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Adaptive Differential Pulse Code Modulation
Adaptive differential pulse-code modulation (ADPCM) is a variant of differential pulse-code modulation (DPCM) that varies the size of the quantization step, to allow further reduction of the required data bandwidth for a given signal-to-noise ratio. Typically, the adaptation to signal statistics in ADPCM consists simply of an adaptive scale factor before quantizing the difference in the DPCM encoder. ADPCM was developed for speech coding by P. Cummiskey, Nikil S. Jayant and James L. Flanagan at Bell Labs in 1973. In telephony In telephony, a standard audio signal for a single phone call is encoded as 8000 analog samples per second, of 8 bits each, giving a 64 kbit/s digital signal known as DS0. The default signal compression encoding on a DS0 is either μ-law (mu-law) PCM (North America and Japan) or A-law PCM (Europe and most of the rest of the world). These are logarithmic compression systems where a 13- or 14-bit linear PCM sample number is mapped into an 8-bit value. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Differential Pulse-code Modulation
Differential pulse-code modulation (DPCM) is a signal encoder that uses the baseline of pulse-code modulation (PCM) but adds some functionalities based on the prediction of the samples of the signal. The input can be an analog signal or a Digital signal (signal processing), digital signal. If the input is a continuous-time analog signal, it needs to be sampling (signal processing), sampled first so that a discrete-time signal is the input to the DPCM encoder. * Option 1: take the values of two consecutive samples; if they are analog samples, quantization (signal processing), quantize them; calculate the difference between the first one and the next; the output is the difference. * Option 2: instead of taking a difference relative to a previous input sample, take the difference relative to the output of a local model of the decoder process; in this option, the difference can be quantized, which allows a good way to incorporate a controlled loss in the encoding. Applying one of thes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subband Coding
In signal processing, sub-band coding (SBC) is any form of transform coding that breaks a signal into a number of different frequency bands, typically by using a fast Fourier transform, and encodes each one independently. This decomposition is often the first step in data compression for audio and video signals. SBC is the core technique used in many popular lossy audio compression algorithms including MP3. Encoding audio signals The simplest way to digitally encode audio signals is pulse-code modulation (PCM), which is used on audio CDs, Digital Audio Tape, DAT recordings, and so on. Digitization transforms continuous signals into discrete ones by sampling a signal's amplitude at uniform intervals and rounding to the nearest value representable with the available Audio bit depth, number of bits. This process is fundamentally inexact, and involves two errors: ''discretization error,'' from sampling at intervals, and ''quantization error,'' from rounding. The more bits used t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Speech Codecs
Speech is the use of the human voice as a medium for language. Spoken language combines vowel and consonant sounds to form units of meaning like words, which belong to a language's lexicon. There are many different intentional speech acts, such as informing, declaring, asking, persuading, directing; acts may vary in various aspects like enunciation, intonation, loudness, and tempo to convey meaning. Individuals may also unintentionally communicate aspects of their social position through speech, such as sex, age, place of origin, physiological and mental condition, education, and experiences. While normally used to facilitate communication with others, people may also use speech without the intent to communicate. Speech may nevertheless express emotions or desires; people talk to themselves sometimes in acts that are a development of what some psychologists (e.g., Lev Vygotsky) have maintained is the use of silent speech in an interior monologue to vivify and organize cog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pulse-code Modulation
Pulse-code modulation (PCM) is a method used to digitally represent analog signals. It is the standard form of digital audio in computers, compact discs, digital telephony and other digital audio applications. In a PCM stream, the amplitude of the analog signal is sampled at uniform intervals, and each sample is quantized to the nearest value within a range of digital steps. Alec Reeves, Claude Shannon, Barney Oliver and John R. Pierce are credited with its invention. Linear pulse-code modulation (LPCM) is a specific type of PCM in which the quantization levels are linearly uniform. This is in contrast to PCM encodings in which quantization levels vary as a function of amplitude (as with the A-law algorithm or the μ-law algorithm). Though ''PCM'' is a more general term, it is often used to describe data encoded as LPCM. A PCM stream has two basic properties that determine the stream's fidelity to the original analog signal: the sampling rate, which is the number of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Audio Data Compression
In information theory, data compression, source coding, or bit-rate reduction is the process of encoding information using fewer bits than the original representation. Any particular compression is either lossy or lossless. Lossless compression reduces bits by identifying and eliminating Redundancy (information theory), statistical redundancy. No information is lost in lossless compression. Lossy compression reduces bits by removing unnecessary or less important information. Typically, a device that performs data compression is referred to as an encoder, and one that performs the reversal of the process (decompression) as a decoder. The process of reducing the size of a data file is often referred to as data compression. In the context of data transmission, it is called source coding: encoding is done at the source of the data before it is stored or transmitted. Source coding should not be confused with channel coding, for error detection and correction or line coding, the means ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Audio Coding Format
An audio coding format (or sometimes audio compression format) is a content representation format for storage or transmission of digital audio (such as in digital television, digital radio and in audio and video files). Examples of audio coding formats include MP3, AAC, Vorbis, FLAC, and Opus. A specific software or hardware implementation capable of audio compression and decompression to/from a specific audio coding format is called an '' audio codec''; an example of an audio codec is LAME, which is one of several different codecs which implements encoding and decoding audio in the MP3 audio coding format in software. Some audio coding formats are documented by a detailed technical specification document known as an audio coding specification. Some such specifications are written and approved by standardization organizations as technical standards, and are thus known as an audio coding standard. The term "standard" is also sometimes used for ''de facto'' standards as wel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GameCube
The is a PowerPC-based home video game console developed and marketed by Nintendo. It was released in Japan on September 14, 2001, in North America on November 18, 2001, in Europe on May 3, 2002, and in Australia on May 17, 2002. It is the successor to the Nintendo 64. As a Sixth generation of video game consoles, sixth-generation console, the GameCube primarily competed with Sony Interactive Entertainment, Sony's PlayStation 2, Sega's Dreamcast and Microsoft's Xbox (console), Xbox. Nintendo began developing the GameCube in 1998 after entering a partnership with ArtX to design a graphics processing unit. The console was formally announced under the codename "Dolphin" the following year, and was released in 2001 as the GameCube. It is Nintendo's first console to use Nintendo optical discs, its own optical discs instead of ROM cartridges, supplemented by writable GameCube accessories#Memory cards, memory cards for saved games. Unlike its competitors, it is solely focused on gami ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GitHub
GitHub () is a Proprietary software, proprietary developer platform that allows developers to create, store, manage, and share their code. It uses Git to provide distributed version control and GitHub itself provides access control, bug tracking system, bug tracking, software feature requests, task management, continuous integration, and wikis for every project. Headquartered in California, GitHub, Inc. has been a subsidiary of Microsoft since 2018. It is commonly used to host open source software development projects. GitHub reported having over 100 million developers and more than 420 million Repository (version control), repositories, including at least 28 million public repositories. It is the world's largest source code host Over five billion developer contributions were made to more than 500 million open source projects in 2024. About Founding The development of the GitHub platform began on October 19, 2005. The site was launched in April 2008 by Tom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Command & Conquer
''Command & Conquer'' (''C&C'') is a real-time strategy (RTS) video game franchise created and originally developed by Westwood Studios and currently owned by Electronic Arts. The first game was one of the earliest of the RTS genre, itself based on Westwood Studios' influential strategy game '' Dune II'' and introducing trademarks followed in the rest of the series. This includes full-motion video cutscenes with an ensemble cast to progress the story, as opposed to digitally in-game rendered cutscenes. Westwood Studios was purchased by Electronic Arts in 1998 and closed down in 2003. The studio and some of its members were absorbed into EA Los Angeles, which continued development on the series. History After Westwood Studios developed the critically acclaimed '' Dune II'', ''Computer Gaming World'' reported in 1993 that the company would not use the ''Dune'' license for Westwood's next strategy game "mostly because the programmers are tired of sand". The magazine stated that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FFmpeg
FFmpeg is a free and open-source software project consisting of a suite of libraries and programs for handling video, audio, and other multimedia files and streams. At its core is the command-line ffmpeg tool itself, designed for processing video and audio files. It is widely used for format transcoding, basic editing (trimming and concatenation), video scaling, video post-production effects, and standards compliance ( SMPTE, ITU). FFmpeg also includes other tools: ffplay, a simple media player, and ffprobe, a command-line tool to display media information. Among included libraries are libavcodec, an audio/video codec library used by many commercial and free software products, libavformat (Lavf), an audio/video container mux and demux library, and libavfilter, a library for enhancing and editing filters through a GStreamer-like filtergraph. FFmpeg is part of the workflow of many other software projects, and its libraries are a core part of software media players such as V ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microsoft Knowledge Base
Microsoft Knowledge Base (MSKB) was a website repository of over 150,000 articles made available to the public by Microsoft Corporation for technical support. It contained information on many problems encountered by users of Microsoft products. Each article bore an ID number and articles were often referred to by their Knowledge Base (KB) ID. Microsoft Windows update names typically start with the letters "KB", in reference to the specific article on that issue. Previously, the letter "Q" was used. As of 2020, Microsoft began to discontinue the Knowledge Base service. Some content was migrated to the learn.microsoft.com sub-site. kbalertz.com was a website that provided email alerts of new articles, although Microsoft had also provided a similar service. See also * MSDN Library * Windows Update Windows Update is a Microsoft service for the Windows 9x and Windows NT families of the Microsoft Windows operating system, which automates downloading and installing Microsoft Windows ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Windows Sound System
Windows Sound System (WSS) is a sound card specification developed by Microsoft, released at the end of 1992 for Windows 3.1. It was sold as a bundle which included an ISA sound card, a microphone, a pair of headphones and a software package. WSS featured support for up to 16-bit, 48 kHz digital sampling, beyond the capabilities of the popular Sound Blaster Pro, although it was less frequently supported than Sound Blaster and Gravis sound cards, as well as Roland sound cards, daughterboards, and sound modules. In addition, the WSS featured RCA analog audio outputs, an uncommon feature among sound cards of this era; other connections were a microphone input, a stereo line input and a stereo headphone output. WSS was supported by most popular DOS sound libraries developed in the 1990s, such as the Miles Sound System and HMI Sound Operating System, as well as less popular ones such as Loudness Sound System, Digital Sound Interface Kit, Digital Sound & Music Interface and Jung ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
