Glossary
A
- AAC
-
Advanced Audio Coding
HE-AAC v2, a version of AAC, is used for both DAB+ and DMB.
- AAC+
-
Used as a synonym for HE-AAC v2
- aacPlus
-
Used as a synonym for HE-AAC v2
- AIC
-
Auxiliary Information Channel
Part of the Main Service Channel (MSC) used to carry data which cannot be accommodated in the Fast Information Channel (FIC).
- ASF
-
Advanced Systems Format
Advanced Systems Format (formerly Advanced Streaming Format, Active Streaming Format) is Microsoft's proprietary digital audio/digital video container format, especially meant for streaming media.
ASF Specification
B
- Band III
-
Frequency band between 174 and 230 MHz of the VHF range, used for DAB services (formerly used for analogue television).
- BIFS
-
Binary Format for Scenes
Scene description language of MPEG-4, designed for representing, delivering and rendering interactive and streamable rich-media services (including audio, video, 2D & 3D graphics).
- BSAC
-
Bit Sliced Arithmetic Coding
Part of the MPEG-4 standard (ISO/IEC 14496-3 subpart 4) for scalable audio coding. It uses a noiseless coding alternative to AAC, with the rest of the processing being identical to AAC. BSAC is one of the two audio codecs used for DMB, the other is HE-AAC v2.
- BWS
-
Broadcast Website
Allows a service provider to deliver HTML content via DAB without the need for a return channel.
C
- CA
-
Conditional Access
Mechanism by which the user access to service components can be restricted.
- CIF
-
Common Interleaved Frames
serial digital output from the main service multiplexer which is contained in the Main Service Channel part of the transmission frame.
- COFDM
-
Coded Orthogonal Frequency Division Multiplex
Synonym: OFDM
Modulation method (division into small units, chronological nesting, transmission on various carrier frequencies). COFDM is used in DAB, DAB+ and DMB.
- Convolutional Coding
-
Coding procedure which generates redundancy in the transmitted data stream in order to provide ruggedness against transmission distortions.
- CRC
-
Cyclic Redundancy Check
A type of function that takes as input a data stream of any length and produces as output a value of a certain fixed size. Can be used as a checksum to detect accidental alteration of data during transmission or storage.
- CU
-
Capacity Unit
Smallest addressable unit of the Common Interleaved Frames (CIF), comprising of 64 bits. The CIF contains 864 CUs, and the MSC is made up of 1 to 4 CIFs, depending on the Transmission Mode.
D
- DAB
-
Digital Audio Broadcasting
Method for the digital transmission of radio signals for mobile reception, developed by EUREKA project 147.
- DAB+
-
Additional audio codec for 'Digital Audio Broadcasting', based on the new audio coding technology HE-AAC v2 (also known as AAC+ or MPEG-4). DAB+ is backwards compatible to the current DAB standard. DAB, DAB+ and DMB are all part of the Eureka-147 family of standards.
- DAB+ upgradeable
-
A DAB receiver is called DAB+ upgradeable if it can be upgraded via USB to a DAB+ receiver.
- DLS
-
Dynamic Label Segment
Supplementary data services in text form (up to 128 characters) running alongside the DAB or DAB+ radio programme. Similar to RDS on FM radio.
- DMB
-
Digital Multimedia Broadcasting
Synonym: T-DMB
Method for the digital transmission of multimedia signals (especially video services) for mobile reception. DMB is part of the same family of standards as DAB and DAB+.
- DQPSK
-
Differential Quadrature Phase-Shift Keying
Digital phase modulation scheme that conveys data by changing or modulating the phase of the carrier wave. DQPSK is used in DAB, DAB+ and DMB.
- DRC
-
Dynamic Range Control
With help of the Dynamic Range Control (DRC) the receiver may reduce the dynamic range of the audio signal. The purpose of this is to adapt the dynamic range of the audio signal to listening in a noisy environment.
- DRM
-
Digital Radio Mondiale
Method for the digital transmission of VHF radio signals (AM), developed by the DRM consortium.
E
- Ensemble
-
Entity of programme and data services (usually about 9 to 12 DAB programmes or about 18 to 32 DAB+ programmes) with a fixed total capacity which is processed and transmitted.
The DAB multiplex data stream has a maximum capacity of 2.25 Mbit/s, normally shared by a number of services (radio / data). The name multiplex relates to the fact that the individual data streams are multiplexed (that is, they are transmitted alternately in chunks). A multiplex needs a bandwidth of about 1.5 MHz on the frequency band. - EPG
-
Electronic Programme Guide
Synonym: SPI
An Electronic Programme Guide is an on-screen guide to scheduled radio or television programmes, allowing a viewer/listener to navigate, select, discover and record content by time, title, channel, genre, etc.
- ES
-
Elementary Stream
Consecutive flow of compressed mono-media data, i.e. one of the coded audio, coded video or other coded bitstreams.
- ETSI
-
European Telecommunications Standards Institute
The European Telecommunications Standards Institute is an independent, non-profit, standardization organization of the telecommunications industry (equipment makers and network operators) in Europe, with worldwide projection.
Official Website - ETSI EN
-
ETSI European Norm
Part of ETSI document name, e.g. EN 300 401
- ETSI TS
-
ETSI Technical Specification
Part of ETSI document name, e.g. ETSI TS 102 428
- EUREKA
-
Initiative for application-oriented research in Europe: framework for cross-border cooperative ventures in the fields of industry and science.
F
- F-PAD
-
Fixed Programme Associated Data
Part of the capacity allocated for supplementary programme data (see article on PAD). Two bytes at the end of each DAB audio frame are reserved for F-PAD.
- FEC
-
Forward Error Correction
Forward Error Correction, in the form of Reed-Solomon (RS) outer error protection and outer interleaving, can be applied to sub-channels carrying service components in packet mode in order to further increase the error robustness of DAB data delivery.
- FIB
-
Fast Information Block
The FIB contains 256 bits and comprises an FIB data field and a CRC. The FIB data field consists of one or more Fast Information Group (FIG).
- FIC
-
Fast Information Channel
The FIC is a non-time-interleaved data channel with fixed equal error protection. In particular it is used to send the DAB Multiplex Configuration Information (MCI) and optionally Service Information and data services.
- FIG
-
Fast Information Group
The FIG carries the following parts: Multiplex Configuration Information (MCI), Service Information (SI), FIC Data Channel (FIDC) and Conditional Access (CA).
H
- H.264
-
Synonym for MPEG-4 Part 10
- HE-AAC v2
-
High Efficiency Advanced Audio Coding version 2
Synonyms: AAC+, MP4, MPEG-4, aacPlus
High Efficiency AAC (HE-AAC) is a lossy data compression scheme for digital audio. It is an extension of Low Complexity AAC (AAC LC) optimized for low-bitrate applications such as streaming audio. HE-AAC version 1 (HE-AAC v1) uses Spectral Band Replication (SBR) to enhance the compression efficiency in the frequency domain. HE-AAC version 2 (HE-AAC v2) couples SBR with Parametric Stereo (PS) to enhance the compression efficiency of stereo signals.
I
- ITU
-
International Telecommunication Union
ITU is the United Nations agency for information and communication technologies.
Official Website
J
- Joint Stereo
-
Audio mode in which two channels forming a stereo pair (left and right) are encoded within one bit stream and for which stereophonic irrelevance or redundancy is exploited for further bit reduction.
L
- L Band
-
Frequency band between 1 and 2,6 GHz of the UHF range, used for local DAB/DMB services.
- LSF
-
Low Sampling Frequency
Low bitrate encoding with halved sampling rate.
M
- M/S
-
Music/Speech indication
A two-bit flag which indicates whether the transmitted sound consists of music or speech. The receiver may use this information to balance the loudness of different types of programme according to the listener taste.
- MCI
-
Multiplex Configuration Information
The MCI lists all services that are available in a DAB ensemble, and defines how they are organised into sub-channels and service components.
- MOT
-
Multimedia Object Transfer
MOT (EN 301 234) is the transmission protocol used in DAB for transferring file oriented data in DAB audio or data channels. It is tailored to the needs of multimedia services and the specific constraints given by the broadcasting characteristics of the DAB system. It supports two different transport modes, MOT header mode and MOT directory mode.
- MOT Directory
-
Multimedia Object Transfer Directory
MOT Directory can be used if file system structures with multiple files are broadcast as a data carousel, like in the Broadcast Website (BWS) application.
- MOT Header
-
Multimedia Object Transfer Header
MOT header mode is used if there is just one MOT object valid at any time (e.g. in the Slide Show application, where a new slide is received, processed, displayed and discarded).
- MP2
-
Used as a synonym for MPEG Audio Layer II
- MP4
-
Used as a synonym for HE-AAC v2
- MPEG Audio Layer II
-
Synonyms: MP2, MPEG-1 Layer II, MUSICAM
MPEG Audio Layer II is an audio codec defined by ISO/IEC 11172-3. It is a dominant encoding standard for audio broadcasting as part of the DAB digital radio and DVB digital television standards, and it is the core of the better known MP3 standard.
- MPEG-1 Layer II
-
Used as a synonym for MPEG Audio Layer II
- MPEG-4
-
Used as a synonym for HE-AAC v2
- MPEG-4 AVC
-
Used as a synonym for MPEG-4 Part 10
- MPEG-4 Part 10
-
Synonyms: H.264, MPEG-4 AVC
Standard for video compression used in DMB. The two standard documents for MPEG-4 AVC (ISO/IEC 14496-10) and H.264 (ITU-T H.264 standard) are jointly maintained so that they have identical technical content.
- MSC
-
Main Service Channel
The MSC is a time-interleaved data channel divided into a number of sub-channels which are individually convolutionally coded, with equal or unequal error protection. Each sub-channel may carry one or more service components. used to carry audio and data service components.
- Multiplex
-
Output of a multiplexer (often used as a synonym for ensemble).
- Multiplexer
-
Synonym: MUX
Multiplexer: Device that performs multiplexing by selecting one of many analog or digital data sources and outputting that source into a single channel.
- MUSICAM
-
Masking Pattern Adapted Universal Subband Integrated Coding And Multiplexing
Used as a synonym for MPEG Audio Layer II
- MUX
-
Used as a synonym for Multiplexer
N
O
P
- Packet Mode
-
Mode of data transmission in which data are carried in addressable blocks called packets. The packet structure supports multiplexing of various service components in one sub-channel; a sequence of packets is conveyed in a sub-channel.
- PAD
-
Programme Associated Data
Data services provided as supplementary information to a radio programme, such as Dynamic Label Segment (DLS) and Multimedia Object Transfer (MOT). Each DAB audio frame contains a number of bytes specifically for carrying Programme Associated Data (PAD). At the end of the DAB audio frame, a capacity of at least two bytes, called Fixed Programme Associated Data (F-PAD), is provided, irrespective of the sampling frequency, bit rate or the audio mode (i.e. single channel, stereo and dual channel modes will all have the same capacity of F-PAD). But the broadcaster may choose to extend this capacity, called Extended Programme Associated Data (X-PAD) in order to transmit more audio related data.
- PES
-
Packetized Elementary Stream
Packetized audio, video or data elementary stream (ES) to be fed into the transport stream (TS) multiplexer.
- Protection Level
-
Level specifying the degree of protection against transmission errors provided by convolution coding.
- PS
-
Parametric Stereo
Feature used in HE-AAC v2 to further enhance efficiency in low bandwidth stereo media. It performs sparse coding in the spatial domain, somewhat similar to what SBR does in the frequency domain. An HE-AAC v2 bitstream is obtained by downmixing the stereo audio to mono at the encoder along with 2-3 kbit/s of side info (the Parametric Stereo information) in order to describe the spatial intensity stereo generation and ambience regeneration at the decoder. By having the Parametric Stereo side info along with the mono audio stream, the decoder (player) can regenerate a faithful spatial approximation of the original stereo panorama at very low bitrates.
- PTy
-
Programme Type
Feature allowing programme contents to be categorized according to their intended audience.
R
- RDS
-
Radio Data System
Transmission of additional text data via FM broadcast.
- RS
-
Reed-Solomon
Error-correcting code that works by oversampling a polynomial constructed from the data. The polynomial is evaluated at several points, and these values are sent or recorded. By sampling the polynomial more often than is necessary, the polynomial is over-determined. As long as "many" of the points are received correctly, the receiver can recover the original polynomial even in the presence of a "few" bad points. Reed-Solomon error correction is used in DAB+ and DMB.
S
- SBR
-
Spectral Band Replication
Technology to enhance audio or speech codecs, especially at low bit rates and is based on harmonic redundancy in the frequency domain. SBR replicates higher frequency content by transposing up harmonics from the lower and mid-frequencies at the decoder.
- Service Following
-
Synonym for Service Linking
- Service Linking
-
Allows cross-referencing to other modes of reception of the same programme, such as FM, DRM, AM and other DAB ensembles. Receivers allowing this function will automatically switch to other modes of reception if the current one becomes unavailable (e.g. when leaving the coverage area). Synonym: Service Following
- SFN
-
Single Frequency Network
Network of DAB transmitters sharing the same radio frequency to achieve a large area coverage.
- SI
-
Service Information
The SI provides supplementary information about audio and data services, which is not included in the Multiplex Configuration Information (MCI). The Service Information (SI) features which may be carried in the FIC include the following: service component language, service linking, date and time, Programme Number, Programme Type (PTy), announcements, regional identification, other ensembles, FM and AM services information, frequency information, transmitter identification information, ensemble, service and service component labels, etc.
- SL
-
Synchronization Layer
Provides timing and synchronization information between elementary stream components in a transport stream (TS).
- SPI
-
Service Programme Information
SPI is an application formerly known as electronic programme guide (EPG), but goes beyond a mere programme guide. Services provide daily broadcast schedules with detailed information about every programme event, start and end times, event names, genre and descriptions. Service information provides service names, identification, frequencies and multimedia (station logo). On-air SPI services can be complemented by online resources using hybrid (RadioDNS) functionality
- SRT
-
Secure Reliable Transport
Secure Reliable Transport (SRT) is an open-source low-latency live video transport protocol.
- Stream Mode
-
Mode of data transmission allowing one service component per sub-channel to be transmitted transparently at a fixed bit rate.
- Synchronization Channel
-
Used internally within the DAB transmission system for basic demodulator functions, such as transmission frame synchronization, automatic frequency control, channel state estimation, and transmitter identification.
T
- T-DMB
-
Terrestrial Digital Multimedia Broadcasting
Used as a synonym for DMB
- TMC
-
Traffic Message Channel
Channel for traffic information.
- TPEG
-
Transport Protocol Experts Group
The group of experts that developed a standard (of the same name) for transmitting traffic information via digital systems such as DAB and DVB.
- Transmission Frame
-
Each transmission frame in the DAB transmission system combines three channels: Synchronization Channel, Fast Information Channel (FIC) and Main Service Channel (MSC).
- Transmission Mode
-
There are 4 different transmission modes defined in DAB: Transmission mode I (intended for SFN in Bands I, II and III), transmission mode II (intended for local services in Bands I, II, III, IV, V and L-band), transmission mode III (intended for frequencies below 3 GHz and cable) and transmission mode IV (intended for local services in Bands I, II, III, IV, V and L-band).
- TS
-
Transport Stream
Communications protocol for audio, video, and data. Allows multiplexing of digital video and audio and synchronisation of the output, and offers features for error correction for transportation over unreliable media.
U
- UHF
-
Ultra high frequency
Range of electromagnetic waves whose frequency is between 300 MHz and 3 GHz (3,000 MHz). Also known as the decimeter band or decimeter wave as the wavelengths range from ten to one decimeters.
V
- VHF
-
Very High Frequency
Radio frequency range from 30 MHz to 300 MHz, also known as the meter band or meter wave as the wavelengths range from ten to one meters.
W
- World DMB Forum
-
Used as a synonym for WorldDMB
- WorldDAB
-
Former name of WorldDMB
- WorldDMB
-
Synonym: World DMB Forum
The WorldDMB Forum is an international non-governmental organisation whose objective is to promote, harmonise and co-ordinate the implementation of DAB Digital services based on the Eureka 147 DAB system. It is dedicated to encouraging international co-operation and co-ordination between sound and data broadcasters, network providers, manufacturers, governments and official bodies, thus gaining consensus for the smooth introduction of DAB based services.