• Updated links to conformance bitstreams and licensing information    07-Nov-2001
• AES 110th Conv. Workshop slides "MPEG-7 Audio ­ What is it about?" available    01-Jun-2001
• Call for Proposals for New Tools for Audio Coding    07-Feb-2001
• Audio Press Release of the 55th MPEG Meeting (January 2001)    07-Feb-2001
• Paper "MP3 and AAC explained" available    28-Mar-2000
• Updated MPEG Audio FAQ available    10-Mar-2000
• December 1999:   MPEG-4 Version 2 Standard approved    09-Feb-2000
• Report on the MPEG-4 Audio Version 2 Verification Test    09-Feb-2000

• MPEG Audio Frequently Asked Questions
• MPEG Audio Public Documents & Verification Test Reports
• MPEG Audio - General Documents, Publications, and Presentations
• MPEG Audio FTP Server - Conformance Bitstreams and Software
• SQAM - Sound Quality Assessment Material

• single-channel ('mono') and two-channel ('stereo' or 'dual mono') coding at 32, 44.1, and 48 kHz sampling rate. The predefined bit rates range from 32 to 448 kbit/s for Layer I, from 32 to 384 kbit/s for Layer II, and from 32 to 320 kbit/s for Layer III.

See also the MPEG-1 Overview.

• a backwards compatible multichannel extension to MPEG-1; up to 5 main channels plus a 'low frequent enhancement' (LFE) channel can be coded; the bit rate range is extended up to about 1 Mbit/s;
• an extension of MPEG-1 towards lower sampling rates 16, 22.05, and 24 kHz for bitrates from 32 to 256 kbit/s (Layer I) and from 8 to 160 kbit/s (Layer II & Layer III).

See also the MPEG-2 Overview.

• a very high-quality audio coding standard for 1 to 48 channels at sampling rates of 8 to 96 kHz, with multichannel, multilingual, and multiprogram capabilities. AAC works at bit rates from 8 kbit/s for a monophonic speech signal up to in excess of 160 kbit/s/channel for very-high-quality coding that permits multiple encode/decode cycles. Three profiles of AAC provide varying levels of complexity and scalability.

• coding and composition of natural and synthetic audio objects at a very wide range of bit rates.

See also the MPEG-4 Overview (PDF).

The MPEG-4 Version 1 Final Draft International Standard was approved in October 1998 at the 45th MPEG meeting.

The MPEG-4 Version 1 Final Committee Draft approved in March 1998 was made publicly available: Audio Reference Software. The Committee Draft approved in October 1997 was also made available: Audio, Reference Software

The MPEG-4 Version 2 Final Draft International Standard (AMD1) was approved in December 1999 at the 50th MPEG meeting.

The MPEG-4 Version 2 Final Committee Draft (AMD1 FPDAM) approved in July 1999 was made publicly available: Audio. The Committee Draft approved in March 1999 was also made available: Audio

• techniques for the description of Audio-Visual Content.

The MPEG-7 Call for Proposals (CfP) was issued in November 1998 at the 45th MPEG meeting. MPEG-7 has reached Working Draft status in December 1999 at the 50th MPEG meeting. Further information is available from the following web pages:

• MPEG-7 Home Page
• MPEG-7 Audio (old location)

See also the MPEG-7 Overview.

The updated MPEG Audio FAQ is available now!

Some selected questions:

• Where can I obtain copies of the MPEG Standards?
• How does MPEG-1 Audio work?
• What is MPEG-2 AAC?
• What does MPEG-4 Audio Version 1 provide above MPEG-2 Audio?
• What kind of support does MPEG provide for implementers of MPEG Audio?
• Where can I find information on MPEG-2 licencing?
• Under what circumstances can I use MPEG-4 FCD reference software?
• What is MPEG-7?

• The official MPEG Home Page
• MPEG Audio     <= you are here
• MPEG-4 Structured Audio / SAOL
• MPEG Video
• MPEG-4 Systems
• MPEG-4 Synthetic/Natural Hybrid Coding
• MPEG-7
• MPEG-7 Audio (old location)
• International Organization for Standardization (ISO)

• FhG IIS: MPEG Audio Compression Technology - MP3 and AAC
• Philips: MPEG Audio Coding Technology
• Mobile Multimedia Systems (MoMuSys)
• CCETT's MPEG Audio Web Site
• MPEG.ORG - MPEG Pointers and Resources
• MIDI Manufacturers Association
• AT&T: a2b music
• Liquid Audio
• MPEG-1 & MPEG-2 Conformance Bitstreams (Philips)
• MPEG-2 AAC & MPEG-4 Conformance Bistreams (AT&T)
• MPEG-4 Structured Audio: Developer Tools
• SAOG - Structured Audio Open Group (mirror site)

• Europe:     University of Hannover (Germany)
  • Web Page: http://www.tnt.uni-hannover.de/project/mpeg/audio/
  • FTP Server: ftp://ftp.tnt.uni-hannover.de/pub/MPEG/audio/
• America:     MIT Media Laboratory (USA)
  • Web Page: http://sound.media.mit.edu/mpeg4/audio/
  • FTP Server: not yet available ...
• Asia:     NEC (Japan)
  • Web Page: http://www.labs.nec.co.jp/mpeg/audio/
  • FTP Server: not yet available ...

Contact Address:     mpegaudio@tnt.uni-hannover.de

Please note that questions submitted to this address will be answered on a voluntary basis!