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Real Audio
RealAudio, or also spelled as Real Audio is a proprietary audio format developed by RealNetworks and first released in April 1995. It uses a variety of audio codecs, ranging from low-bitrate formats that can be used over dialup modems, to high-fidelity formats for music. It can also be used as a streaming audio format, that is played at the same time as it is downloaded. In the past, many internet radio stations used RealAudio to stream their programming over the internet in real time. In recent years, however, the format has become less common and has given way to more popular audio formats. RealAudio was heavily used by the BBC websites until 2009, though it was discontinued due to its declining use. BBC World Service, the last of the BBC websites to use RealAudio, discontinued its use in March 2011. File extensions RealAudio files were originally identified by a filename extension of .ra (for Real Audio). In 1997, RealNetworks also began offering a video format called RealVideo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RealNetworks
RealNetworks, Inc. is a provider of artificial intelligence and computer vision based products. RealNetworks was a pioneer in Internet streaming software and services. They are based in Seattle, Washington, United States. The company also provides subscription-based online entertainment services and mobile entertainment and messaging services. History RealNetworks (then known as Progressive Networks) was founded in 1994 by Rob Glaser, an ex-Microsoft executive, and a management team including Phil Barrett, Andy Sharpless, and Stephen Buerkle. The original goal of the company was to provide a distribution channel for politically progressive content. It evolved into a technology venture to leverage the Internet as an alternative distribution medium for audio broadcasts. Progressive Networks became RealNetworks in September 1997, in advance of the company's initial public offering (IPO) in October 1997 when shares of the company started trading on Nasdaq as "RNWK". RealNetw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hyperlink
In computing, a hyperlink, or simply a link, is a digital reference to data that the user can follow or be guided by clicking or tapping. A hyperlink points to a whole document or to a specific element within a document. Hypertext is text with hyperlinks. The text that is linked from is known as anchor text. A software system that is used for viewing and creating hypertext is a ''hypertext system'', and to create a hyperlink is ''to hyperlink'' (or simply ''to link''). A user following hyperlinks is said to ''navigate'' or ''browse'' the hypertext. The document containing a hyperlink is known as its source document. For example, in an online reference work such as Wikipedia or Google, many words and terms in the text are hyperlinked to definitions of those terms. Hyperlinks are often used to implement reference mechanisms such as tables of contents, footnotes, bibliographies, indexes, letters, and glossaries. In some hypertext, hyperlinks can be bidirectional: they can be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LD-CELP
G.728 is an ITU-T standard for speech coding operating at 16 kbit/s. It is officially described as ''Coding of speech at 16 kbit/s using low-delay code excited linear prediction''. Technology used is LD-CELP, low-delay code excited linear prediction. Delay of the codec is only 5 samples (0.625 ms). The linear prediction is calculated backwards with a 50th order linear predictive coding filter. The excitation is generated with gain scaled VQ. The standard was finished in 1992 in the form of algorithm exact floating point code. In 1994 a bit exact fixed point codec was released. G.728 passes low bit rate modem signals up to 2400 bit/s. Also network signaling goes through. The complexity of the codec is 30 MIPS. 2 kilobytes of RAM is needed for codebooks. Mean opinion score for G.728 is 3.61. The essence of CELP techniques, which is an analysis-by-synthesis approach to codebook search, is retained in LD-CELP. The LD-CELP however, uses backward adaptation of predictors an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
VSELP
Vector sum excited linear prediction (VSELP) is a speech coding method used in several cellular standards. The VSELP algorithm is an analysis-by-synthesis coding technique and belongs to the class of speech coding algorithms known as CELP (Code Excited Linear Prediction).ETSIEN 300 969 - Half rate speech transcoding (GSM 06.20 version 8.0.1 Release 1999) Retrieved on 2009-07-11 Variations of this codec have been used in several 2G cellular telephony standards, including IS-54, IS-136 (D-AMPS), GSM (Half Rate speech) and iDEN. It was also used in the first version of RealAudio for audio over the Internet. The IS-54 VSELP standard was published by the Telecommunications Industry Association in 1989. D-AMPS (IS-54 and IS-136) VSELP specifies an encoding of each 20 ms of speech into 159-bit frames, thus achieving a raw data rate of 7.95 kbit/s. In an actual TDMA cell phone, the vocoder output is packaged with error correction and signaling information, resulting in an over-the-air da ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IS-54
IS-54 and IS-136 are second-generation ( 2G) mobile phone systems, known as Digital AMPS (D-AMPS), and a further development of the North American 1G mobile system Advanced Mobile Phone System (AMPS). It was once prevalent throughout the Americas, particularly in the United States and Canada since the first commercial network was deployed in 1993. D-AMPS is considered end-of-life, and existing networks have mostly been replaced by GSM/GPRS or CDMA2000 technologies. This system is most often referred to as TDMA. That name is based on the abbreviation for time-division multiple access, a common multiple access technique which is used in most 2G standards, including GSM, as well as in IS-54 and IS-136. D-AMPS competed against GSM and systems based on code-division multiple access (CDMA). D-AMPS uses existing AMPS channels and allows for smooth transition between digital and analog systems in the same area. Capacity was increased over the preceding analog design by dividing each ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FourCC
A FourCC ("four-character code") is a sequence of four bytes (typically ASCII) used to uniquely identify data formats. It originated from the OSType or ResType metadata system used in classic Mac OS and was adopted for the Amiga/Electronic Arts Interchange File Format and derivatives. The idea was later reused to identify compressed data types in QuickTime and DirectShow. History In 1984, the earliest version of a Macintosh OS, Apple System 1, was released. It used the single-level Macintosh File System with metadata fields including file types, creator (application) information, and forks to store additional resources. All these fields are four-character codes known as OSType. It was possible to change this information without changing the data itself, so that they could be interpreted differently. Identical codes were used throughout the system, as type tags for all kinds of data. In 1985, Electronic Arts introduced the Interchange File Format (IFF) meta-format (family of f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Audio Codec
An audio codec is a device or computer program capable of encoding or decoding a digital data stream (a codec) that encodes or decodes audio. In software, an audio codec is a computer program implementing an algorithm that compresses and decompresses digital audio data according to a given audio file or streaming media audio coding format. The objective of the algorithm is to represent the high-fidelity audio signal with minimum number of bits while retaining quality. This can effectively reduce the storage space and the bandwidth required for transmission of the stored audio file. Most software codecs are implemented as libraries which interface to one or more multimedia players. Most modern audio compression algorithms are based on modified discrete cosine transform (MDCT) coding and linear predictive coding (LPC). In hardware, audio codec refers to a single device that encodes analog audio as digital signals and decodes digital back into analog. In other words, it contains bo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
VLC Media Player
VLC media player (previously the VideoLAN Client and commonly known as simply VLC) is a free and open-source, portable, cross-platform media player software and streaming media server developed by the VideoLAN project. VLC is available for desktop operating systems and mobile platforms, such as Android, iOS and iPadOS. VLC is also available on digital distribution platforms such as Apple's App Store, Google Play, and Microsoft Store. VLC supports many audio and video compression methods and file formats, including DVD-Video, Video CD and streaming protocols. It is able to stream media over computer networks and can transcode multimedia files. The default distribution of VLC includes many free decoding and encoding libraries, avoiding the need for finding/calibrating proprietary plugins. The libavcodec library from the FFmpeg project provides many of VLC's codecs, but the player mainly uses its own muxers and demuxers. It also has its own protocol implementations. It also gain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
