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EAAC
High-Efficiency Advanced Audio Coding (HE-AAC) is an audio coding format for lossy data compression of digital audio as part of the MPEG-4 standards. It is an extension of Low Complexity AAC (AAC-LC) optimized for low- bitrate applications such as streaming audio. The usage profile HE-AAC v1 uses spectral band replication (SBR) to enhance the modified discrete cosine transform (MDCT) compression efficiency in the frequency domain. The usage profile HE-AAC v2 couples SBR with Parametric Stereo (PS) to further enhance the compression efficiency of stereo signals. HE-AAC is defined as an MPEG-4 Audio profile in ISO/ IEC 14496–3. HE-AAC is used in digital radio standards like HD Radio, DAB+ and Digital Radio Mondiale. History The progenitor of HE-AAC was developed by Coding Technologies by combining MPEG-2 AAC-LC with a proprietary mechanism for spectral band replication (SBR), to be used by XM Radio for their satellite radio service. Subsequently, Coding Tec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HE-AAC And HE-AAC V2
High-Efficiency Advanced Audio Coding (HE-AAC) is an audio coding format for lossy data compression of digital audio as part of the MPEG-4 standards. It is an extension of Low Complexity AAC (AAC-LC) optimized for low-bitrate applications such as streaming audio. The usage profile HE-AAC v1 uses spectral band replication (SBR) to enhance the modified discrete cosine transform (MDCT) compression efficiency in the frequency domain. The usage profile HE-AAC v2 couples SBR with Parametric Stereo (PS) to further enhance the compression efficiency of stereo signals. HE-AAC is defined as an MPEG-4 Audio profile in ISO/IEC 14496–3. HE-AAC is used in digital radio standards like HD Radio, DAB+ and Digital Radio Mondiale. History The progenitor of HE-AAC was developed by Coding Technologies by combining MPEG-2 AAC-LC with a proprietary mechanism for spectral band replication (SBR), to be used by XM Radio for their satellite radio service. Subsequently, Coding Technologies sub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MPEG-4 SLS
MPEG-4 SLS, or MPEG-4 Scalable to Lossless as per International Organization for Standardization, ISO/International Electrotechnical Commission, IEC 14496-3:2005/Amd 3:2006 (Scalable Lossless Coding), is an extension to the MPEG-4 Part 3 (MPEG-4 Audio) standard to allow Lossless data compression, lossless Audio data compression, audio compression scalable to lossy MPEG-4 General Audio coding methods (e.g., variations of Advanced Audio Coding, AAC). It was developed jointly by the Institute for Infocomm Research (I2R) and Fraunhofer Society, Fraunhofer, which commercializes its implementation of a limited subset of the standard under the name of HD-AAC. Standardization of the HD-AAC profile for MPEG-4 Audio is under development (as of September 2009). MPEG-4 SLS allows having both a lossy layer and a lossless correction layer similar to Wavpack Hybrid, OptimFROG DualStream and DTS-HD Master Audio, providing backwards compatibility to MPEG Advanced Audio Coding, AAC-compliant bitstr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frequency Domain
In mathematics, physics, electronics, control systems engineering, and statistics, the frequency domain refers to the analysis of mathematical functions or signals with respect to frequency (and possibly phase), rather than time, as in time series. While a time-domain graph shows how a signal changes over time, a frequency-domain graph shows how the signal is distributed within different frequency bands over a range of frequencies. A complex valued frequency-domain representation consists of both the magnitude and the phase of a set of sinusoids (or other basis waveforms) at the frequency components of the signal. Although it is common to refer to the magnitude portion (the real valued frequency-domain) as the frequency response of a signal, the phase portion is required to uniquely define the signal. A given function or signal can be converted between the time and frequency domains with a pair of mathematical operators called transforms. An example is the Fourier transfo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ogg Vorbis
Vorbis is a free and open-source software project headed by the Xiph.Org Foundation. The project produces an audio coding format and software reference encoder/decoder (codec) for lossy audio compression, libvorbis. Vorbis is most commonly used in conjunction with the Ogg container format and it is therefore often referred to as Ogg Vorbis. Version 1.0 of Vorbis was released in May 2000. Since 2013, the Xiph.Org Foundation has stated that the use of Vorbis should be deprecated in favor of the Opus codec, an improved and more efficient format that has also been developed by Xiph.Org. Name Vorbis is named after the character Exquisitor Vorbis in the '' Discworld'' novel '' Small Gods'' by Terry Pratchett. The Ogg format is named after ''ogging'', jargon from the computer game ''Netrek''. Development Vorbis is a continuation of audio compression development started in 1993 by Chris Montgomery. Intensive development began following a September 1998 letter from the Fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mp3PRO
mp3PRO is an unmaintained proprietary audio compression codec that combines the MP3 audio format with the spectral band replication (SBR) compression method. At the time it was developed it could reduce the size of a stereo MP3 by as much as 50% while maintaining the same relative quality. This works, fundamentally, by discarding the higher half of the frequency range and algorithmically replicating that information while decoding. The technology behind SBR was developed by the former Swedish company Coding Technologies AB (acquired by Dolby Laboratories in 2007) in the late 1990s. It was included in their MPEG-2 AAC derived codec aacPlus, which would later be standardized as MPEG-4 HE-AAC. Thomson Multimedia (now Technicolor SA) licensed the technology and used it to extend the MP3 format, for which they held patents, hoping to also extend its profitable lifetime. This was released as mp3PRO in 2001. It was originally claimed that mp3PRO files were compatible with existing MP3 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RMSD
The root mean square deviation (RMSD) or root mean square error (RMSE) is either one of two closely related and frequently used measures of the differences between true or predicted values on the one hand and observed values or an estimator on the other. The deviation is typically simply a differences of scalars; it can also be generalized to the vector lengths of a displacement, as in the bioinformatics concept of root mean square deviation of atomic positions. RMSD of a sample The RMSD of a sample is the quadratic mean of the differences between the observed values and predicted ones. These deviations are called '' residuals'' when the calculations are performed over the data sample that was used for estimation (and are therefore always in reference to an estimate) and are called ''errors'' (or prediction errors) when computed out-of-sample (aka on the full set, referencing a true value rather than an estimate). The RMSD serves to aggregate the magnitudes of the errors in p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moving Picture Experts Group
The Moving Picture Experts Group (MPEG) is an alliance of working groups established jointly by ISO and IEC that sets standards for media coding, including compression coding of audio, video, graphics, and genomic data; and transmission and file formats for various applications.John Watkinson, ''The MPEG Handbook'', p. 1 Together with JPEG, MPEG is organized under ISO/IEC JTC 1/ SC 29 – ''Coding of audio, picture, multimedia and hypermedia information'' (ISO/IEC Joint Technical Committee 1, Subcommittee 29). MPEG formats are used in various multimedia systems. The most well known older MPEG media formats typically use MPEG-1, MPEG-2, and MPEG-4 AVC media coding and MPEG-2 systems transport streams and program streams. Newer systems typically use the MPEG base media file format and dynamic streaming (a.k.a. MPEG-DASH). History MPEG was established in 1988 by the initiative of Dr. Hiroshi Yasuda ( NTT) and Dr. Leonardo Chiariglione ( CSELT). Chiariglione was th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
XM Radio
XM Satellite Radio Holdings Inc. (XM) was one of the three satellite radio ( SDARS) and online radio services in the United States and Canada, operated by Sirius XM Holdings. It provided pay-for-service radio, analogous to subscription cable television. Its service included 73 different music channels, 39 news, sports, talk and entertainment channels, 21 regional traffic and weather channels, and 23 play-by-play sports channels. XM channels were identified by Arbitron with the label "XM" (e.g., "XM32" for " The Bridge"). The company had its origins in the 1988 formation of the American Mobile Satellite Corporation (AMSC), a consortium of several organizations originally dedicated to satellite broadcasting of telephone, fax, and data signals. In 1992, AMSC established a unit called the American Mobile Radio Corporation dedicated to developing a satellite-based digital radio service; this was spun off as XM Satellite Radio Holdings, Inc. in 1999. The satellite service officially ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coding Technologies
Coding Technologies AB was a Swedish technology company that pioneered the use of spectral band replication in Advanced Audio Coding. It is a major provider of audio compression technologies for digital broadcasting. Background The company was founded in Stockholm, Sweden, in 1997 by Lars Liljeryd. A German subsidiary was formed in 2000 as Coding Technologies GmbH (later renamed Dolby Germany GmbH) with support from the research organization Fraunhofer IIS. The company also had offices in the United States and China. Coding Technologies was acquired by Dolby Laboratories in 2007 for $250 million in cash. Since then it was renamed to ''Dolby International AB''. Technologies Coding Technologies’ MPEG-2 AAC-derived codec, called aacPlus, was published in 2001 and submitted to the MPEG for standardization. The codec would become the MPEG-4 High-Efficiency AAC (HE-AAC) profile in 2003. XM Satellite Radio used aacPlus for its streams. aacPlus with Parametric stereo, called ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Radio Mondiale
Digital Radio Mondiale (DRM; ''mondiale'' being Italian and French for "worldwide") is a set of digital audio broadcasting technologies designed to work over the bands currently used for analogue radio broadcasting including AM broadcasting—particularly shortwave—and FM broadcasting. DRM is more spectrally efficient than AM and FM, allowing more stations, at higher quality, into a given amount of bandwidth, using xHE-AAC audio coding format. Various other MPEG-4 codecs and Opus are also compatible, but the standard now specifies xHE-AAC. Digital Radio Mondiale is also the name of the international non-profit consortium that has designed the platform and is now promoting its introduction. Radio France Internationale, TéléDiffusion de France, BBC World Service, Deutsche Welle, Voice of America, Telefunken (now Transradio) and Thomcast (now Ampegon) took part at the formation of the DRM consortium. The principle of DRM is that bandwidth is the limiting factor, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Audio Broadcasting
Digital Audio Broadcasting (DAB) is a digital radio international standard, standard for broadcasting digital audio radio services in many countries around the world, defined, supported, marketed and promoted by the WorldDAB organisation. The standard is dominant in Europe and is also used in Australia, and in parts of Africa and as of 2025, countries using DAB/DMB, 55 countries are actively running DAB broadcasts as an alternative platform to analogue FM. DAB was the result of a European research project and first publicly rolled out in 1995, with consumer-grade DAB Radio receiver, receivers appearing at the start of this millennium. Initially it was expected in many countries that existing FM broadcasting, FM services would switch over to DAB, although the take-up of DAB has been much slower than expected. In 2023, Norway became the first country to have implemented a national FM radio switch-off, with others to follow in the next years, Switzerland and the United Kingdom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HD Radio
HD Radio (HDR) is a trademark for in-band on-channel (IBOC) digital radio broadcast technology. HD radio generally simulcast, simulcasts an existing analog radio station in digital format with less noise and with additional text information. HD Radio is used primarily by FM broadcasting, FM radio stations in the United States, U.S. Virgin Islands, Canada, Mexico and the Philippines, with a few implementations outside North America. HD Radio transmits the digital signals in unused portions of the same band as the analog AM and FM signals. As a result, radios are more easily designed to pick up both signals, which is why the HD in HD Radio is sometimes referred to stand for "hybrid digital", not "high definition". Officially, HD is not intended to stand for any term in HD Radio, it is simply part of iBiquity's trademark, and does not have any meaning on its own. HD Radios tune into the station's analog signal first and then look for a digital signal. The European DRM system shares c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
