AES Standards News Blog

A new multi-part revision of AES41 has been published 2012-07-20. In this revision, the application of the underlying technology has beens expanded from the single role of carrying re-coding metadata to carrying a range of audio-related metadata types.This five-part suite revises and substantially extends AES41-2009: "AES standard for digital audio - Recoding data set for audio bit-rate reduction". 

AES41 provides for the carriage of audio metadata by embedding it in the audio samples themselves. This tightly associates the metadata with the audio, yet makes it fragile so that changes to the audio will invalidate the metadata. Several metadata sets have been defined, covering applications such as cascaded compression (bit-rate reduction), and loudness control. These parts are:

AES41-1-2012, "AES standard for digital audio - Audio-embedded metadata - Part 1: General"  Part 1 specifies the method by which a metadata set is embedded in the audio samples. Other parts define the content and format of the metadata sets. This part revises AES41-2009.  http://www.aes.org/publications/standards/search.cfm?docID=37

AES41-2-2012, "AES standard for digital audio - Audio-embedded metadata - Part 2: MPEG-1 Layer II or MPEG-2 LSF Layer II"  Part 2 describes the format for the data to be transmitted with audio decoded from MPEG-1 Layer II or MPEG-2 LSF Layer II encoding. The data may be used to aid a subsequent re-encoding process. This part revises AES41-2009.  http://www.aes.org/publications/standards/search.cfm?docID=87

AES41-3-2012, "AES standard for digital audio - Audio-embedded metadata - Part 3: AAC & HE-AAC"  Part 3 describes the format for the data to be transmitted with audio to signal downmix coefficients, loudness and dynamic range control metadata as used in ISO/IEC 14496-3:2009 Subpart 4 (AAC and HE-AAC). A method of carrying this data is described in Part 1 of this Standard. This part is new.  http://www.aes.org/publications/standards/search.cfm?docID=88

AES41-4-2012, "AES standard for digital audio - Audio-embedded metadata - Part 4: Dolby E"  Part 4 describes the format for the data to be transmitted with audio to signal downmix coefficients, loudness, and channel configuration metadata as used Dolby E. This part is new.  http://www.aes.org/publications/standards/search.cfm?docID=89

AES41-5-2012, "AES standard for digital audio - Audio-embedded metadata - Part 5: EBU loudness, true-peak, and downmix"  Part 5 describes the format for the data to be transmitted with audio to signal loudness and true peak metadata as used in EBU Technical Recommendation R128. This part is new.  http://www.aes.org/publications/standards/search.cfm?docID=90

Click on the links above to access individual documents.  Alternatively, go to http://www.aes.org/publications/standards/  and search using "AES41" to find the whole set. 

 A Call for Comment on DRAFT AES63-xxxx, AES standard for interconnections - Data connector in an XLR connector shell, has been published 2012-06-04.  

http://www.aes.org/standards/comments/cfc-draft-aes63-xxxx.cfm

Scope

The scope of this standard is to specify a ruggedized data connector that is compatible with 8-way modular connectors, also called RJ-45 connectors. Basic physical properties and mechanical dimensions are specified in order to enable proper mating and locking and to ensure reliable electrical contact in the locked position. No further requirements are specified with respect to electrical and other mechanical properties.

A Call for Comment on DRAFT AES59-xxxy AES standard for professional audio - Audio application of 25-way D-type connectors in balanced circuits, has been published 2012-06-04

http://www.aes.org/standards/comments/cfc-draft-aes59-xxxy.cfm

Scope

This standard specifies a contact assignment and gender for 25 contact D type connectors used to connect multiple audio signals in balanced analogue or AES3 digital form. This document shall not consider the suitability of connector and cable types for specific applications. This document shall not consider issues of safety. NOTE Use of this connector may be restricted by safety regulations. 

Calls for comment have been published on the multiple parts revising AES41-2009, "AES standard for digital audio  -  Recoding data set for audio bit-rate reduction". For ease of future maintenance each part is presented independently. Parts 1 and 2 represent a revision of the earlier document; parts 3, 4, and 5 are new draft standards.

The Call for Comment on DRAFT REVISED AES41-1-xxxx "AES standard for digital audio - Audio-embedded metadata - Part 1: General" was published 2012-04-03

The Call for Comment on DRAFT REVISED AES41-2-xxxx "AES standard for digital audio - Audio-embedded metadata - Part 2: MPEG-1 Layer II or MPEG-2 LSF Layer II" was published 2012-04-03

The Call for Comment on DRAFT AES41-3-xxxx, "AES standard for digital audio - Audio-embedded metadata - Part 3: AAC & HE-AAC" was published 2012-04-03

The Call for Comment on DRAFT AES41-4-xxxx, "AES standard for digital audio - Audio-embedded metadata - Part 4: Dolby E" was published 2012-04-03

The Call for Comment on DRAFT AES41-5-xxxx, "AES standard for digital audio - Audio-embedded metadata - Part 5: EBU loudness, true-peak, and downmix" was published 2012-04-03

These calls are posted at http://www.aes.org/standards/comments/

AES53-2006 (r2011) AES standard for digital audio — Digital input-output interfacing — Sample-accurate timing in AES47 has been reaffirmed.

This document specifies how the timing markers specified in AES47 may be used to associate an absolute timestamp with individual audio samples.  AES47 specifies a format for the transmission of digital audio over asynchronous transfer mode (ATM) networks.  A recommendation is made to refer these timestamps to the SMPTE epoch which in turn provides a reference to UTC and GPS time.

 AES52-2006 (r2011) AES standard for digital audio engineering — Insertion of unique identifiers into the AES3 transport stream has been reaffirmed.

The AES3 transport stream continues to be used extensively in both discrete and network based audio systems alongside audio stored as files. Audio content is moving towards being handled by asset management systems and descriptive metadata associated with that content is also being stored within systems. In order to provide a mechanism for AES3 transport streams to have similar abilities to work with content management systems, some form of unique label is required which can provide the link with these systems. One of the unique labels currently standardised in the media industry is the SMPTE UMID while another commonly used in the Information Technology area is the IEC UUID.

This standard specifies the method for inserting unique identifiers into the user data area of an AES3 stream. This specifically covers the use of UUID as well as a basic or extended SMPTE UMID.

AES51-2006 (r2011) AES standard for digital audio – Digital input-output interfacing – Transmission of ATM cells over Ethernet physical layer has been reaffirmed

This standard specifies a method, also known as “ATM-E”, of carrying asynchronous transfer mode (ATM) cells over hardware specified for IEEE 802.3 (Ethernet). It is intended as a companion standard to AES47 (Transmission of digital audio over ATM networks), to provide a standard method of carrying ATM cells and real-time clock over hardware specified for Ethernet.  

AES47-2006 (r2011), AES standard for digital audio - Digital input-output interfacing - Transmission of digital audio over asynchronous transfer mode (ATM) networks, has  been reaffirmed. 

This document specifies the method of carrying multiple channels of audio in linear PCM or AES3 format in calls across an asynchronous transfer mode (ATM) network to ensure interoperability. The specification includes the method of conveying information concerning the format and sampling frequency of the digital audio signal when setting up the calls.

 AES31-1-2001 (r2011), AES standard for network and file transfer of audio - Audio-file transfer and exchange - Part 1: Disk format has been reaffirmed.

This document defines a disk format specification to maintain compatibility with as wide a user base as possible to facilitate audio-file transfer and exchange between differing systems. The document does not describe a complete disk format but provides enough information for choosing a proprietary system that will maintain compatibility.

AES62-2011 AES standard for audio connectors - Modified XLR-3 Connector for Digital Audio has been published.

http://www.aes.org/publications/standards/search.cfm?docID=86

This new standard covers new connector types in order to identify AES3 equipment, signals and transmission circuits (tie lines). By extension, the same connectors will also identify AES42 microphone connections. The new “digital” connectors are based on the conventional analogue three pole XLR-type connectors with the difference of additional keying. The keying is realized in a manner as to prevent mating with conventional XLR-type connectors. Furthermore new “compatible” connectors that mate with both “digital” and conventional types are specified. 

This standard specifies variants of the XLR connector family to be used for professional audio applications that include AES3 digital audio interfaces.

Test methods to confirm the correct function of the keying are indicated. Additional means supporting identification of different connector types are under consideration. 

The document does not include any electrical requirements.