Integrated Services Digital Broadcasting (ISDB) is a
Japanese standard for digital television(DTV) and digital radioused by the country's radio and television stations. ISDB replaced the previously used MUSE "Hi-vision" analogue HDTV system.
ISDB is maintained by the Japanese organization
ARIB. The standards can be obtained for free at the Japanese organization DiBEGwebsite and at ARIB.
The core standards of ISDB are ISDB-S (satellite television), ISDB-T(terrestrial), ISDB-C (cable) and 2.6GHz band mobile broadcasting which are all based on
MPEG-2video and audio coding as well as the transport stream described by the MPEG-2 standard, and are capable of high definition television (HDTV). ISDB-T and ISDB-Tsb are for mobile reception in TV bands. 1segis the name of an ISDB-T service for reception on cell phones, laptop computersand vehicles.
The concept was named for its similarity to ISDN, because both allow multiple channels of data to be transmitted together (a process called multiplexing). This is also much like another
digital radiosystem, 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 taken by other countries for TV but never before for radio.
Video and audio compression
ISDB has adopted the
MPEG-2video and audio compression system. ATSC and DVB also adopted the same system. DVB and ISDB also provide for other video compression methods to be used, including JPEGand MPEG-4, although JPEG is only a required part of the MHEGstandard.
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 is used, for example, for interactive interfaces like data broadcasting (ARIB STD B-24) 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 (ARIB STD-B25) with the Common Scrambling Algorithm (CAS) system called
MULTI2required for (de-)scrambling television.
The ISDB CAS system is operated by a company named "B-CAS" in Japan; 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".Fact|date=September 2008 An interface for mobile reception is under consideration.Fact|date=September 2008
RMP(Rights management and protection). Since all digitial television (DTV) systems carry digital data content, a DVDor high-definition (HD) recorder could easily copy content losslessly. HollywoodWho|date=September 2008 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 disc 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 permanently prevent further copying. “Copy never” programming may only be timeshifted and cannot be permanently stored. Currentlywhen, 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 [ [http://feed.japan.cnet.com/news/com/story/0,2000056021,20094312,00.htm JEITA、地デジのコンテンツ保護策として暗号方式 EPN を提案:ニュース - CNET Japan ] ] .
There are two types of ISDB receiver: TV and STB (Set top box).The aspect ratio of ISDB television is 16:9; televisions fulfilling these specs are called
Hi-visionTVs.There are three TV types: CRT (Cathode ray tube), PDP (Plasma display panel) and LCD(Liquid crystal display), with LCD being the most popular Hi-Vision format on the Japanese market right now.
LCD share as measured by
JEITAin November 2004 was about 60%.While PDP set occupies the high end market with units that are over 50 inches (1270 mm), PDP and CRT set shares are about 20% each. CRT set are considered low end for Hi-Vision.
STB is sometimes referred to as digital tuner. High-end ISDB STB have several interfaces:
F connector(s) for RF input.
* D4 connector for HDTV monitor in
* Optical digital audio interface for audio amplifier and speakers for 5.1 surround audio in a home cinema.
* IEEE 1394 (aka FireWire) interface for digital data recorders (like
DVDrecorders) in a home cinema.
* RCA video jack provides
SDTVsignal 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
* S video are for
VCRs or analog CRT television sets.
10BASE-T/ 100BASE-Tand modular jack telephone line modem interfaces for an internet connection.
* B-CAS card interface to de-scramble.
* IR interface jack for controlling a VHS or DVD player.
Though ISDB is a feature-rich system, many problems have surfaced recently.
Copy Protection Technology
Every TV broadcast (including free TV) is encrypted with "Copy-Once", which allows users to record to a digital media (
D-VHS, DVD, HDD, etc) but does not allow dubbing to another digital media. On the other hand, the "Copy-Once" technology does not prohibit all types of dubbing. It is possible to dub to an analog media (such as standard VHS) and if recorded to an HDD, it will allow users to "Move" the contents to a D-VHS, but not copy. In contrast, 1segdigital 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 very worried about the recent news of severe protection in the future.There are modes in ISDB to not allow the output of signal from an Analog connector (D-connector, Component, Composite,
S-Video, etc). There are already plans to not allow analog output for "Copyright Protection" reasons. (Same as Blu-rayand HD DVD) This will make all currently sold STB Tuners, and the majority of LCD/Plasma TVs without HDMI inputs unusable. Plus all analog VHS, D-VHS that can only record via analog input, and all DVD players will also become 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, and viewers without proper devices will be forced to buy a new compatible TV or set top box in order to view 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. [ [http://pbx.mine.nu/isdb/b-cas/ Software B-CAS Conditional Access Module with MULTI2 decoder ] ]
The B-CAS card is required to decode all broadcasts. These cards are included with every digital TV or Tuner at no charge. To use this card, you must agree to the statement written on the registration card. Despite the fact that the card must be inserted to watch TV, if you don't agree to the statement, then the user cannot watch digital broadcasts. Essentially, users are "forced" to agree with the statement. Though registration is not required, it is recommended to fully enjoy interactive programs. Unregistered B-CAS card displays a
watermarkin a 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, new B-CAS card of the same number can be issued for a fee of 2,000 yen. [cite web |title=B-CAS＊各種手続き＊ |url=http://www.b-cas.co.jp/ |accessdate=2007-09-01 |language=Japanese]
# One HDTV or up to three SDTV services within one channel.
# Interactive services such as games or shopping, via telephone line or broadband internet.
# EPG (Electronic Program Guide)
# Ability to send firmware patches for the TV/tuner over the air.
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, ARIBdeveloped the ISDB-S standards. 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 bit stream 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 develop 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!, 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.
Summary of ISDB-S (Satellite digital broadcasting)
Countries and territories using ISDB-T
Digital terrestrial television
Digital audio broadcasting
* SDTV, EDTV, HDTV
SBTVD- Brazilian Digital Television System based on ISDB-T
New Tokyo Tower- ISDB-T broadcasting for Kanto Plain
ATSC Standards- Advanced Television Systems Committee Standard
DMB-T- Digital Multimedia Broadcast-Terrestrial
DVB-T- Digital Video Broadcasting-Terrestrial
* SFN, multi-frequency network
* [http://www.dibeg.org DiBEG - Digital Broadcasting Experts Group]
* [http://www.nhk.or.jp/strl/open99/de-2/shosai-e.html Technical explanation by NHK]
* [http://www.dibeg.org/PressR/BrazilSET2007/mobility_Portability.pdf ISDB-T & ISDB-Tmm] (Terrestrial mobile multi-media)
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