Apple
- Overview of their implementation and contribution to the MPEG-4 standard.
- http://www.apple.com/quicktime/technologies/mpeg4/

IBM Composite Media Group
- Overview of their implementation and contribution to the MPEG-4 standard, especially for the Systems part.
- http://researchweb.watson.ibm.com/mpeg4/Projects/

Introduction to Digital Audio Coding and Standards
- Book by Marina Bosi and Richard E. Goldberg.
- http://www.springer.com/east/home?SGWID=5-40109-22-33356358-0

Applications of Digital Signal Processing to Audio and Acoustics
- Book by Mark Kahrs and Karlheinz Brandenburg.
- http://www.amazon.com/exec/obidos/ASIN/0792381300

Principles of digital audio
- Book by Ken C. Pohlmann.
- http://www.amazon.com/exec/obidos/ASIN/0071348190

ISO/IEC
- Publicly available standards from the International Organization for Standardization including MPEG-4 with 14496-5 containing the Audio, Visual and Systems parts.
- http://standards.iso.org/ittf/PubliclyAvailableStandards/

EE Times
- "Meeting MPEG-4 advanced audio coding requirements", knowledgeable article summarizing the most important properties of AAC for hardware playback.
- http://www.eet.com/story/OEG20011218S0048/

Mobiledia
- Reviews, articles and forum discussions about cell phones capable of AAC/MP4/3GP playback (also called "iTunes" format sometimes, use the site search).
- http://www.mobiledia.com/

Speech Synthesis Examples
- Many TTS demos in several languages from different systems with links to their homepages.
- http://www.ims.uni-stuttgart.de/~moehler/synthspeech/

Text-To-Speech Synthesis
- Bell Labs' / Lucent Technologies multi-lingual TTS demos and introduction to this coding method.
- http://www.bell-labs.com/project/tts/

Facial Animation
- AT&T Labs develops a computer human interface using 2D and 3D talking head-and-shoulder models driven by a Text-To-Speech synthesizer (TTS).
- http://www.research.att.com/projects/AnimatedHead/

Audio Research Labs
- ARL is a commercial laboratory involved in subjective quality assessment methods like preparing and analyzing codec comparisons for 3GPP.
- http://www.audioresearchlabs.com/

Digital Radio Mondiale
- DRM is a world-wide initiative to use analog AM radio for digital sound and services implementing aacPlus at very low bitrates, often mixed up with Digital Rights Management for copy protection.
- http://www.drm.org/

3GPP SA4
- This working group of the standardization organization deals with codecs like enhanced aacPlus or AMR-WB+ used in mobile telecommunication.
- http://www.3gpp.org/TB/SA/SA4/SA4.htm

MPEG LA
- Patent pool administrator for the MPEG-4 Systems part of the standard including the MP4 file format.
- http://www.mpegla.com/m4s/

MPEG4.net
- Resource for news, information and products about MPEG-4, H.264, Windows Media, High-Definition, Streaming Media and related technologies.
- http://www.mpeg4.net/

Tuner2
- List of internet radio stations using aacPlus for their low bitrate streams, among them SomaFM.com and Boomer Radio.
- http://www.tuner2.com/

Roberto's listening tests
- Provides public group comparisons of several AAC codecs and other formats at different bitrates.
- http://www.rjamorim.com/test/

Telos Systems
- Hardware manufacturer of the Zephyr ISDN codecs for radio and television broadcasters providing articles and brochures about different AAC implementations.
- http://www.telos-systems.com/techtalk/

Machine Listening
- Reading list for an MIT seminar, most of the mentioned publications are directly available on their web server or linked to Amazon's book section.
- http://web.media.mit.edu/~tristan/Classes/MAS.945/technical.html

Faac.sourceforge.net
- The old Audiocoding.com forum is still available providing valuable content like FAAC compiling issues with its search tool.
- http://faac.sourceforge.net/oldsite/phorum/

Nokia developer forum
- Platform to support the implementation of their software SDKs including AAC/MP4.
- http://discussion.forum.nokia.com/forum/

AES Publications
- All available articles and documents from the Journal of Audio Engineering Society with search tool including a CD about coding artifacts.
- http://www.aes.org/publications/

Mayah
- Hard- and software company for professional broadcasting products with AAC/MP4 support.
- http://www.mayah.com/

QuickTime development
- Apple offers technical FAQs, knowledge base and publicly available documentation files including the MOV file format.
- http://developer.apple.com/quicktime/

Via Licensing
- Patent pool administrator for AAC with FAQs and overviews of royalty fees for commercial implementations.
- http://www.vialicensing.com/

Coding Technologies
- Company that invented Spectral Band Replication (SBR) and combined it with MP3 (mp3PRO) and AAC (aacPlus or HE AAC).
- http://www.codingtechnologies.com/

Mp4-tech
- The web archive of the public MPEG Industry Forum mailing list with many knowledgeable participants from companies like FhG, Apple and Microsoft.
- http://lists.mpegif.org/pipermail/mp4-tech/

Hydrogen Audio
- Forum about audio coding in general with two separate boards for AAC.
- http://www.hydrogenaudio.org/

Doom9
- Besides this forum for audio codecs there are others for container formats and video encoding in general with FAQs.
- http://forum.doom9.org/forumdisplay.php?forumid=11

Everwicked.com
- Comprehensive guides about DivX, XviD and MPEG4IP, a forum and other resources about digital audio/video coding and streaming.
- http://www.everwicked.com/

Fraunhofer IIS
- Information about the different parts of MPEG-4 Natural or General Audio (GA) from one of the inventors of these formats, see also their page about MPEG-2 AAC.
- http://www.iis.fraunhofer.de/amm/techinf/mpeg4/audio.html

Structured Audio Open Group
- The main goal of the SAOG was to implement Structured Audio (SA) in open source applications offering a portal for their users with forum and downloads of samples and software.
- http://lsiwww.epfl.ch/saog/

MP4-SA Developer Tools
- John Lazarro and John Wawrzynek from the CS Division, UC Berkeley provide tutorials, downloads, manuals and links related to the Structured Audio format.
- http://www.cs.berkeley.edu/~lazzaro/sa/

MPEG-4 Structured Audio
- Technical information and developer resources from the Machine Listening Group at the MIT Media Laboratory, the official homepage for this format maintained by Eric Scheirer.
- http://sound.media.mit.edu/mpeg4/