China Mobile Multimedia Broadcasting (CMMB) is a mobile television and multimedia standard developed and specified in
China
China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...
by the
State Administration of Radio, Film, and Television
The National Radio and Television Administration (NRTA) is a ministry-level executive agency controlled by the Propaganda Department of the Chinese Communist Party (CCP). Its main task is the administration and supervision of state-owned enterp ...
(SARFT).
It is based on the
(STiMi), developed by TiMiTech, a company formed by the Chinese Academy of Broadcasting Science.
Announced in October 2006,
it has been described as being similar to Europe's
DVB-SH
DVB-SH ("Digital Video Broadcasting - Satellite services to Handhelds") is a physical layer standard for delivering IP based media content and data to handheld terminals such as mobile phones or PDAs, based on a hybrid satellite/terrestrial dow ...
standard for digital video broadcast from both
satellite
A satellite or artificial satellite is an object intentionally placed into orbit in outer space. Except for passive satellites, most satellites have an electricity generation system for equipment on board, such as solar panels or radioisotope ...
s and terrestrial repeaters to handheld devices.
It specifies usage of the S-band/U-band and occupies 25 MHz bandwidth within which it provides 25 video and 30 radio channels with some additional data channels.
Multiple companies have chips that support CMMB standard - Innofidei who was the first with a solution 28 March 2007.
Other manufacturers, such as Unique Broadband Systems, were quick to enter the race and grab a share of the handheld broadcasting market with thei
hardware platformsupporting both CMMB and DTMB (as well as others) standard waveforms.
RF Details
CMMB uses frequencies in the range 2635 - 2660 MHz (S-band) for satellite and "gap-filler" terrestrial broadcast, with additional terrestrial broadcast in the UHF band 470 – 862 MHz.
The channel bandwidth can be either 2 or 8 MHz, depending on data rate.
Coverage
China Satellite Mobile Broadcasting Corporation (CSMBC), as of 2 June 2010, had completed CMMB network coverage in 317
prefecture-level cities
A prefecture-level city () or prefectural city is an administrative division of the People's Republic of China (PRC), ranking below a province and above a county in China's administrative structure.
During the Republican era, many of China' ...
.
Versus DTMB
* The CMMB is not a Chinese national standard (GB), but the DTMB is
GB 20600-2006.
* The CMMB uses
QCIF CIF (''Common Intermediate Format'' or ''Common Interchange Format''), also known as FCIF (''Full Common Intermediate Format''), is a standardized format for the picture resolution, frame rate, color space, and color subsampling of digital video s ...
or
QVGA
The graphics display resolution is the width and height dimension of an electronic visual display device, measured in pixels. This information is used for electronic devices such as a computer monitor. Certain combinations of width and height ar ...
, so can not broadcast the HDTV (1080i/1080p), but the DTMB can.
* The CMMB is intended for use on small screen devices (such as GPS, PDA, or smartphone...) in a mobile scenario, while DTMB is intended for use on large screen devices (such as PC, LCD TV, PDP TV...) in a fixed scenario.
See also
*
DTMB
DTMB (Digital Terrestrial Multimedia Broadcast) is the digital TV standard for mobile and fixed devices, developed in the People's Republic of China. It is used there and in both of their special administrative regions (Hong Kong and Macau), and ...
*
Digital Multimedia Broadcasting
*
DVB
Digital Video Broadcasting (DVB) is a set of international open standards for digital television. DVB standards are maintained by the DVB Project, an international industry consortium, and are published by a Joint Technical Committee (JTC) o ...
(Digital Video Broadcasting)
*
DVB-T
DVB-T, short for Digital Video Broadcasting – Terrestrial, is the DVB European-based consortium standard for the broadcast transmission of digital terrestrial television that was first published in 1997 and first broadcast in Singapore in Febr ...
(Digital Video Broadcasting - Terrestrial)
*
DVB-H
DVB-H (Digital Video Broadcasting - Handheld) is one of three prevalent mobile TV formats. It is a technical specification for bringing broadcast services to mobile handsets. DVB-H was formally adopted as ETSI standard EN 302 304 in November 20 ...
(Digital Video Broadcasting - Handheld)
*
International standard
international standard is a technical standard developed by one or more international standards organizations. International standards are available for consideration and use worldwide. The most prominent such organization is the International Or ...
References
External links
IEEE Spectrum Article*https://archive.today/20130116033332/http://www.cbc.cn/ (Chinese)
Unique Broadband Systems
{{Authority control
Digital television
Chinese inventions
2006 introductions
2006 establishments in China