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ISDB

Integrated Services Digital Broadcasting (ISDB; Japanese: 統合デジタル放送サービス, Tōgō dejitaru hōsō sābisu) is a Japanese broadcasting standard for digital television (DTV) and digital radio.

ISDB supersedes both the NTSC-J analog television system and the previously used MUSE Hi-vision analog HDTV system in Japan. An improved version of ISDB-T (ISDB-T International) will soon replace the NTSC, PAL-M, and PAL-N broadcast standards in South America and the Philippines. Digital Terrestrial Television Broadcasting (DTTB) services using ISDB-T started in Japan in December 2003, and since then, many countries have adopted ISDB over other digital broadcasting standards.

A newer and "advanced" version of the ISDB standard (that will eventually allow up to 8K terrestrial broadcasts and 1080p mobile broadcasts via the VVC codec, including HDR and HFR) is currently under development.

Asia

 * 🇯🇵 japan
 * 🇵🇭 philippines (officially adopted ISDB-T, started broadcasting in digital)
 * 🇲🇻 maldives (officially adopted ISDB-T)
 * 🇱🇰 sri lanka (officially adopted ISDB-T HD)

Americas

 * 🇧🇷 brazil (officially adopted ISDB-T International, started broadcasting in digital)
 * 🇦🇷 argentina (officially adopted ISDB-T International, started broadcasting in digital)
 * 🇺🇾 uruguay (officially adopted ISDB-T International, started broadcasting in digital)
 * 🇵🇪 peru (officially adopted ISDB-T International, started broadcasting in digital)
 * 🇨🇱 chile (officially adopted ISDB-T International, started broadcasting in digital)
 * 🇻🇪 venezuela (officially adopted ISDB-T International, started broadcasting in digital)
 * 🇪🇨 ecuador (officially adopted ISDB-T International, started broadcasting in digital)
 * 🇨🇷 costa rica (officially adopted ISDB-T International, started broadcasting in digital)
 * 🇵🇾 paraguay (officially adopted ISDB-T International, started broadcasting in digital)
 * 🇧🇴 bolivia (officially adopted ISDB-T International, started broadcasting in digital)
 * 🇳🇮 nicaragua (officially adopted ISDB-T International, started pre-implementation stage)
 * 🇬🇹 guatemala (officially adopted ISDB-T International, started pre-implementation stage, briefly experimented with ATSC)
 * 🇭🇳 honduras (officially adopted ISDB-T International, briefly experimented with ATSC, started broadcasting in digital)
 * 🇸🇻 el salvador (officially adopted ISDB-T international, started pre-implementation stage)
 * 🇧🇿 belize (currently assessing digital platform)
 * 🇰🇳 saint kitts and nevis (officially adopted ISDB-T international, started pre-implementation stage)

Africa

 * 🇧🇼 botswana (officially adopted ISDB-T International (SBTVD), started pre-implementation stage)

 * 🇦🇴 angola (In 2013, decided on European digital terrestrial TV. However, Angola reviewed the adoption to ISDB-T International system in March 2019.)

Americas

 * undefined
 * 🇲🇸 montserrat

Asia

 * 🇮🇳 india
 * undefined
 * 🇲🇾 malaysia
 * undefined

Africa

 * 🇰🇪 kenya
 * 🇳🇬 nigeria
 * 🇲🇬 madagascar
 * 🇱🇸 lesotho
 * 🇿🇼 zimbabwe

Europe

 * 🇨🇭 switzerland
 * undefined

Introduction

ISDB is maintained by the Japanese organization ARIB. The standards can be obtained for free at the Japanese organization DiBEG website and at ARIB.

The core standards of ISDB are ISDB-S (satellite television), ISDB-T (terrestrial), ISDB-C (cable) and 2.6 GHz band mobile broadcasting which are all based on MPEG-2, MPEG-4, or HEVC standard for multiplexing with transport stream structure and video and audio coding (MPEG-2, H.264, or HEVC) and are capable of UHD, high-definition television (HDTV) and standard-definition television. ISDB-T and ISDB-Tsb are for mobile reception in TV bands. 1seg is the name of an ISDB-T component that allows viewers to watch TV channels via cell phones, laptop computers, and vehicles.

The concept was named for its similarity to ISDN as both allow multiple channels of data to be transmitted together (a process called multiplexing). This broadcast standard is also much like another digital radio system, Eureka 147, which calls each group of stations on a transmitter an ensemble; this is very much like the multi-channel digital TV standard DVB-T. ISDB-T operates on unused TV channels, an approach that was taken by other countries for TV but never before for radio.

Transmission
The various flavors of ISDB differ mainly in the modulations used, due to the requirements of different frequency bands. The 12 GHz band ISDB-S uses PSK modulation, 2.6 GHz band digital sound broadcasting uses CDM, and ISDB-T (in VHF and/or UHF band) uses COFDM with PSK/QAM.

Interaction
Besides audio and video transmission, ISDB also defines data connections (Data broadcasting) with the internet as a return channel over several media (10/100 Ethernet, telephone line modem, mobile phone, wireless LAN (IEEE 802.11), etc.) and with different protocols. This component is used, for example, for interactive interfaces like data broadcasting (ARIB STD-B24) and electronic program guides (EPG).

Interfaces and Encryption
The ISDB specification describes a lot of (network) interfaces, but most importantly, the Common Interface for Conditional Access System (CAS). While ISDB has examples of implementing various kinds of CAS systems, in Japan, a CAS system called "B-CAS" is used. ARIB STD-B25 defines the Common Scrambling Algorithm (CSA) system called MULTI2 required for (de-)scrambling television.

The ISDB CAS system in Japan is operated by a company named B-CAS; the CAS card is called B-CAS card. The Japanese ISDB signal is always encrypted by the B-CAS system even if it is a free television program. That is why it is commonly called "Pay per view system without charge". An interface for mobile reception is under consideration.

ISDB supports RMP (Rights management and protection). Since all digital television (DTV) systems carry digital data content, a DVD or high-definition (HD) recorder could easily copy content losslessly. US major film studios requested copy protection; this was the main reason for RMP being mandated. The content has three modes: "copy once", "copy free" and "copy never". In "copy once" mode, a program can be stored on a hard disk recorder, but cannot be further copied; only moved to another copy-protected media—and this move operation will mark the content "copy one generation", which is mandated to prevent further copying permanently. "Copy never" programs may only be timeshifted and cannot be permanently stored. In 2006, the Japanese government is evaluating using the Digital Transmission Content Protection (DTCP) "Encryption plus Non-Assertion" mechanism to allow making multiple copies of digital content between compliant devices.

Receiver
There are two types of ISDB receiver: Television and set-top box. The aspect ratio of an ISDB-receiving television set is 16:9; televisions fulfilling these specs are called Hi-Vision TV. There are four TV types: Cathode ray tube (CRT), plasma display panel (PDP), organic light-emitting diode (OLED) and liquid crystal display (LCD), with LCD being the most popular Hi-Vision TV on the Japanese market nowadays.

The LCD share, as measured by JEITA in November 2004, was about 60%. While PDP sets occupy the high-end market with units that are over 50 inches (1270 mm), PDP and CRT set shares are about 20% each. CRT sets are considered low end for Hi-Vision. An STB is sometimes referred to as a digital tuner.

Typical middle to high-end ISDB receivers marketed in Japan have several interfaces:

 * F connectors for RF input.
 * HDMI or D4 connector for an HDTV monitor in a home cinema.
 * Optical digital audio interface for an audio amplifier and speakers for 5.1 surround audio in a home cinema.
 * IEEE 1394 (aka FireWire) interface for digital data recorders (like DVD recorders) in a home cinema.
 * RCA video jack provides SDTV signal that is sampled down from the HDTV signal for analog CRT television sets or VCRs.
 * RCA audio jacks provide stereo audio for analog CRT television sets or VCRs.
 * S video is for VCRs or analog CRT television sets.
 * 10/100 and modular jack telephone line modem interfaces are for an internet connection.
 * B-CAS card interface to de-scramble.
 * IR interface jack for controlling a VHS or DVD player.

Copy-protection technology
All TV broadcasters in Japan are encrypted with Copy-Once, which allows users to record to a digital medium (such as a D-VHS, a DVD, or an HDD) but does not allow dubbing to another digital medium. On the other hand, the "Copy-Once" technology does not prohibit all types of dubbing. It is possible to dub to an analog medium (such as standard VHS), and if recorded to an HDD, it allows users to "Move" the contents to a D-VHS, but not copy. In contrast, 1seg digital broadcasts, which are for low-bandwidth mobile reception and occupy 1/13th of a digital channel, are transmitted "in the clear" and do not carry copy protection information.

Many users are also anxious about the recent news of severe protection in the future. There are modes in ISDB that do not allow the output of a signal from an Analog connector (such as D-connector, Component, Composite, or S-Video). There are already plans to restrict analog output (similar to Blu-ray and HD DVD) for "Copyright Protection" reasons, making all currently sold STB Tuners, LCD/Plasma TVs (without HDMI inputs), analog-output-only VHS and D-VHS systems, and DVD players, unusable. These more limiting copy protection technologies will all start after analog broadcasting ends (when there won't be any choice for viewers). Currently, no financial assistance schemes have been announced, forcing viewers without proper devices to buy new TVs or STB boxes that receive ISDB broadcasts. Though not clear, it is said that there are also plans to protect all programs with "Copy-Never".

The copy protection on ISDB broadcasts can be circumvented with the proper hardware and software.

Brazilian standard ISDB-Tb does not implement this copy protection mechanism. For other countries, there are some examples of implementing a CAS system (such as Verimatrix) by the operators' choice.

B-CAS card
The B-CAS card is required to decode television broadcasts in Japan. These cards are included with every digital television or tuner at no charge. To use this card, the end-user must agree to the statement written on the registration card. Although the card must be inserted to watch TV, if the end-user refuses to accept the terms/conditions contained within the statement, the user cannot watch digital broadcasts. Essentially, users are "forced" to agree with the statement. Though registration is not required, it is recommended to enjoy interactive programs. Unregistered B-CAS cards display a watermark in the corner of the screen, suggesting the user to register. However, many viewers worry about the leaking of personal information, and the power/rights the TV stations have to access personal information for almost every citizen in Japan. In case of loss or destruction, a new B-CAS card of the same number can be issued for a fee of 2,000 yen.

Services
A typical Japanese broadcast service consists as follows:
 * 1) One HDTV or up to three SDTV services within one channel.
 * 2) Provides interactive television through datacasting.
 * 3) Interactive services such as games or shopping, via telephone line or broadband internet.
 * 4) Equipped with an electronic program guide.
 * 5) Ability to send firmware patches for the TV/tuner over the air.
 * 6) During emergencies, the service utilizes Emergency Warning Broadcast system to quickly inform the public of various threats for the areas at risk.

There are examples providing more than 10 SDTV services with H.264 coding in some countries.

History
Japan started digital broadcasting using the DVB-S standard by PerfecTV in October/1996, and DirecTV in December/1997, with communication satellites. Still, DVB-S did not satisfy the requirements of Japanese broadcasters, such as NHK, key commercial broadcasting stations like Nippon Television, TBS, Fuji Television, TV Asahi, TV Tokyo, and WOWOW (Movie-only Pay-TV broadcasting). Consequently, ARIB developed a new broadcast standard called ISDB-S. The requirements were HDTV capability, interactive services, network access and effective frequency utilization, and other technical requirements. The DVB-S standard allows the transmission of a bitstream of roughly 34 Mbit/s with a satellite transponder, which means the transponder can send one HDTV channel. Unfortunately, the NHK broadcasting satellite had only four vacant transponders, which led ARIB and NHK to work on ISDB-S: the new standard could transmit at 51 Mbit/s with a single transponder, which means that ISDB-S is 1.5 times more efficient than DVB-S and that one transponder can transmit two HDTV channels, along with other independent audio and data. Digital satellite broadcasting (BS digital) was started by NHK and followed commercial broadcasting stations on 1 December 2000. Today, SKY PerfecTV! (the successor of Skyport TV and Sky D), CS burn, Platone, EP, DirecTV, J Sky B, and PerfecTV!, adopted the ISDB-S system for use on the 110-degree (east longitude) wide-band communication satellite.

Technical specification
This table shows the summary of ISDB-S (satellite digital broadcasting).

Channel
Frequency and channel specification of Japanese Satellites using ISDB-S

ISDB-S3
ISDB-S3 is a satellite digital broadcasting specification supporting 4K, 8K, HDR, HFR, and 22.2 audio.

ISDB-C
ISDB-C is a cable digital broadcasting specification. The technical specification J.83/C is developed by JCTEA. ISDB-C is identical to DVB-C but has a different channel bandwidth of 6 MHz (instead of 8 MHz) and roll-off factor.

History
HDTV was invented at NHK Science & Technology Research Laboratories (Japan Broadcasting Corporation's Science & Technical Research Laboratories). The research for HDTV started as early as the 1960s, though a standard was proposed to the ITU-R (CCIR) only in 1973.

By the 1980s, a high definition television camera, cathode-ray tube, videotape recorder, and editing equipment, among others, had been developed. In 1982 NHK developed MUSE (Multiple sub-Nyquist sampling encoding), the first HDTV video compression and transmission system. MUSE used digital video compression, but for transmission frequency modulation was used after a digital-to-analog converter converted the digital signal.

In 1987, NHK demonstrated MUSE in Washington D.C. as well as NAB. The demonstration made a great impression in the U.S., leading to the development of the ATSC terrestrial DTV system. Europe also developed a DTV system called DVB. Japan began R&D of a completely digital system in the 1980s that led to ISDB. Japan began terrestrial digital broadcasting, using ISDB-T standard by NHK and commercial broadcasting stations, on 1 December 2003.

Features

ISDB-T is characterized by the following features:

 * ISDB-T (Integrated Services Digital Broadcasting-Terrestrial) in Japan use UHF 470 MHz-710 MHz, bandwidth of 240 MHz, allocate 40 channels namely channels 13 to 52 (previously used also 710 MHz-770 MHz, 53 to 62, but this range was re-assigned to cell phones), each channel is 6 MHz width (actually 5.572 MHz effective bandwidth and 430 kHz guard band between channels). These channels are called "physical channel(物理チャンネル)". For other countries, US channel table or European channel table are used.
 * For channel tables with 6 MHz width, ISDB-T single channel bandwidths 5.572 MHz has number of carriers 5,617 with interval of 0.99206 kHz. For 7 MHz channel, channel bandwidth is 6.50 MHz; for 8 MHz 7.42 MHz.
 * ISDB-T allows to accommodate any combination of HDTV (roughly 8 Mbit/s in H.264) and SDTV (roughly 2 Mbit/s in H.264) within the given bitrate determined by the transmission parameters such as bandwidth, code-rate, guard interval, etc. Typically, among the 13 segments, the center segment is used for 1seg with QPSK modulation and the remaining 12 segments for the HDTV or SDTV payloads for 64QAM modulation. The bitstream of the 12 segments are combined into one transport stream, within which any combination of programs can be carried based on the MPEG-2 transport stream definition.
 * ISDB-T transmits an HDTV channel and a mobile TV channel 1seg within one channel. 1seg is a mobile terrestrial digital audio/video broadcasting service in Japan. Although 1seg is designed for mobile usage, reception is sometimes problematic in moving vehicles. Because of reception on high speed vehicle, UHF transmission is shaded by buildings and hills frequently, but reported well receiving in Shinkansen as far as run in flat or rural area.
 * ISDB-T provides interactive services with data broadcasting. Such as Electronic Program Guides. ISDB-T supports internet access as a return channel that works to support the data broadcasting. Internet access is also provided on mobile phones.
 * ISDB-T provides Single-Frequency Network (SFN) and on-channel repeater technology. SFN makes efficient utilization of the frequency resource (spectrum). For example, the Kanto area (greater Tokyo area including most part of Tokyo prefecture and some part of Chiba, Ibaragi, Tochigi, Saitama and Kanagawa prefecture) are covered with SFN with roughly 10 million population coverage.
 * ISDB-T can be received indoors with a simple indoor antenna.
 * ISDB-T provides robustness to multipath interference ("ghosting"), co-channel analog television interference, and electromagnetic interferences that come from motor vehicles and power lines in urban environments.
 * ISDB-T is claimed to allow HDTV to be received on moving vehicles at over 100 km/h; DVB-T can only receive SDTV on moving vehicles, and it is claimed that ATSC can not be received on moving vehicles at all (however, in early 2007 there were reports of successful reception of ATSC on laptops using USB tuners in moving vehicles).

Adoption
ISDB-T was adopted for commercial transmissions in Japan in December 2003. It currently comprises a market of about 100 million television sets. ISDB-T had 10 million subscribers by the end of April 2005. Along with the wide use of ISDB-T, the price of receivers is getting low. The price of ISDB-T STB in the lower end of the market is ¥19800 as of 19 April 2006. By November 2007 only a few older, low-end STB models could be found in the Japanese market (average price U$180), showing a tendency towards replacement by mid to high-end equipment like PVRs and TV sets with inbuilt tuners. In November 2009, a retail chain AEON introduced STB in 40 USD, followed by variety of low-cost tuners. The Dibeg web page confirms this tendency by showing low significance of the digital tuner STB market in Japan.

Brazil, which used an analogue TV system (PAL-M) that slightly differed from any other countries, has chosen ISDB-T as a base for its DTV format, calling it ISDB-Tb or internally SBTVD (Sistema Brasileiro de Televisão Digital-Terrestre). The Japanese DiBEG group incorporated the advancements made by Brazil -MPEG4 video codec instead of ISDB-T's MPEG2 and a powerful interaction middleware called Ginga- and has renamed the standard to "ISDB-T International". Other than Argentina, Brazil, Peru, Chile and Ecuador which have selected ISDB-Tb, there are other South American countries, mainly from Mercosur, such as Venezuela, that chose ISDB-Tb, which providing economies of scale and common market benefits from the regional South American manufacturing instead of importing ready-made STBs as is the case with the other standards. Also, it has been confirmed with extensive tests realized by Brazilian Association of Radio and Television Broadcasters (ABERT), Brazilian Television Engineering Society (SET) and Universidade Presbiteriana Mackenzie the insufficient quality for indoor reception presented by ATSC and, between DVB-T and ISDB-T, the latter presented superior performance in indoor reception and flexibility to access digital services and TV programs through non-mobile, mobile or portable receivers with impressive quality.

The ABERT–SET group in Brazil did system comparison tests of DTV under the supervision of the CPqD foundation. The comparison tests were done under the direction of a work group of SET and ABERT. The ABERT/SET group selected ISDB-T as the best choice in digital broadcasting modulation systems among ATSC, DVB-T and ISDB-T. Another study found that ISDB-T and DVB-T performed similarly, and that both were outperformed by DVB-T2.

ISDB-T was singled out as the most flexible of all for meeting the needs of mobility and portability. It is most efficient for mobile and portable reception. On June 29, 2006, Brazil announced ISDB-T-based SBTVD as the chosen standard for digital TV transmissions, to be fully implemented by 2016. By November 2007 (one month prior DTTV launch), a few suppliers started to announce zapper STBs of the new Nippon-Brazilian SBTVD-T standard, at that time without interactivity.

As in 2019, the implementation rollout in Brazil proceeded successfully, with terrestrial analog services (PAL-M) phased out in most of the country (for some less populated regions, analog signal shutdown was postponed to 2023).

Adoption by country
This lists the other countries who adopted the ISDB-T standard, chronologically arranged.

 * On June 30, 2006, Brazil announced its decision to adopt ISDB-T as the digital terrestrial television standard, by means of presidential decree 5820/2006.
 * On April 23, 2009, Peru announced its decision to adopt ISDB-T as the digital terrestrial television standard. This decision was taken on the basis of the recommendations by the Multi-sectional Commission to assess the most appropriate standard for the country.
 * On August 28, 2009, Argentina officially adopted the ISDB-T system calling it internally SATVD-T (Sistema Argentino de Televisión – Terrestre).
 * On September 14, 2009, Chile announced it was adopting the ISDB-T standard because it adapts better to the geographical makeup of the country, while allowing signal reception in cell phones, high-definition content delivery and a wider variety of channels.
 * On October 6, 2009, Venezuela officially adopted the ISDB-T standard.
 * On March 26, 2010, Ecuador announced its decision to adopt ISDB-T standard. This decision was taken on the basis of the recommendations by the Superintendent of Telecommunications.
 * On April 29, 2010, Costa Rica officially announced the adoption of ISDB-Tb standard based upon a commission in charge of analyzing which protocol to accept.
 * On June 1, 2010, Paraguay officially adopted ISDB-T International, via a presidential decree #4483.
 * On June 11, 2010, the Philippines (NTC) officially adopted the ISDB-T standard.
 * On July 6, 2010, Bolivia announced its decision to adopt ISDB-T standard as well.
 * On December 27, 2010, the Uruguayan Government adopts the ISDB-T standard., voiding a previous 2007 decree which adopted the European DVB system.
 * On November 15, 2011, the Maldivian Government adopts the ISDB-T standard. As the first country in the region that use European channel table and 1 channel bandwidth is 8 MHz.
 * On February 26, 2013, the Botswana government adopts the ISDB-T standard; as the first country within the SADC region and even the first country within the continent of Africa as a whole.
 * On September 12, 2013, Honduras adopted the ISDB-T standard.
 * On May 20, 2014, Government of Sri Lanka officially announced its decision to adopt ISDB-T standard, and on September 7, 2014 Japanese Prime Minister Shinzo Abe signed an agreement with Sri Lankan President Mahinda Rajapakse for constructing infrastructure such as ISDB-T networks with a view to smooth conversion to ISDB-T, and cooperating in the field of content and developing human resources.
 * On January 23, 2017, El Salvador adopted the ISDB-T standard.
 * On March 20, 2019, Angola adopted the ISDB-T standard.

Technical specification
 Segment structure

ARIB has developed a segment structure called BST-OFDM (see figure). ISDB-T divides the frequency band of one channel into thirteen segments. The broadcaster can select which combination of segments to use; this choice of segment structure allows for service flexibility. For example, ISDB-T can transmit both LDTV and HDTV using one TV channel or change to 3 SDTV, a switch that can be performed at any time. ISDB-T can also change the modulation scheme at the same time.

The above figure shows the spectrum of 13 segments structure of ISDB-T.

(s0 is generally used for 1seg, s1-s12 are used for one HDTV or three SDTVs)

Summary of ISDB-T

 * H.264 Baseline profile is used in one segment (1seg) broadcasting for portables and Mobile phone.
 * H.264 High-profile is used in ISDB-Tb to high definition broadcasts.

Channel
Specification of Japanese terrestrial digital broadcasting using ISDB-T.

ISDB-Tsb
ISDB-Tsb is the terrestrial digital sound broadcasting specification. The technical specification is the same as ISDB-T. ISDB-Tsb supports the coded transmission of OFDM signals.

ISDB-Tmm
ISDB-Tmm (Terrestrial mobile multi-media) utilised suitable number of segments by station with video coding MPEG-4 AVC/H.264. With multiple channels, ISDB-Tmm served dedicated channels such as sport, movie, music channels and others with CD quality sound, allowing for better broadcast quality as compared to 1seg. This service used the VHF band, 207.5–222 MHz which began to be utilised after Japan's switchover to digital television in July 2011.

Japan's Ministry of Internal Affairs and Communications licensed to NTT Docomo subsidiary mmbi, Inc. for ISDB-Tmm method on September 9, 2010. The MediaFLO method offered with KDDI was not licensed.

The ISDB-Tmm broadcasting service by mmbi, Inc. is named モバキャス (pronounced mobakyasu), literally short form of mobile casting on July 14, 2011, and had been branded as NOTTV since October 4, 2011. The Minister of Internal Affairs and Communications approved the start of operations of NOTTV on October 13, 2011. Planning the service with monthly subscription fee of 420 yen for south Kanto Plain, Aichi, Osaka, Kyoto and some other prefectures from April 1, 2012. The deployment plan was to cover approximately 73% of households by the end of 2012, approximately 91% by the end of 2014, and 125 stations or repeaters to be installed in 2016 to cover cities nationwide. Android smartphones and tablets with ISDB-Tmm receiving capability were also sold mainly by NTT DoCoMo, although a separate tuner (TV BoX manufactured by Huawei; or StationTV manufactured by Pixela) could be purchased for iPhones and iPads as well as Android smartphones and tablets sold by au by KDDI and SoftBank Mobile to receive ISDB-Tmm broadcasts.

Due to the continued unprofitability of NOTTV, mmbi, Inc. shut down the service on June 30, 2016.

2.6 GHz Mobile satellite digital audio/video broadcasting
MobaHo! is the name of the services that uses the Mobile satellite digital audio broadcasting specifications. MobaHo! started its service on 20 October 2004. Ended on 31 March 2009

Standards
ARIB and JCTEA developed the following standards. Some part of standards are located on the pages of ITU-R and ITU-T.

title: ISDB


text:
The Amazing Maurice and His Educated Rodents

The Amazing Maurice and His Educated Rodents is a children's fantasy novel by British writer Terry Pratchett, published by Doubleday in 2001. It is the twenty-eighth novel in the Discworld series and the first written for children. The story is a new take on the German fairy tale about the Pied Piper of Hamelin and a parody of the folk tale genre.

Pratchett won the annual Carnegie Medal from the British librarians, recognising the year's best children's book published in the U.K. It was his first major award.

Series
Discworld had been a comic fantasy series for adults, beginning with The Colour of Magic in 1983. Amazing Maurice was marketed as a children's book, to be followed in that respect by The Wee Free Men (2003, #30). It differs from earlier Discworld novels also by its division into chapters, though chapters become far more common in later books of the series. Contrary to the contrast between adult and child markets, reflected in catalogues, The Guardian observed on the occasion of the Carnegie Medal that "[t]he main audience for Pratchett's 48 books, all busily in print, is teenagers, who are drawn by his irrepressible invention and sense of mischief."

Maurice and his educated rodents were previously mentioned in the eleventh Discworld novel, Reaper Man (1991), although the characters in that novel are aware of the fraud perpetrated by Maurice and the rats.

Plot summary
The book opens with Amazing Maurice (a sentient cat), a group of talking rats (the Clan), and the human boy Keith travelling in a mail coach to a small town called Bad Blintz. The group plans to enact a scheme they have used many times before, where in the rats pretend to infest the town and Keith poses as a rat piper to lead the "vermin" away for a small sum of cash. Although Maurice sees nothing wrong with this hustling business, the rats find it immoral, and convince Maurice that this town will be the last one they rob. Upon arriving in town, the group discovers that the people are convinced of a massive rat infestation, and have spent much of their savings on two rat catchers. Despite their efforts, food continues to disappear from the town. As the rats move into the town's underground, they discover an overwhelmingly large number of rat traps, but no live keekees (rats who cannot talk or think). Aboveground, Maurice makes similar observations, including that many of the rat tails the rat catchers display as proof of their successful hunting are in fact shoelaces. Maurice and Keith meet the mayor's daughter Malicia and introduce her to the talking rats.

Malicia believes that the rat catchers are up to something and so she, Maurice, and Keith break into the rat catchers' hut. They discover a great deal of food stolen by the men and large cages where the local keekees are being bred for coursing. The rat catchers return and lock up the humans, taking away the rat leader Hamnpork who had met up with them. Maurice hides and feels a voice trying to enter his mind, inciting a great sense of fear. The rats of the Clan feel it too, and many become so afraid that they all but forget how to think and reason. Dangerous Beans, the rats' spiritual leader, is crushed by the realization that the rats are just mindless animals at heart, and leaves with his assistant Peaches. Darktan, the rats' trap expert, leads a group to rescue Hamnpork, and succeeds after nearly dying in a trap. Hamnpork dies of injuries sustained while fighting in the rat coursing pit, and Darktan reluctantly assumes leadership of the Clan.

Malicia and Keith, after freeing themselves, trick the rat catchers into admitting their crimes. The rat catchers have created a powerful rat king named Spider, which is the source of the mysterious voice that has been plaguing the rats and Maurice. Using its mental control over the rat catchers, Spider plans to wage war on the humans that created it. It sends the rats it controls to attack Maurice, Peaches, and Dangerous Beans. However, Maurice (so terrified that he stops thinking and acts instinctively) pounces on the rat king and destroys it. In his panic, Maurice also unwittingly kills Dangerous Beans. Maurice emerges from Spider's chamber carrying the body of Dangerous Beans. When he is safely out, he collapses and dies. In ghostly form, he sees the Death of Rats coming for Dangerous Beans and makes a deal with Death: two of his remaining lives in exchange for both his life and the albino rat's.

The rats corral all the keekees and block their ears. When a real rat piper arrives in town, Keith challenges him to a duel. The piper plays his magic rat pipe but none of the rats come out. Keith plays on a trombone and Sardines (an intelligent rat) emerges and dances for the crowd. Keith is proclaimed the winner, and leads the keekees out of town with the piper. After the piper leaves, the Clan rats emerge from hiding and tell the humans about the rat catchers' duplicity. The humans bargain with the rats: if the Clan will keep the keekees out of the town, the rats may stay and live as though they were just smaller humans. Keith decides to stay behind as Bad Blintz's ceremonial rat piper, while Maurice moves on to find a new scheme.

Characters

 * Maurice – an intelligent cat who leads the group of rats. He is cunning and manipulative and has a very good (but cynical) understanding of how the world works. Late in the novel, he guiltily admits that he accidentally ate one of the intelligent rats of the Clan early in their history, and thus became sentient himself.
 * Malicia – the daughter of Bad Blintz's mayor, perennially obsessed with fairy tales, having adventures, and storytelling.
 * Keith – called the "stupid-looking kid", Keith is an orphan raised by the Musician's Guild. He goes along with Maurice's scheme mainly to have something to do, although he is very defensive of his rat family.
 * Dangerous Beans – an albino rat who has acted as a kind of spiritual leader for the Clan since they became intelligent after eating rubbish from behind Unseen University. Darktan observes that Dangerous Beans is the Clan's much-needed philosopher, finding and "disarming" dangerous ideas for the group. For example, Dangerous Beans is the one who they all turn to for answers to questions of rat cannibalism, stealing, and the phenomenon of dreaming. He is also the interpreter of the rats' "bible", a children's book called Mr. Bunnsy Has An Adventure, which depicts rats and other animals living in harmony with humans, speaking and dressing like them. When Malicia observes that this book's utopian society is entirely fictional, Dangerous Beans and his assistant Peaches run off in despair.
 * Peaches – a small female rat who acts as Dangerous Beans' assistant and the Clan's scribe. She is the unofficial carrier (dragger would be the more appropriate term) of the Thoughts, and Mr. Bunnsy Has An Adventure.
 * Hamnpork – the aging leader of the Clan, leftover from before they could think. Hamnpork resists the idea of "thinking" and leads the Clan through the brute force and cunning that traditional kee kee leaders use.
 * Darktan – the leader of the rats' Trap Disposal Squad. After his near-death experience and the death of Hamnpork, Darktan becomes the Clan's new leader. Darktan, although an older rat, is much more progressive than Hamnpork. He is well-respected by all the rats because his knowledge of how to disarm traps helps keep them alive.
 * Sardines – an older rat who wears a hat and tap dances. Sardines epitomizes the group of rats who harass the humans into thinking they have a full-blown infestation. He does not seek to lead but provides insightful help to Darktan after the latter becomes the leader of the Clan. He understands how to read both humans and rats and can manipulate both (but much more kindly than Maurice).

Recognition
Karen Usher, who chaired the panel of Carnegie judges, declared that the selection was unanimous: "This is an outstanding work of literary excellence – a brilliant twist on the tale of the Pied Piper that is funny and irreverent, but also dark and subversive."

The Carnegie Medal for Maurice was Pratchett's first major award. The Guardian alluded to "16 years of disdain by the British literary establishment" and reported about his acceptance speech that he "rounded on" that establishment, "tilted at" Tolkien, and showed ambivalence about the fantasy label: "though his work dealt with profound themes, 'stick in one lousy dragon and they call you a fantasy writer'."

Ideas and themes
All the rats' names derive from the words they have seen written on tins before they knew what the words meant, and they have called themselves whatever they thought sounded interesting. Pratchett puns on this, such as the doubting rat, who was called "Tomato" (as in Doubting Thomas).

Adaptations

 * BBC Radio 4 broadcast a 90-minute dramatisation on 23 August 2003, which was repeated on BBC 7 on 2 June 2007 and 27 April 2008. The character of Dangerous Beans was voiced by David Tennant. Darktan's voice was a spoof version of Sean Connery's Scottish burr. The narrator in the adaptation was Maurice himself, describing to Dangerous Beans how they arrived at the perilous situation near the end of the plot. Quotes from Mr. Bunnsy Has an Adventure, which appear as chapter heads in the book, were read by Rebecca Norfolk, aged 8, who played "Child reader" in the BBC Radio 4 production. To mark the occasion of Terry Pratchett's knighthood, it was broadcast on BBC 7 again, along with other dramatizations of his work, in February 2009.4
 * The book has been adapted for the stage twice: first by Stephen Briggs in 2003 and published by Oxford Playscripts, then in 2011 as a musical by Matthew Holmes, published by Collins Musicals. Both versions are designed for use in schools.
 * In June 2019, it was announced that an animated film adaptation, The Amazing Maurice was in the works. It is a co-production between Ulysses Filmproduktion and Cantilever Media, with Terry Rossio writing the screenplay. The budget will be €15 million ($17 million). The voice cast of Hugh Laurie, Emilia Clarke, David Thewlis, Himesh Patel, Gemma Arterton and Hugh Bonneville was announced in November 2020.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


text:
Talk:Messerschmitt Bf 109

Explanation of "Flugzeugwerke"
The article explains that "Bayerische Flugzeugwerke" literally [means] "Bavarian Aircraft Works", meaning "Bavarian Aircraft Factory". Isn't this explanation a bit of an overkill, as Works is used in English in the same way, e. g. Swindon Works? --KnightMove (talk) 06:11, 11 May 2016 (UTC)

Well, that's what "Fleugzeugwerke" translates to. Are you suggesting we leave "Works" out of the translation because "anyone can see" that "Werke" obviously is the same as "works"? So we'd end up saying "Bayerische Flugzeugwerke means Bavarian Aircraft"? How else would you leave out the word "werke"? Flugzeugwerke = aircraft works. I don't see the problem. Even ignoring that, if it didn't say that, you'd have someone in the comments asking "doesn't "werke" mean "works/factory" in English? So why doesn't the translation include the word "works" in it?"AnnaGoFast (talk) 10:24, 11 December 2017 (UTC)

 * The OP was stating that " ... . meaning "Bavarian Aircraft Factory" was unnecessary and that "Bayerische Flugzeugwerke" literally [means] "Bavarian Aircraft Works" in English was sufficient. — Preceding unsigned comment added by 95.149.173.127 (talk) 09:18, 19 January 2019 (UTC)
 * "Works" may equal "Werke" in some dialects of English, but not in all. "Factory" is used in the most used dialect.  Lineagegeek (talk) 23:46, 17 December 2022 (UTC)

Movie appearances
so after world war 2 the produced aircraft that were look like Bf-109 are Ha-1112 ex: Battle Of Britain it used repainted Ha-1112 because the produced aircraft of the time are Ha-1112 that probably cheaper than remaining 109 Wibu in 1945 (talk) 23:20, 31 May 2023 (UTC)

title: Talk:Messerschmitt Bf 109


text:
Bit rate

In telecommunications and computing, bit rate (bitrate or as a variable R) is the number of bits that are conveyed or processed per unit of time.

The bit rate is expressed in the unit bit per second (symbol: bit/s), often in conjunction with an SI prefix such as kilo (1 kbit/s = 1,000 bit/s), mega (1 Mbit/s = 1,000 kbit/s), giga (1 Gbit/s = 1,000 Mbit/s) or tera (1 Tbit/s = 1,000 Gbit/s). The non-standard abbreviation bps is often used to replace the standard symbol bit/s, so that, for example, 1 Mbps is used to mean one million bits per second.

In most computing and digital communication environments, one byte per second (symbol: B/s) corresponds to 8 bit/s.

Prefixes
When quantifying large or small bit rates, SI prefixes (also known as metric prefixes or decimal prefixes) are used, thus:

Binary prefixes are sometimes used for bit rates. The International Standard (IEC 80000-13) specifies different symbols for binary and decimal (SI) prefixes (e.g., 1 KiB/s = 1024 B/s = 8192 bit/s, and 1 MiB/s = 1024 KiB/s).

Gross bit rate
In digital communication systems, the physical layer gross bitrate, raw bitrate, data signaling rate, gross data transfer rate or uncoded transmission rate (sometimes written as a variable Rb or fb ) is the total number of physically transferred bits per second over a communication link, including useful data as well as protocol overhead.

In case of serial communications, the gross bit rate is related to the bit transmission time $$T_\text{b}$$ as:
 * $$R_\text{b} = {1 \over T_\text{b}},$$

The gross bit rate is related to the symbol rate or modulation rate, which is expressed in bauds or symbols per second. However, the gross bit rate and the baud value are equal only when there are only two levels per symbol, representing 0 and 1, meaning that each symbol of a data transmission system carries exactly one bit of data; for example, this is not the case for modern modulation systems used in modems and LAN equipment.

For most line codes and modulation methods:
 * $$\text{symbol rate} \leq \text{gross bit rate}$$

More specifically, a line code (or baseband transmission scheme) representing the data using pulse-amplitude modulation with $$2^N$$ different voltage levels, can transfer $$N$$ bits per pulse. A digital modulation method (or passband transmission scheme) using $$2^N$$ different symbols, for example $$2^N$$ amplitudes, phases or frequencies, can transfer $$N$$ bits per symbol. This results in:
 * $$\text{gross bit rate} =  \text{symbol rate} \times N$$

An exception from the above is some self-synchronizing line codes, for example Manchester coding and return-to-zero (RTZ) coding, where each bit is represented by two pulses (signal states), resulting in:
 * $$\text{gross bit rate =  symbol rate/2}$$

A theoretical upper bound for the symbol rate in baud, symbols/s or pulses/s for a certain spectral bandwidth in hertz is given by the Nyquist law:
 * $$\text{symbol rate} \leq \text{Nyquist rate} = 2 \times \text{bandwidth}$$

In practice this upper bound can only be approached for line coding schemes and for so-called vestigial sideband digital modulation. Most other digital carrier-modulated schemes, for example ASK, PSK, QAM and OFDM, can be characterized as double sideband modulation, resulting in the following relation:
 * $$\text{symbol rate} \leq \text{bandwidth}$$

In case of parallel communication, the gross bit rate is given by
 * $$\sum_{i = 1}^{n} \frac{\log_2 {M_i} }{T_i}$$

where n is the number of parallel channels, Mi is the number of symbols or levels of the modulation in the ith channel, and Ti is the symbol duration time, expressed in seconds, for the ith channel.

Information rate
The physical layer net bitrate, information rate, useful bit rate, payload rate,  net data transfer rate, coded transmission rate, effective data rate or wire speed (informal language) of a digital communication channel is the capacity excluding the physical layer protocol overhead, for example time division multiplex (TDM) framing bits, redundant forward error correction (FEC) codes, equalizer training symbols and other channel coding. Error-correcting codes are common especially in wireless communication systems, broadband modem standards and modern copper-based high-speed LANs. The physical layer net bitrate is the datarate measured at a reference point in the interface between the data link layer and physical layer, and may consequently include data link and higher layer overhead.

In modems and wireless systems, link adaptation (automatic adaptation of the data rate and the modulation and/or error coding scheme to the signal quality) is often applied. In that context, the term peak bitrate denotes the net bitrate of the fastest and least robust transmission mode, used for example when the distance is very short between sender and transmitter. Some operating systems and network equipment may detect the "connection speed" (informal language) of a network access technology or communication device, implying the current net bit rate. The term line rate in some textbooks is defined as gross bit rate, in others as net bit rate.

The relationship between the gross bit rate and net bit rate is affected by the FEC code rate according to the following.
 * net bit rate ≤ gross bit rate × code rate

The connection speed of a technology that involves forward error correction typically refers to the physical layer net bit rate in accordance with the above definition.

For example, the net bitrate (and thus the "connection speed") of an IEEE 802.11a wireless network is the net bit rate of between 6 and 54 Mbit/s, while the gross bit rate is between 12 and 72 Mbit/s inclusive of error-correcting codes.

The net bit rate of ISDN2 Basic Rate Interface (2 B-channels + 1 D-channel) of 64+64+16 = 144 kbit/s also refers to the payload data rates, while the D channel signalling rate is 16 kbit/s.

The net bit rate of the Ethernet 100BASE-TX physical layer standard is 100 Mbit/s, while the gross bitrate is 125 Mbit/s, due to the 4B5B (four bit over five bit) encoding. In this case, the gross bit rate is equal to the symbol rate or pulse rate of 125 megabaud, due to the NRZI line code.

In communications technologies without forward error correction and other physical layer protocol overhead, there is no distinction between gross bit rate and physical layer net bit rate. For example, the net as well as gross bit rate of Ethernet 10BASE-T is 10 Mbit/s. Due to the Manchester line code, each bit is represented by two pulses, resulting in a pulse rate of 20 megabaud.

The "connection speed" of a V.92 voiceband modem typically refers to the gross bit rate, since there is no additional error-correction code. It can be up to 56,000 bit/s downstream and 48,000 bit/s upstream. A lower bit rate may be chosen during the connection establishment phase due to adaptive modulation – slower but more robust modulation schemes are chosen in case of poor signal-to-noise ratio. Due to data compression, the actual data transmission rate or throughput (see below) may be higher.

The channel capacity, also known as the Shannon capacity, is a theoretical upper bound for the maximum net bitrate, exclusive of forward error correction coding, that is possible without bit errors for a certain physical analog node-to-node communication link.
 * net bit rate ≤ channel capacity

The channel capacity is proportional to the analog bandwidth in hertz. This proportionality is called Hartley's law. Consequently, the net bit rate is sometimes called digital bandwidth capacity in bit/s.

Network throughput
The term throughput, essentially the same thing as digital bandwidth consumption, denotes the achieved average useful bit rate in a computer network over a logical or physical communication link or through a network node, typically measured at a reference point above the data link layer. This implies that the throughput often excludes data link layer protocol overhead. The throughput is affected by the traffic load from the data source in question, as well as from other sources sharing the same network resources. See also measuring network throughput.

Goodput (data transfer rate)
Goodput or data transfer rate refers to the achieved average net bit rate that is delivered to the application layer, exclusive of all protocol overhead, data packets retransmissions, etc. For example, in the case of file transfer, the goodput corresponds to the achieved file transfer rate. The file transfer rate in bit/s can be calculated as the file size (in bytes) divided by the file transfer time (in seconds) and multiplied by eight.

As an example, the goodput or data transfer rate of a V.92 voiceband modem is affected by the modem physical layer and data link layer protocols. It is sometimes higher than the physical layer data rate due to V.44 data compression, and sometimes lower due to bit-errors and automatic repeat request retransmissions.

If no data compression is provided by the network equipment or protocols, we have the following relation:
 * goodput ≤ throughput ≤ maximum throughput ≤ net bit rate

for a certain communication path.

Progress trends
These are examples of physical layer net bit rates in proposed communication standard interfaces and devices:

Multimedia
In digital multimedia, bit rate represents the amount of information, or detail, that is stored per unit of time of a recording. The bitrate depends on several factors:

 * The original material may be sampled at different frequencies.
 * The samples may use different numbers of bits.
 * The data may be encoded by different schemes.
 * The information may be digitally compressed by different algorithms or to different degrees.

Generally, choices are made about the above factors in order to achieve the desired trade-off between minimizing the bitrate and maximizing the quality of the material when it is played.

If lossy data compression is used on audio or visual data, differences from the original signal will be introduced; if the compression is substantial, or lossy data is decompressed and recompressed, this may become noticeable in the form of compression artifacts. Whether these affect the perceived quality, and if so how much, depends on the compression scheme, encoder power, the characteristics of the input data, the listener's perceptions, the listener's familiarity with artifacts, and the listening or viewing environment.

The encoding bit rate of a multimedia file is its size in bytes divided by the playback time of the recording (in seconds), multiplied by eight.

For real-time streaming multimedia, the encoding bit rate is the goodput that is required to avoid playback interruption.

The term average bitrate is used in case of variable bitrate multimedia source coding schemes. In this context, the peak bit rate is the maximum number of bits required for any short-term block of compressed data.

A theoretical lower bound for the encoding bit rate for lossless data compression is the source information rate, also known as the entropy rate.

The bitrates in this section are approximately the minimum that the average listener in a typical listening or viewing environment, when using the best available compression, would perceive as not significantly worse than the reference standard.

CD-DA
Compact Disc Digital Audio (CD-DA) uses 44,100 samples per second, each with a bit depth of 16, a format sometimes abbreviated like "16bit / 44.1kHz". CD-DA is also stereo, using a left and right channel, so the amount of audio data per second is double that of mono, where only a single channel is used.

The bit rate of PCM audio data can be calculated with the following formula:
 * $$\text{bit rate} = \text{sample rate} \times \text{bit depth} \times \text{channels}$$

For example, the bit rate of a CD-DA recording (44.1 kHz sampling rate, 16 bits per sample and two channels) can be calculated as follows:
 * $$44,100 \times 16 \times 2 = 1,411,200\ \text{bit/s} = 1,411.2\ \text{kbit/s}$$

The cumulative size of a length of PCM audio data (excluding a file header or other metadata) can be calculated using the following formula:
 * $$\text{size in bits} = \text{sample rate} \times \text{bit depth} \times \text{channels} \times \text{time}.$$

The cumulative size in bytes can be found by dividing the file size in bits by the number of bits in a byte, which is eight:
 * $$\text{size in bytes} = \frac{\text{size in bits}}{8}$$

Therefore, 80 minutes (4,800 seconds) of CD-DA data requires 846,720,000 bytes of storage:
 * $$\frac{44,100 \times 16 \times 2 \times 4,800}{8} = 846,720,000\ \text{bytes} \approx 847\ \text{MB} \approx 807.5\ \text{MiB}$$

where MiB is mebibytes with binary prefix Mi, meaning 220 = 1,048,576.

MP3
The MP3 audio format provides lossy data compression. Audio quality improves with increasing bitrate:
 * 32 kbit/s – generally acceptable only for speech
 * 96 kbit/s – generally used for speech or low-quality streaming
 * 128 or 160 kbit/s – mid-range bitrate quality
 * 192 kbit/s – medium quality bitrate
 * 256 kbit/s – a commonly used high-quality bitrate
 * 320 kbit/s – highest level supported by the MP3 standard

Other audio

 * 700 bit/s – lowest bitrate open-source speech codec Codec2, but Codec2 sounds much better at 1.2 kbit/s
 * 800 bit/s – minimum necessary for recognizable speech, using the special-purpose FS-1015 speech codecs
 * 2.15 kbit/s – minimum bitrate available through the open-source Speex codec
 * 6 kbit/s – minimum bitrate available through the open-source Opus codec
 * 8 kbit/s – telephone quality using speech codecs
 * 32–500 kbit/s – lossy audio as used in Ogg Vorbis
 * 256 kbit/s – Digital Audio Broadcasting (DAB) MP2 bit rate required to achieve a high quality signal
 * 292 kbit/s – Sony Adaptive Transform Acoustic Coding (ATRAC) for use on the MiniDisc Format
 * 400 kbit/s–1,411 kbit/s – lossless audio as used in formats such as Free Lossless Audio Codec, WavPack, or Monkey's Audio to compress CD audio
 * 1,411.2 kbit/s – Linear PCM sound format of CD-DA
 * 5,644.8 kbit/s – DSD, which is a trademarked implementation of PDM sound format used on Super Audio CD.
 * 6.144 Mbit/s – E-AC-3 (Dolby Digital Plus), an enhanced coding system based on the AC-3 codec
 * 9.6 Mbit/s – DVD-Audio, a digital format for delivering high-fidelity audio content on a DVD. DVD-Audio is not intended to be a video delivery format and is not the same as video DVDs containing concert films or music videos. These discs cannot be played on a standard DVD-player without DVD-Audio logo.
 * 18 Mbit/s – advanced lossless audio codec based on Meridian Lossless Packing (MLP)

Video

 * 16 kbit/s – videophone quality (minimum necessary for a consumer-acceptable "talking head" picture using various video compression schemes)
 * 128–384 kbit/s – business-oriented videoconferencing quality using video compression
 * 400 kbit/s YouTube 240p videos (using H.264)
 * 750 kbit/s YouTube 360p videos (using H.264)
 * 1 Mbit/s YouTube 480p videos (using H.264)
 * 1.15 Mbit/s max – VCD quality (using MPEG1 compression)
 * 2.5 Mbit/s YouTube 720p videos (using H.264)
 * 3.5 Mbit/s typ – Standard-definition television quality (with bit-rate reduction from MPEG-2 compression)
 * 3.8 Mbit/s YouTube 720p60 (60 FPS) videos (using H.264)
 * 4.5 Mbit/s YouTube 1080p videos (using H.264)
 * 6.8 Mbit/s YouTube 1080p60 (60 FPS) videos (using H.264)
 * 9.8 Mbit/s max – DVD (using MPEG2 compression)
 * 8 to 15 Mbit/s typ – HDTV quality (with bit-rate reduction from MPEG-4 AVC compression)
 * 19 Mbit/s approximate – HDV 720p (using MPEG2 compression)
 * 24 Mbit/s max – AVCHD (using MPEG4 AVC compression)
 * 25 Mbit/s approximate – HDV 1080i (using MPEG2 compression)
 * 29.4 Mbit/s max – HD DVD
 * 40 Mbit/s max – 1080p Blu-ray Disc (using MPEG2, MPEG4 AVC or VC-1 compression)
 * 250 Mbit/s max – DCP (using JPEG 2000 compression)
 * 1.4 Gbit/s – 10-bit 4:4:4 uncompressed 1080p at 24 FPS

title: Bit rate


text:
Brasstown Bald

Brasstown Bald is the highest point in the U.S. state of Georgia. It is located in the northeastern part of the state in the Blue Ridge Mountains on the border between Towns and Union counties south of the city of Hiawassee. The mountain is known to the native Cherokee people as Enotah.

Description
The name in English is derived from a mistaken translation of the term for the nearby Cherokee village of Brasstown, located along the upper Brasstown Creek (named in English from the same error) feeding the Hiawassee River.

Immediately north of the mountain and across the state line with North Carolina are other places named by English settlers: Brasstown, a community in the Brasstown township of Clay County, North Carolina.

Brasstown Bald encompasses Towns and Union counties with the county line intersecting the peak. The mountain is part of the Blue Ridge Mountains (part of the Appalachian Mountains) and within the borders of the Blue Ridge Ranger District of the Chattahoochee National Forest. The mountain consists mostly of soapstone and dunite.

On a clear day it is possible to see the tallest buildings of Atlanta, some 85 miles away from the summit. The U.S. Forest Service has webcams atop the observation tower and a RAWS weather station further down the mountain. The public can drive to a parking lot 0.5 mi from the top via Georgia State Route 180 Spur and then continue to the summit via a shuttle bus or a short hike on a paved trail.

History
According to the two Georgia historical markers, the area surrounding Brasstown Bald was settled by the Cherokee people. English-speaking settlers derived the word "Brasstown" from a translation error of the Cherokee word for its village place. Settlers confused the word Itse'yĭ (meaning "New Green Place" or "Place of Fresh Green"), which the Cherokee used for their village, with Ûňtsaiyĭ ("brass"), and referred to the settlement as Brasstown. The Cherokee gave the locative name, Itse'yĭ, to several distinct areas in their territory, including an area nearby in what is considered present-day North Carolina.

According to Cherokee legend about Itse'yĭ, a great flood swept over the land. All the people died except a few Cherokee families who sought refuge in a giant canoe. The canoe ran aground at the summit of a forested mountain (now known as Enotah). As there was no wild game for the people to hunt and no place for them to plant crops, the Great Spirit killed all the trees on the top of the mountain so that the surviving people could plant crops. They continued planting and lived from their crops until the water subsided.

Other transliterated spellings of the Cherokee name for the mountain include Echia, Echoee, Etchowee, and Enotah.

The term "Bald" is common terminology in the southern Appalachians describing mountaintops that have 360-degree unobstructed views.

Former Georgia Supreme Court Judge Thomas S. Candler is memorialized with a stone monument at Brasstown Bald. It was erected in 1971 three months before he died in recognition of his efforts to support getting more visitors to the mountain and establishing a visitor center there for them.

Distances to summit
From the northeast, starting at the intersection of Owl Creek Road and the concurrent Georgia 17 and Georgia 75 near Mountain Scene, the climb is 13.5 mi long, gaining 828 ft.

From the southeast, starting at the intersection of Georgia 180 and Georgia 17/75 near Sooky Gap, the climb is 13.1 mi long, gaining 790 ft, an average of 6.0% grade.

From the west, starting at the intersection of Georgia 180 and Georgia 348 near Choestoe, the climb is 14.9 mi, gaining 856 ft, an average of 5.7% grade.

From the intersection of Route 180 and Route 180 Spur at Jacks Gap the climb is 4.9 mi at an average gradient of 11.2%, (height gain: 551 ft).

An additional route to the summit is the Wagon Train Trail, starting at Young Harris College. The trail is traditionally hiked by graduating students and their families on the evening before graduation; a vespers service is held at the summit.

Tour de Georgia
In the 2005 through 2008 editions of the Tour de Georgia, a long-distance bicycle race, Brasstown Bald was the site of an hors categorie "King of the Mountains stage" finish.

Broadcasting
NOAA Weather Radio station KXI22 transmits from atop the mountain, simulcasting with KXI75 from Blue Ridge, Georgia. The programming originates from NWSFO Peachtree City.

Georgia Public Broadcasting had or has construction permits from the Federal Communications Commission (FCC) for two low-power broadcast translator stations at the summit. The digital TV station on channel 12 (W25FP-D, licensed December 2009) is the direct replacement for analog TV station W04BJ in nearby Young Harris, and also covers for W50AB in nearby Hiawassee (both to the north). New station WBTB FM 90.3 will transmit at just 97 watts, equivalent to several hundred watts because of the height above average terrain of over 700 meters, or more than 2,300 feet. Both stations will have Young Harris as the city of license.

title: Brasstown Bald


text:
Charles Hawtrey (actor, born 1858)

Sir Charles Henry Hawtrey (21 September 1858 – 30 July 1923) was an English actor, director, producer and manager. He pursued a successful career as an actor-manager, specialising in debonair, often disreputable, parts in popular comedies. He occasionally played in Sheridan and other classics, but was generally associated with new works by writers including Oscar Wilde and Somerset Maugham.

Born to a long-established county family, Hawtrey was one of three of his parents' five sons to pursue a theatrical career. Before going on the stage he had considered joining the army, but failed to apply himself to the necessary studies to qualify for a commission. Once established as an actor he quickly took on the additional role of a manager, boosted by an early success with his own adaptation of a German farce presented in London as The Private Secretary, which made his fortune. A lifelong gambler, both with theatrical productions and on horseracing, to which he was addicted, he was bankrupted several times during his career.

Regarded as Britain's leading comedy actor of his generation, Hawtrey was mentor and role model to younger actors including Noël Coward. Towards the end of his career Hawtrey starred in a handful of silent movies.

Early life
Hawtrey was born at Slough and educated at Eton College, the fifth son and eighth of the ten children of the Rev. John William Hawtrey and his first wife, Frances Mary Anne, née Procter. The Hawtrey family had a long association with Eton; at the time of Hawtrey's birth his father was a housemaster there, and a cousin, Edward Craven Hawtrey, was Provost. At the age of eight Hawtrey entered the lower school of the college. Three years later John Hawtrey left Eton to found St Michael's School, Slough; Hawtrey was educated there from 1869 to 1872, when he returned to Eton for a year, before moving to Rugby. As a schoolboy he became known as "a sportsman of dash and endurance". At the age of fourteen he became a keen follower of horse-racing, a lifelong obsession that continually disrupted his finances. He commented that his first encounter with racing was "a fatal day for me. I had one bet and lost half-a-crown, and I have been trying for fifty years to win it back."

From Rugby, Hawtrey went briefly to a crammer in London, to study for a career in the army, but soon abandoned the idea. He worked as a private tutor from 1876 to 1879 and then he began his theatrical career. It started badly: he broke his collar-bone while playing football and had to withdraw from the cast before the opening night. In February 1881 he matriculated at Pembroke College, Oxford, but withdrew in October, having been cast in the supporting role of Edward Langton in F. C. Burnand's The Colonel at the Prince of Wales's Theatre, London. Uncertain of success, he temporarily adopted the stage name Charles Bankes. He was well received in the play, and was given valuable lessons in stagecraft from the producer: "He taught me a great many elementary rules which were most helpful – such as the actions of my hands and arms, walking on the stage, holding myself as easily as I could, and above all things he would never let me put my hands in my pockets. Of course my hands always felt like two great hams and I never knew what to do with them, but I found that eventually I forgot all about them and then they behaved naturally!"

Actor-manager
In early 1882 Hawtrey played Jack Merryweather in The Marble Arch, which starred Herbert Beerbohm Tree. Later in that year he toured in The Colonel in a cast headed by Charles Collette. Two of Hawtrey's brothers, William and George (father of the economist Ralph Hawtrey), had also become actors, and in early 1883, Charles and William led a small touring company to towns in south-east England.

In 1884 Hawtrey had a huge success in London presenting his own adaptation of a German farce by Gustav von Moser, Der Bibliothekar, rewritten as The Private Secretary with the action moved to an English setting. It opened in March to disparaging reviews and at first played to small audiences, but Hawtrey persisted and further rewrote the play. It moved from the Prince's to the Globe Theatre, the principal roles were recast (with Hawtrey playing the crusty old Cattermole), and in the words of The Manchester Guardian "the audiences steadily laughed it into a success." The production ran for 785 performances, and Hawtrey made £123,000 from it – an enormous sum for those days. The play was revived in London eight times during his life.

Hawtrey pursued a career as an actor-manager, making a speciality of suave, sometimes immoral, but likable characters. His managerial career was chequered: great successes were often followed by expensive failures, and he was bankrupt several times. He was in charge over the years at eighteen London theatres – including the Globe until 1887 and two spells at the Comedy Theatre, 1887–93 and 1896–98. He staged, "with great attention to detail", about a hundred plays. His biographers H H Child and Michael Read list his most celebrated productions as two more adaptations from Moser (The Pickpocket, 1886, adapted by George Hawtrey, and The Arabian Nights, 1887, by Sydney Grundy); Jane (1890) by Harry Nicholls and William Lestocq; One Summer's Day (1897) by H. V. Esmond; Lord and Lady Algy (1898) by R. C. Carton co-starring with the author's wife, Katherine Compton; A Message from Mars (1899) by Richard Ganthony; The Man from Blankley's (1906) by F. Anstey; and Ambrose Applejohn's Adventure (1921) by Walter Hackett, in which Hawtrey played two roles: a respectable modern man and his disreputable ancestor. Hawtrey's career was long enough to allow him to create leading roles in plays by Oscar Wilde in the 1890s and Somerset Maugham after the First World War – he was Wilde's Lord Goring in An Ideal Husband (1895) and William in Maugham's Home and Beauty (1919). In between his successes he went bankrupt several times, and on one occasion discharged his debts by successfully gambling at baccarat.

After the war Hawtrey appeared occasionally in silent films: A Message From Mars (1913) as Horace Parker, Honeymoon for Three (1915) as Prince Ferdinand, and Masks and Faces (1918) with George Alexander, George Bernard Shaw and J. M. Barrie.

Hawtrey was generous in fostering talent. Among the young actors whose careers he encouraged was Noël Coward, who wrote in his memoirs about "the kindness and care of Hawtrey's direction. He took endless trouble with me ... and taught me during those two short weeks many technical points of comedy acting which I use to this day." One of the dramatists that he promoted was Horace Newte whose one act drama A Labour of Love Hawtrey presented at The Comedy Theatre in 1897.

Personal life
Hawtrey was twice married. His first wife, whom he married on 3 June 1886, was Madeline ("Mae") Harriet, née Sheriffe; he left her in 1891 and she divorced him in 1893. She died in 1905. In 1909 his then partner, Olive Morris, bore him a son, Anthony Hawtrey. On 10 November 1919 Hawtrey married the Hon Mrs Albert Petre (née Katherine Elsie Clark), daughter of the Rev William Robinson Clark and widow of the youngest son of the 11th Baron Petre. There were no children of either of his marriages. His second wife died on 14 November 1930. According to Ada Coleman, head bartender at the Savoy Hotel London, Hawtrey was responsible for naming the Hanky-Panky cocktail, which she created specifically for him.

Last years and posterity
From 1920 Hawtrey's health deteriorated. He was knighted in 1922. He died, aged 64, on 30 July 1923 and is buried at Richmond. His memoirs were edited by Maugham and published in 1924 as The Truth at Last. He is mentioned in the opening line of the Beatles song "Two of Us".

Notes and references

 * Notes

 * References

title: Charles Hawtrey (actor, born 1858)


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ATSC standards

Advanced Television Systems Committee (ATSC) standards are an International set of standards for broadcast and digital television transmission over terrestrial, cable and satellite networks. It is largely a replacement for the analog NTSC standard and, like that standard, is used mostly in the United States, Mexico, Canada, South Korea and Trinidad & Tobago. Several former NTSC users, such as Japan, have not used ATSC during their digital television transition, because they adopted other systems such as ISDB developed by Japan, and DVB developed in Europe, for example.

The ATSC standards were developed in the early 1990s by the Grand Alliance, a consortium of electronics and telecommunications companies that assembled to develop a specification for what is now known as HDTV. The standard is now administered by the Advanced Television Systems Committee. It includes a number of patented elements, and licensing is required for devices that use these parts of the standard. Key among these is the 8VSB modulation system used for over-the-air broadcasts. ATSC technology was primarily developed with patent contributions from LG Electronics, which holds most of the patents for the ATSC standard.

ATSC includes two primary high definition video formats, 1080i and 720p. It also includes standard-definition formats, although initially only HDTV services were launched in the digital format. ATSC can carry multiple channels of information on a single stream, and it is common for there to be a single high-definition signal and several standard-definition signals carried on a single 6 MHz (former NTSC) channel allocation.

Background
The high-definition television standards defined by the ATSC produce widescreen 16:9 images up to 1920×1080 pixels in size – more than six times the display resolution of the earlier standard. However, many different image sizes are also supported. The reduced bandwidth requirements of lower-resolution images allow up to six standard-definition "subchannels" to be broadcast on a single 6 MHz TV channel.

ATSC standards are marked A/x (x is the standard number) and can be downloaded for free from the ATSC's website at ATSC.org. ATSC Standard A/53, which implemented the system developed by the Grand Alliance, was published in 1995; the standard was adopted by the Federal Communications Commission in the United States in 1996. It was revised in 2009. ATSC Standard A/72 was approved in 2008 and introduces H.264/AVC video coding to the ATSC system.

ATSC supports 5.1-channel surround sound using Dolby Digital's AC-3 format. Numerous auxiliary datacasting services can also be provided.

Many aspects of ATSC were patented, including elements of the MPEG video coding, the AC-3 audio coding, and the 8VSB modulation. The cost of patent licensing, estimated at up to $50 per digital TV receiver, had prompted complaints by manufacturers.

As with other systems, ATSC depends on numerous interwoven standards, e.g., the EIA-708 standard for digital closed captioning, leading to variations in implementation.

Digital switchover
ATSC replaced much of the analog NTSC television system in the United States on June 12, 2009, on August 31, 2011 in Canada, on December 31, 2012 in South Korea, and on December 31, 2015 in Mexico.

Broadcasters who used ATSC and wanted to retain an analog signal were temporarily forced to broadcast on two separate channels, as the ATSC system requires the use of an entire separate channel. Channel numbers in ATSC do not correspond to RF frequency ranges, as they did with analog television. Instead, virtual channels, sent as part of the metadata along with the program(s), allow channel numbers to be remapped from their physical RF channel to any other number 1 to 99, so that ATSC stations can either be associated with the related NTSC channel numbers, or all stations on a network can use the same number. There is also a standard for distributed transmission systems (DTx), a form of single-frequency network which allows for the synchronised operation of multiple on-channel booster stations.

Audio
Dolby Digital AC-3 is used as the audio codec, though it was standardized as A/52 by the ATSC. It allows the transport of up to five channels of sound with a sixth channel for low-frequency effects (the so-called "5.1" configuration). In contrast, Japanese ISDB HDTV broadcasts use MPEG's Advanced Audio Coding (AAC) as the audio codec, which also allows 5.1 audio output. DVB (see below) allows both.

MPEG-2 audio was a contender for the ATSC standard during the DTV "Grand Alliance" shootout, but lost out to Dolby AC-3. The Grand Alliance issued a statement finding the MPEG-2 system to be "essentially equivalent" to Dolby, but only after the Dolby selection had been made. Later, a story emerged that MIT had entered into an agreement with Dolby whereupon the university would be awarded a large sum of money if the MPEG-2 system was rejected. Dolby also offered an incentive for Zenith to switch their vote (which they did); however, it is unknown whether they accepted the offer.

Video
The ATSC system supports a number of different display resolutions, aspect ratios, and frame rates. The formats are listed here by resolution, form of scanning (progressive or interlaced), and number of frames (or fields) per second (see also the TV resolution overview at the end of this article).

For transport, ATSC uses the MPEG systems specification, known as an MPEG transport stream, to encapsulate data, subject to certain constraints. ATSC uses 188-byte MPEG transport stream packets to carry data. Before decoding of audio and video takes place, the receiver must demodulate and apply error correction to the signal. Then, the transport stream may be demultiplexed into its constituent streams.

MPEG-2
There are four basic display sizes for ATSC, generally known by referring to the number of lines of the picture height. NTSC and PAL image sizes are smallest, with a width of 720 (or 704) and a height of 480 or 576 lines. The third size is HDTV images that have 720 scan lines in height and are 1280 pixels wide. The largest size has 1080 lines high and 1920 pixels wide. 1080-line video is actually encoded with 1920×1088 pixel frames, but the last eight lines are discarded prior to display. This is due to a restriction of the MPEG-2 video format, which requires the height of the picture in luma samples (i.e. pixels) to be divisible by 16.

The lower resolutions can operate either in progressive scan or interlaced mode, but not the largest picture sizes. The 1080-line system does not support progressive images at the highest frame rates of 50, 59.94 or 60 frames per second, because such technology was seen as too advanced at the time. The standard also requires 720-line video be progressive scan, since that provides better picture quality than interlaced scan at a given frame rate, and there was no legacy use of interlaced scan for that format. The result is that the combination of maximum frame rate and picture size results in approximately the same number of samples per second for both the 1080-line interlaced format and the 720-line format, as 1920*1080*30 is roughly equal to 1280*720*60. A similar equality relationship applies for 576 lines at 25 frame per second versus 480 lines at 30 frames per second.

A terrestrial (over-the-air) transmission carries 19.39 megabits of data per second (a fluctuating bandwidth of about 18.3 Mbit/s left after overhead such as error correction, program guide, closed captioning, etc.), compared to a maximum possible MPEG-2 bitrate of 10.08 Mbit/s (7 Mbit/s typical) allowed in the DVD standard and 48 Mbit/s (36 Mbit/s typical) allowed in the Blu-ray disc standard.

Although the ATSC A/53 standard limits MPEG-2 transmission to the formats listed below (with integer frame rates paired with 1000/1001-rate versions), the U.S. Federal Communications Commission declined to mandate that television stations obey this part of the ATSC's standard. In theory, television stations in the U.S. are free to choose any resolution, aspect ratio, and frame/field rate, within the limits of Main Profile @ High Level. Many stations do go outside the bounds of the ATSC specification by using other resolutions – for example, 352 x 480 or 720 x 480.

"EDTV" displays can reproduce progressive scan content and frequently have a 16:9 wide screen format. Such resolutions are 704×480 or 720×480 in NTSC and 720×576 in PAL, allowing 60 progressive frames per second in NTSC or 50 in PAL.

ATSC also supports PAL frame rates and resolutions which are defined in ATSC A/63 standard.

The ATSC A/53 specification imposes certain constraints on MPEG-2 video stream:

 * The maximum bit rate value in the sequence header of the MPEG-2 video stream is 19.4 Mbit/s for broadcast television, and 38.8 Mbit/s for the "high data rate" mode (e.g., cable television). The actual MPEG-2 video bit rate will be lower, since the MPEG-2 video stream must fit inside a transport stream.
 * The amount of MPEG-2 stream buffer required at the decoder (the vbv_buffer_size_value) must be less than or equal to 999,424 bytes.
 * In most cases, the transmitter can't start sending a coded image until within a half-second of when it's to be decoded (vbv_delay less than or equal to 45000 90-kHz clock increments).
 * The stream must include colorimetry information (gamma curve, the precise RGB colors used, and the relationship between RGB and the coded YCbCr).
 * The video must be 4:2:0 (chrominance resolution must be 1/2 of luma horizontal resolution and 1/2 of luma vertical resolution).

The ATSC specification and MPEG-2 allow the use of progressive frames coded within an interlaced video sequence. For example, NBC stations transmit a 1080i60 video sequence, meaning the formal output of the MPEG-2 decoding process is sixty 540-line fields per second. However, for prime-time television shows, those 60 fields can be coded using 24 progressive frames as a base – actually, an 1080p24 video stream (a sequence of 24 progressive frames per second) is transmitted, and MPEG-2 metadata instructs the decoder to interlace these fields and perform 3:2 pulldown before display, as in soft telecine.

The ATSC specification also allows 1080p30 and 1080p24 MPEG-2 sequences, however they are not used in practice, because broadcasters want to be able to switch between 60 Hz interlaced (news), 30 Hz progressive or PsF (soap operas), and 24 Hz progressive (prime-time) content without ending the 1080i60 MPEG-2 sequence.

The 1080-line formats are encoded with 1920 × 1088 pixel luma matrices and 960 × 540 chroma matrices, but the last 8 lines are discarded by the MPEG-2 decoding and display process.

H.264/MPEG-4 AVC
In July 2008, ATSC was updated to support the ITU-T H.264 video codec. The new standard is split in two parts:

 * A/72 part 1: Video System Characteristics of AVC in the ATSC Digital Television System
 * A/72 part 2 : AVC Video Transport Subsystem Characteristics

The new standards support 1080p at 50, 59.94 and 60 frames per second; such frame rates require H.264/AVC High Profile Level 4.2, while standard HDTV frame rates only require Levels 3.2 and 4, and SDTV frame rates require Levels 3 and 3.1.

Transport stream (TS)
The file extension ".TS" stands for "transport stream", which is a media container format. It may contain a number of streams of audio or video content multiplexed within the transport stream. Transport streams are designed with synchronization and recovery in mind for potentially lossy distribution (such as over-the-air ATSC broadcast) in order to continue a media stream with minimal interruption in the face of data loss in transmission. When an over-the-air ATSC signal is captured to a file via hardware/software the resulting file is often in a .TS file format.

Modulation and transmission
ATSC signals are designed to use the same 6 MHz bandwidth as analog NTSC television channels (the interference requirements of A/53 DTV standards with adjacent NTSC or other DTV channels are very strict). Once the digital video and audio signals have been compressed and multiplexed, the transport stream can be modulated in different ways depending on the method of transmission.

 * Terrestrial (local) broadcasters use 8VSB modulation that can transfer at a maximum rate of 19.39 Mbit/s, sufficient to carry several video and audio programs and metadata.
 * Cable television stations can generally operate at a higher signal-to-noise ratio and can use either the 16VSB as defined in ATSC or the 256-QAM defined in SCTE, to achieve a throughput of 38.78 Mbit/s, using the same 6 MHz channel.

The proposals for modulation schemes for digital television were developed when cable operators carried standard-resolution video as uncompressed analog signals. In recent years, cable operators have become accustomed to compressing standard-resolution video for digital cable systems, making it harder to find duplicate 6 MHz channels for local broadcasters on uncompressed "basic" cable.

Currently, the Federal Communications Commission requires cable operators in the United States to carry the analog or digital transmission of a terrestrial broadcaster (but not both), when so requested by the broadcaster (the "must-carry rule"). The Canadian Radio-television and Telecommunications Commission in Canada does not have similar rules in force with respect to carrying ATSC signals.

However, cable operators have still been slow to add ATSC channels to their lineups for legal, regulatory, and plant & equipment related reasons. One key technical and regulatory issue is the modulation scheme used on the cable: cable operators in the U.S. (and to a lesser extent Canada) can determine their own method of modulation for their plants. Multiple standards bodies exist in the industry: the SCTE defined 256-QAM as a modulation scheme for cable in a cable industry standard, ANSI/SCTE 07 2006: Digital Transmission Standard For Cable Television. Consequently, most U.S. and Canadian cable operators seeking additional capacity on the cable system have moved to 256-QAM from the 64-QAM modulation used in their plant, in preference to the 16VSB standard originally proposed by ATSC. Over time 256-QAM is expected to be included in the ATSC standard.

There is also a standard for transmitting ATSC via satellite; however, this is only used by TV networks. Very few teleports outside the U.S. support the ATSC satellite transmission standard, but teleport support for the standard is improving. The ATSC satellite transmission system is not used for direct-broadcast satellite systems; in the U.S. and Canada these have long used either DVB-S (in standard or modified form) or a proprietary system such as DSS or DigiCipher 2.

Other systems

ATSC coexists with the DVB-T standard, and with ISDB-T. A similar standard called ADTB-T was developed for use as part of China's new DMB-T/H dual standard. While China has officially chosen a dual standard, there is no requirement that a receiver work with both standards and there is no support for the ADTB modulation from broadcasters or equipment and receiver manufacturers.

For compatibility with material from various regions and sources, ATSC supports the 480i video format used in the NTSC analog system (480 lines, approximately 60 fields or 30 frames per second), 576i formats used in most PAL regions (576 lines, 50 fields or 25 frames per second), and 24 frames-per-second formats used in film.

While the ATSC system has been criticized as being complicated and expensive to implement and use, both broadcasting and receiving equipment are now comparable in cost with that of DVB.

The ATSC signal is more susceptible to changes in radio propagation conditions than DVB-T and ISDB-T. It also lacks true hierarchical modulation, which would allow the SDTV part of an HDTV signal (or the audio portion of a television program) to be received uninterrupted even in fringe areas where signal strength is low. For this reason, an additional modulation mode, enhanced-VSB (E-VSB) has been introduced, allowing for a similar benefit.

In spite of ATSC's fixed transmission mode, it is still a robust signal under various conditions. 8VSB was chosen over COFDM in part because many areas are rural and have a much lower population density, thereby requiring larger transmitters and resulting in large fringe areas. In these areas, 8VSB was shown to perform better than other systems.

COFDM is used in both DVB-T and ISDB-T, and for 1seg, as well as DVB-H and HD Radio in the United States. In metropolitan areas, where population density is highest, COFDM is said to be better at handling multipath propagation. While ATSC is also incapable of true single-frequency network (SFN) operation, the distributed transmission mode, using multiple synchronized on-channel transmitters, has been shown to improve reception under similar conditions. Thus, it may not require more spectrum allocation than DVB-T using SFNs. A comparison study found that ISDB-T and DVB-T performed similarly, and that both were outperformed by DVB-T2.

Mobile TV
Mobile reception of digital stations using ATSC has, until 2008, been difficult to impossible, especially when moving at vehicular speeds. To overcome this, there are several proposed systems that report improved mobile reception: Samsung/Rhode & Schwarz's A-VSB, Harris/LG's MPH, and a recent proposal from Thomson/Micronas; all of these systems have been submitted as candidates for a new ATSC standard, ATSC-M/H. After one year of standardization, the solution merged between Samsung's AVSB and LGE's MPH technology has been adopted and would have been deployed in 2009. This is in addition to other standards like the now-defunct MediaFLO, and worldwide open standards such as DVB-H and T-DMB. Like DVB-H and ISDB 1seg, the proposed ATSC mobile standards are backward-compatible with existing tuners, despite being added to the standard well after the original standard was in wide use.

Mobile reception of some stations will still be more difficult, because 18 UHF channels in the U.S. have been removed from TV service, forcing some broadcasters to stay on VHF. This band requires larger antennas for reception, and is more prone to electromagnetic interference from engines and rapidly changing multipath conditions.

ATSC 2.0
ATSC 2.0 was a planned major new revision of the standard which would have been backward compatible with ATSC 1.0. The standard was to have allowed interactive and hybrid television technologies by connecting the TV with the Internet services and allowing interactive elements into the broadcast stream. Other features were to have included advanced video compression, audience measurement, targeted advertising, enhanced programming guides, video on demand services, and the ability to store information on new receivers, including Non-realtime (NRT) content.

However, ATSC 2.0 was never actually launched, as it was essentially outdated before it could be launched. All of the changes that were a part of the ATSC 2.0 revision were adopted into ATSC 3.0.

ATSC 3.0
ATSC 3.0 will provide even more services to the viewer and increased bandwidth efficiency and compression performance, which requires breaking backwards compatibility with the current version. On November 17, 2017, the FCC voted 3–2 in favor of authorizing voluntary deployments of ATSC 3.0, and issued a Report and Order to that effect. ATSC 3.0 broadcasts and receivers are expected to emerge within the next decade.

LG Electronics tested the standard with 4K on February 23, 2016. With the test considered a success, South Korea announced that ATSC 3.0 broadcasts would start in February 2017.

On March 28, 2016, the Bootstrap component of ATSC 3.0 (System Discovery and Signalling) was upgraded from candidate standard to finalized standard.

On June 29, 2016, NBC affiliate WRAL-TV in Raleigh, North Carolina, a station known for its pioneering roles in testing the original DTV standards, launched an experimental ATSC 3.0 channel carrying the station's programming in 1080p, as well as a 4K demo loop.

 * Structure/ATSC 3.0 System Layers
 * 1) Bootstrap: System Discovery and Signalling
 * 2) Physical Layer: Transmission (OFDM)
 * 3) Protocols: IP, MMT
 * 4) Presentation: Audio and Video standards (to be determined), Ultra HD with High Definition and standard-definition multicast,  Immersive Audio
 * 5) Applications: Screen is a web page

ATSC 3.0 advantages

 * 1) Better image quality. ATSC 3.0 allows 4K UHD transmission, including high-dynamic-range television (HDR-TV), wide color gamut (WCG), and high frame rate (HFR).
 * 2) Reception upgrades. ATSC 3.0 allows the same aerial to receive more channels with better quality.
 * 3) Portable devices such as mobile phones, tablets, and car infotainment systems can receive TV signals.
 * 4) Enhanced emergency alerts. Emergency signals can be geographically oriented and inform only the specific areas where they are required.
 * 5) Audience measure. Telecommunication companies can easily take audience data gatherings.
 * 6) Targeted advertising with the assistance of local network Wi-Fi.
 * 7) Content variety and diversification.

North America

 * undefined 2018
 * 🇧🇸 bahamas On December 14, 2011, the Bahamas' national public broadcaster ZNS-TV announced that it would adopt ATSC, in line with the United States and its territories.
 * 🇧🇧 barbados
 * 🇨🇦 canada adopted ATSC, with full-power analog stations in specified "mandatory markets" (which included provincial capitals, and cities with a population of 300,000 or higher) shutting down on August 31, 2011. The CBC only converted its originating stations to digital; it was given permission to operate its repeaters in mandatory markets (such as CBKST in Saskatoon) for an additional year, but later announced that it would shut down all of its analog repeaters on July 31, 2012—citing budget issues and their distribution network as being obsolete.
 * 🇩🇲 dominica
 * 🇩🇴 dominican republic The Dominican Republic announced its adoption on August 10, 2010, completing the transition on September 24, 2015, but most companies were not able to meet the deadline and the government had to move it forward to the year 2021.
 * 🇬🇩 grenada
 * 🇭🇹 haiti
 * 🇯🇲 jamaica Will convert to ATSC 3.0 instead of 1.0. The conversion will begin in 2022 and is expected to be completed by 2023.
 * 🇲🇽 mexico began converting to ATSC in 2013; a full transition was scheduled for December 31, 2015, but due to technical and economic issues for some transmitters, the full transition was extended to December 31, 2016.
 * 🇱🇨 saint lucia opened on Saint Lucia on ATSC on March 5, 2024.
 * 🇹🇹 trinidad and tobago will convert to ATSC 3.0 instead of ATSC 1.0. The conversion process will begin in March 2023 and is expected to be completed by 2026.
 * 🇺🇸 united states Full-power television stations in the United States ended analog television service on June 12, 2009. Analog low-power stations and translators were all wound down by July 13, 2021.

South America

 * 🇬🇾 guyana
 * 🇸🇷 suriname Suriname has undergone transitioning from analogue NTSC broadcasts to digital ATSC broadcasts. Channel ATV started with ATSC broadcasts in the Paramaribo area in June 2014, which was followed by ATSC broadcasts from stations in Brokopondo, Wageningen and Albina. The stations in Brokopondo, Wageningen and Albina broadcast both the channels of ATV (i.e., ATV and TV2) and STVS. In 2016 all channels in Suriname had already made the switch to ATSC.

Asia/Pacific

 * 🇰🇷 south korea South Korea completed its transition to ATSC on December 31, 2012, although it still operates some analog signals along its northern border for reception in North Korea.
 * 🇺🇸 united states territories in the Pacific, including American Samoa, Guam, and the Northern Mariana Islands have adopted ATSC, as with the mainland.

Countries and territories are available in using ATSC

 * undefined
 * 🇻🇨 saint vincent and the grenadines

Patent holders
The following organizations hold patents for the development of ATSC technology, as listed in the patent pool administered by MPEG LA. As of March 2024 about 77% of the patents are expired. By February 2025 all of the relevant patents registered in USA and Canada are expected to expire.

title: ATSC standards