|List of digital television broadcast standards|
|DVB standards (countries)|
|ATSC standards (countries)|
|ISDB standards (countries)|
|DTMB standards (countries)|
|DMB standard (countries)|
The 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 standard for digital television (DTV) and digital radio used by the country's radio and television networks. ISDB supersedes both the NTSC-J analog television system and the previously used MUSE Hi-vision analog HDTV system in Japan as well as 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 Brazil in December 2007 as a trial. Since then, many countries have adopted ISDB over other digital broadcasting standards.
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 or MPEG-4 standard for multiplexing with transport stream structure and video and audio coding (MPEG-2 or H.264) and are capable of 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.
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.
Besides audio and video transmission, ISDB also defines data connections (Data broadcasting) with the internet as a return channel over several media (10Base-T/100Base-T, 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).
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. Hollywood 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.
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:
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.
The B-CAS card is required to decode all broadcasts in Japan. These cards are included with every digital TV 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.
A typical Japanese broadcast service consists as follows:
There are examples providing more than 10 SDTV services with H.264 coding in some countries.
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.
This table shows the summary of ISDB-S (satellite digital broadcasting).
|Transmission channel coding||Modulation||TC8PSK, QPSK, BPSK (Hierarchical transmission)|
|Error correction coding||Inner coding||Trellis [TC8PSK] and Convolution|
|Outer coding||RS (204,188)|
|Time domain multiplexing||TMCC|
|Data broadcasting||ARIB STD-B24 (BML, ECMA script)|
|Service information||ARIB STD-B10|
|Audio coding||MPEG-2 Audio (AAC)|
|Video coding||MPEG-2 Video|
Frequency and channel specification of Japanese Satellites using ISDB-S
|Method||BS digital broadcasting||Wide band CS digital broadcasting|
|Frequency band||11.7 to 12.2 GHz||12.2 to 12.75 GHz|
|Transmission bit rate||51 Mbit/s (TC8PSK)||40 Mbit/s (QPSK)|
|Transmission band width||34.5 MHz*||34.5 MHz|
|*Compatible with 27 MHz band satellite transponder for analog FM broadcasting.|
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.
ISDB-T is characterized by the following features:
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 currently uses an analogue TV system (PAL-M) that slightly differs 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 already selected ISDB-Tb, there are other South American countries, mainly from Mercosur, such as Venezuela, that are considering ISDB-Tb, which could provide 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.
The implementation rollout in Brazil is proceeding successfully although some voice like Philips' say that its implementation could be faster. It terms of broadcasting, the implementation plan seems to be on target. In only eight months since the start, the digital signal is present in four state capitals and by the end of 2008 another three capitals will receive the signal.
This lists the countries who adopted the ISDB-T standard, chronologically arranged.
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.
|s11||s 9||s 7||s 5||s 3||s 1||s 0||s 2||s 4||s 6||s 8||s10||s12|
|Error correction coding||Data:
Inner coding: Convolutional 7/8,5/6,3/4,2/3,1/2
Outer coding: Reed-Solomon(204,188)
Shortened code (184,102)
of Difference Cyclic Code (273,191)
|Interleaving||Time, Frequency, bit, byte|
|Frequency domain multiplexing||BST-OFDM |
(Segmented structure OFDM)
|Data broadcasting||ARIB STD-B24 (BML, ECMA script)|
|Service information||ARIB STD-B10|
|Audio coding||MPEG-2 Audio (AAC)|
|Video coding||MPEG-2 Video||MPEG-4 AVC /H.264*|
Specification of Japanese terrestrial digital broadcasting using ISDB-T.
|Method||Terrestrial digital broadcasting|
|Frequency band||VHF/UHF, super high band|
|Transmission bit rate||23 Mbit/s(64QAM)|
|Transmission band width||5.6 MHz*|
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 siginals.
ISDB-C is 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.
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 mmbi, Inc. or Multimedia Broadcasting, Inc (マルチメディア放送, Maruchi Medhia Hōsō) 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.
|Terrestrial television||Satellite Sound||Terrestrial Sound||Cable television|
|Nickname||-||ISDB-S||ISDB-T||2.6 GHz mobile broadcasting||ISDB-Tsb||64QAM, Trans-modulation (ISDB-C)|
|Transmission||DVB-S||ARIB STD-B20||ARIB STD-B31||ARIB STD-B41||ARIB STD-B29||-|
|-||ITU-R BO.1408||ITU-R BT.1306-1||-||ITU-R BS.1114||ITU-T J.83 Annex C, J.183|
|Receiver||ARIB STD-B16||ARIB STD-B21||ARIB STD-B42||ARIB STD-B30||JCTEA STD-004, STD-007|
|Server type broadcasting||-||ARIB STD-B38||-|
|Conditional access||-||ARIB STD-B25 (Multi-2)||JCTEA STD-001|
|Service information||-||ARIB STD-B10||JCTEA STD-003|
|Data broadcasting||-||ARIB STD-B24 (BML), ARIB STD-B23 (EE or MHP like)||-|
|Video/Audio compression and multiplexing||MPEG-2||ARIB STD-B32 (MPEG)||-|
|Technical report||-||ARIB TR-B13||ARIB TR-B14||-||-||-|
|Systems||ATSC 8-VSB||DVB COFDM||ISDB BST-COFDM|
|Video||Main profile syntax of ISO/IEC 13818-2 (MPEG-2 - video)|
|Audio||ATSC Standard A/52 (Dolby AC-3)||ISO/IEC 13818-2 (MPEG-2 – layer II audio) and Dolby AC-3||ISO/IEC 13818-7 (MPEG-2 – AAC audio)|
|Outer coding||R-S (207, 187, t = 10)||R-S (204, 188, t = 8)|
|Outer interleaver||52 R-S block interleaver||12 R-S block interleaver|
|Inner coding||Rate 2/3 trellis code||Punctured convolution code: Rate 1/2, 2/3,3/4, 5/6, 7/8 Constraint length = 7, Polynomials (octal) = 171, 133|
|Inner interleaver||12 to 1 trellis code interleaver||Bit-wise interleaving and frequency interleaving||Bit-wise interleaving, frequency interleaving and selectable time interleaving|
|Data randomization||16-bit PRBS|
|Modulation||8-VSB and 16-VSB||COFDM
QPSK, 16QAM and 64QAM
Hierarchical modulation: multi-resolution constellation (16QAM and 64 QAM)
Guard interval: 1/32, 1/16, 1/8 & 1/4 of OFDM symbol
2 modes: 2k and 8k FFT
|BST-COFDM with 13 frequency segments |
DQPSK, QPSK, 16QAM and 64QAM
Hierarchical modulation: choice of three different modulations on each segment
Guard interval: 1/32, 1/16, 1/8 & 1/4 of OFDM symbol
3 modes: 2k, 4k and 8k FFT