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Sound Server
A sound server is software that manages the use of and access to audio devices (usually a sound card). It commonly runs as a background process. Sound server in an operating system In a Unix-like operating system, a sound server mixes different data streams (usually raw PCM audio) and sends out a single unified audio to an output device. The mixing is usually done by software, or by hardware if there is a supported sound card. Layers The "sound stack" can be visualized as follows, with programs in the upper layers calling elements in the lower layers: * Applications (e.g. mp3 player, web video) * Sound server (e.g. aRts, ESD, JACK, PulseAudio) * Sound subsystem (described as kernel modules or drivers; e.g. OSS, ALSA) * Operating system kernel (e.g. Linux, Unix) Motivation Sound servers appeared in Unix-like operating systems after limitations in Open Sound System were recognized. OSS is a basic sound interface that was incapable of playing multiple streams simultaneous ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
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Software
Software consists of computer programs that instruct the Execution (computing), execution of a computer. Software also includes design documents and specifications. The history of software is closely tied to the development of digital computers in the mid-20th century. Early programs were written in the machine language specific to the hardware. The introduction of high-level programming languages in 1958 allowed for more human-readable instructions, making software development easier and more portable across different computer architectures. Software in a programming language is run through a compiler or Interpreter (computing), interpreter to execution (computing), execute on the architecture's hardware. Over time, software has become complex, owing to developments in Computer network, networking, operating systems, and databases. Software can generally be categorized into two main types: # operating systems, which manage hardware resources and provide services for applicat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
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Advanced Linux Sound Architecture
Advanced Linux Sound Architecture (ALSA) is a software framework and part of the Linux kernel that provides an application programming interface (API) for sound card device drivers. Some of the goals of the ALSA project at its inception were automatic configuration of sound-card hardware and graceful handling of multiple sound devices in a system. ALSA is released under GPL-2.0-or-later and LGPL-2.1-or-later. On Linux, sound servers, like sndio, PulseAudio, JACK (low-latency professional-grade audio editing and mixing) and PipeWire, and higher-level APIs (e.g OpenAL, SDL audio, etc.) work on top of ALSA and its sound card device drivers. ALSA succeeded the older Linux port of the Open Sound System (OSS). History The project to develop ALSA was led by Jaroslav Kysela, and was based on the Linux device driver for the Gravis Ultrasound sound card. It started in 1998 and was developed separately from the Linux kernel until it was introduced in the 2.5 development serie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
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Icecast
Icecast is a streaming media project released as free software maintained by the Xiph.Org Foundation. It also refers specifically to the Server (computing), server program which is part of the project. Icecast was created in December 1998/January 1999 by Jack Moffitt (computer scientist), Jack Moffitt and Barath Raghavan to provide an open-source software, open-source audio streaming server that anyone could modify, use, and tinker with. Version 2, a Rewrite (programming), ground-up rewrite aimed at multi-format support (initially targeting Vorbis, Ogg Vorbis) and scalability, was started in 2001 and released in January 2004. History Icecast was originally developed by Moffitt in 1998 for Southern Methodist University, SMU's radio station. At the time, the station was constantly losing its FCC license and was at the time only able to reach listeners in the same building. Given that all of the dorms throughout campus had Ethernet connectivity, using streaming audio to broadcast ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
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OpenBSD
OpenBSD is a security-focused operating system, security-focused, free software, Unix-like operating system based on the Berkeley Software Distribution (BSD). Theo de Raadt created OpenBSD in 1995 by fork (software development), forking NetBSD 1.0. The OpenBSD project emphasizes software portability, portability, software standard, standardization, software bug, correctness, proactive computer security, security, and integrated cryptography. The OpenBSD project maintains portable versions of many subsystems as package manager, packages for other operating systems. Because of the project's preferred BSD license, which allows binary redistributions without the source code, many components are reused in proprietary and corporate-sponsored software projects. The firewall (computing), firewall code in Apple Inc., Apple's macOS is based on OpenBSD's PF (firewall), PF firewall code, Android (operating system), Android's Bionic (software), Bionic C standard library is based on OpenBSD c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
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Sndio
sndio is the software layer of the OpenBSD operating system that manages sound cards and MIDI ports. It provides an optional sound server and a documented application programming interface to access either the server or the audio and MIDI hardware in a uniform way. sndio is designed to work for desktop applications, but pays special attention to synchronization mechanisms and reliability required by music applications. Features The audio and MIDI server is the main component of sndio. It aims to fill the gap between programs requirements and the bare hardware as exposed by operating system device drivers. This includes: * perform re-sampling and format conversions; for instance to allow a program that requires 44.1 kHz sample frequency to use a device that supports 48 kHz only. * mix and route the sound of multiple programs; this allows multiple programs to use the audio device concurrently. * split an audio device into sub-devices, for instance allowing one program ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
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PipeWire
PipeWire is a low-level server and multimedia framework for handling audio and video streams on Linux. Created by Wim Taymans at Red Hat, it aims to unify audio and video processing by providing low-latency capture and playback functionality. Pipewire facilitates advanced multimedia routing and pipeline processing, and is designed to replace and be compatible with existing sound systems. History In 2015, Taymans started work on PipeWire. It was based on ideas from several existing projects, including one called PulseVideo by William Manley. According to Red Hat's Christian Schaller, it drew many of its ideas from an early PulseVideo prototype by Manley and builds upon some of the code that was merged into GStreamer due to that effort. A goal of the project was to improve handling of video on Linux in the same way that PulseAudio improved handling of audio. Although a separate project from PulseAudio, Taymans initially considered using the name "PulseVideo" for the new project. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
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Network Audio System
Network, networking and networked may refer to: Science and technology * Network theory, the study of graphs as a representation of relations between discrete objects * Network science, an academic field that studies complex networks Mathematics * Networks, a graph with attributes studied in network theory ** Scale-free network, a network whose degree distribution follows a power law ** Small-world network, a mathematical graph in which most nodes are not neighbors, but have neighbors in common * Flow network, a directed graph where each edge has a capacity and each edge receives a flow Biology * Biological network, any network that applies to biological systems * Ecological network, a representation of interacting species in an ecosystem * Neural network, a network or circuit of neurons Technology and communication * Artificial neural network, a computing system inspired by animal brains * Broadcast network, radio stations, television stations, or other electronic media outlets ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
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Daemon (computer Software)
In computing, a daemon is a program that runs as a background process, rather than being under the direct control of an interactive user. Customary convention is to name a daemon process with the letter ''d'' as a suffix to indicate that it's a daemon. For example, is a daemon that implements system logging facility, and is a daemon that serves incoming SSH connections. Even though the concept can apply to many computing systems, the term ''daemon'' is used almost exclusively in the context of Unix-based systems. In other contexts, different terms are used for the same concept. Systems often start daemons at boot time that will respond to network requests, hardware activity, or other programs by performing some task. Daemons such as cron may also perform defined tasks at scheduled times. Terminology In the context of computing, the word is generally pronounced either as or . The term was coined by the programmers at MIT's Project MAC. According to Fernando J. Corbat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
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Unix
Unix (, ; trademarked as UNIX) is a family of multitasking, multi-user computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, and others. Initially intended for use inside the Bell System, AT&T licensed Unix to outside parties in the late 1970s, leading to a variety of both academic and commercial Unix variants from vendors including University of California, Berkeley ( BSD), Microsoft (Xenix), Sun Microsystems ( SunOS/ Solaris), HP/ HPE ( HP-UX), and IBM ( AIX). The early versions of Unix—which are retrospectively referred to as " Research Unix"—ran on computers such as the PDP-11 and VAX; Unix was commonly used on minicomputers and mainframes from the 1970s onwards. It distinguished itself from its predecessors as the first portable operating system: almost the entire operating system is written in the C programming language (in 1973), which allows U ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
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Linux
Linux ( ) is a family of open source Unix-like operating systems based on the Linux kernel, an kernel (operating system), operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically package manager, packaged as a Linux distribution (distro), which includes the kernel and supporting system software and library (computing), libraries—most of which are provided by third parties—to create a complete operating system, designed as a clone of Unix and released under the copyleft GPL license. List of Linux distributions, Thousands of Linux distributions exist, many based directly or indirectly on other distributions; popular Linux distributions include Debian, Fedora Linux, Linux Mint, Arch Linux, and Ubuntu, while commercial distributions include Red Hat Enterprise Linux, SUSE Linux Enterprise, and ChromeOS. Linux distributions are frequently used in server platforms. Many Linux distributions use the word "Linux" in their name, but the Free ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
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Open Sound System
The Open Sound System (OSS) is an interface for making and capturing sound in Unix and Unix-like operating systems. It is based on standard Unix devices system calls (i.e. POSIX read, write, ioctl, etc.). The term also sometimes refers to the software in a Unix kernel that provides the OSS interface; it can be thought of as a device driver (or a collection of device drivers) for sound controller hardware. The goal of OSS is to allow the writing of sound-based applications that are agnostic of the underlying sound hardware. OSS was created by Hannu Savolainen and is distributed under four license options, three of which are free software licences, thus making OSS free software. API The API is designed to use the traditional Unix framework of open(), read(), write(), and ioctl(), via device files. For instance, the default device for sound input and output is /dev/dsp. Examples using the shell: cat /dev/random > /dev/dsp # plays white noise through the speaker c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
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Sound Reproduction
Sound recording and reproduction is the electrical, mechanical, electronic, or digital inscription and re-creation of sound waves, such as spoken voice, singing, instrumental music, or sound effects. The two main classes of sound recording technology are analog recording and digital recording. Acoustic analog recording is achieved by a microphone diaphragm that senses changes in atmospheric pressure caused by acoustic sound waves and records them as a mechanical representation of the sound waves on a medium such as a phonograph record (in which a stylus cuts grooves on a record). In magnetic tape recording, the sound waves vibrate the microphone diaphragm and are converted into a varying electric current, which is then converted to a varying magnetic field by an electromagnet, which makes a representation of the sound as magnetized areas on a plastic tape with a magnetic coating on it. Analog sound reproduction is the reverse process, with a larger loudspeaker diaphragm c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |