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Adaptive Transform Acoustic Coding
Adaptive Transform Acoustic Coding (ATRAC) is a family of proprietary audio compression algorithms developed by Sony. MiniDisc was the first commercial product to incorporate ATRAC, in 1992. ATRAC allowed a relatively small disc like MiniDisc to have the same running time as a CD while storing audio information with minimal perceptible loss in quality. Improvements to the codec in the form of ATRAC3, ATRAC3plus, and ATRAC Advanced Lossless followed in 1999, 2002, and 2006 respectively. Files in ATRAC3 format originally had the extension; however, in most cases, the files would be stored in an OpenMG Audio container using the extension . Previously, files that were encrypted with OpenMG had the extension, which was replaced by starting in SonicStage v2.1. Encryption is no longer compulsory as of v3.2. Other MiniDisc manufacturers such as Sharp and Panasonic also implemented their own versions of the ATRAC codec. History ATRAC was developed for Sony's MiniDisc format. ATR ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
OpenMG
OpenMG is a digital rights management (DRM) system developed by Sony for managing and protecting digital music data on a personal computer. It was originally designed for audio files in ATRAC3 format; the compliant software, e.g. Sony SonicStage, is usually capable of transcoding MP3 and WAV files to OpenMG/ATRAC3. The file extensions OpenMG-encrypted files use are and . Sister technologies OpenMG Light (for mobile devices) and OpenMG X were also created. Development OpenMG was created alongside MagicGate in an effort to protect digital music copyright. It was released alongside the Memory Stick Walkman and VAIO Music Clip. It is compliant with the Secure Digital Music Initiative (SDMI) version 1.0 industry group specification formed in February 1999. There has been at least one reported case when a security update of Windows XP and Windows 2000 broke OpenMG-compliant software. This issue was later resolved. Method Audio files encrypted using OpenMG cannot be played on a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
FLAC
FLAC (; Free Lossless Audio Codec) is an audio coding format for lossless compression of digital audio, developed by the Xiph.Org Foundation, and is also the name of the free software project producing the FLAC tools, the reference software package that includes a codec implementation. Digital audio compressed by FLAC's algorithm can typically be reduced to between 50 and 70 percent of its original size and decompresses to an identical copy of the original audio data. FLAC is an open format with royalty-free licensing and a reference implementation which is free software. FLAC supports metadata tagging, album cover art, and fast seeking. History Development was started in 2000 by Josh Coalson. The bitstream format was frozen with the release of version 0.9 of the reference implementation on 31 March 2001. Version 1.0 was released on 20 July 2001. On 29 January 2003, the Xiph.Org Foundation and the FLAC project announced the incorporation of FLAC under the Xiph.org banner. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Frequency
Frequency is the number of occurrences of a repeating event per unit of time. Frequency is an important parameter used in science and engineering to specify the rate of oscillatory and vibratory phenomena, such as mechanical vibrations, audio signals (sound), radio waves, and light. The interval of time between events is called the period. It is the reciprocal of the frequency. For example, if a heart beats at a frequency of 120 times per minute (2 hertz), its period is one half of a second. Special definitions of frequency are used in certain contexts, such as the angular frequency in rotational or cyclical properties, when the rate of angular progress is measured. Spatial frequency is defined for properties that vary or cccur repeatedly in geometry or space. The unit of measurement of frequency in the International System of Units (SI) is the hertz, having the symbol Hz. Definitions and units For cyclical phenomena such as oscillations, waves, or for examp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Stereophonic Sound
Stereophonic sound, commonly shortened to stereo, is a method of sound reproduction that recreates a multi-directional, 3-dimensional audible perspective. This is usually achieved by using two independent audio channels through a configuration of two loudspeakers (or stereo headphones) in such a way as to create the impression of sound heard from various directions, as in natural hearing. Because the multi-dimensional perspective is the crucial aspect, the term ''stereophonic'' also applies to systems with more than two channels or speakers such as quadraphonic and surround sound. Binaural recording, Binaural sound systems are also ''stereophonic''. Stereo sound has been in common use since the 1970s in entertainment media such as broadcast radio, recorded music, television, video cameras, cinema, computer audio, and the Internet. Etymology The word ''stereophonic'' derives from the Greek language, Greek (''stereós'', "firm, solid") + (''phōnḗ'', "sound, tone, voice" ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Signal (information Theory)
A signal is both the process and the result of Signal transmission, transmission of data over some transmission media, media accomplished by embedding some variation. Signals are important in multiple subject fields including signal processing, information theory and biology. In signal processing, a signal is a function that conveys information about a phenomenon. Any quantity that can vary over space or time can be used as a signal to share messages between observers. The ''IEEE Transactions on Signal Processing'' includes audio signal, audio, video, speech, image, sonar, and radar as examples of signals. A signal may also be defined as observable change in a quantity over space or time (a time series), even if it does not carry information. In nature, signals can be actions done by an organism to alert other organisms, ranging from the release of plant chemicals to warn nearby plants of a predator, to sounds or motions made by animals to alert other animals of food. Signa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Quadrature Mirror Filter
In digital signal processing, a quadrature mirror filter is a filter whose magnitude response is the mirror image around \pi/2 of that of another filter. Together these filters, first introduced by Croisier et al., are known as the quadrature mirror filter pair. A filter H_1(z) is the quadrature mirror filter of H_0(z) if H_1(z) = H_0(-z). The filter responses are symmetric about \Omega = \pi / 2: : \big, H_1\big(e^\big)\big, = \big, H_0\big(e^\big)\big, . In audio/voice codecs, a quadrature mirror filter pair is often used to implement a filter bank that splits an input signal into two bands. The resulting high-pass and low-pass signals are often reduced by a factor of 2, giving a critically sampled two-channel representation of the original signal. The analysis filters are often related by the following formula in addition to quadrate mirror property: : \big, H_0\big(e^\big)\big, ^2 + \big, H_1\big(e^\big)\big, ^2 = 1, where \Omega is the frequency, and the sampling rate is no ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
DTS (sound System)
DTS, Inc. (originally Digital Theater Systems) is an American company. DTS company makes multichannel audio technologies for film and video. Based in Calabasas, California, the company introduced its DTS technology in 1993 as a competitor to Dolby Laboratories, incorporating DTS in the film ''Jurassic Park'' (1993). The DTS product is used in surround sound formats for both commercial/theatrical and consumer-grade applications. It was known as The Digital Experience until 1995. DTS licenses its technologies to consumer electronics manufacturers. DTS, Inc. was acquired by Tessera Technologies Inc. in December 2016 and combined under the newly created Tessera Holding Corporation. The combined company was renamed to Xperi Corporation in February 2017. History DTS was founded by Terry Beard, an audio engineer and Caltech graduate. Beard, speaking to a friend of a friend, was able to get in touch with Steven Spielberg to audition a remastering of Spielberg's film '' Close Encounte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Dolby Digital
Dolby Digital, originally synonymous with Dolby AC-3 (see below), is the name for a family of audio compression technologies developed by Dolby Laboratories. Called Dolby Stereo Digital until 1995, it is lossy compression (except for Dolby TrueHD). The first use of Dolby Digital was to provide digital sound in cinemas from 35 mm film prints. It has since also been used for TV broadcast, radio broadcast via satellite, digital video streaming, DVDs, Blu-ray discs and game consoles. Dolby AC-3 was the original version of the Dolby Digital codec. The basis of the Dolby AC-3 multi-channel audio coding standard is the modified discrete cosine transform (MDCT), a lossy audio compression algorithm. It is a modification of the discrete cosine transform (DCT) algorithm, which was proposed by Nasir Ahmed in 1972 for image compression. The DCT was adapted into the MDCT by J.P. Princen, A.W. Johnson and Alan B. Bradley at the University of Surrey in 1987. Dolby Laboratories adap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Sony Dynamic Digital Sound
is a cinema sound system developed by Sony, in which compressed digital sound information is recorded on both outer edges of the 35mm film release print. The system supports up to eight independent channels of sound: five front channels, two surround channels and a single sub-bass channel. The eight channel arrangement is similar to large format film magnetic sound formats such as Cinerama and Cinemiracle. The five front channels are useful for very large cinema auditoriums where the angular distance between center and left/right channels may be considerable. SDDS decoders provide the ability to downmix to fewer channels if required. History Although originally slated to premiere with 1991's ''Hook'', the SDDS project was delayed and instead premiered on April 2, 1992. and on June 17, 1993 premiered it First Film Last Action Hero. Since then, over 2000 movies have been mixed and remastered in Sony Dynamic Digital Sound, and as early as 1999 over 6,750 movie theaters were ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
ATRAC CD
An ATRAC CD is a compressed audio optical disc containing audio compression (data), compressed digital audio in the ATRAC3 or ATRAC3plus formats, which are part of Sony's ATRAC (Adaptive Transform Acoustic Coding) family of proprietary audio compression algorithms. Description ATRAC CD was used with SonicStage Simple Burner software (Ver.1.0 / 1.1) in February 2003, and was subsequently replaced with SonicStage in 2004. The new Discman, CD Walkman product was called "ATRAC CD Walkman". In the following year (2004-2005), ATRAC CD boombox was introduced, as a new product. Software for burning ATRAC CD The ATRAC CD can be burned with SonicStage Simple Burner Ver.1.1, SonicStage 2.x to 3.x and SonicStage CP. This software is able to create a disk image from MP3 files and compact discs and can be Optical disc authoring, burned with the included Optical disc drive, CD-R/RW drive on a computer. See also *Walkman *SonicStage *Adaptive Transform Acoustic Coding, ATRAC *OpenMG ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
UMTS
The Universal Mobile Telecommunications System (UMTS) is a 3G mobile cellular system for networks based on the GSM standard. UMTS uses Wideband Code Division Multiple Access, wideband code-division multiple access (W-CDMA) radio access technology to offer greater spectral efficiency and bandwidth to mobile network operators compared to previous 2G systems like GPRS and Circuit Switched Data, CSD. UMTS on its provides a peak theoretical data rate of 2 Data-rate units, Mbit/s. Developed and maintained by the 3GPP (3rd Generation Partnership Project), UMTS is a component of the International Telecommunication Union IMT-2000 standard set and compares with the CDMA2000 standard set for networks based on the competing IS-95, cdmaOne technology. The technology described in UMTS is sometimes also referred to as Freedom of Mobile Multimedia Access (FOMA) or 3GSM. UMTS specifies a complete network system, which includes the radio access network (UMTS Terrestrial Radio Access Network, or U ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
