DVB

Digital Video Broadcasting 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 of the European Telecommunications Standards Institute, European Committee for Electrotechnical Standardization and European Broadcasting Union.

Transmission

DVB systems distribute data using a variety of approaches, including:

Satellite: DVB-S, DVB-DSNG, DVB-S2, DVB-S2X and DVB-SH
* DVB-SMATV for distribution via SMATV
Cable: DVB-C, DVB-C2
Terrestrial television: DVB-T, DVB-T2
* Digital terrestrial television for handhelds: DVB-H, DVB-SH
Microwave: using DTT, the MMDS, and/or MVDS standards

These standards define the physical layer and data link layer of the distribution system. Devices interact with the physical layer via a synchronous parallel interface, synchronous serial interface or asynchronous serial interface. All data is transmitted in MPEG transport streams with some additional constraints. A standard for temporally-compressed distribution to mobile devices was published in November 2004.
These distribution systems differ mainly in the modulation schemes used and error correcting codes used, due to the different technical constraints. DVB-S uses QPSK, 8-PSK or 16-QAM. DVB-S2 uses QPSK, 8-PSK, 16-APSK or 32-APSK, at the broadcasters decision. QPSK and 8-PSK are the only versions regularly used. DVB-C uses QAM: 16-QAM, 32-QAM, 64-QAM, 128-QAM or 256-QAM. Lastly, DVB-T uses 16-QAM or 64-QAM in combination with OFDM and can support hierarchical modulation.
The DVB-T2 specification was approved by the DVB Steering Board in June 2008 and sent to ETSI for adoption as a formal standard. ETSI adopted the standard on 9 September 2009. The DVB-T2 standard gives more robust TV reception and increases the possible bit rate by over 30% for single transmitters and will increase the maximum bit rate by over 50% in large single-frequency networks.
DVB has established a 3D TV group to identify "what kind of 3D-TV solution does the market want and need, and how can DVB play an active part in the creation of that solution?" The CM-3DTV group held a DVB 3D-TV Kick-off Workshop in Geneva on 25 January 2010, followed by the first CM-3DTV meeting the next day. DVB now defines a new standard for 3D video broadcast: DVB 3D-TV.
Modes and features of latest DVB-x2 system standards in comparison:

	DVB-S2	DVB-T2	DVB-C2
Input interface	Multiple transport stream and generic stream encapsulation	Multiple transport stream and generic stream encapsulation	Multiple transport stream and generic stream encapsulation
Modes	Variable coding & modulation and adaptive coding & modulation	Variable coding & modulation	Variable coding & modulation and adaptive coding & modulation
FEC	LDPC + BCH 1/4, 1/3, 2/5, 1/2, 3/5, 2/3, 3/4, 4/5, 5/6, 8/9, 9/10	LDPC + BCH 1/2, 3/5, 2/3, 3/4, 4/5, 5/6	LDPC + BCH 1/2, 2/3, 3/4, 4/5, 5/6, 8/9, 9/10
Modulation	Single carrier, PSK or APSK, multiple streams	OFDM	absolute OFDM
Modulation schemes	QPSK, 8-PSK, 16-APSK, 32-APSK	QPSK, 16-QAM, 64-QAM, 256-QAM	16- to 4096-QAM
Guard interval	Not applicable	1/4, 19/256, 1/8, 19/128, 1/16, 1/32, 1/128	1/64 or 1/128
Fourier transform size	Not applicable	1k, 2k, 4k, 8k, 16k, 32k DFT	4k Inverse FFT
Interleaving	Bit-Interleaving	Bit- time- and frequency-interleaving	Bit- time- and frequency-interleaving
Pilots	Pilot symbols	Scattered and continual pilots	Scattered and continual pilots

Content

content is encoded using discrete cosine transform based video coding standards, such as the H.26x and MPEG formats. Digital audio content is encoded using modified discrete cosine transform based audio coding standards, such as Advanced Audio Coding, Dolby Digital and MP3.
Besides digital audio and digital video transmission, DVB also defines data connections with return channels for several media and protocols.
Older technologies such as teletext and vertical blanking interval data are also supported by the standards to ease conversion. However, for many applications, more advanced alternatives like DVB-SUB for subtitling are available.

Encryption and metadata

The conditional access system defines a Common Scrambling Algorithm and a physical Common Interface for accessing scrambled content. DVB-CA providers develop their wholly proprietary conditional access systems with reference to these specifications. Multiple simultaneous CA systems can be assigned to a scrambled DVB program stream providing operational and commercial flexibility for the service provider.
The DVB Project developed a Content Protection and Copy Management system for protecting content after it has been received, which was intended to allow flexible use of recorded content on a home network or beyond, while preventing unconstrained sharing on the Internet. DVB-CPCM was the source of much controversy in the popular press and it was said that CPCM was the DVB Project's answer to the failed American Broadcast Flag. The DVB-CPCM specifications, which were standardized by ETSI as a multipart document between 2008 and 2013, were deprecated by the DVB Steering Board in February 2019.
DVB transports include metadata called Service Information that links the various elementary streams into coherent programs and provides human-readable descriptions for electronic program guides as well as for automatic searching and filtering. The dating system used with this metadata suffers from a year 2038 problem in which due to the limited 16 bits and modified Julian day offset used will cause an overflow issue similar to the year 2000 problem. By comparison, the rival DigiCipher 2 based ATSC system will not have this issue until 2048, due in part to 32 bits being used.
DVB adopted a profile of the metadata defined by the TV-Anytime Forum. This is an XML Schema based technology and the DVB profile is tailored for enhanced Personal Digital Recorders.
In the early 2000s, DVB started an activity to develop specifications for IPTV, which also included metadata definitions for a broadband content guide.

DVB-I

In October 2017, the DVB Project established a working group to begin the definition of a specification for "standalone TV services over IP, referred to as DVB-I services". Work on the commercial requirements for DVB-I began in January 2018 and the terms of reference were agreed in March 2018.
The DVB-I specification, titled "Service Discovery and Programme Metadata for DVB-I", was approved by the DVB Project in November 2019
and first published as DVB BlueBook A177 in June 2020 and as an ETSI standard TS 103 770 in November 2020.
The DVB-I specification defines ways in which devices and displays connected to the internet can discover and access sets of audiovisual media services. These can include services delivered online through fixed and wireless Internet Protocol connections as well as broadcast radio and television channels received over radio frequency networks using traditional cable, satellite, or terrestrial transmissions.
Tests and pilots of DVB-I services have been undertaken in several countries including Iran, Germany, Italy, Spain and Ireland.

Software platform

The DVB Multimedia Home Platform defines a Java-based platform for the development of consumer video system applications. In addition to providing abstractions for many DVB and MPEG-2 concepts, it provides interfaces for other features like network card control, application download, and layered graphics.

Return channel

DVB has standardized a number of return channels that work together with DVB to create bi-directional communication. RCS is short for Return Channel Satellite, and specifies return channels in C, K_u and K_a frequency bands with return bandwidth of up to 2 Mbit/s. DVB-RCT is short for Return Channel Terrestrial, specified by ETSI EN 301958.

Service discovery

The DVB-I standard defines an internet-based request and response mechanism to discover and access audiovisual services delivered over traditional digital broadcast transmissions or Internet Protocol networks and present them in a unified way.

Adoption

DVB-S and DVB-C were ratified in 1994. DVB-T was ratified in early 1997. The first commercial DVB-T broadcasts were performed by the United Kingdom's Digital TV Group in late 1998. In 2003 Berlin, Germany was the first area to completely stop broadcasting analogue TV signals. Most European countries are fully covered by digital television and many have switched off PAL/SECAM services.
DVB standards are used throughout Europe, as well as in Australia, South Africa and India. They are also used for cable and satellite broadcasting in most Asian, African and many South American countries. Some have chosen ISDB-T instead of DVB-T and a few have chosen ATSC instead of DVB-T.

Africa

Kenya

DVB-T broadcasts were launched by the President of Kenya, Mwai Kibaki on 9 December 2009. Broadcasts are using H.264, with the University of Nairobi supplying the decoders. Kenya has also been broadcasting DVB-H since July 2009, available on selected Nokia and ZTE handsets on the Safaricom and other GSM networks.

Madagascar

Since 2011, the pay TV operator Blueline launched a DVB-T service branded BluelineTV. It supplies both smart cards and set-top-boxes.

South Africa

Since 1995, the pay TV operator DStv used the DVB-S standard to broadcast its services. In 2010, it started a DVB over IP service, and in 2011 it started DStv mobile using the DVB-H standard.
In late 2010, the South African cabinet endorsed a decision by a Southern African Development Community task team to adopt the DVB-T2 standard.