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Topic: Advanced Audio Coding


Related Topics
MP3
MP4
MP2
WMA

  
  Advanced Audio Coding - Wikipedia, the free encyclopedia
AAC was declared an international standard by the MPEG group by the end of April 1997.
AAC was promoted as the successor to MP3 for audio coding at medium to high bit rates, though has yet to overtake the MP3 format or Microsoft's rival WMA format in terms of popularity or availability within the portable audio devices market.
AAC is a wideband audio coding algorithm that exploits two primary coding strategies to dramatically reduce the amount of data needed to convey high-quality digital audio.
en.wikipedia.org /wiki/Advanced_Audio_Coding   (1676 words)

  
 NationMaster - Encyclopedia: Advanced Audio Coding
Advanced Audio Coding (AAC) is a lossy data compression A lossy data compression method is one where compressing data and then decompressing it retrieves data that may well be different to the original, but is "close enough" to be useful in some way.
AAC was designed as an improved-performance codec relative to MP3 MP3 is a popular digital audio encoding and lossy compression format invented and standardised in 1991 by a team of engineers working in the framework of the ISO/IEC MPEG audio committee under the chairmanship of Professor Hans Musmann (University of Hannover - Germany).
AAC, which was first specified in the standard known formally as ISO The International Organization for Standardization (ISO or iso) is an international standard-setting body composed of representatives from national standards bodies.
www.nationmaster.com /encyclopedia/Advanced-Audio-Coding   (3565 words)

  
 EETimes.com - Meeting MPEG-4 advanced audio coding requirements   (Site not responding. Last check: 2007-10-21)
MPEG-4 audio does not require a single or small set of highly efficient compression schemes but rather a complex toolbox to perform a wide range of operations from low-bit-rate speech coding to high-quality audio coding and music synthesis.
The MPEG-4 audio coding algorithm family spans the range from low bit-rate speech coding (down to 2 kbits/second) to high-quality audio coding (at 64 kbits/s per channel and higher).
The sensitivity is represented by the "threshold in quiet." The threshold in quiet is increased by the masking effect of a tonal or noisy audio signal.
www.eet.com /story/OEG20011218S0048   (1430 words)

  
 Linux.com Article DB: Using Advanced Audio Coding Under Linux - 1/1
Advanced Audio Coding (AAC) is one such audio coding format, which made its debut as a part of MPEG-2, and was revised and included in the MPEG-4 specification.
AAC is probably the most advanced audio encoding system in the world.
Freeware Advanced Audio Coder (FAAC) is an opensource GPL'd suite of tools which allow a person to use the AAC format.
linux.omnipotent.net /article.php?article_id=11500   (662 words)

  
 Perceptual Audio Coding - Wikipedia, the free encyclopedia
Perceptual Audio Coding (PAC) is an algorithm, like MPEG's MP3 standard, used to compress digital audio by removing extraneous information not perceived by most people.
PAC is very similar to Advanced Audio Coding, the latter sharing many design elements.
The term is sometimes used non-capitalized, to describe all lossy compression formats for audio.
en.wikipedia.org /wiki/Perceptual_Audio_Coding   (168 words)

  
 Overview of MPEG AAC Audio Coding
AAC is the newest audio coding method selected by MPEG and became an international standard in April 1997.
It is a fully state-of-the-art audio compression tool kit that provides performance superior to any known approach at bit rates greater than 64 kbps and excellent performance relative to the alternatives at bit rates reaching as low as 16 kbps.
AAC is the most powerful coding method available in Zephyr Xstream, and we particularly like it because it is perfectly matched to the bitrates available on ISDN BRI lines.
www.telos-systems.com /techtalk/aac   (673 words)

  
 Advanced audio coding: Tutte le informazioni su Advanced audio coding su Encyclopedia.it   (Site not responding. Last check: 2007-10-21)
Advanced audio coding: Tutte le informazioni su Advanced audio coding su Encyclopedia.it
Il formato Advanced Audio Coding (AAC) è un formato di compressione audio creato dal consorzio MPEG e incluso ufficialmente nel'MPEG 4.
L'obbiettivo del AAC è quello di fornire una qualità audio superiore al formato MP3 con una codifica più compatta.
www.encyclopedia.it /a/ad/advanced_audio_coding.html   (83 words)

  
 MPEG-4 Part 3 -   (Site not responding. Last check: 2007-10-21)
The Advanced Audio Coding in MPEG-4 Part 3 was enhanced relative to what was previously specified in MPEG-2 Part 7, in order to provide better sound quality relative to the bit rate used for the encoding.
This is similar to normal MPEG-4 AAC which uses MDCTs with a size k of 128 or 1024 directly on the audio signal.
BSAC coding is best performed in the range of 40 kbit/s to 64 kbit/s, though it operates in the range of 16 kbit/s to 64 kbit/s.
psychcentral.com /psypsych/MPEG-4_Part_3   (824 words)

  
 MPEG-4 AAC Standard   (Site not responding. Last check: 2007-10-21)
Advanced Audio Coding (AAC) is a wideband audio coding algorithm that exploits two primary coding strategies to dramatically reduce the amount of data needed to convey high-quality digital audio.
Efficient audio compression is achieved by a variety of perceptual audio coding and data compression tools, which are combined in the MPEG-4 AAC specification.
The MPEG-4 AAC standard incorporates MPEG-2 AAC, forming the basis of the MPEG-4 audio compression technology for data rates above 32 kbps per channel.
www.vialicensing.com /products/mpeg4aac/standard.html   (185 words)

  
 Rane Professional Audio Reference (A)   (Site not responding. Last check: 2007-10-21)
AAC (Advanced Audio Coding) Shortened name for the MPEG-2 Advanced Audio Coding specification, declared an international standard by MPEG in April 1997; however, now the term is used also to refer to MPEG-4 advanced audio coding.
Power amplifier is the name applied to the last amplifier in the audio chain, used to increase the line-level signals to whatever is necessary to drive the loudspeakers to the loudness required.
Audio Timeline A most fascinating audio development timeline created by three esteemed AES members, Jerry Bruck, Al Grundy and Irv Joel, as part of the 50th anniversary of the AES.
www.rane.com /par-a.html   (7952 words)

  
 AudioCoding.com - Knowledge Base   (Site not responding. Last check: 2007-10-21)
AAC means "Advanced Audio Coding", and in the beginning it was also called MPEG-2 NBC for "Non-Backwards Compatible" as opposed to the MPEG-1 and MPEG-2 BC (with 5.1 channels) standards.
It is considered to be the actual "state of the art" in general audio coding and the natural successor of MPEG-1/2 Layer III / MP3 in the multimedia standard MPEG-4 that uses MP4 as the container format for all kinds of content.
This became more obvious with the standardization and implementation of HE AAC / aacPlus, as the older extensions were also aiming at a higher coding efficiency for low bitrates, but mostly for special purposes like speech coding.
www.audiocoding.com /modules/wiki?page=AAC   (1521 words)

  
 Overview of MPEG-2 AAC Audio Coding
Today almost all agree not only that audio bit rate reduction is effective and useful, but that the MPEG process has been successful at picking the best technology and encouraging compatibility across a wide variety of equipment.
When audio in a particular band falls below the masking threshold, few or no bits are devoted to encoding that signal, resulting in a conservation of bits that can then be used for the bands where they are needed.
Its audio coding scheme is used in a wide variety of broadcasting, storage, and telecommunications applications.
www.telos-systems.com /techtalk/mpeg   (1044 words)

  
 MPEG . ORG - MPEG-2 Advanced Audio Coding (AAC)
AAC (Advanced Audio Coding) is one of the audio compression formats defined by the MPEG-2 standard.
AAC used to be called NBC (Non-Backward-Compatible), because it is not compatible with the MPEG-1 audio formats.
AAC is more efficient than MP3 (MPEG-1 Layer 3) and is the state of the art in audio compression technology.
www.mpeg.org /MPEG/aac.html   (343 words)

  
 Citations: ISO/IEC MPEG-2 Advanced Audio Coding - Bosi, Brandenburg, Quackenbush, Fielder, Akagiri, Fuchs, Dietz, ...
coded music in the Enhanced General Packet Radio Services (EGPRS) network [3] In one extreme, voice service in the EGPRS network has a very stringent delay requirement, which precludes the possibility of retransmission in case of packet error.
With AAC, the audio stream is divided into subbands using a filter bank, which uses a 1024 point Modified Discrete Cosine Transform (MDCT) Quantization noise (step size) is set separately in each subband to fall below the masking threshold.
For audio, the MPEG 2 Advanced Audio Coder
citeseer.ist.psu.edu /context/371534/0   (1310 words)

  
 Fraunhofer IIS - Audio & Multimedia - MPEG-2 AAC
It is called MPEG-2 Advanced Audio Coding (AAC) and was declared international standard by MPEG by the end of April 1997.
MPEG-2 AAC is the consequent continuation of the truly successful coding method ISO/MPEG Audio Layer-3 developed in Erlangen.
Compared to well-known coding methods such as MPEG-2 Layer-2, it is possible to cut the required bitrate by a factor of two with no loss of subjective quality.
www.iis.fraunhofer.de /amm/techinf/aac   (775 words)

  
 AES 115th Convention: PAPERS - SESSION Z7
Encoder implementations of MPEG advanced audio coding and Layer-3 on 32-bit or 16-bit fixed-point processors are challenging due to the fact that the usable word length is restricted to 32 bits if low processing power is required.
An advanced Audio Spectral Coder (ASC) is described that implements a new approach to the problem of efficient audio compression by combining source coding with perceptual coding techniques.
The coding performance of ASC is characterized and it is shown that due to its underlying structure, additional functionalities other than compression are also possible namely bitstream semantic scalability, access, and classification.
www.aes.org /events/115/papers/SessionZ7.cfm   (1101 words)

  
 AAC Audio Codec   (Site not responding. Last check: 2007-10-21)
AAC (Advanced Audio Coding) is the latest audio coding standard, defined in the MPEG-2 standard, is used for high-quality audio compression.
AAC provides higher quality than MP3 at the same bit rate, or for the same audio quality it uses a 30 percent lower bit rate.
Main Profile of AAC decoder provides the best audio quality at any given rate though memory and processing power requirements are higher.
www.spiritdsp.com /aac_decoder.html   (281 words)

  
 JingleVoice Audio e-Productions Technical Page
By using MPEG audio coding, you may shrink down the original sound data from a CD by a factor of 12, without losing sound quality.
By exploiting stereo effects and by limiting the audio bandwidth, the coding schemes may achieve an acceptable sound quality at even lower bitrates.
For the use of low bit-rate audio coding schemes in broadcast applications at bitrates of 60 kbit/s per audio channel, the ITU-R recommends MPEG Layer-3.
web.uccs.edu /jgolden/techno.htm   (370 words)

  
 Consumer IC Advances -> Meeting MPEG-4 advanced audio coding requirements
It is also important to note that an MPEG-4 AAC main decoder can decode MPEG-2 AAC files.
The first is used to i mplement joint IS coding between two channels of a channel pair.
It is 10 times more efficient at implementing the same AAC algorithms because the ACM's SATS process targets the exact hardware req uired, algorithm by algorithm, for that moment in time.
www.us.design-reuse.com /articles/article2268.html   (1344 words)

  
 Advanced Audio Coding - Wikipedia
Advanced Audio Coding (AAC), ist ein von der MPEG, Moving Picture Experts Group (Dolby, Fraunhofer-Institut für Integrierte Schaltungen in Erlangen, ATandT, Nokia, Sony), entwickeltes Audiokompressionsverfahren, das als Weiterentwicklung des MPEG-2-Standards spezifiziert wurde.
So findet AAC unter anderem Verwendung in Online-Musikgeschäften wie dem iTunes Music Store oder dem Real Music Store sowie ehemals LiquidAudio und wird dort gepaart mit DRM-Systemen wie beispielsweise FairPlay von Apple.
Nokia, Samsung, SonyEricsson und andere verwenden ebenfalls AAC, um das Hören von Musik auf dem Handy zu ermöglichen.
de.wikipedia.org /wiki/Advanced_Audio_Coding   (355 words)

  
 MPEG-2 AAC Standard   (Site not responding. Last check: 2007-10-21)
Advanced Audio Coding, or AAC, is one of several audio coding systems specified in the MPEG-2 standard (ISO/IEC 13818-7).
MPEG-2 AAC is the audio format utilized in the Japanese Digital Broadcast system, known as ISDB (Integrated Services Digital Broadcasting).
MPEG-2 AAC is also the basis of the audio coding technology used by XM Radio, one of two satellite radio services currently operating in the United States.
www.vialicensing.com /products/mpeg2aac/standard.html   (158 words)

  
 AAC INFORMATION PAGE
A new AAC encoder, Astrid/Quartex was released in october 98
The AAC Main 128 was indistinguishable from the original for 80% of professional
MPEG-2 AAC is the Data Compression for the 21st Century and AAC shall be incorporated
www.fortunecity.com /tinpan/miles/528/aacinfo.htm   (823 words)

  
 Business Wire: Digigram Licenses MPEG Advanced Audio Coding, AAC; Premium Codec Will be Incorporated Into Digigram's ...
AAC is the latest technology co-developed by experts in the art and science of audio compression, and standardized as part of the MPEG-2 specification.
AAC is a product of the combined efforts of several organizations including AT&T, Dolby Laboratories, Fraunhofer Institute for Integrated Circuits, and Sony Corporation.
"AAC has gained momentum as exciting new hardware players from major consumer electronics manufacturers are appearing on retail shelves, and record companies such as BMG, Universal, and Warner Music have begun to distribute online music in AAC format", said Ramzi Haidamus, Dolby's director of business development.
www.findarticles.com /p/articles/mi_m0EIN/is_2001_Jan_11/ai_68991667   (415 words)

  
 Advanced Audio Coding (MPEG-4)
Information technology -- Coding of audio-visual objects -- Part 3: Audio (formal name for the relevant part of the MPEG-4 standard; note that this part covers several types of audio coding including Advanced Audio Coding).
Perceptual audio encoding format designed for efficient distribution of sound files over moderate bandwidth connections; may be used at higher data rates for better fidelity.
AAC has provision for up to 48 channels, and supports 5.1 (and 7.1?) surround sound.
www.digitalpreservation.gov /formats/fdd/fdd000114.shtml   (627 words)

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