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| Digital multimedia broadcasting | |
| Hangul | 디지털 멀티미디어 방송 |
|---|---|
| Hanja | 디지털 멀티미디어 放送 |
| Revised Romanization | Dijiteol Meoltimidieo Bangsong |
| McCune–Reischauer | Tijit'ŏl Mŏltimidiŏ Pangsong |
| List ofdigital television broadcast standards |
|---|
| DVB standards(countries) |
| ATSC standards(countries) |
|
| ISDB standards(countries) |
| DTMB standards(countries) |
| DMB standard(countries) |
| Codecs |
|
| TerrestrialFrequency bands |
| SatelliteFrequency bands |
Digital multimedia broadcasting (DMB) is a digitalradio transmissiontechnology developed inSouth Korea[1][2][3] as part of the nationalIT project for sending multimedia such asTV,radio anddatacasting tomobile devices such as mobile phones, laptops and GPS navigation systems. Thistechnology, sometimes known asmobile TV, should not be confused withDigital Audio Broadcasting (DAB) which was developed as a research project for theEuropean Union.
DMB was developed in South Korea as the next generation digital technology to replaceFM radio,[4] but the technological foundations were laid by Prof. Dr. Gert Siegle and Dr. Hamed Amor atBosch in Germany.[5] The world's first official mobile TV service started in South Korea in May 2005, although trials were available much earlier. It can operate viasatellite (S-DMB) or terrestrial (T-DMB) transmission. DMB has also some similarities with its former competing mobile TV standard,DVB-H.[6]
T-DMB is made for terrestrial transmissions on band III (VHF) andL (UHF) frequencies. DMB is unavailable in the United States because those frequencies areallocated for television broadcasting (VHF channels 7 to 13) and military applications. USA is adoptingATSC-M/H for free broadcasts to mobiles, and for a time,Qualcomm's proprietaryMediaFLO system. In Japan,1seg is the standard, usingISDB.
T-DMB usesMPEG-4 Part 10 (H.264) for the video andMPEG-4 Part 3 BSAC orHE-AAC v2 for the audio. The audio and video is encapsulated in anMPEG transport stream (MPEG-TS). The stream is forward error corrected byReed Solomon encoding and the parity word is 16 bytes long. There isconvolutionalinterleaving made on this stream, then the stream is broadcast in data stream mode onDAB. In order to diminish the channel effects such as fading and shadowing, the DMB modem usesOFDM-DQPSK modulation. A single-chip T-DMB receiver is also provided by anMPEG transport streamdemultiplexer. DMB has several applicable devices such as mobile phone, portable TV, PDA andtelematics devices for automobiles.
T-DMB is an [ETSI] standard (TS 102 427 and TS 102 428). As of December 14, 2007,ITU formally approved T-DMB as the global standard, along with three other standards, like DVB-H, 1seg, and MediaFLO.[7]
Smart DMB started in January 2013 in South Korea. Smart DMB has a VOD service and quality has been improved from 240p to 480p. Smart DMB is built in many Korean smartphones starting with the Galaxy Grand in January 2013.[8]
HD DMB started in August 2016 in South Korea. HD DMB has been improved from 240p to 720p. It uses HEVC.5 codec. There are currently[when?] 6 HD DMB stations in Seoul. Smartphones integrated Qualcomm Snapdragon 801 or higher received firmware upgrade to support HD DMB.
Currently, DMB is being put into use in a number of countries, although mainly used in South Korea. Also see list ofCountries using DAB/DMB.
In 2005,South Korea became the world's first country to start S-DMB and T-DMB service on May 1 and December 1, respectively.[9][10] In December 2006, T-DMB service in South Korea consists of, 7 TV channels, 12 radio channels, and 8 data channels. These are broadcast on sixmultiplexes in the VHF band on TV channels 8 and 12 (6 MHz raster). In October 2007, South Korea added broadcasting channel MBCNET to the DMB channel. But in 2010, this channel changed tnN go. In 2009 there were eight DMB video channels in Seoul, and six in other metropolitan cities. As of April 2013, S-DMB service in South Korea consists of 15 TV channels, 2 radio channels and 6 data channels.[11]
South Korea has had Full T-DMB services including JSS (Jpeg Slide Show), DLS (Dynamic Label Segment),BWS, andTPEG since 2006.
S-DMB service in South Korea is provided on asubscription basis throughTU Media and is accessible throughout the country. T-DMB service is provided free of charge, but access is limited to selected regions.
Around one million receivers have been sold as of June 2006[update]. 14 million DMB receivers were sold including T-DMB and S-DMB in South Korea, and 40% of the new cell phones have the capability to see DMB.[12]
Receivers are integrated in carnavigation systems, mobile phones,portable media players, laptop computers and digital cameras. In mid-August 2007,Iriver, a multimedia and micro-technology company released their "NV", which utilizes South Korea's DMB service.
Since the advent ofsmartphones DMBs have been made available on phones with receivers throughsmartphone applications, most of which come pre-installed in phones made and sold in South Korea.
 | This article needs to beupdated. The reason given is: DMB outside Korea and DVB-H are dead; and in all other standards, there's been heavy movement in since 2008, which seems to be the state of the section.. Please help update this article to reflect recent events or newly available information.(August 2024) |
Some T-DMBtrials are currently available or planned aroundEurope and other countries:
T-DMB works flawlessly in vehicles traveling up to 300 km/h.[citation needed] In tunnels or underground areas, both television and radio broadcast is still available, though DMB may skip occasionally. In South Korea, some long-distance buses adopted T-DMB instead of satellite TV such as Sky TV. It works quite well even though the resolution is 240p, lower than satellite. In comparison, satellite is usually 480p or higher.[citation needed]
