Since MPEG-4 is a comprehensive multimedia standard, this category lists sites about several audio formats, all being part of MPEG-4 Audio. "Natural" coding of sound: Advanced Audio Coding (AAC, also its MPEG-2 version), TwinVQ (aka VQF), CELP, Parametric Codecs (HVXC, HILN). "Synthetic" coding of sound: Structured Audio Orchestra Language (SAOL) and Structured Audio Score Language (SASL), Text-To-Speech (TTS). The container format MP4 also belongs to this category, as long as it includes audio-only tracks with *.m4a, *.m4b or *.mp4 file extension and not video or other parts of the MPEG-4 standard like 2D/3D graphics. Due to the new developments in mobile communication the 3GPP/3GP2 standard and its audio codecs (several AMR and AAC variants) should be included here, also because their container formats *.3gp and *.3g2 are very similar to MP4, although not the same.
Subcategories 4
Related categories 8
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- Mobiledia Reviews, articles and forum discussions about cell phones capable of AAC/MP4/3GP playback (also called "iTunes" format sometimes, use the site search).
- Doom9 Besides this forum for audio codecs there are others for container formats and video encoding in general with FAQs.
- Via Licensing Patent pool administrator for AAC with FAQs and overviews of royalty fees for commercial implementations.
- QuickTime development Apple offers technical FAQs, knowledge base and publicly available documentation files including the MOV file format.
- Mayah Hard- and software company for professional broadcasting products with AAC/MP4 support.
- AES Publications All available articles and documents from the Journal of Audio Engineering Society with search tool including a CD about coding artifacts.
- 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.
- Tuner2 List of internet radio stations using aacPlus for their low bitrate streams, among them SomaFM.com and Boomer Radio.
- 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.
- Audio Research Labs ARL is a commercial laboratory involved in subjective quality assessment methods like preparing and analyzing codec comparisons for 3GPP.
- ISO/IEC Publicly available standards from the International Organization for Standardization including MPEG-4 with 14496-5 containing the Audio, Visual and Systems parts.
- Principles of digital audio Book by Ken C. Pohlmann.
- Applications of Digital Signal Processing to Audio and Acoustics Book by Mark Kahrs and Karlheinz Brandenburg.
- Examples of Synthesized Speech Many TTS demos in several languages from different systems with links to their homepages.
- Hydrogen Audio Forum about audio coding in general with two separate boards for AAC.
- MP4 Structured Audio: 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.