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Enhanced Voice Services
Enhanced Voice Services (EVS) is a Wideband audio, superwideband Speech coding, speech Audio coding format, audio coding standard that was developed for Voice over LTE, VoLTE. It offers up to 20 kHz audio bandwidth and has high robustness to delay jitter and packet losses due to its channel aware coding and improved packet loss concealment. It has been developed in 3GPP and is described i3GPP TS 26.441 The application areas of EVS consist of improved telephony and teleconferencing, audiovisual conferencing services, and streaming audio. Source code of both decoder and encoder in ANSI C is available a3GPP TS 26.442and is being updated regularly. Samsung uses the term HD+ when doing a call using EVS. History Work on EVS was started in 2007. The standardization process lasted from 2010 to 2014, being completed in December 2014 with 3GPP Release 12. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fraunhofer IIS
The Fraunhofer Society (german: Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V., lit=Fraunhofer Society for the Advancement of Applied Research) is a German research organization with 76institutes spread throughout Germany, each focusing on different fields of applied science (as opposed to the Max Planck Society, which works primarily on basic science). With some 29,000 employees, mainly scientists and engineers, and with an annual research budget of about €2.8billion, it is the biggest organization for applied research and development services in Europe. Some basic funding for the Fraunhofer Society is provided by the state (the German public, through the federal government together with the states or ''Länder'', "owns" the Fraunhofer Society), but more than 70% of the funding is earned through contract work, either for government-sponsored projects or from industry. It is named after Joseph von Fraunhofer who, as a scientist, an engineer, and an entr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nokia
Nokia Corporation (natively Nokia Oyj, referred to as Nokia) is a Finnish multinational corporation, multinational telecommunications industry, telecommunications, technology company, information technology, and consumer electronics corporation, established in 1865. Nokia's main headquarters are in Espoo, Finland, in the greater Helsinki Greater Helsinki, metropolitan area, but the company's actual roots are in the Tampere region of Pirkanmaa.HS: Nokian juuret ovat Tammerkosken rannalla (in Finnish) In 2020, Nokia employed approximately 92,000 people across over 100 countries, did business in more than 130 countries, and reported annual revenues of around €23 billion. Nokia is a public limited company listed on the Helsinki Stock Exchange and New York Stock Exchange. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adaptive Multi-Rate Audio Codec
The Adaptive Multi-Rate (AMR, AMR-NB or GSM-AMR) audio codec is an audio compression format optimized for speech coding. AMR speech codec consists of a multi-rate narrowband speech codec that encodes narrowband (200–3400 Hz) signals at variable bit rates ranging from 4.75 to 12.2 kbit/s with toll quality speech starting at 7.4 kbit/s. AMR was adopted as the standard speech codec by 3GPP in October 1999 and is now widely used in GSM and UMTS. It uses link adaptation to select from one of eight different bit rates based on link conditions. AMR is also a file format for storing spoken audio using the AMR codec. Many modern mobile telephone handsets can store short audio recordings in the AMR format, and both free and proprietary programs exist (see Software support) to convert between this and other formats, although AMR is a speech format and is unlikely to give ideal results for other audio. The common filename extension is .amr. There also exists another stor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mean Opinion Score
Mean opinion score (MOS) is a measure used in the domain of Quality of Experience and telecommunications engineering, representing overall quality of a stimulus or system. It is the arithmetic mean over all individual "values on a predefined scale that a subject assigns to his opinion of the performance of a system quality". Such ratings are usually gathered in a subjective quality evaluation test, but they can also be algorithmically estimated. MOS is a commonly used measure for video, audio, and audiovisual quality evaluation, but not restricted to those modalities. ITU-T has defined several ways of referring to a MOS in RecommendatioITU-T P.800.1 depending on whether the score was obtained from audiovisual, conversational, listening, talking, or video quality tests. Rating scales and mathematical definition The MOS is expressed as a single rational number, typically in the range 1–5, where 1 is lowest perceived quality, and 5 is the highest perceived quality. Other MOS ranges ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jitter Buffer
In electronics and telecommunications, jitter is the deviation from true periodicity of a presumably periodic signal, often in relation to a reference clock signal. In clock recovery applications it is called timing jitter. Jitter is a significant, and usually undesired, factor in the design of almost all communications links. Jitter can be quantified in the same terms as all time-varying signals, e.g., root mean square (RMS), or peak-to-peak displacement. Also, like other time-varying signals, jitter can be expressed in terms of spectral density. Jitter period is the interval between two times of maximum effect (or minimum effect) of a signal characteristic that varies regularly with time. Jitter frequency, the more commonly quoted figure, is its inverse. ITU-T G.810 classifies jitter frequencies below 10 Hz as wander and frequencies at or above 10 Hz as jitter. Jitter may be caused by electromagnetic interference and crosstalk with carriers of other signals. Jitte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Error Concealment
Error concealment is a technique used in signal processing that aims to minimize the deterioration of signals caused by missing data, called packet loss. A signal is a message sent from a transmitter to a receiver in multiple small packets. Packet loss occurs when these packets are misdirected, delayed, resequenced, or corrupted. Receiver-Based Techniques When error recovery occurs at the receiving end of the signal, it is receiver-based. These techniques focus on correcting corrupted or missing data. Waveform substitution Preliminary attempts at receiver-based error concealment involved packet repetition, replacing lost packets with copies of previously received packets. This function is computationally simple and is performed by a device on the receiver end called a "drop-out compensator". Zero Insertion When this technique is used, if a packet is lost, its entries are replaced with 0s. Interpolation Interpolation involves making educated guesses about the nature of a missi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Variable Bitrate
Variable bitrate (VBR) is a term used in telecommunications and computing that relates to the bitrate used in sound or video encoding. As opposed to constant bitrate (CBR), VBR files vary the amount of output data per time segment. VBR allows a higher bitrate (and therefore more storage space) to be allocated to the more complex segments of media files while less space is allocated to less complex segments. The average of these rates can be calculated to produce an average bitrate for the file. MP3, WMA and AAC audio files can optionally be encoded in VBR, while Opus and Vorbis are encoded in VBR by default. Variable bit rate encoding is also commonly used on MPEG-2 video, MPEG-4 Part 2 video (Xvid, DivX, etc.), MPEG-4 Part 10/H.264 video, Theora, Dirac and other video compression formats. Additionally, variable rate encoding is inherent in lossless compression schemes such as FLAC and Apple Lossless. Advantages and disadvantages of VBR The advantages of VBR are that it pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MDCT
The modified discrete cosine transform (MDCT) is a 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 of one block coincides with the first half of the next block. This overlapping, in addition to the energy-compaction qualities of the DCT, makes the MDCT especially attractive for signal compression applications, since it helps to avoid artifacts stemming from the block boundaries. As a result of these advantages, the MDCT is the most widely used lossy compression technique in audio data compression. It is employed in most modern audio coding standards, including MP3, Dolby Digital (AC-3), Vorbis (Ogg), Windows Media Audio (WMA), ATRAC, Cook, Advanced Audio Coding (AAC), High-Definition Coding (HDC), LDAC, Dolby AC-4, and MPEG-H 3D Audio, as well as speech coding standards such as AAC- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ACELP
Algebraic code-excited linear prediction (ACELP) is a speech coding algorithm in which a limited set of pulses is distributed as excitation to a linear prediction filter. It is a linear predictive coding (LPC) algorithm that is based on the code-excited linear prediction (CELP) method and has an algebraic structure. ACELP was developed in 1989 by the researchers at the Université de Sherbrooke in Canada. The ACELP method is widely employed in current speech coding standards such as AMR, EFR, AMR-WB (G.722.2), VMR-WB, EVRC, EVRC-B, SMV, TETRA, PCS 1900, MPEG-4 CELP and ITU-T G-series standards G.729, G.729.1 (first coding stage) and G.723.1. The ACELP algorithm is also used in the proprietary ACELP.net codec. Audible Inc. use a modified version for their speaking books. It is also used in conference-calling software, speech compression tools and has become one of the 3GPP formats. The ACELP patent expired in 2018 and is now royalty-free. Features The main advantage of ACE ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AMR-WB
Adaptive Multi-Rate Wideband (AMR-WB) is a patented wideband speech audio coding standard developed based on Adaptive Multi-Rate encoding, using a similar methodology to algebraic code-excited linear prediction (ACELP). AMR-WB provides improved speech quality due to a wider speech bandwidth of 50–7000 Hz compared to narrowband speech coders which in general are optimized for POTS wireline quality of 300–3400 Hz. AMR-WB was developed by Nokia and VoiceAge and it was first specified by 3GPP. AMR-WB is codified as G.722.2, an ITU-T standard speech codec, formally known as ''Wideband coding of speech at around 16 kbit/s using Adaptive Multi-Rate Wideband (AMR-WB)''. G.722.2 AMR-WB is the same codec as the 3GPP AMR-WB. The corresponding 3GPP specifications are TS 26.190 for the speech codec and TS 26.194 for the Voice Activity Detector. The AMR-WB format has the following parameters: * Frequency bands processed: 50–6400 Hz (all modes) plus 6400–7000 Hz (23 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Patent Pool
In patent law, a patent pool is a consortium of at least two companies agreeing to cross-license patents relating to a particular technology. The creation of a patent pool can save patentees and licensees time and money, and, in case of blocking patents, it may also be the only reasonable method for making the invention available to the public. Competition law issues are usually important when a large consortium is formed. History In 1856, sewing machine manufacturers Grover & Baker, Singer, and Wheeler & Wilson, all accusing each other of patent infringement, met in Albany, New York to pursue their suits. Orlando B. Potter, a lawyer and president of Grover & Baker, proposed that, rather than squander their profits on litigation, they pool their patents. This was the first patent pool, a process which enables the production of complicated machines without legal battles over patent rights. In 1917, the two major patent holders for airplanes, the Wright Company and the Curtiss Co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ZTE Corporation
ZTE Corporation is a Chinese partially state-owned technology company that specializes in telecommunication. Founded in 1985, ZTE is listed on both the Hong Kong and Shenzhen Stock Exchanges. ZTE's core business is wireless, exchange, optical transmission, data telecommunications gear, telecommunications software, and mobile phones. ZTE primarily sells products under its own name, but it is also an OEM. The company has faced criticism in the United States, India, and Sweden over ties to the Chinese government that could enable mass surveillance. In 2017, ZTE was fined for illegally exporting U.S. technology to Iran and North Korea in violations of economic sanctions. In April 2018, after the company failed to properly reprimand the employees involved, the U.S. Department of Commerce banned U.S. companies (semiconductors) from exporting to ZTE for seven years. The ban was lifted in July 2018 after ZTE replaced its senior management, and agreed to pay additional fines and esta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
