AES47
Encyclopedia
AES47 describes a standardised method for packing AES3 professional digital audio streams over Asynchronous Transfer Mode
networks. The AES47 method is published by the International Electrotechnical Commission
as IEC 62365.
networks. The details of these standards can be studied at the Audio Engineering Society standards web site by downloading copies of AES47-2006, AES-R4-2002 and AES3-2003. AES47 was originally published in 2002 and has been republished with minor revisions in February 2006. Amendment 1 to AES47 has been published in February 2009. This Amendment adds code points in the ATM Adaptation Layer Parameters Information Element to signal that the time to which each audio sample relates can be identified as specified in AES53
.
The change in thinking from traditional ATM network design is not to necessarily use ATM to pass IP traffic (apart from management traffic) but to use AES47 in parallel with standard Ethernet structures to deal with extremely high performance secure media streams. From work carried out at the British Broadcasting Corporation’s (BBC
) R&D department and published as "White Paper 074", it has been established that this approach provides the necessary performance for professional media production. AES47 has been developed to allow the simultaneous transport and switched distribution of a large number of AES3 linear audio streams at different sample frequencies. AES47 can support any of the standard AES3 sample rates and word size. AES11
Annex D (the November 2005 printing or version of AES11-2003) shows an example method to provide isochronous
timing relationships for distributed AES3 structures over asynchronous networks such as AES47 where reference signals may be locked to common timing sources such as GPS. AES53
specifies how timing markers within AES47 can be used to associate an absolute time stamp with individual audio samples as described in AES47 Amendment 1.
An additional standard has been published by the Audio Engineering Society
to extend AES3 digital audio carried as AES47 streams to enable this to be transported over standard physical Ethernet
hardware. This additional standard is known as AES51
-2006.
Asynchronous Transfer Mode
Asynchronous Transfer Mode is a standard switching technique designed to unify telecommunication and computer networks. It uses asynchronous time-division multiplexing, and it encodes data into small, fixed-sized cells. This differs from approaches such as the Internet Protocol or Ethernet that...
networks. The AES47 method is published by the International Electrotechnical Commission
International Electrotechnical Commission
The International Electrotechnical Commission is a non-profit, non-governmental international standards organization that prepares and publishes International Standards for all electrical, electronic and related technologies – collectively known as "electrotechnology"...
as IEC 62365.
Introduction
Many professional audio systems are now combined with telecommunication and IT technologies to provide new functionality, flexibility and connectivity over both local and wide area networks. AES47 was developed to provide a standardised method of transporting the existing standard for digital audio (AES3) over current telecommunication interconnection standards that provide a quality of service required by many professional low latency, uncompressed live audio uses. It may be used directly between specialist audio devices or in combination with telecommunication and computer equipment with suitable network interfaces and utilises the same physical structured cable used as standard by those networks.AES47 details
AES47 (IEC 62365) is an open standard that specifies a method for packing AES3 professional digital audio streams over Asynchronous Transfer ModeAsynchronous Transfer Mode
Asynchronous Transfer Mode is a standard switching technique designed to unify telecommunication and computer networks. It uses asynchronous time-division multiplexing, and it encodes data into small, fixed-sized cells. This differs from approaches such as the Internet Protocol or Ethernet that...
networks. The details of these standards can be studied at the Audio Engineering Society standards web site by downloading copies of AES47-2006, AES-R4-2002 and AES3-2003. AES47 was originally published in 2002 and has been republished with minor revisions in February 2006. Amendment 1 to AES47 has been published in February 2009. This Amendment adds code points in the ATM Adaptation Layer Parameters Information Element to signal that the time to which each audio sample relates can be identified as specified in AES53
AES53
AES53 is a standard first published in October 2006 by the Audio Engineering Society that specifies how the timing markers specified in AES47 may be used to associate an absolute time-stamp with individual audio samples. AES47 specifies a format for the transmission of digital audio over...
.
The change in thinking from traditional ATM network design is not to necessarily use ATM to pass IP traffic (apart from management traffic) but to use AES47 in parallel with standard Ethernet structures to deal with extremely high performance secure media streams. From work carried out at the British Broadcasting Corporation’s (BBC
BBC
The British Broadcasting Corporation is a British public service broadcaster. Its headquarters is at Broadcasting House in the City of Westminster, London. It is the largest broadcaster in the world, with about 23,000 staff...
) R&D department and published as "White Paper 074", it has been established that this approach provides the necessary performance for professional media production. AES47 has been developed to allow the simultaneous transport and switched distribution of a large number of AES3 linear audio streams at different sample frequencies. AES47 can support any of the standard AES3 sample rates and word size. AES11
AES11
The AES11 standard published by the Audio Engineering Society provides a systematic approach to the synchronization of digital audio signals. Recommendations are made concerning the accuracy of sample clocks as embodied in the interface signal and the use of this format as a convenient...
Annex D (the November 2005 printing or version of AES11-2003) shows an example method to provide isochronous
Isochronous
Isochronous : From Greek iso, equal + chronos, time. It literally means regularly, or at equal time intervals. In general English language, it refers to something that occurs at a regular interval, of the same duration; as opposed to synchronous which refers to more than one thing happening at the...
timing relationships for distributed AES3 structures over asynchronous networks such as AES47 where reference signals may be locked to common timing sources such as GPS. AES53
AES53
AES53 is a standard first published in October 2006 by the Audio Engineering Society that specifies how the timing markers specified in AES47 may be used to associate an absolute time-stamp with individual audio samples. AES47 specifies a format for the transmission of digital audio over...
specifies how timing markers within AES47 can be used to associate an absolute time stamp with individual audio samples as described in AES47 Amendment 1.
An additional standard has been published by the Audio Engineering Society
Audio Engineering Society
Established in 1948, the Audio Engineering Society draws its membership from amongst engineers, scientists, other individuals with an interest or involvement in the professional audio industry. The membership largely comprises engineers developing devices or products for audio, and persons working...
to extend AES3 digital audio carried as AES47 streams to enable this to be transported over standard physical Ethernet
Ethernet
Ethernet is a family of computer networking technologies for local area networks commercially introduced in 1980. Standardized in IEEE 802.3, Ethernet has largely replaced competing wired LAN technologies....
hardware. This additional standard is known as AES51
AES51
AES51 is a standard first published by the Audio Engineering Society in June 2006 that specifies a method of carrying ATM cells over Ethernet physical structure intended in particular for use with AES47 to carry AES3 digital audio transport structure...
-2006.