IP audio codec
Encyclopedia
IP audio codecs are used to send broadcast quality audio over IP
from remote locations to radio and television studios around the globe. IP codecs are ideal for use in remote broadcast
s, as studio/transmitter link
s (STLs) or for studio-to-studio audio distribution.
IP audio codecs use audio compression
algorithm
s to send high fidelity audio over both wired broadband
IP
networks and wireless 3G
, 3.5G and 4G
broadband networks.
Audio-over-IP has proved itself to be the broadcast network infrastructure of the future, and as a consequence, increasing numbers of broadcasters are migrating to low-cost wired and wireless IP
networks instead of older and more costly fixed line technologies such as ISDN, X.21
and POTS
/PSTN. ISDN and POTS/PSTN leased lines are also being phased out in Europe and Australia, increasing the push into IP technologies for audio broadcasting.
IP networks are more flexible, cheaper to upgrade and just as reliable as older network technologies. As a result, broadcasters using IP codecs are able to design and operate more adaptable audio networks with streamlined workflows and reduced operating costs.
Technology is one company focused on both wired and wireless broadband IP codec solutions. The latest IP
audio codecs can send broadcast audio over stereo unicast
, multicast
and multiple unicast connections. Using multicast and multiple unicast connections, audio can be sent over IP networks from one IP audio codec to several destination audio codecs.
IP codecs generally use session initiation protocol
in order to connect to a variety of different codecs designed by different manufacturers.
Another example would be APT Codecs who provide IP Audio Codecs for use in professional studio transmitter links (STLs) and studio networking. IP STLs and Studio-to-Studio Links are absolutely vital for broadcasters. Traditionally these links have been implemented with synchronous (Tx, Rx and Clock) data circuits. For wired circuits, broadcasters usually contract Telephone Companies to provide fixed bandwidth T1, E1 or X.21 / V.35 terminated circuits (or the Telco transports the audio for the radio station using synchronous networks as the preferred carrier).
While this arrangement has worked well for many years, it requires broadcasters to allocate considerable amounts from their budget for the ongoing operational costs of the Telco services. With the advent of IP technology, broadcasters have been looking at minimizing these operational costs by replacing their existing synchronous networks with packetized ones.
However, as a transport mechanism, IP presents a number of challenges that need to be addressed by the Chief Engineer before migrating away from synchronous networks. These issues are not insurmountable, and, if correctly and intelligently implemented; the use of IP will greatly assist a radio station’s efficiency.
Primary issues of concern for a Chief Engineer are as follows:
•Latency
•Lost Packets
•Packet Size
•UDP versus TCP
•Jitter
•Error Correction / Concealment
•Clock Skew
•Audio Algorithms
•IPv6
Compatibility
IP as a transport mechanism for broadcasters is here to stay because it allows Radio broadcast networks to bundle their audio with data, reduce operational costs and amalgamate IT and audio into a single resource. However, these massive and well-defined advantages come with some safety warnings - networks should be well managed, packets should be prioritized and correct choices should be made with regard to audio compression. Assuming all these boxes are ticked, then broadcasters will enjoy the benefits of the transition away from synchronous networks without running into serious problems
Audio over IP
Streaming audio over IP networks is being increasingly used by broadcasting companies, among others, to provide high-quality audio feeds over distance across an IP network such as the Internet. The application is also known as audio contribution over IP in reference to the programming...
from remote locations to radio and television studios around the globe. IP codecs are ideal for use in remote broadcast
Remote broadcast
In broadcast engineering, a remote broadcast is broadcasting done from a location away from a formal television studio and is considered an electronic field production . A remote pickup unit is usually used to transmit the audio and/or video back to the television station, where it joins the...
s, as studio/transmitter link
Studio/transmitter link
A studio-transmitter link sends a radio station's or television station's audio and video from the broadcast studio to a radio transmitter or television transmitter in another location....
s (STLs) or for studio-to-studio audio distribution.
IP audio codecs use audio compression
Audio compression
Audio compression may refer to:*Audio compression , a type of lossy compression in which the amount of data in a recorded waveform is reduced for transmission with some loss of quality, used in CD and MP3 encoding, Internet radio, and the like...
algorithm
Algorithm
In mathematics and computer science, an algorithm is an effective method expressed as a finite list of well-defined instructions for calculating a function. Algorithms are used for calculation, data processing, and automated reasoning...
s to send high fidelity audio over both wired broadband
Broadband
The term broadband refers to a telecommunications signal or device of greater bandwidth, in some sense, than another standard or usual signal or device . Different criteria for "broad" have been applied in different contexts and at different times...
IP
Internet Protocol
The Internet Protocol is the principal communications protocol used for relaying datagrams across an internetwork using the Internet Protocol Suite...
networks and wireless 3G
3G
3G or 3rd generation mobile telecommunications is a generation of standards for mobile phones and mobile telecommunication services fulfilling the International Mobile Telecommunications-2000 specifications by the International Telecommunication Union...
, 3.5G and 4G
4G
In telecommunications, 4G is the fourth generation of cellular wireless standards. It is a successor to the 3G and 2G families of standards. In 2009, the ITU-R organization specified the IMT-Advanced requirements for 4G standards, setting peak speed requirements for 4G service at 100 Mbit/s...
broadband networks.
Audio-over-IP has proved itself to be the broadcast network infrastructure of the future, and as a consequence, increasing numbers of broadcasters are migrating to low-cost wired and wireless IP
Internet Protocol
The Internet Protocol is the principal communications protocol used for relaying datagrams across an internetwork using the Internet Protocol Suite...
networks instead of older and more costly fixed line technologies such as ISDN, X.21
X.21
X.21 is an interface specification for differential communications introduced in the mid 1970s by the ITU-T. X.21 was first introduced as a means to provide a digital signaling interface for telecommunications between carriers and customers' equipment...
and POTS
Plain old telephone service
Plain old telephone service is the voice-grade telephone service that remains the basic form of residential and small business service connection to the telephone network in many parts of the world....
/PSTN. ISDN and POTS/PSTN leased lines are also being phased out in Europe and Australia, increasing the push into IP technologies for audio broadcasting.
IP networks are more flexible, cheaper to upgrade and just as reliable as older network technologies. As a result, broadcasters using IP codecs are able to design and operate more adaptable audio networks with streamlined workflows and reduced operating costs.
Examples of Use
TielineTieline
Tieline Technology has offices in Indianapolis in the USA and in Perth, Western Australia . The company has a wide and established distribution network throughout Europe, the Americas and Australasia. Tieline develops a range of broadcast audio codecs that are sold to television and radio networks...
Technology is one company focused on both wired and wireless broadband IP codec solutions. The latest IP
Internet Protocol
The Internet Protocol is the principal communications protocol used for relaying datagrams across an internetwork using the Internet Protocol Suite...
audio codecs can send broadcast audio over stereo unicast
Unicast
right|200pxIn computer networking, unicast transmission is the sending of messages to a single network destination identified by a unique address.-Addressing methodologies:...
, multicast
Multicast
In computer networking, multicast is the delivery of a message or information to a group of destination computers simultaneously in a single transmission from the source creating copies automatically in other network elements, such as routers, only when the topology of the network requires...
and multiple unicast connections. Using multicast and multiple unicast connections, audio can be sent over IP networks from one IP audio codec to several destination audio codecs.
IP codecs generally use session initiation protocol
Session Initiation Protocol
The Session Initiation Protocol is an IETF-defined signaling protocol widely used for controlling communication sessions such as voice and video calls over Internet Protocol . The protocol can be used for creating, modifying and terminating two-party or multiparty sessions...
in order to connect to a variety of different codecs designed by different manufacturers.
Another example would be APT Codecs who provide IP Audio Codecs for use in professional studio transmitter links (STLs) and studio networking. IP STLs and Studio-to-Studio Links are absolutely vital for broadcasters. Traditionally these links have been implemented with synchronous (Tx, Rx and Clock) data circuits. For wired circuits, broadcasters usually contract Telephone Companies to provide fixed bandwidth T1, E1 or X.21 / V.35 terminated circuits (or the Telco transports the audio for the radio station using synchronous networks as the preferred carrier).
While this arrangement has worked well for many years, it requires broadcasters to allocate considerable amounts from their budget for the ongoing operational costs of the Telco services. With the advent of IP technology, broadcasters have been looking at minimizing these operational costs by replacing their existing synchronous networks with packetized ones.
However, as a transport mechanism, IP presents a number of challenges that need to be addressed by the Chief Engineer before migrating away from synchronous networks. These issues are not insurmountable, and, if correctly and intelligently implemented; the use of IP will greatly assist a radio station’s efficiency.
Primary issues of concern for a Chief Engineer are as follows:
•Latency
•Lost Packets
•Packet Size
•UDP versus TCP
•Jitter
•Error Correction / Concealment
•Clock Skew
•Audio Algorithms
•IPv6
IPv6
Internet Protocol version 6 is a version of the Internet Protocol . It is designed to succeed the Internet Protocol version 4...
Compatibility
IP as a transport mechanism for broadcasters is here to stay because it allows Radio broadcast networks to bundle their audio with data, reduce operational costs and amalgamate IT and audio into a single resource. However, these massive and well-defined advantages come with some safety warnings - networks should be well managed, packets should be prioritized and correct choices should be made with regard to audio compression. Assuming all these boxes are ticked, then broadcasters will enjoy the benefits of the transition away from synchronous networks without running into serious problems
External links
- Tieline Website Explaining Audio Over IP
- IP Audio website with audio over IP broadcast information
- APT's Definitive Guide to IP Audio Networking
- http://www.audio-via-ip.com/ Official Audio-via-IP Experts Group website.
- http://radioworld.com/article/why-ipv6-matters-to-your-station/23533 Why broadcasters need to know about IPv6 compatibility for IP audio codecs
- EBU - Tech 3326 for Audio Contribution over IP
- EBU - Tech 3329 Tutorial on Audio Contribution over IP
See also
- CodecCodecA codec is a device or computer program capable of encoding or decoding a digital data stream or signal. The word codec is a portmanteau of "compressor-decompressor" or, more commonly, "coder-decoder"...
- IPInternet ProtocolThe Internet Protocol is the principal communications protocol used for relaying datagrams across an internetwork using the Internet Protocol Suite...
- APT Codecs
- TielineTielineTieline Technology has offices in Indianapolis in the USA and in Perth, Western Australia . The company has a wide and established distribution network throughout Europe, the Americas and Australasia. Tieline develops a range of broadcast audio codecs that are sold to television and radio networks...
- BroadcastingBroadcastingBroadcasting is the distribution of audio and video content to a dispersed audience via any audio visual medium. Receiving parties may include the general public or a relatively large subset of thereof...
- Audio over IPAudio over IPStreaming audio over IP networks is being increasingly used by broadcasting companies, among others, to provide high-quality audio feeds over distance across an IP network such as the Internet. The application is also known as audio contribution over IP in reference to the programming...