is a mobile terrestrial digital audio/video and data broadcasting service in

Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

Chile Chile, officially the Republic of Chile, is a country in western South America. It is the southernmost country in the world and the closest to Antarctica, stretching along a narrow strip of land between the Andes, Andes Mountains and the Paci ...

Uruguay Uruguay, officially the Oriental Republic of Uruguay, is a country in South America. It shares borders with Argentina to its west and southwest and Brazil to its north and northeast, while bordering the Río de la Plata to the south and the A ...

Paraguay Paraguay, officially the Republic of Paraguay, is a landlocked country in South America. It is bordered by Argentina to the Argentina–Paraguay border, south and southwest, Brazil to the Brazil–Paraguay border, east and northeast, and Boli ...

Peru Peru, officially the Republic of Peru, is a country in western South America. It is bordered in the north by Ecuador and Colombia, in the east by Brazil, in the southeast by Bolivia, in the south by Chile, and in the south and west by the Pac ...

and the

Philippines The Philippines, officially the Republic of the Philippines, is an Archipelagic state, archipelagic country in Southeast Asia. Located in the western Pacific Ocean, it consists of List of islands of the Philippines, 7,641 islands, with a tot ...

. Service began experimentally during 2005 and commercially on April 1, 2006. It is designed as a component of ISDB-T, the terrestrial digital broadcast system used in those countries, as each channel is divided into 13 segments, with a further segment separating it from the next channel; an

HDTV High-definition television (HDTV) describes a television or video system which provides a substantially higher image resolution than the previous generation of technologies. The term has been used since at least 1933; in more recent times, it ref ...

broadcast signal occupies 12 segments, leaving the remaining (13th) segment for mobile receivers, hence the name, "1seg" or "One Seg". Its use in Brazil was established in late 2007 (starting in just a few cities), with a slight difference from the Japanese counterpart: it is broadcast under a 30 fps transmission setting (Japanese broadcasts are under the 15 fps transmission setting).

Technical information

The

ISDB Integrated Services Digital Broadcasting (ISDB; Japanese: , ''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 ...

-T system uses the

UHF Ultra high frequency (UHF) is the ITU designation for radio frequencies in the range between 300 megahertz (MHz) and 3 gigahertz (GHz), also known as the decimetre band as the wavelengths range from one meter to one tenth of a meter ...

band at frequencies between 470 and 770 MHz (806 MHz in Brazil), giving a total bandwidth 300 MHz. The bandwidth is divided into fifty name channels 13 through 62. Each channel is 6 MHz wide consisting of a 5.57 MHz wide signalling band and a 430 kHz guard band to limit cross channel interference. Each of these channels is further divided into 13 segments, each with 428 kHz of bandwidth. 1 seg uses a single of these segments to carry the 1seg transport stream. 1seg, like ISDB-T uses

QPSK Phase-shift keying (PSK) is a digital modulation process which conveys data by changing (modulating) the phase of a constant frequency carrier wave. The modulation is accomplished by varying the sine and cosine inputs at a precise time. It is ...

for

modulation Signal modulation is the process of varying one or more properties of a periodic waveform in electronics and telecommunication for the purpose of transmitting information. The process encodes information in form of the modulation or message ...

, with 2/3

forward error correction In computing, telecommunication, information theory, and coding theory, forward error correction (FEC) or channel coding is a technique used for controlling errors in data transmission over unreliable or noisy communication channels. The centra ...

and 1/4 guard ratio. The total datarate is 416 kbit/s. The television system uses an H.264/MPEG-4 AVC video stream and an

HE-AAC High-Efficiency Advanced Audio Coding (HE-AAC) is an audio coding format for lossy data compression of digital audio as part of the MPEG-4 standards. It is an extension of Low Complexity AAC (AAC-LC) optimized for low- bitrate applicati ...

audio stream multiplexed into an

MPEG transport stream MPEG transport stream (MPEG-TS, MTS) or simply transport stream (TS) is a standard digital container format for transmission and storage of audio, video, and Program and System Information Protocol (PSIP) data. It is used in broadcast syst ...

. The maximum video resolution is 320x240 pixels, with a video bitrate of between 220 and 320 kbit/s. Audio conforms to

profile, with a bitrate of 48 to 64 kbit/s. Additional data (

EPG Electronic programming guides (EPGs) and interactive programming guides (IPGs) are menu-based systems that provide users of television, radio, and other media applications with continuously updated menus that display scheduling information fo ...

, interactive services, etc.) is transmitted using BML and occupies the remaining 10 to 100 kbit/s of bandwidth. Conditional access and copy control are implemented in 1seg broadcasting by the use of

Broadcast Flag A broadcast flag is a bit field sent in the data stream of a digital television program that indicates whether or not the data stream can be recorded, or if there are any restrictions on recorded content. Possible restrictions include the inabili ...

-like structure contained in the "Copy Control Descriptor" within the broadcast. The broadcast contents themselves are not encrypted, but the Copy Control information forces the device to encrypt stored recordings and disallows making a copy of the recording.

Broadcast Markup Language

Broadcast Markup Language (BML), is a data-transmission service allowing text to be displayed on a 1seg TV screen. The text contains news, sports, weather forecasts, emergency warnings such as

Earthquake Early Warning An earthquake early warning (EEW) system is a system of accelerometers, seismometers, communication, computers, and alarms that is devised for rapidly notifying adjoining regions of a substantial earthquake once one begins. This is not the same ...

, etc. free of charge. Further information can be found through links to content on websites, frequently those belonging to the television station itself.

(program guides) is not included, but transmitted in separate stream (EIT).

Multiple-program arrangement

On June 23, 2008, broadcaster

Tokyo MX JOMX-DTV (channel 9), branded as Tokyo MX (officially stylized as TOKYO MX), is an independent station, independent television station in Tokyo, Japan, owned by the . It is the only television station that exclusively serves the city and parts ...

officially began using technology to simultaneously broadcast two programs on a single divided segment. Most 1seg receivers manufactured after September 2008 are compatible with this technology. Multiple-program arrangement in 1seg is named as . NHK Educational TV (from 1 April 2009) and (from 1 December 2009) are also started for several number of programs.

Popularity

Until the end of March 2008, Japanese regulation required that the programs on 1seg were fundamentally the same as those broadcast on the equivalent HDTV channel. On April 1 the regulation was revised, and experimental programs by 1seg or third parties have begun airing on several stations. On January 16, 2008, JEITA released their monthly shipping survey showing approx. 4.806 million

mobile phone A mobile phone or cell phone is a portable telephone that allows users to make and receive calls over a radio frequency link while moving within a designated telephone service area, unlike fixed-location phones ( landline phones). This rad ...

s were sold in

in November 2007. Of these, approx. 3.054 million phones, 63.5% of the total, can receive 1seg broadcasts. In the fiscal year of 2007, on average 45% of mobile phones had 1seg reception capability out of the 22.284 million units sold. The percent increased from 26.8% in April 2007 to 64.2% at end of fiscal year March 2008.2007年度移動電話国内出荷実績
(2007 fiscal year mobile phone ship out record) (In Japanese)

Receivers

;

Electronic dictionary An electronic dictionary is a dictionary whose data exists in digital form and can be accessed through a number of different media. Electronic dictionaries can be found in several forms, including software installed on tablet or desktop computer ...

: Sharp Papyrus PW-TC900 : Sharp Papyrus PW-TC920 : Sharp Papyrus PW-TC930 : Sharp Papyrus PW-TC980 ; PC connect type : Pixela PC : Monster TV 1D

PC card PC Card is a technical standard specifying an expansion card interface for laptops and personal digital assistants, PDAs. The PCMCIA originally introduced the 16-bit Industry Standard Architecture, ISA-based PCMCIA Card in 1990, but renamed it to ...

Type II 1seg receiver by SKNET : Cowon D2TV : and more. ;

Car navigation system A car, or an automobile, is a motor vehicle with wheels. Most definitions of cars state that they run primarily on roads, seat one to eight people, have four wheels, and mainly transport people rather than cargo. There are around one billio ...

: Sanyo One-seg & car navigation system :
Pioneer AVIC BZ500
: and more. ;

Handheld game console A handheld game console, or simply handheld console, is a small, portable self-contained video game console with a built-in screen, game controls and speakers. Handheld game consoles are smaller than home video game consoles and contain the con ...

:
1seg PSP-2000 Tuner
:

Nintendo DS The is a foldable handheld game console produced by Nintendo, released globally across 2004 and 2005. The DS, an initialism for "Developers' System" or "Dual Screen", introduced distinctive new features to handheld games: two LCD screens worki ...

(via an add-on called "DS Terebi") ; Portable devices ; Set top box ; Others :

Sony is a Japanese multinational conglomerate (company), conglomerate headquartered at Sony City in Minato, Tokyo, Japan. The Sony Group encompasses various businesses, including Sony Corporation (electronics), Sony Semiconductor Solutions (i ...

Walkman is a brand of Personal stereo, portable audio players manufactured by Sony since 1979. It was originally introduced as a portable Compact Cassette, cassette player and later expanded to include a range of portable audio products. Since 2011, ...

NW-A919 :

Kodak The Eastman Kodak Company, referred to simply as Kodak (), is an American public company that produces various products related to its historic basis in film photography. The company is headquartered in Rochester, New York, and is incorporated i ...

3-inch OLED TV : and more. ;

Mobile phone A mobile phone or cell phone is a portable telephone that allows users to make and receive calls over a radio frequency link while moving within a designated telephone service area, unlike fixed-location phones ( landline phones). This rad ...

s : The first mobile phone to support 1seg was the

Sanyo is a former Japanese electronics manufacturer founded in 1947 by Toshio Iue, the brother-in-law of Kōnosuke Matsushita, the founder of Matsushita Electric Industrial, now known as Panasonic. Iue left Matsushita Electric to start his own bu ...

which was released by au by KDDI to consumers in autumn 2005. Until around 2021, the vast majority of and carrier-branded Android phones sold in Japan featured support for 1seg. While

iOS Ios, Io or Nio (, ; ; locally Nios, Νιός) is a Greek island in the Cyclades group in the Aegean Sea. Ios is a hilly island with cliffs down to the sea on most sides. It is situated halfway between Naxos and Santorini. It is about long an ...

users have always required to purchase a third-party 1seg antenna separately in order to access 1seg, the rise of 5G NR and unlimited data plans means that 1seg support is gradually becoming less important, hence it is increasingly omitted on newer Japanese iOS and Android mobile devices.

References

External links

*
ISDB-T, Application, Present and Future

PDF Portable document format (PDF), standardized as ISO 32000, is a file format developed by Adobe Inc., Adobe in 1992 to present documents, including text formatting and images, in a manner independent of application software, computer hardware, ...

File *
1seg official site (Japanese)

ACCESS Ginga Edition for 1Seg in Brazil

GPS fitted with ISDB-T OneSeg sales grow in Brazil
{{Video formats 1seg Audiovisual introductions in 2006 2005 establishments in Japan Broadcast engineering Digital television Mobile telephone broadcasting Mobile television Television transmission standards Japanese inventions