Advanced Audio Coding (AAC) is a standardized, lossy compression and encoding scheme for digital audio. AAC is promoted as the successor to the MP3 format by MP3’s creator, Fraunhofer IIS. A filename extension is a suffix to the name of a computer file applied to indicate its type. ... 3GP is a multimedia container format defined by the Third Generation Partnership Project (3GPP) for use on 3G mobile phones. ... Original Image (lossless PNG, 60. ... A lossy data compression method is one where compressing data and then decompressing it retrieves data that may well be different from the original, but is close enough to be useful in some way. ... Audio compression is a form of data compression designed to reduce the size of audio files. ... An encoder is a device used to encode a signal (such as a bitstream) or data into a form that is acceptable for transmission or storage. ... Digital audio comprises audio signals stored in a digital format. ... For other uses, see MP3 (disambiguation). ... The Fraunhofer Society (German: Fraunhofer-Gesellschaft) is a German research organization with 58 institutes spread throughout Germany, each focusing on different fields of applied science (as opposed to the Max-Planck-Gesellschaft, which works primarily on basic science). ...

AAC generally achieves better sound quality than MP3 at the same bitrate, particularly below 192 kbit/s.^[1] For other uses, see MP3 (disambiguation). ... In telecommunications and computing, bitrate (sometimes written bit rate, data rate or as a variable Rbit) is the number of bits that are conveyed or processed per unit of time. ... A kilobit is a unit of information storage, abbreviated kbit or sometimes kb. ...

AAC’s most famous usage is as the default audio format of Apple's iPhone, iPod, iTunes, and the format used for all iTunes Store audio (with extensions for proprietary Digital Rights Management (DRM) where used). Apple Inc. ... For the Internet appliance line, see Linksys iPhone. ... iPod is a brand of portable media players designed and marketed by Apple and launched in October 2001. ... This article is about the iTunes application. ... The iTunes Store is an online business run by Apple Inc. ... Digital rights management (DRM) is an umbrella term that refers to access control technologies used by publishers and copyright holders to limit usage of digital media or devices. ...

AAC is also the standard audio format for Sony’s PlayStation 3 and the MPEG-4 video standard. HE-AAC is part of digital radio standards like DAB+ and Digital Radio Mondiale. Sony Corporation ) is a Japanese multinational corporation and one of the worlds largest media conglomerates with revenue of $66. ... The PlayStation 3 , trademarked PLAYSTATION®3,[3] commonly abbreviated PS3) is the third home video game console produced by Sony Computer Entertainment; successor to the PlayStation 2. ... MPEG-4 is a standard used primarily to compress audio and visual (AV) digital data. ... High Efficiency AAC (HE-AAC) is a lossy data compression scheme for digital audio. ... This article needs to be cleaned up to conform to a higher standard of quality. ... Digital Audio Broadcasting (DAB), also known as Eureka 147, is a technology for broadcasting of audio using digital radio transmission. ... Digital Radio Mondiale (DRM) is a set of digital audio broadcasting technologies designed to work over the bands currently used for AM broadcast, particularly shortwave. ...

History

AAC was developed with the cooperation and contributions of companies including Dolby, Fraunhofer IIS, AT&T, Sony and Nokia, and was officially declared an international standard by the Moving Pictures Experts Group in April 1997. Dolby Laboratories, Incorporated (Dolby Labs) is a company specializing in audio compression and reproduction. ... The Fraunhofer Society (German: Fraunhofer-Gesellschaft) is a German research organization with 58 institutes spread throughout Germany, each focusing on different fields of applied science (as opposed to the Max-Planck-Gesellschaft, which works primarily on basic science). ... This article is about the current AT&T. For the 1885-2005 company, see American Telephone & Telegraph. ... Sony Corporation ) is a Japanese multinational corporation and one of the worlds largest media conglomerates with revenue of $66. ... This article is about the telecommunications corporation. ... The Moving Picture Experts Group or MPEG is a working group of ISO/IEC charged with the development of video and audio encoding standards. ...

Standardization

It is specified both as Part 7 of the MPEG-2 standard, and Part 3 of the MPEG-4 standard. As such, it can be referred to as MPEG-2 Part 7 and MPEG-4 Part 3 depending on its implementation, however it is most often referred to as MPEG-4 AAC, or AAC for short.

AAC was first specified in the standard MPEG-2 Part 7 (known formally as ISO/IEC 13818-7:1997) in 1997 as a new "part" (distinct from ISO/IEC 13818-3) in the MPEG-2 family of international standards. “ISO” redirects here. ... The International Electrotechnical Commission (IEC) is an international standards organization dealing with electrical, electronic and related technologies. ... “ISO” redirects here. ... The International Electrotechnical Commission (IEC) is an international standards organization dealing with electrical, electronic and related technologies. ... MPEG-2 is a standard for the generic coding of moving pictures and associated audio information [1]. It is widely used around the world to specify the format of the digital television signals that are broadcast by terrestrial (over-the-air), cable, and direct broadcast satellite TV systems. ... Standards are produced by many organizations, some for internal usage only, others for use by a groups of people, groups of companies, or a subsection of an industry. ...

It was updated in MPEG-4 Part 3 (known formally as ISO/IEC 14496-3:1999) in 1999. The reference software is specified in MPEG-4 Part 4 and the conformance bitstreams are specified in MPEG-4 Part 5. A notable addition in this version of the standard is Perceptual Noise Substitution (PNS). MPEG-4 Part 3 (formally ISO/IEC 14496-3) is the third part of the ISO/IEC MPEG-4 international standard. ...

HE-AAC (AAC with SBR) was first standardized in ISO/IEC 14496-3:2001/Amd.1. HE-AAC v2 (AAC with Parametric Stereo) was first specified in ISO/IEC 14496-3:2001/Amd.4. ^[2] High Efficiency AAC (HE-AAC) is a lossy data compression scheme for digital audio. ... Spectral band replication (SBR) is a technology to enhance audio or speech codecs, especially at low bit rates. ...

The current version of the AAC standard is ISO/IEC 14496-3:2005 (with 14496-3:2005/Amd.2. for HE-AAC v2^[3])

AacPlus v2 is also standardized by ETSI (European Telecommunications Standards Institute) as TS 102005.^[2] The European Telecommunications Standards Institute (ETSI) is a standardization organization of the telecommunications industry (equipment makers and network operators) in Europe, with worldwide projection. ... The European Telecommunications Standards Institute (ETSI) is a standardization organization of the telecommunications industry (equipment makers and network operators) in Europe, with worldwide projection. ...

The MPEG4 standard also contains other ways of compressing sound. These are low bit rate and generally used for speech.

AAC’s improvements over MP3

AAC was designed to have better performance than MP3 (which was specified in MPEG-1 and MPEG-2) by the ISO/IEC in 11172-3 and 13818-3. For other uses, see MP3 (disambiguation). ... MPEG-1 defines a group of Audio and Video (AV) coding and compression standards agreed upon by MPEG (Moving Picture Experts Group). ... MPEG-2 is a standard for the generic coding of moving pictures and associated audio information [1]. It is widely used around the world to specify the format of the digital television signals that are broadcast by terrestrial (over-the-air), cable, and direct broadcast satellite TV systems. ... “ISO” redirects here. ... The International Electrotechnical Commission (IEC) is an international standards organization dealing with electrical, electronic and related technologies. ...

Improvements include:

• More sample frequencies (from 8 kHz to 96 kHz) than MP3 (16 kHz to 48 kHz)
• Up to 48 channels (MP3 supports up to two channels in MPEG-1 mode and up to 5.1 channels in MPEG-2 mode)
• Arbitrary bitrates and variable frame length. Standardized constant bit rate with bit reservoir.
• Higher efficiency and simpler filterbank (hybrid → pure MDCT)
• Higher coding efficiency for stationary signals (blocksize: 576 → 1024 samples)
• Higher coding efficiency for transient signals (blocksize: 192 → 128 samples)
• Can use Kaiser-Bessel derived window function to eliminate spectral leakage at the expense of widening the main lobe
• Much better handling of audio frequencies above 16 kHz
• More flexible joint stereo (separate for every scale band)
• Adds additional modules (tools) to increase compression efficiency: TNS, Backwards Prediction, PNS etc... These modules can be combined to constitute different encoding profiles.

Overall, the AAC format allows developers more flexibility to design codecs than MP3 does. This increased flexibility often leads to more concurrent encoding strategies and, as a result, to more efficient compression. However in terms of whether AAC is better than MP3, the advantages of AAC are not entirely conclusive, and the MP3 specification, while outdated, has proven surprisingly robust. AAC and HE-AAC are better than MP3 at low bitrates (typically less than 192 kbit/s). The sampling frequency or sampling rate defines the number of samples per second taken from a continuous signal to make a discrete signal. ... A kilohertz (kHz) is a unit of frequency equal to 1,000 hertz (1,000 cycles per second). ... A kilohertz (kHz) is a unit of frequency equal to 1,000 hertz (1,000 cycles per second). ... In telecommunications and computing, bit rate (sometimes written bitrate) is the frequency at which bits are passing a given (physical or metaphorical) point. It is quantified using the bit per second (bit/s) unit. ... A filter bank is an array of band-pass filters that separates the input signal into several components, each one carrying a single frequency subband of the original signal. ... modified discrete cosine transform (MDCT) is a Fourier-related transform based on the type-IV discrete cosine transform (DCT-IV), with the additional property of being lapped: it is designed to be performed on consecutive blocks of a larger dataset, where subsequent blocks are overlapped so that the last half... In the mathematical sciences, a stationary process (or strict(ly) stationary process) is a stochastic process in which the probability density function of some random variable X does not change over time or position. ... In acoustics and audio, a transient is a short-duration signal that represents a non-harmonic attack phase of a musical sound or spoken word. ... The Kaiser window is a nearly optimal window function wk used for digital signal processing, and is defined by the formula: Kaiser window function for n=100 and α= 0. ... When taking the discrete Fourier transform (DFT) of a signal (e. ... Main lobe: Of an antenna radiation pattern, the lobe containing the maximum power (exhibiting the greatest field strength). ... In audio engineering, joint refers to a joining of several channels of similar information in some way, in order to obtain, for example, higher quality or smaller file size. ...

How AAC works

AAC is a wideband audio coding algorithm that exploits two primary coding strategies to dramatically reduce the amount of data needed to represent high-quality digital audio.

1. Signal components that are perceptually irrelevant are discarded;
2. Redundancies in the coded audio signal are eliminated.

Furthermore:

• The signal is processed by a modified discrete cosine transform (MDCT) according to its complexity;
• Internal error correction codes are added;
• The signal is stored or transmitted.
• In order to prevent corrupt samples, a modern implementation of the Luhn mod N algorithm is applied to each frame

The MPEG-4 audio standard does not define a single or small set of highly efficient compression schemes but rather a complex toolbox to perform a wide range of operations from low bitrate speech coding to high-quality audio coding and music synthesis. modified discrete cosine transform (MDCT) is a Fourier-related transform based on the type-IV discrete cosine transform (DCT-IV), with the additional property of being lapped: it is designed to be performed on consecutive blocks of a larger dataset, where subsequent blocks are overlapped so that the last half... The Luhn mod N algorithm is an extension to the Luhn algorithm (also known as mod 10 algorithm) that allows it to work with sequences of non-numeric characters. ... MPEG-4 is a standard used primarily to compress audio and visual (AV) digital data. ...

• The MPEG-4 audio coding algorithm family spans the range from low bitrate speech encoding (down to 2 kbit/s) to high-quality audio coding (at 64 kbit/s per channel and higher).
• AAC offers sampling frequencies between 8 kHz and 96 kHz and any number of channels between 1 and 48.
• In contrast to MP3's hybrid filter bank, AAC uses the modified discrete cosine transform (MDCT) together with the increased window lengths of 1024 points.

AAC encoders can switch dynamically between a single MDCT block of length 1024 points or 8 blocks of 128 points. MPEG-4 is a standard used primarily to compress audio and visual (AV) digital data. ... The modified discrete cosine transform (MDCT) is a Fourier-related transform based on the type-IV discrete cosine transform (DCT-IV), with the additional property of being lapped: it is designed to be performed on consecutive blocks of a larger dataset, where subsequent blocks are overlapped so that the last...

• If a signal change or a transient occurs, 8 shorter windows of 128 points each are chosen for their better temporal resolution.
• By default, the longer 1024-point window is otherwise used because the increased frequency resolution allows for a more sophisticated psychoacoustic model, resulting in improved coding efficiency.

Modular encoding

AAC takes a modular approach to encoding. Depending on the complexity of the bitstream to be encoded, the desired performance and the acceptable output, implementers may create profiles to define which of a specific set of tools they want use for a particular application. The standard offers four default profiles:

• Low Complexity (LC) - the simplest and most widely used and supported;
• Main Profile (MAIN) - like the LC profile, with the addition of backwards prediction;
• Sample-Rate Scalable (SRS), a.k.a. Scalable Sample Rate (MPEG-4 AAC-SSR);
• Long Term Prediction (LTP); added in the MPEG-4 standard – an improvement of the MAIN profile using a forward predictor with lower computational complexity.

Depending on the AAC profile and the MP3 encoder, 96 kbit/s AAC can give nearly the same or better perceptional quality as 128 kbit/s MP3.^[4] MPEG-4 AAC-SSR or MPEG-4 Advanced Audio Coding - Scalable Sample Rate was introduced by Sony to the MPEG-4 standard. ...

AAC error protection toolkit

Applying error protection enables error correction up to a certain extent. Error correcting codes are usually applied equally to the whole payload. However since different parts of an AAC payload show different sensitivity to transmission errors, this would not be a very efficient approach.

The AAC payload can be subdivided into parts with different error sensitivities.

• Independent error correcting codes can be applied to any of these parts using the Error Protection (EP) tool defined in MPEG-4 Audio.
• This toolkit provides the error correcting capability to the most sensitive parts of the payload in order to keep the additional overhead low.

Error Resilient (ER) AAC

Error Resilience (ER) techniques can be used to make the coding scheme itself more robust against errors.

For AAC, three custom-tailored methods were developed and defined in MPEG-4 Audio

• Huffman Codeword Reordering (HCR) to avoid error propagation within spectral data;
• Virtual Codebooks (VCB11) to detect serious errors within spectral data;
• Reversible Variable Length Code (RVLC) to reduce error propagation within scale factor data.

AAC Low Delay

Main article: AAC-LD

The MPEG-4 Low Delay Audio Coder (AAC-LD) is designed to combine the advantages of perceptual audio coding with the low delay necessary for two-way communication. It is closely derived from the MPEG-2 Advanced Audio Coding (AAC) format. AAC Low Delay The MPEG-4 Low Delay Audio Coder (AAC-LD) is designed to combine the advantages of perceptual audio coding with the low delay necessary for two-way communication. ... AAC Low Delay The MPEG-4 Low Delay Audio Coder (AAC-LD) is designed to combine the advantages of perceptual audio coding with the low delay necessary for two-way communication. ...

Promoting aspects

Licensing and patents

No licenses or payments are required to be able to stream or distribute content in AAC format. ^[5] This reason alone makes AAC a much more attractive format to distribute content than MP3, particularly for streaming content (such as Internet radio).

However, a patent license is required for all manufacturers or developers of AAC codecs, that require encoding or decoding.^[6] It is for this reason FOSS implementations such as FAAC and FAAD are distributed in source form only, in order to avoid patent infringement. FOSS is an acronym for free and open source software that is most often used in English-speaking military software communities. ... Advanced Audio Coding (AAC) is a standardized, lossy compression and encoding scheme for digital audio. ... Source code (commonly just source or code) is any series of statements written in some human-readable computer programming language. ...

AAC requires a patent license, and thus uses proprietary technology. But contrary to popular belief, it is not the property of a single company, having been developed in a standards-making organization. Proprietary indicates that a party, or proprietor, exercises private ownership, control or use over an item of property, usually to the exclusion of other parties. ...

Marketing aspects

AAC was promoted as the successor to MPEG 1.0 audio, layer III (MP3) for audio coding at medium to high bitrates, although lower bitrates are its forte. While much less popular than MP3, its sustainability is currently maintained by it being the default Apple iTunes codec, the media player which inter-operates with the iPod, the market leading digital audio player.^[7] Furthermore, the iTunes Store, whose sales account for 85% of the market for legal online downloads in the US, ^[8] sells AAC-encoded songs (mostly encapsulated within FairPlay Digital Rights Management). Apple Inc. ... This article is about the iTunes application. ... A codec is a device or program capable of performing encoding and decoding on a digital data stream or signal. ... iPod is a brand of portable media players designed and marketed by Apple and launched in October 2001. ... The iTunes Store is an online business run by Apple Inc. ... FairPlay is a digital rights management (DRM) technology created by Apple Inc. ... Digital rights management (DRM) is an umbrella term that refers to access control technologies used by publishers and copyright holders to limit usage of digital media or devices. ...

Products that support AAC

Hardware

iTunes and iPod

In April 2003, Apple Computer brought mainstream attention to AAC by announcing that its iTunes and iPod products would support songs in MPEG-4 AAC format (via a firmware update for older iPods). Customers could download music in a proprietary Digital Rights Management (DRM)-restricted form of AAC (see FairPlay) via the iTunes Store or create files without DRM from their own CDs using iTunes. In later years, Apple began offering music videos and movies, which also use AAC for audio encoding. Apple Inc. ... This article is about the iTunes application. ... iPod is a brand of portable media players designed and marketed by Apple and launched in October 2001. ... A microcontroller, like this PIC18F8720 is controlled by firmware stored inside on FLASH memory In computing, firmware is a computer program that is embedded in a hardware device, for example a microcontroller. ... Digital rights management (DRM) is an umbrella term that refers to access control technologies used by publishers and copyright holders to limit usage of digital media or devices. ... FairPlay is a digital rights management (DRM) technology created by Apple Inc. ... The iTunes Store is an online business run by Apple Inc. ...

On May 29, 2007, Apple began selling songs and music videos free of DRM from participating record labels. These files mostly adhere to the AAC standard and are playable on many non-Apple products but they do include custom iTunes information such as album artwork and a purchase receipt.

iTunes supports a "Variable bit rate" (VBR) encoding option which encodes AAC tracks in an "Average bit rate" (ABR) scheme. As of October 2007, Apple has still not added support for HE-AAC which is fully part of the MP4 standard or true VBR encoding to iTunes. High Efficiency AAC (HE-AAC) is a lossy data compression scheme for digital audio. ...

Other Portable Players

• Creative Zen Portable
• Microsoft Zune
• SanDisk Sansa e200R
• Sony PlayStation Portable (PSP) with firmware 2.0 or greater
• Sony Walkman S

The Creative ZEN (formerly known as Creative NOMAD Jukebox Zen) is a range of digital audio players (DAPs) and portable media players (PMPs) made by Creative Technology. ... Microsoft Corporation, (NASDAQ: MSFT, HKSE: 4338) is a multinational computer technology corporation with global annual revenue of US$44. ... This article is about the digital media brand. ... SanDisk Corporation (NASDAQ: SNDK), formerly SunDisk, is an American multinational corporation which designs and markets flash memory card products. ... The SanDisk Sansa is a line of flash memory-based digital audio players produced by SanDisk. ... Sony Corporation ) is a Japanese multinational corporation and one of the worlds largest media conglomerates with revenue of $66. ... The PlayStation Portable , officially abbreviated as PSP) is a handheld game console released and currently manufactured by Sony Computer Entertainment. ... Sony Corporation ) is a Japanese multinational corporation and one of the worlds largest media conglomerates with revenue of $66. ... Sony Walkman Official Logo (2000 — present) Various products of the Walkman line Walkman is a popular Sony brand used to market its portable audio and video players. ...

Mobile phones

For a number of years, many mobile phones from manufacturers such as Nokia, Motorola, Samsung, Sony Ericsson, BenQ-Siemens and Philips have supported AAC playback. The first such phone was the Nokia 5510 released in 2002 which also plays MP3s. However this phone was a commercial failure and such phones with integrated music players did not gain mainstream popularity until 2005 when the trend of having AAC as well as MP3 support continued. Most new smartphones and music-themed phones support playback of these formats. This article is about the telecommunications corporation. ... Motorola Inc. ... Samsung Group is one of the largest South Korean business groupings. ... For an arrangement of Sony Ericsson products, see list of Sony Ericsson products Sony Ericsson is a joint venture established in 2001 by the Japanese consumer electronics company Sony Corporation and the Swedish telecommunications company Ericsson to make mobile phones. ... BenQ Corporation (IPA: ; Chinese: ) is a Taiwan-based company specializing in the manufacturing of computing, communications, and consumer electronics devices. ... Philips HQ in Amsterdam Koninklijke Philips Electronics N.V. (Royal Philips Electronics N.V.), usually known as Philips, (Euronext: PHIA, NYSE: PHG) is one of the largest electronics companies in the world, founded and headquartered in the Netherlands. ... Nokia 5510. ...

• Apple's iPhone supports AAC and FairPlay protected AAC files used as the default encoding format in the iTunes store.
• Sony Ericsson phones support various AAC formats in MP4 container. AAC-LC is supported in all phones beginning with K700, phones beginning with W550 have support of HE-AAC. The latest devices such as the P990, K800 and later support HE-AAC v2.
• Nokia Nseries and other Nokia multimedia phones: also support AAC format.
• BlackBerry: RIM’s latest series of Smartphones such as the 8100 ("Pearl") and 8800 support AAC.
• The Samsung SGH-X630 plays AAC only as raw files and refuses to play when AAC is wrapped in the MP4 container^{[citation needed]}. It plays LC files as well as HE-AAC and HE-AAC v2 files.Also the d807x only allows for the use of .aac.dm files as ringtones.
• The LG Ku250 3G For All Phone

Apple Inc. ... For the Internet appliance line, see Linksys iPhone. ... FairPlay is a digital rights management (DRM) technology created by Apple Inc. ... For an arrangement of Sony Ericsson products, see list of Sony Ericsson products Sony Ericsson is a joint venture established in 2001 by the Japanese consumer electronics company Sony Corporation and the Swedish telecommunications company Ericsson to make mobile phones. ... The Sony Ericsson K700i was introduced in 2004 as a high-end mobile phone, and as a successor to the T630. ... // The Phone W600/w550 is sonyericssons second swivel phone and first swivel walkman phone. ... Sony Ericsson P990 is a smartphone and the successor of Sony Ericsson P910. ... The Sony Ericsson K800, and its variant, the Sony Ericsson K790, are the latest mobile phones of their class from Sony Ericsson. ... Nokia Nseries is a product family consisting of multimedia computers. ... This article is about the wireless e-mail device. ...

Other Devices

• Palm OS PDAs: Many Palm OS based PDAs and smartphones can play AAC and HE-AAC with the 3rd party software Pocket Tunes. Version 4.0, released in December 2006, added support for native AAC and HE-AAC files. The AAC codec for TCPMP, a popular video player, was withdrawn after version 0.66 due to patent issues, but can still be downloaded from sites other than corecodec.org. CorePlayer, the commercial follow-on to TCPMP, includes AAC support. Other PalmOS programs supporting AAC include Kinoma Player and AeroPlayer.
• Microsoft Windows Mobile platforms support AAC either by the native Windows Media Player or by third-party products (TCPMP, CorePlayer)
• Epson supports AAC playback in the P-2000 and P-4000 Multimedia/Photo Storage Viewers. This support is not available with their older models, however.

• Vosonic supports AAC recording and playback in the VP8350, VP8360 and VP8390 MultiMedia Viewers.

• The Sony Reader portable eBook plays M4A files containing AAC, and displays metadata created by iTunes. Other Sony products, including the A and E series Network Walkmans, support AAC with firmware updates (released May 2006). While the S series supports it out of the box.

• Nearly every major car stereo manufacturer offers models that will play back .m4a files recorded onto CD in a data format. This includes Pioneer, Sony, Alpine, Kenwood, Clarion, Panasonic, and JVC.

• The Sonos Digital Media Player supports playback of AAC files.

• The Roku SoundBridge network audio player supports playback of AAC encoded files.

• The Squeezebox network audio player (made by Slim Devices, a Logitech company) supports playback of AAC files.

• Nintendo has announced that version 1.1 of the Wii Photo Channel will replace MP3 compatibility with the ability to play AAC files. ^[9]

Palm OS is an embedded operating system initially developed by U.S. Robotics owned Palm Computing, Inc. ... User with Treo (PDA with smartphone functionality) Personal digital assistants (PDAs) are handheld computers, but have become much more versatile over the years. ... Pocket Tunes is shareware software for PalmOS 5, an operating system for PDAs, used for playing music or other sound files. ... The Core Pocket Media Player (TCPMP) is the most versitile and dual license Media Player available today. ... Windows Mobile is a compact operating system combined with a suite of basic applications for mobile devices based on the Microsoft Win32 API. Devices which run Windows Mobile include Pocket PCs, Smartphones, Portable Media Centers, and on-board computers for certain Automobiles. ... Windows Media Player (WMP) is a digital media player and media library application developed by Microsoft that is used for playing audio, video and viewing images on personal computers running the Microsoft Windows operating system, as well as on Pocket PC and Windows Mobile-based devices. ... A four colour Epson Stylus C45 inkjet printer Epson is one of the worlds largest manufacturers of inkjet, dot-matrix and laser printers, scanners, desktop computers, business, multimedia and home theatre projectors, point of sale docket printers and cash registers, laptops, integrated circuits, LCD components and other associated electronic... The Sony PRS-500 Reader is an e-book reader for the U.S. market. ... Old Pioneer Logo (Until 1998) Pioneer Corporation ) (TYO: 6773 ) is a Japanese multinational corporation that specializes in digital entertainment products, based in Tokyo, Japan. ... Sony Corporation ) is a Japanese multinational corporation and one of the worlds largest media conglomerates with revenue of $66. ... Alpine may refer to: Alpine, a breed of goat. ... Kenwood has multiple meanings, among them: Kenwood House in London, and its surrounding woods. ... Clarion can be: Clarion programming language Clarion, Iowa Clarion, Pennsylvania The Clarion Workshop, a six-week workshop for aspiring science fiction writers, held each summer at Michigan State University Clarion (car audio), a car audio brand Clarion (newspaper), a British socialist newspaper of the nineteenth century Clarion (musical instrument), a... Panasonic is an international brand name for Japanese electric products manufacturer Matsushita Electric Industrial Co. ... Victor Company of Japan, Limited ) (TYO: 6792 ), usually referred to as JVC, is an international consumer and professional electronics corporation based in Yokohama, Japan which was founded in 1927. ... Wikipedia does not have an article with this exact name. ... A SoundBridge is a remote hardware device from Roku designed to play internet radio or digital audio streamed to it across a home network, either WiFi or Ethernet. ... The Squeezebox is a hardware device from Slim Devices. ... Slim Devices are a consumer electronics company based in Mountain View, California. ... This article or section does not cite any references or sources. ... Nintendo Company, Limited (任天堂 or ニンテンドー Nintendō; NASDAQ: NTDOY, TYO: 7974 usually referred to as simply Nintendo, or Big N ) is a multinational corporation founded on September 23, 1889[1] in Kyoto, Japan by Fusajiro Yamauchi to produce handmade hanafuda cards. ... The Wii (pronounced as the pronoun we, IPA: ) is the fifth home video game console released by Nintendo. ... The Wii Menu is the top level menu interface of the Wii game console. ...

Software

The Rockbox Open source firmware (available for multiple portable players) also offers support for AAC to varying degrees, depending on the model of player and the AAC profile. Rockbox is a free software replacement for the firmware held on various forms of digital audio players (DAPs). ... Open source refers to projects that are open to the public and which draw on other projects that are freely available to the general public. ... A microcontroller, like this PIC18F8720 is controlled by firmware stored inside on FLASH memory In computing, firmware is a computer program that is embedded in a hardware device, for example a microcontroller. ...

Optional iPod Support (playback of unprotected AAC files) for the Xbox 360 is available as a free download from Xbox Live.^[10] It has been suggested that Xbox 360 Elite be merged into this article or section. ... Xbox Live is a subscription-based online gaming service for Microsofts Xbox and Xbox 360 video game consoles. ...

Other software media players

Almost all current computer media players include built-in decoders for AAC, or can utilize a library to decode it. On Microsoft Windows, DirectShow can be utilized this way with the corresponding filters to enable AAC playback in any DirectShow based player. Software player applications of particular note include: Illustration of an application which may use libvorbisfile. ... Windows redirects here. ... Logo of the DirectX Media SDK - the first time DirectShow was distributed under its current name. ... Logo of the DirectX Media SDK - the first time DirectShow was distributed under its current name. ...

• ffdshow is a free open source DirectShow filter for Microsoft Windows operating systems that uses FAAD2 to support AAC decoding
• foobar2000 is a freeware audio player for Windows that supports LC and HE AAC
• Winamp for Windows, which includes an AAC encoder that supports LC and HE AAC;
• Songbird (software) for Windows, Linux and Apple Macintosh, which is based on I-Tunes that supports AAC encoder, including the DRM rights management encoding used for purchased music from the I-Tunes store.
• MPlayer or xine are often used as AAC decoders on Linux
• RealPlayer includes RealNetworks’s RealAudio 10 AAC encoder
• Another Real product, Rhapsody supports the RealAudio AAC codec, in addition to offering subscription tracks encoded with AAC.
• VLC media player supports playback of MP4 and AAC files
• Media Player Classic
• XBMC (XBox Media Center) supports both AAC (LC and HE) on modified Xbox game-consoles.
• KSP Sound Player also supports AAC
• Sony SonicStage also support AAC in the version 4,
• The KMPlayer also supports AAC
• XMMS supports mp4 playback using a plugin provided by the faad2 library.
• ConvertDirect.com serves AAC Files using Youtube Video conversion. It converts Youtube video to AACs.

Some of these players (e.g., foobar2000, Winamp, and VLC) also support the decoding of raw or MP4-contained AAC streamed over HTTP using the SHOUTcast protocol. Plug-ins for Winamp and foobar2000 enable the creation of such streams. ffdshow is an open source decoder (and encoder) mainly used for the fast and high-quality decoding of video in the MPEG-4 ASP (e. ... Open source refers to projects that are open to the public and which draw on other projects that are freely available to the general public. ... Logo of the DirectX Media SDK - the first time DirectShow was distributed under its current name. ... Windows redirects here. ... foobar2000 is a freeware audio player for Windows developed by Peter Pawlowski, a former freelance contractor for Nullsoft. ... The term Freeware refers to gratis proprietary software with closed source. ... An audio player is a kind of media player for playing back digital audio, including optical discs such as CDs, SACDs, DVD-Audio, HDCD, and audio files. ... Windows redirects here. ... Winamp is a proprietary media player written by Nullsoft, now a subsidiary of Time Warner. ... Windows redirects here. ... Songbird is a free software media player and web browser developed by The Songbird Team, (previously responsible for both Winamp and the Yahoo! Music Engine), with a stated mission to incubate Songbird, the first Web player, to catalyze and champion a diverse, open Media Web. ... Windows redirects here. ... This article is about operating systems that use the Linux kernel. ... The first Macintosh computer, introduced in 1984, upgraded to a 512K Fat Mac. The Macintosh or Mac, is a line of personal computers designed, developed, manufactured, and marketed by Apple Computer. ... This article is about the open source media player. ... xine (officially pronounced [ksi:n], like the name Maxine without Ma[1]) is a multimedia playback engine for Unix-like operating systems released under the GNU General Public License. ... This article is about operating systems that use the Linux kernel. ... RealPlayer, briefly known also as RealOne Player, is a cross-platform media player by RealNetworks that plays a number of multimedia formats including MP3, MPEG-4, QuickTime, Windows Media and multiple versions of proprietary RealAudio and RealVideo formats. ... This article does not cite any references or sources. ... Rhapsody is an online music service run by RealNetworks. ... VLC media player is a free software media player by the VideoLAN project. ... Media Player Classic (MPC) is a compact free software media player for Microsoft Windows. ... Xbox Media Center (aka XBMC) is a feature-rich open source media player for the Xbox that many have called a killer app. ... The Xbox is a sixth generation era video game console produced by Microsoft Corporation. ... KSP (KSP Sound Player or Kalliope Sound Player) is a free audio player for Windows which is developed and distributed by Kalliope s. ... Sony Corporation ) is a Japanese multinational corporation and one of the worlds largest media conglomerates with revenue of $66. ... SonicStage is the name for Sony software that is used for managing portable devices when they are plugged into a computer running Windows. ... Not to be confused with KMPlayer. ... XMMSs default appearance The X Multimedia System (XMMS) is a free audio player very similar to Winamp, that runs on many Unix-like operating systems. ... SHOUTcast is a multiplatform freeware digital audio streaming technology developed by Nullsoft. ...

Nero Digital Audio

In May 2006, Nero AG released a free AAC encoding tool, Nero Digital Audio [2], which is capable of encoding LC, HE and HEv2 AAC streams. The tool is a Command Line Interface tool only, and a separate utility is included to decode to PCM WAV. Nero AG is a German software company based in Karlsbad, Germany. ... This article or section does not adequately cite its references or sources. ... WAV (or WAVE), short for Waveform audio format, is a Microsoft and IBM audio file format standard for storing audio on PCs. ...

Various tools including the foobar2000 audio player and MeGUI can provide a GUI for the encoder. foobar2000 is a freeware audio player for Windows developed by Peter Pawlowski, a former freelance contractor for Nullsoft. ... The introduction to this article provides insufficient context for those unfamiliar with the subject matter. ... GUI can refer to the following: GUI is short for graphical user interface, a term used to describe a type of interface in computing. ...

FAAC and FAAD2

FAAC and FAAD2 stand for Freeware Advanced Audio Coder and Decoder 2 respectively, collectively make up an open source implementation of AAC.

Extensions and improvements

Some extensions have been added to the original AAC standard:

• Perceptual Noise Substitution (PNS) – added in MPEG-4. It allows the coding of noise as pseudorandom data;
• MPEG-4 Scalable To Lossless (SLS);
• High Efficiency AAC (HE-AAC), a.k.a. aacPlus v1 or AAC+ – the combination of SBR (Spectral Band Replication) and AAC; used for low bitrates;
• HE-AAC v2, a.k.a. aacPlus v2 or eAAC+ – the combination of Parametric Stereo (PS) and HE-AAC; used for even lower bitrates;
• Long Term Predictor (LTP) – added in MPEG-4.

MPEG-4 Part 3 (formally ISO/IEC 14496-3) is the third part of the ISO/IEC MPEG-4 international standard. ... A pseudo-random number is a number belonging to a sequence which appears to be random, but can in fact be generated by a finite computation. ... MPEG-4 SLS, also known as as MPEG-4 Scalable to Lossless as per ISO/IEC 14496-3:2005/Amd 3:2006 (Scalable Lossless Coding), is an extension to the MPEG-4 audio standard to allow lossless audio compression scalable to lossy AAC. It was developed jointly by Infocomm Research... High Efficiency AAC (HE-AAC) is a lossy data compression scheme for digital audio. ... Spectral band replication (SBR) is a technology to enhance audio or speech codecs, especially at low bit rates. ... High Efficiency AAC (HE-AAC) is a lossy data compression scheme for digital audio. ... Parametric Stereo is a feature used in Advanced Audio Coding to further enhance efficiency in low bandwidth stereo media. ...

See also

• AAC-LD
• MPEG-4 container format

AAC Low Delay The MPEG-4 Low Delay Audio Coder (AAC-LD) is designed to combine the advantages of perceptual audio coding with the low delay necessary for two-way communication. ... MP4 can refer to: MPEG-4 Part 14 file format Møller-Plesset perturbation theory of the fourth order This is a disambiguation page — a navigational aid which lists pages that might otherwise share the same title. ...

Notes

1. ^ http://www.soundexpert.info/
2. ^ ^{a b} http://www.codingtechnologies.com/products/assets/CT_aacPlus_whitepaper.pdf
3. ^ ISO/IEC 14496-3:2005/Amd.2 [1]
4. ^ http://www.apple.com/quicktime/technologies/aac/
5. ^ Via Licensing. MPEG-4 Audio Licensing FAQ Q6.
6. ^ Via Licensing. MPEG-4 AAC License Fees.
7. ^ http://www.apple.com/pr/library/2006/jul/19results.html
8. ^ http://www.appleinsider.com/article.php?id=1896
9. ^ http://www.nintendo.com/consumer/systems/wii/en_na/channelsPhoto.jsp#photo1.1
10. ^ http://www.xbox.com/en-US/support/systemuse/xbox360/digitalmedia/ipod.htm

External Links

• Apple's page on MPEG-4 AAC
• Fraunhofer MPEG-2 AAC Information
• AudioCoding.com - home of FAAC and FAAD2