhd has launched its IP-over-UHF service in September 2005. The full digital broadcast capacity is being used to deliver IP services which such as multicast streaming and datacasting.

South Africa

Mindset Network has developed an IP satellite datacast platform for the distribution of educational and health content to sites around South Africa and increasingly throughout the rest of Africa as well. he model is a forward and store model allowing users of the platform to view content in an on-demand fashion. Content distributed in this way includes video content, print-based content (in the form of PDF files), as well as interactive computer-based multimedia content.

Significantly, the model also includes access to a GPRS network that allows the receiving sites to communicate back to the Mindset central server. Communications include statistics about the physical health of the machine (e.g. power status, disk drive usage) as well as usage statistics indicating what content has been viewed.

The model also includes a distributed deployment of the Moodle LMS, allowing users to take assessments and then have the results transmitted via GPRS to the Mindset server for accreditation.

United Kingdom

Teletext was used extensively on analogue channels; a type of datacasting using the overscan on analogue transmissions. Teletext Limited and Ceefax were the main providers. Within digital terrestrial television, the Digital Teletext name is used extensively although the technology used to provide this service is unrelated and uses the MHEG-5 UK profile.

Worldwide

Outernet

Outernet's goal is to provide free access to content from the web through geostationary and Low Earth Orbit satellites, made available effectively to all parts of the world. The project uses datacasting and User Datagram Protocol through both small satellites, such as CubeSats, and larger, more conventional geostationary communications satellites in a satellite constellation network. Wi-Fi enabled devices would communicate with the satellite hotspots, which receive data broadcasts from satellites.

See also

References

  1. ^ "Datacasting | Homeland Security". www.dhs.gov.
4ME

4ME was a digital advertorial datacasting service that launched on 18 September 2011 by Prime Media Group and Brand New Media. It was formerly available to homes in the Prime7/GWN7 viewing area on channel 64, and the Seven-owned viewing area on channel 74. The channel was closed at midnight on 30 April 2016 in regional areas after Brand New Media entered administration due to business troubles. 4ME later ceased broadcasting in Seven-owned areas on 19 May 2016.

As a datacasting channel, the content on the channel is regulated, it must consist of mostly information, and the scope for entertainment is limited. It shows mainly Australian made informational programs and infomercials, and as a datacasting service is prohibited from broadcasting programs that are wholly or substantially infotainment or lifestyle programs longer than 10 minutes.

AMC-18

AMC-18 is a geostationary Lockheed Martin A2100A communications satellite owned by SES Americom. It was launched on December 8, 2006 from Kourou aboard an Ariane 5 launch vehicle and is situated at 105° west longitude, providing coverage of North America with twenty-four C band transponders of 12-18 watts each. Future users in May 2007 include The CW Television Network, NASA TV and Canadian Broadcasting Corporation, among other services.

AMC-18 is used by thousands of terrestrial radio stations for network feeds using ground equipment from Starguide, X-Digital Systems, Wegener and International Datacasting. Major tenants are Cumulus Media Networks Satellite Services (which includes Citadel Media, Westwood One Networks, Talk Radio Network, WOR Radio Network and others), Skyview Networks (which includes ABC News, ABC Radio, California News Network, Arizona News Network, numerous Professional and Collegian Sports networks, and others), Orbital Media Networks (which includes United Stations Radio Networks, John Tesh, and others), Premiere Radio Networks, Dial Global, Westwood One, Learfield Communications, The Free Beer and Hot Wings Show, etc.

The spacecraft can deliver and receive signals from 50 states, the Caribbean and Mexico and has been designated as the third HD-PRIME satellite.

Originally built as a ground spare to the AMC-10 and AMC-11 satellite program, AMC-18 is optimized for digital television distribution from the center of the U.S. orbital arc.The satellite has an expected lifetime of at least 15 years.

AMC-8

AMC-8, also known as Americom-8 and Aurora III, previously GE-8, is a C-band satellite located at 139° West, covering the United States, Canada and the Caribbean. It is owned and operated by SES World Skies, formerly SES Americom and before that GE Americom. The satellite, provides critical telecommunications services to AT&T Alascom which occupies most of the satellite's capacity. AMC-8 was launched in 2000 as GE-8, and replaced Satcom C-5 in March 2001.

AMC-8 was used by thousands of terrestrial radio stations for network feeds using ground equipment from Starguide, X-Digital Systems, Wegener and International Datacasting. Major tenants were Cumulus Media Networks Satellite Services (which includes Citadel Media, Talk Radio Network, WOR Radio Network and others), Skyview Networks (which includes ABC News, ABC Radio, California News Network, Arizona News Network, numerous Professional and Collegian Sports networks, and others), Orbital Media Networks (which includes United Stations Radio Networks, John Tesh, and others), Premiere Radio Networks, Dial Global, Westwood One, Learfield Communications, The Free Beer and Hot Wings Show (Transponder 15), and others. However, these were moved over to another satellite, AMC-18. Audio network transmissions on AMC-8 ended as of midnight June 30, 2017.

Since AMC-8 is past its design life, it will soon be decommissioned. As of July 1, 2017 there are no plans to put another satellite in AMC-8's orbital slot (139 degrees).

It carries 24 36 MHz G/H band (IEEE C band) transponders, with 20 watt SSPA amplifiers. Its amplifier redundancy is 16 for 12, and its receiver redundancy is four for two. It carries two beacons, one broadcasting on a horizontal frequency of 3700.5 MHz, and the other on a vertical frequency of 4199.5 MHz.

Ambient Devices

Ambient Devices, Inc. is a privately held company founded in 2001 and based in Cambridge, Massachusetts, USA that designs and markets various ambient devices for display of information ranging from weather to traffic reports to stock quotes. The company was founded by David L. Rose, Ben Resner, Nabeel Hyatt and Pritesh Gandhi, and is a spin-off from the MIT Media Lab. It is funded by First Round Capital, .406 Ventures, and Nicholas Negroponte. The company also maintains the Ambient Information Network, a U.S. nationwide datacasting network presently hosted by U.S.A. Mobility, a U.S. paging service. The service is similar to the discontinued Microsoft's SPOT service.

Aspire TV

Aspire TV is an Australian advertorial datacasting channel launched on 21 May 2013. The channel operates a 24-hour / day format of mostly US produced infomercial and, to a lesser extent, other paid program content including religious programming.

When introduced, the "datacasting" concept was promoted (by the government of the day) to provide opportunity for the new services to broadcast information to schools, broadcast university lectures and other non traditional broadcast TV content.

However, without any legislative restriction on its use, the "datacasting" services have been solely used for advertising purposes, with airtime sold almost exclusively to "home shopping" companies.

Aspire TV ceased broadcasting via Southern Cross Television in Tasmania and Darwin on 29 August 2015 in order to accommodate for the launch of Racing.com; and in Spencer Gulf, SA and Broken Hill, NSW via SGS/SCN on 1 July 2016. In Northern NSW, Aspire TV ceased broadcasting via Ten Northern NSW on 31st August 2017, due to rival WIN Television taking over ownership of NRN.

Digital Forty Four

Digital Forty Four was a Sydney-only trial datacasting service that was licensed by the Australian Broadcasting Authority (now the Australian Communications and Media Authority) beginning on 17 March 2004 for an initial three-year run until late 2007. The license was extended on several occasions past 2007, however on 29 January 2010 it was announced that Broadcast Australia's datacasting licence for Digital Forty Four would not be extended past 30 April 2010. At midnight on 30 April 2010, all services from Digital Forty Four ceased broadcasting.

The services provided at various times during its six years of operation have included a television guide for free-to-air television, a community service channel providing information on road, weather and surf conditions, with live broadcasts every fifteen minutes, the Australian Christian Channel, Expo shopping channel, NITV, Teachers TV information channel and live broadcasts of the meetings of the Australian Parliament, with audio-video coverage of the House of Representatives and Senate.

Digital multimedia broadcasting

Digital multimedia broadcasting (DMB) is a digital radio transmission technology developed in South Korea as part of the national IT project for sending multimedia such as TV, radio and datacasting to mobile devices such as mobile phones, laptops and GPS navigation systems. This technology, sometimes known as mobile TV, should not be confused with Digital Audio Broadcasting which was developed as a research project for the European Union. DMB was developed in South Korea as the next generation digital technology to replace FM radio, but the technological foundations were laid by Prof. Dr. Gert Siegle and Dr. Hamed Amor at Robert Bosch GmbH in Germany. The world's first official mobile TV service started in South Korea in May 2005, although trials were available much earlier. It can operate via satellite (S-DMB) or terrestrial (T-DMB) transmission. DMB has also some similarities with the main competing mobile TV standard, DVB-H.

Digital terrestrial television in Australia

Digital terrestrial television in Australia commenced on 1 January 2001 in Sydney, Melbourne, Brisbane, Adelaide and Perth using DVB-T standards. The phase out of analogue PAL transmissions began in 2010 and was completed by 10 December 2013.

Digital terrestrial television brought a number of enhancements over the previous analogue television, primarily higher-quality picture and sound, as well as datacasting and multi-view services such as video program guides, high definition, and now-and-next program information. There are a number of additional channels, datacasting, as well as high definition services, available to digital terrestrial television viewers in Australia. Digital-only content is subject to availability and differs greatly in various television markets.

Although approximately 96% of the population had access to at least one digital service, take up was initially sluggish, with only 28% of Australia's 7.8 million households having adopted free-to-air digital television by March 2007. However, by August 2010, 75% of Australian households had made the switch. Analogue transmissions began to be phased out in 2010, and ceased to be available nationwide by the end of 2013.

From 2009, the free-to-air digital television platform has been promoted under the Freeview brand name.

FMeXtra

FMeXtra is a deprecated in-band on-channel digital radio broadcasting technology created by Digital Radio Express. Unlike iBiquity's HD Radio system, it uses any FM radio station's existing equipment and transmitter plant to transmit digital audio data on subcarriers instead of sidebands. It also requires no royalties for its use, which can run thousands of dollars per year for HD Radio because of the 3% of revenue on HD-2, HD-3 channels.

The system is run from a single rack unit box called the X1 Encoder, which is actually based upon a personal computer server and digital audio hardware from Lynx Studio Technologies (LST). Control is entirely via software, via gigabit Ethernet, USB, serial port, and SVGA video monitor. All processing is handled internally by a Pentium 4 running Windows XP.

FMeXtra is fully compatible with HD Radio, which uses additional radio spectrum beyond the ±100 kHz signal. It is not compatible with all existing subcarriers. Thus, a radio station might have to remove its radio reading service for the blind, and replace it (and its dependent listeners' receivers) with a digital one. This would take up much less bandwidth, particularly since voice can be highly compressed. The signal is partitioned so that RBDS, stereo, or other existing subcarriers can be protected, at the expense of bandwidth. If used only for monophonic transmissions, no RDS protection exists for stations in Europe.

The codecs used are AAC and aacPlus v1 and v2 and sample rates of 8 kHz (telephone quality) to 96 kHz (surround sound quality). The other codecs used are AMR-WB+ that can create more multiple audio programs as well as limited multimedia can also be broadcast, as with HD Radio and DAB. The available broadcasting bandwidth for digital audio varies from 40 kbit/s while sharing the space with existing analog signals, or 156 kbit/s if all analog signals (except the base monophonic signal) are dropped. (For comparison, iBiquity's Hybrid Digital/analog system offers 100-150 kbit/s in shared mode, and 300 kbit/s in pure digital mode.)

The coverage is similar to FM Stereo, and therefore high ERP is required in larger urban areas, as with normal FM transmissions.

Digital Radio Express has since gone out of business, after a brief stretch where it rebranded itself as VuCast in an effort to emphasize the technology's datacasting capabilities.

Gold (Australian TV channel)

Gold (stylised as WIN GOLD) is an Australian advertorial datacasting channel that launched on 1 May 2012 by the WIN Corporation. It is available to homes in most regional WIN Television viewing areas on LCN 85. The channel broadcasts mostly infomercials, as well as education, lifestyle, community programming as well as television classics from the Crawfords library.

MovieBeam

MovieBeam was a video-on-demand service started by The Walt Disney Company, specifically its subsidiary Buena Vista Datacasting, LLC. Movies were sent wirelessly into the subscriber's home by embedding digital data (datacasting) within local Public Broadcasting Service (PBS) stations' analog TV (NTSC) broadcast to deliver the movies to a set-top box. The data was embedded using dNTSC technology licensed from Dotcast, and distributed to TV stations via National Datacast. Up to 10 new movies were delivered to the player each week. The player also contained free movie trailers, previews, and other extras.

The set-top box was sold for a one-time fee ($149.99 as of August 2007). The cost of viewing a movie varied from $1.99 for older movies in standard definition to $4.99 for newer releases in HD. Movie rentals expired 24 hours after the rental period began.

The box had high-end hardware, including HDMI, component video outputs, and coaxial (SPDIF) and optical (TosLink) digital audio outputs. The box also had USB and Ethernet ports, although these were not activated in the last release of the firmware. An HDMI or DVI connection was required to watch HD content, which was in 720p resolution.MovieBeam connected to the servers by telephone line to trigger billing of rented movies. The modem may or may not have worked with VOIP lines, depending on the quality of the connection.

Disney spun off this company in January 2006. Intel Corporation, Cisco, Disney and several venture capital firms including Intel Capital, Mayfield Fund, Norwest Venture Partners and Vantage Point Venture Partners had invested $48.5 million in MovieBeam.On March 7, 2007, Movie Gallery, Inc. acquired MovieBeam, Inc. Movie Gallery at the time stated that the expected cost of acquisition, plus operating expenses for 2007, was $10 million.

On December 5, 2007, MovieBeam began calling its customers informing them that MovieBeam would be ceasing operations on December 15, 2007, and on that date MovieBeam officially shut down service.The main reason the service failed to penetrate and capture a portion of the video-on-demand market was the presumption that viewers would watch those movies that the network thought they would be interested in. The dependence on precise positioning of the reception TV antenna to obtain movies was another big problem. Differences of a centimeter or two, or poor weather conditions, could cause movies to be missed being downloaded over-the-air. Contemporary cable and satellite TV set-top boxes provide video-on-demand services with far better features than MovieBeam. The video quality of MovieBeam was greatly criticized by viewers due to excessive video compression, made necessary by using distribution via analog instead of digital TV (ATSC). Analog TV broadcasting was already slated to end in the United States in mid-2009 (and subsequently did so). These and other challenges sealed the fate of this much-hyped company into a flop of technology history.

National Datacast

National Datacast Incorporated (NDI) is a pioneer in data broadcasting.

It is a for-profit subsidiary of the Public Broadcasting Service (PBS) which handles datacasting on PBS TV stations throughout the United States. Services using ATSC digital TV include MovieBeam and UpdateTV, for which bandwidth is leased by other companies.

National Datacast was formed in 1988 based on PBS' early work in closed captioning for the hearing impaired.It uses line 21 and other vertical interval lines for data transmission.

Overscan

Overscan is a behaviour in certain television sets, in which part of the input picture is shown outside of the visible bounds of the screen. It exists because cathode-ray tube (CRT) television sets from the 1930s through to the early 2000s were highly variable in how the video image was positioned within the borders of the screen. It then became common practice to have video signals with black edges around the picture, which the television was meant to discard in this way.

Program and System Information Protocol

The Program and System Information Protocol (PSIP) is the MPEG (a video and audio industry group) and privately defined program-specific information originally defined by General Instrument for the DigiCipher 2 system and later extended for the ATSC digital television system for carrying metadata about each channel in the broadcast MPEG transport stream of a television station and for publishing information about television programs so that viewers can select what to watch by title and description.

Qterics

Qterics (formerly Broadcast Data Corporation and later UpdateLogic Incorporated ) is a company which has developed a system for datacasting firmware upgrades to digital television devices. It appears that UpdateTV is the only product the company, founded in 2003, has yet developed.

Subcarrier

A subcarrier is a sideband of a radio frequency carrier wave, which is modulated to send additional information. Examples include the provision of colour in a black and white television system or the provision of stereo in a monophonic radio broadcast. There is no physical difference between a carrier and a subcarrier; the "sub" implies that it has been derived from a carrier, which has been amplitude modulated by a steady signal and has a constant frequency relation to it.

TV4

TV4 or TV 4 may refer to:

TV4 (Poland), a private Polish television station

TV4 (Sweden), a Swedish television network

TV4 Group, owners of the Swedish television station

South African Broadcasting Corporation TV4, a channel operated by the state-owned broadcaster

Four (New Zealand), a defunct New Zealand television channel formerly named TV4

Television 4, a digital advertorial datacasting service

Vision Four, a cable television channel in Malaysia

TV 4 (Estonia)

TV-4, former name of Turkmenistan (TV channel)

TV4, the state network of the Mexican state of Guanajuato

Television broadcasting in Australia

As early as 1929, two Melbourne commercial radio stations, 3UZ and 3DB were conducting experimental mechanical television broadcasts - these were conducted in the early hours of the morning, after the stations had officially closed down. In 1934 Dr Val McDowall at amateur station 4CM Brisbane conducted experiments in electronic television.

Television broadcasting in Australia began officially on 16 September 1956, with the opening of TCN-9, quickly followed by national and commercial stations in Sydney and Melbourne, all these being in 625-line black and white. The commencement date was designed so as to provide coverage of the Olympic Games in Melbourne. It has now grown to be a nationwide system that includes a broad range of public, commercial, community, subscription, narrowcast, and amateur stations.

Colour television in the PAL 625-line format was introuduced in 1967 and went to a full-time basis on 1 March 1975 while subscription television, on the Galaxy platform, began in January 1995. Digital terrestrial television was introduced on 1 January 2001 in Australia's five largest capital cities.

Vertical blanking interval

In a raster graphics display, the vertical blanking interval (VBI), also known as the vertical interval or VBLANK, is the time between the end of the final line of a frame or field and the beginning of the first line of the next frame. It is present in analog television, VGA, DVI and other signals. During the VBI, the incoming data stream is not displayed on the screen. In raster cathode ray tube displays, the beam is blanked to avoid displaying the retrace line; see raster scan for details. The signal source, such as a television broadcast, does not supply image information during the blanking period.

The VBI was originally needed because of the inductive inertia of the magnetic coils which deflect the electron beam vertically in a CRT; the magnetic field, and hence the position being drawn, cannot change instantly. Additionally, the speed of older circuits was limited. For horizontal deflection, there is also a pause between successive lines, to allow the beam to return from right to left, called the horizontal retrace or horizontal blanking interval. Modern CRT circuitry does not require such a long blanking interval, and thin panel displays require none, but the standards were established when the delay was needed (and to allow the continued use of older equipment). Blanking of a CRT may not be perfect due to equipment faults or brightness set very high; in this case a white retrace line shows on the screen, from bottom right to top left.

In analog television systems the vertical blanking interval can be used for datacasting (to carry digital data), since nothing sent during the VBI is displayed on the screen; various test signals, time codes, closed captioning, teletext, CGMS-A copy-protection indicators, and various data encoded by the XDS protocol (e.g., the content ratings for V-chip use) and other digital data can be sent during this time period. In U.S. analog broadcast television, line 19 was reserved for a Ghost-canceling reference line 21 was reserved for captioning data. The obsolete Teletext service contemplated the use of line 22 for data transmission.

The pause between sending video data is used in real time computer graphics to perform various operations on the back buffer before copying it to the front buffer instead of just switching both pointers, or to provide a time reference for when switching such pointers is safe.

In video game systems the vertical blanking pulses are extensively used to time the plotting of new graphics/removal of old ones in order to avoid screen tearing, as they occur at an accurately known frequency, and many systems up to the 16-bit era featured games and other graphical programs where drawing was conducted during the blanking interval for this reason. Cases where synchronising game code this way was more necessary than preferable and made early video game systems such as the Atari 2600 difficult to program.

Special raster techniques on the Atari 2600, Nintendo Entertainment System, and other consoles allowed extending this interval at the cost of some blank scanlines at the top or bottom of the screen, which may or may not end up in the overscan area. The use of double buffering in modern graphics hardware has rendered these techniques obsolete.

Most consumer VCRs use the known black level of the vertical blanking pulse to set their recording levels. The Macrovision copy protection scheme inserts pulses in the VBI, where the recorder expects a constant level, to disrupt recording to videotapes.

This page is based on a Wikipedia article written by authors (here).
Text is available under the CC BY-SA 3.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.