The United States Advanced Television Systems Committee (ATSC), Inc., was formed by the
member organizations of the Joint Committee on InterSociety Coordination (JCIC)1, recognizing
that the prompt, efficient and effective development of a coordinated set of national standards is
essential to the future development of domestic television services.
One of the activities of the ATSC is exploring the need for and, where appropriate,
coordinating the development of voluntary national technical standards for Advanced Television
Systems (ATV). The ATSC Executive Committee assigned the work of documenting the U.S.
ATV standard to a number of specialist groups working under the Technology Group on
Distribution (T3). The Audio Specialist Group (T3/S7) was charged with documenting the ATV
This document was prepared initially by the Audio Specialist Group as part of its efforts to
document the United States Advanced Television Broadcast Standard. It was approved by the
Technology Group on Distribution on 26 September 1994, and by the full ATSC membership as
an ATSC Standard on 10 November 1994. Annex A, “AC-3 Elementary Streams in an MPEG-2
Multiplex,” was approved by the Technology Group on Distribution on 23 February 1995, and by
the full ATSC membership on 12 April 1995. Annex B, “AC-3 Data Stream in IEC958 Interface,”
and Annex C, “AC-3 Karaoke Mode,” were approved by the Technology Group on Distribution on
24 October 1995 and by the full ATSC Membership on 20 December 1995.
Revision A of this standard was approved by the full ATSC membership on 20 August 2001.
Revision A corrected some errata in the detailed specifications, revised Annex A to include
additional information about the DVB standard, removed Annex B that described an interface
specification (superseeded by IEC and SMPTE standards), and added a new annex, “Alternate Bit
Stream Syntax,” which contributes (in a compatible fashion) some new features to the AC-3 bit
Revision B of this standard was approved by the full ATSC membership on 14 June 2005.
Revision B corrected some errata in the detailed specifications, and added a new annex,
“Enhanced AC-3 Bit Stream Syntax” which specifies a non-backwards compatible syntax that
offers additional coding tools and features. Informative references were removed from the body of
the document and placed in a new Annex B.
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