1.
XMMS2
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XMMS2 is a new generation of the XMMS audio player. It is a new design, written from scratch, separate from the XMMS codebase, lXMusic, the default music player application in LXDE, is an XMMS2 client. XMMS2 borrows concepts from XMMS-era music players, such as control, a playlist, plugins, user-configurable GUI, and adds features such as a media library. Like XMMS, XMMS2 has an architecture, a type of modular architecture where certain functions are delegated to loadable libraries which provide particular functions at run-time. XMMS recognised five different types of plugins, Input plugins for reading and decoding files or streams, output plugins to handle sound output. Effects plugins to add effects to decoded audio data, before being output, visualisation plugins to provide visual animations that vary according to the audio being played. General plugins which allow for functions such as controlling XMMS via an Infrared remote control or a Joystick. XMMS2 also recognises five types of plugins, but they perform different functions. Decoder plugins for decoding data read by transport plugins, effect plugins to add effects to decoded audio data, before being output. Output plugins to handle sound output, playlist plugins to handle the importing and exporting of playlist data. Unlike XMMS2, XMMS had no library where it stored information about a users media collection, the only media resources XMMS knew about were its playlist. XMMS2s media library is integrated with the playlist. This integration means that every file or stream added to the playlist has its metadata automatically cached by the media library and this only happens once for every unique URL, so metadata isnt read again if it already exists in the library. Besides metadata, the library can also quickly and efficiently store and reload playlists. One feature of XMMS2 that has been implemented in media players is its client-server architecture. XMMS2 allows the user to choose from a number of implementations for searching, selecting and playing media. The interface can be reopened at any time for further use, other players with similar features on *nix include the Music Player Daemon and Music on Console. When first conceived, XMMS2 was simply a shared library and that is, XMMS2 would be back end code to take care of the mechanics of decoding and playing audio streams, requiring to be linked into a compiled program that provided a user interface
2.
Software developer
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A software developer is a person concerned with facets of the software development process, including the research, design, programming, and testing of computer software. Other job titles which are used with similar meanings are programmer, software analyst. According to developer Eric Sink, the differences between system design, software development, and programming are more apparent, even more so that developers become systems architects, those who design the multi-leveled architecture or component interactions of a large software system. In a large company, there may be employees whose sole responsibility consists of one of the phases above. In smaller development environments, a few people or even an individual might handle the complete process. The word software was coined as a prank as early as 1953, before this time, computers were programmed either by customers, or the few commercial computer vendors of the time, such as UNIVAC and IBM. The first company founded to provide products and services was Computer Usage Company in 1955. The software industry expanded in the early 1960s, almost immediately after computers were first sold in mass-produced quantities, universities, government, and business customers created a demand for software. Many of these programs were written in-house by full-time staff programmers, some were distributed freely between users of a particular machine for no charge. Others were done on a basis, and other firms such as Computer Sciences Corporation started to grow. The computer/hardware makers started bundling operating systems, systems software and programming environments with their machines, new software was built for microcomputers, so other manufacturers including IBM, followed DECs example quickly, resulting in the IBM AS/400 amongst others. The industry expanded greatly with the rise of the computer in the mid-1970s. In the following years, it created a growing market for games, applications. DOS, Microsofts first operating system product, was the dominant operating system at the time, by 2014 the role of cloud developer had been defined, in this context, one definition of a developer in general was published, Developers make software for the world to use. The job of a developer is to crank out code -- fresh code for new products, code fixes for maintenance, code for business logic, bus factor Software Developer description from the US Department of Labor
3.
Software release life cycle
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Usage of the alpha/beta test terminology originated at IBM. As long ago as the 1950s, IBM used similar terminology for their hardware development, a test was the verification of a new product before public announcement. B test was the verification before releasing the product to be manufactured, C test was the final test before general availability of the product. Martin Belsky, a manager on some of IBMs earlier software projects claimed to have invented the terminology, IBM dropped the alpha/beta terminology during the 1960s, but by then it had received fairly wide notice. The usage of beta test to refer to testing done by customers was not done in IBM, rather, IBM used the term field test. Pre-alpha refers to all activities performed during the project before formal testing. These activities can include requirements analysis, software design, software development, in typical open source development, there are several types of pre-alpha versions. Milestone versions include specific sets of functions and are released as soon as the functionality is complete, the alpha phase of the release life cycle is the first phase to begin software testing. In this phase, developers generally test the software using white-box techniques, additional validation is then performed using black-box or gray-box techniques, by another testing team. Moving to black-box testing inside the organization is known as alpha release, alpha software can be unstable and could cause crashes or data loss. Alpha software may not contain all of the features that are planned for the final version, in general, external availability of alpha software is uncommon in proprietary software, while open source software often has publicly available alpha versions. The alpha phase usually ends with a freeze, indicating that no more features will be added to the software. At this time, the software is said to be feature complete, Beta, named after the second letter of the Greek alphabet, is the software development phase following alpha. Software in the stage is also known as betaware. Beta phase generally begins when the software is complete but likely to contain a number of known or unknown bugs. Software in the phase will generally have many more bugs in it than completed software, as well as speed/performance issues. The focus of beta testing is reducing impacts to users, often incorporating usability testing, the process of delivering a beta version to the users is called beta release and this is typically the first time that the software is available outside of the organization that developed it. Beta version software is useful for demonstrations and previews within an organization
4.
Repository (version control)
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In revision control systems, a repository is an on-disk data structure which stores metadata for a set of files and/or directory structure. Some of the metadata that a repository contains includes, among other things, a set of references to commit objects, called heads. The main purpose of a repository is to store a set of files and these differences in methodology have generally led to diverse uses of revision control by different groups, depending on their needs. Software repository Codebase Forge Comparison of source code hosting facilities
5.
C (programming language)
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C was originally developed by Dennis Ritchie between 1969 and 1973 at Bell Labs, and used to re-implement the Unix operating system. C has been standardized by the American National Standards Institute since 1989, C is an imperative procedural language. Therefore, C was useful for applications that had formerly been coded in assembly language. Despite its low-level capabilities, the language was designed to encourage cross-platform programming, a standards-compliant and portably written C program can be compiled for a very wide variety of computer platforms and operating systems with few changes to its source code. The language has become available on a wide range of platforms. In C, all code is contained within subroutines, which are called functions. Function parameters are passed by value. Pass-by-reference is simulated in C by explicitly passing pointer values, C program source text is free-format, using the semicolon as a statement terminator and curly braces for grouping blocks of statements. The C language also exhibits the characteristics, There is a small, fixed number of keywords, including a full set of flow of control primitives, for, if/else, while, switch. User-defined names are not distinguished from keywords by any kind of sigil, There are a large number of arithmetical and logical operators, such as +, +=, ++, &, ~, etc. More than one assignment may be performed in a single statement, function return values can be ignored when not needed. Typing is static, but weakly enforced, all data has a type, C has no define keyword, instead, a statement beginning with the name of a type is taken as a declaration. There is no function keyword, instead, a function is indicated by the parentheses of an argument list, user-defined and compound types are possible. Heterogeneous aggregate data types allow related data elements to be accessed and assigned as a unit, array indexing is a secondary notation, defined in terms of pointer arithmetic. Unlike structs, arrays are not first-class objects, they cannot be assigned or compared using single built-in operators, There is no array keyword, in use or definition, instead, square brackets indicate arrays syntactically, for example month. Enumerated types are possible with the enum keyword and they are not tagged, and are freely interconvertible with integers. Strings are not a data type, but are conventionally implemented as null-terminated arrays of characters. Low-level access to memory is possible by converting machine addresses to typed pointers
6.
C++
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C++ is a general-purpose programming language. It has imperative, object-oriented and generic programming features, while also providing facilities for low-level memory manipulation and it was designed with a bias toward system programming and embedded, resource-constrained and large systems, with performance, efficiency and flexibility of use as its design highlights. C++ is a language, with implementations of it available on many platforms and provided by various organizations, including the Free Software Foundation, LLVM, Microsoft, Intel. C++ is standardized by the International Organization for Standardization, with the latest standard version ratified and published by ISO in December 2014 as ISO/IEC14882,2014. The C++ programming language was standardized in 1998 as ISO/IEC14882,1998. The current C++14 standard supersedes these and C++11, with new features, the C++17 standard is due in 2017, with the draft largely implemented by some compilers already, and C++20 is the next planned standard thereafter. Many other programming languages have influenced by C++, including C#, D, Java. In 1979, Bjarne Stroustrup, a Danish computer scientist, began work on C with Classes, the motivation for creating a new language originated from Stroustrups experience in programming for his Ph. D. thesis. When Stroustrup started working in AT&T Bell Labs, he had the problem of analyzing the UNIX kernel with respect to distributed computing, remembering his Ph. D. experience, Stroustrup set out to enhance the C language with Simula-like features. C was chosen because it was general-purpose, fast, portable, as well as C and Simulas influences, other languages also influenced C++, including ALGOL68, Ada, CLU and ML. Initially, Stroustrups C with Classes added features to the C compiler, Cpre, including classes, derived classes, strong typing, inlining, furthermore, it included the development of a standalone compiler for C++, Cfront. In 1985, the first edition of The C++ Programming Language was released, the first commercial implementation of C++ was released in October of the same year. In 1989, C++2.0 was released, followed by the second edition of The C++ Programming Language in 1991. New features in 2.0 included multiple inheritance, abstract classes, static functions, const member functions. In 1990, The Annotated C++ Reference Manual was published and this work became the basis for the future standard. Later feature additions included templates, exceptions, namespaces, new casts, after a minor C++14 update released in December 2014, various new additions are planned for 2017 and 2020. According to Stroustrup, the name signifies the nature of the changes from C. This name is credited to Rick Mascitti and was first used in December 1983, when Mascitti was questioned informally in 1992 about the naming, he indicated that it was given in a tongue-in-cheek spirit
7.
GTK+
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GTK+ is a cross-platform widget toolkit for creating graphical user interfaces. It is licensed under the terms of the GNU Lesser General Public License and it is one of the most popular toolkits for the Wayland and X11 windowing systems, along with Qt. The GTK+ library contains a set of graphical elements, version 3.13.3 contains 203 active and 37 deprecated widgets. GTK+ is a widget toolkit written in the C programming language, it uses GObject. While GTK+ is primarily targeted at windowing systems based upon X11 and Wayland, it works on other platforms, including Microsoft Windows, there is also an HTML5 back-end called Broadway. GTK+ can be configured to change the look of the widgets drawn, several display engines exist which try to emulate the look of the native widgets on the platform in use. Starting with version 2.8, released in 2005, GTK+ began the transition to using Cairo to render the majority of its control elements. Since GTK+ version 3.0, all the rendering is done using Cairo, GDK acts as a wrapper around the low-level functions provided by the underlying windowing and graphics systems. GDK is found in the /gdk directory, GSK is the rendering and scene graph API for GTK+. GSK lies between the control elements and the rendering. GSK was finally merged into GTK+ version 3.90 released March 2017, GSK is found in the /gsk directory. GtkInspector has been introduced with version 3.14, gtkInspector can only be invoked after installing the development package libgtk-3-dev/gtk+-devel. There are several GUI designers for GTK+, the following projects are active as of July 2011, Glade, supports GtkBuilder, which is a GTK+ built-in GUI description format. Gazpacho, GUI builder for the GTK+ toolkit written in Python Crow Designer, relies on its own GuiXml format, Stetic, part of MonoDevelop, oriented towards Gtk#. GtkBuilder allows user interfaces to be designed without writing code, the interface is described in an Extensible Markup Language file, which is then loaded at runtime and the objects created automatically. The Glade Interface Designer allows creation of the interface in a WYSIWYG manner. The description of the interface is independent from the programming language being used. A library written in one programming language may be used in another language if bindings are written, Gtk# is a set of. NET bindings for the GTK+ GUI toolkit and assorted GNOME libraries
8.
Operating system
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An operating system is system software that manages computer hardware and software resources and provides common services for computer programs. All computer programs, excluding firmware, require a system to function. Operating systems are found on many devices that contain a computer – from cellular phones, the dominant desktop operating system is Microsoft Windows with a market share of around 83. 3%. MacOS by Apple Inc. is in place, and the varieties of Linux is in third position. Linux distributions are dominant in the server and supercomputing sectors, other specialized classes of operating systems, such as embedded and real-time systems, exist for many applications. A single-tasking system can run one program at a time. Multi-tasking may be characterized in preemptive and co-operative types, in preemptive multitasking, the operating system slices the CPU time and dedicates a slot to each of the programs. Unix-like operating systems, e. g. Solaris, Linux, cooperative multitasking is achieved by relying on each process to provide time to the other processes in a defined manner. 16-bit versions of Microsoft Windows used cooperative multi-tasking, 32-bit versions of both Windows NT and Win9x, used preemptive multi-tasking. Single-user operating systems have no facilities to distinguish users, but may allow multiple programs to run in tandem, a distributed operating system manages a group of distinct computers and makes them appear to be a single computer. The development of networked computers that could be linked and communicate with each other gave rise to distributed computing, distributed computations are carried out on more than one machine. When computers in a work in cooperation, they form a distributed system. The technique is used both in virtualization and cloud computing management, and is common in large server warehouses, embedded operating systems are designed to be used in embedded computer systems. They are designed to operate on small machines like PDAs with less autonomy and they are able to operate with a limited number of resources. They are very compact and extremely efficient by design, Windows CE and Minix 3 are some examples of embedded operating systems. A real-time operating system is a system that guarantees to process events or data by a specific moment in time. A real-time operating system may be single- or multi-tasking, but when multitasking, early computers were built to perform a series of single tasks, like a calculator. Basic operating system features were developed in the 1950s, such as resident monitor functions that could run different programs in succession to speed up processing
9.
Unix-like
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A Unix-like operating system is one that behaves in a manner similar to a Unix system, while not necessarily conforming to or being certified to any version of the Single UNIX Specification. A Unix-like application is one that behaves like the corresponding Unix command or shell, there is no standard for defining the term, and some difference of opinion is possible as to the degree to which a given operating system or application is Unix-like. The Open Group owns the UNIX trademark and administers the Single UNIX Specification and they do not approve of the construction Unix-like, and consider it a misuse of their trademark. Other parties frequently treat Unix as a genericized trademark, in 2007, Wayne R. Gray sued to dispute the status of UNIX as a trademark, but lost his case, and lost again on appeal, with the court upholding the trademark and its ownership. Unix-like systems started to appear in the late 1970s and early 1980s, many proprietary versions, such as Idris, UNOS, Coherent, and UniFlex, aimed to provide businesses with the functionality available to academic users of UNIX. These largely displaced the proprietary clones, growing incompatibility among these systems led to the creation of interoperability standards, including POSIX and the Single UNIX Specification. Various free, low-cost, and unrestricted substitutes for UNIX emerged in the 1980s and 1990s, including 4. 4BSD, Linux, some of these have in turn been the basis for commercial Unix-like systems, such as BSD/OS and OS X. The various BSD variants are notable in that they are in fact descendants of UNIX, however, the BSD code base has evolved since then, replacing all of the AT&T code. Since the BSD variants are not certified as compliant with the Single UNIX Specification, dennis Ritchie, one of the original creators of Unix, expressed his opinion that Unix-like systems such as Linux are de facto Unix systems. Eric S. Raymond and Rob Landley have suggested there are three kinds of Unix-like systems, Genetic UNIX Those systems with a historical connection to the AT&T codebase. Most commercial UNIX systems fall into this category, so do the BSD systems, which are descendants of work done at the University of California, Berkeley in the late 1970s and early 1980s. Some of these systems have no original AT&T code but can trace their ancestry to AT&T designs. Trademark or branded UNIX These systems—largely commercial in nature—have been determined by the Open Group to meet the Single UNIX Specification and are allowed to carry the UNIX name, many ancient UNIX systems no longer meet this definition. Around 2001, Linux was given the opportunity to get a certification including free help from the POSIX chair Andrew Josey for the price of one dollar. Some non-Unix-like operating systems provide a Unix-like compatibility layer, with degrees of Unix-like functionality. IBM z/OSs UNIX System Services is sufficiently complete to be certified as trademark UNIX, cygwin and MSYS both provide a GNU environment on top of the Microsoft Windows user API, sufficient for most common open source software to be compiled and run. Subsystem for Unix-based Applications provides Unix-like functionality as a Windows NT subsystem, Windows Subsystem for Linux provides a Linux-compatible kernel interface developed by Microsoft and containing no Linux code, with Ubuntu user-mode binaries running on top of it
10.
Software license
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A software license is a legal instrument governing the use or redistribution of software. Under United States copyright law all software is copyright protected, in code as also object code form. The only exception is software in the public domain, most distributed software can be categorized according to its license type. Two common categories for software under copyright law, and therefore with licenses which grant the licensee specific rights, are proprietary software and free, unlicensed software outside the copyright protection is either public domain software or software which is non-distributed, non-licensed and handled as internal business trade secret. Contrary to popular belief, distributed unlicensed software is copyright protected. Examples for this are unauthorized software leaks or software projects which are placed on public software repositories like GitHub without specified license. As voluntarily handing software into the domain is problematic in some international law domains, there are also licenses granting PD-like rights. Therefore, the owner of a copy of software is legally entitled to use that copy of software. Hence, if the end-user of software is the owner of the respective copy, as many proprietary licenses only enumerate the rights that the user already has under 17 U. S. C. §117, and yet proclaim to take away from the user. Proprietary software licenses often proclaim to give software publishers more control over the way their software is used by keeping ownership of each copy of software with the software publisher. The form of the relationship if it is a lease or a purchase, for example UMG v. Augusto or Vernor v. Autodesk. The ownership of goods, like software applications and video games, is challenged by licensed. The Swiss based company UsedSoft innovated the resale of business software and this feature of proprietary software licenses means that certain rights regarding the software are reserved by the software publisher. Therefore, it is typical of EULAs to include terms which define the uses of the software, the most significant effect of this form of licensing is that, if ownership of the software remains with the software publisher, then the end-user must accept the software license. In other words, without acceptance of the license, the end-user may not use the software at all, one example of such a proprietary software license is the license for Microsoft Windows. The most common licensing models are per single user or per user in the appropriate volume discount level, Licensing per concurrent/floating user also occurs, where all users in a network have access to the program, but only a specific number at the same time. Another license model is licensing per dongle which allows the owner of the dongle to use the program on any computer, Licensing per server, CPU or points, regardless the number of users, is common practice as well as site or company licenses
11.
GNU General Public License
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The GNU General Public License is a widely used free software license, which guarantees end users the freedom to run, study, share and modify the software. The license was written by Richard Stallman of the Free Software Foundation for the GNU Project. The GPL is a license, which means that derivative work can only be distributed under the same license terms. This is in distinction to permissive free licenses, of which the BSD licenses. GPL was the first copyleft license for general use, historically, the GPL license family has been one of the most popular software licenses in the free and open-source software domain. Prominent free software licensed under the GPL include the Linux kernel. In 2007, the version of the license was released to address some perceived problems with the second version that were discovered during its long-time usage. To keep the license up to date, the GPL license includes an optional any later version clause, developers can omit it when licensing their software, for instance the Linux kernel is licensed under GPLv2 without the any later version clause. The GPL was written by Richard Stallman in 1989, for use with programs released as part of the GNU project, the original GPL was based on a unification of similar licenses used for early versions of GNU Emacs, the GNU Debugger and the GNU C Compiler. These licenses contained similar provisions to the modern GPL, but were specific to each program, rendering them incompatible, Stallmans goal was to produce one license that could be used for any project, thus making it possible for many projects to share code. The second version of the license, version 2, was released in 1991, version 3 was developed to attempt to address these concerns and was officially released on 29 June 2007. Version 1 of the GNU GPL, released on 25 February 1989, the first problem was that distributors may publish binary files only—executable, but not readable or modifiable by humans. To prevent this, GPLv1 stated that any vendor distributing binaries must also make the source code available under the same licensing terms. The second problem was that distributors might add restrictions, either to the license, the union of two sets of restrictions would apply to the combined work, thus adding unacceptable restrictions. To prevent this, GPLv1 stated that modified versions, as a whole, had to be distributed under the terms in GPLv1. Therefore, software distributed under the terms of GPLv1 could be combined with software under more permissive terms, according to Richard Stallman, the major change in GPLv2 was the Liberty or Death clause, as he calls it – Section 7. The section says that licensees may distribute a GPL-covered work only if they can all of the licenses obligations. In other words, the obligations of the license may not be severed due to conflicting obligations and this provision is intended to discourage any party from using a patent infringement claim or other litigation to impair users freedom under the license
12.
Media player (software)
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A media player is a computer program for playing multimedia files like videos movies and music. Media players display standard media control icons known from physical devices such as recorders and CD players, such as play, pause, fastforward, backforward. Mainstream operating systems have at least one media player. For example, Windows comes with Windows Media Player while OS X comes with QuickTime Player, linux distributions may also come with a media players, such as SMPlayer, Amarok, Audacious, Banshee, MPlayer, Rhythmbox, Totem, VLC Media Player, and xine. Android OS comes with Google Play Music as default media player and many apps like Poweramp, Beautiful Music Player, different media players may have different goals and feature sets. Video players are a group of players that have their features geared more towards playing digital video. For example, Windows DVD Player exclusively plays DVD-Video discs and nothing else, audio players, on the other hand, specialize in digital audio. For example, AIMP exclusively plays audio formats, in addition, watching video files on it can be a trying feat. General-purpose media players also do exist, for example, Windows Media Player has exclusive features for both audio and video material, although it cannot match the feature set of Media Player Classic and MediaMonkey combined. 3D video players are used to play 2D video in 3D format, a high-quality three-dimensional video presentation requires that each frame of a motion picture be embedded with information on the depth of objects present in the scene. Tedious and costly, this method is used in a small fraction of movies produced worldwide. It is, however, possible to give an otherwise two-dimensional picture the appearance of depth, using a technique known as anaglyph processing a flat picture can be transformed so as to give an illusion of depth when viewed through anaglyph glasses. An image viewed through anaglyph glasses appears to have both protruding and deeply embedded objects in it, at the expense of somewhat distorted colours. e. as the video is being played back. Although computers with some of these capabilities were available from the late 1980s, since 2007, other types of consumer electronics, including gaming systems and dedicated media devices have crossed over to manage video and music content. The term media center also refers to specialized computer programs designed to run on personal computers
13.
Winamp
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Since version 2 it has been sold as freemium and supports extensibility with plug-ins and skins, and features music visualization, playlist and a media library, supported by a large online community. Version 1 of Winamp was released in 1997, and grew popular with over 3 million downloads. Winamp 2.0 was released on September 8,1998, the 2. x versions were widely used and made Winamp one of the most downloaded Windows applications. By 2000, Winamp had over 25 million registered users, a poor reception to the 2002 rewrite, Winamp3, was followed by the release of Winamp 5 in 2003, and a later release of version 5.5 in 2007. Playback formats Winamp supports music playback using MP3, MIDI, MOD, MPEG-1 audio layers 1 and 2, AAC, M4A, FLAC, WAV, Winamp was one of the first widely used music players on Windows to support playback of Ogg Vorbis by default. It supports gapless playback for MP3 and AAC and ReplayGain for volume leveling across tracks, CD support includes playing and importing music from audio CDs, optionally with CD-Text, and burning music to CDs. The standard version limits maximum speed and datarate, the Pro version removes these limitations. Winamp supports playback of Windows Media Video and Nullsoft Streaming Video, for MPEG Video, AVI, and other unsupported video types, Winamp uses Microsofts DirectShow API for playback, allowing playback of most of the video formats supported by Windows Media Player. 5.1 Surround sound is supported where formats and decoders allow, Media Library At installation, Winamp scans the users system for media files to add to the Media Library database. It supports full Unicode filenames and Unicode metadata for media files, in the Media Library user interface pane, under Local Media, several selectors permit display of subsets of media files with greater detail. Adding album art and track tags Get Album Art permits retrieval of cover art, autotagging analyzes a tracks audio using the Gracenote service and retrieves the songs ID2 and ID3 metadata. Podcatcher Winamp can also be used as an RSS media feeds aggregator capable of displaying articles, downloading, SHOUTcast Wire provides a directory and RSS subscription system for podcasts. Media Monitor Winamp Media Monitor allows web-based browsing and bookmarking music blog websites, the Media Monitor is preloaded with music blog URLs. Winamp Remote Winamp Remote allows remote playback of unprotected media files on the users PC via the Internet, Remote adjusts bitrate based on available bandwidth, and can be controlled by web interface, Wii, PlayStation 3, Xbox 360, and mobile phones. Plug-ins In February 1998, Winamp was rewritten as an audio player with a plug-in architecture. This feature was received well by reviewers, development was early, diverse, and rapid,66 plugins were published by November 1998. The Winamp software development kit allows developers to create seven different types of plug-ins. Input. Output, sends data to devices or files
14.
Source code
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In computing, source code is any collection of computer instructions, possibly with comments, written using a human-readable programming language, usually as ordinary text. The source code of a program is designed to facilitate the work of computer programmers. The source code is often transformed by an assembler or compiler into binary machine code understood by the computer, the machine code might then be stored for execution at a later time. Alternatively, source code may be interpreted and thus immediately executed, most application software is distributed in a form that includes only executable files. If the source code were included it would be useful to a user, programmer or a system administrator, the Linux Information Project defines source code as, Source code is the version of software as it is originally written by a human in plain text. The notion of source code may also be more broadly, to include machine code and notations in graphical languages. It is therefore so construed as to include code, very high level languages. Often there are several steps of program translation or minification between the source code typed by a human and an executable program. The earliest programs for stored-program computers were entered in binary through the front panel switches of the computer and this first-generation programming language had no distinction between source code and machine code. When IBM first offered software to work with its machine, the code was provided at no additional charge. At that time, the cost of developing and supporting software was included in the price of the hardware, for decades, IBM distributed source code with its software product licenses, until 1983. Most early computer magazines published source code as type-in programs, Source code can also be stored in a database or elsewhere. The source code for a piece of software may be contained in a single file or many files. Though the practice is uncommon, a source code can be written in different programming languages. For example, a program written primarily in the C programming language, in some languages, such as Java, this can be done at run time. The code base of a programming project is the larger collection of all the source code of all the computer programs which make up the project. It has become practice to maintain code bases in version control systems. Moderately complex software customarily requires the compilation or assembly of several, sometimes dozens or even hundreds, in these cases, instructions for compilations, such as a Makefile, are included with the source code
15.
NCR Corporation
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They also provide IT maintenance support services. NCR had been based in Dayton, Ohio, starting in 1884, NCR was founded in 1884 and acquired by AT&T in 1991. A restructuring of AT&T in 1996 led to NCRs re-establishment January 1,1997 as a separate company, NCR is the only AT&T spin-off company that has retained its original name—all the others have either been purchased or renamed following subsequent mergers. The company began as the National Manufacturing Company of Dayton, Ohio, was established to manufacture, in 1884, the company and patents were bought by John Henry Patterson and his brother Frank Jefferson Patterson, and the firm was renamed the National Cash Register Company. Patterson formed NCR into one of the first modern American companies by introducing new, aggressive sales methods and he established the first sales training school in 1893 and introduced a comprehensive social welfare program for his factory workers. Other significant figures in the history of the company were Charles F. Kettering, Thomas J. Watson, Sr. Deeds and Kettering went on to found Dayton Engineering Laboratories Company which later became Delco Products Division of General Motors, Watson eventually worked his way up to general sales manager. At an uninspiring sales meeting, Watson interrupted, saying The trouble with one of us is that we dont think enough. We dont get paid for working with our feet — we get paid for working with our heads, Watson then wrote THINK on the easel. Signs with this motto were erected in factory buildings, sales offices, THINK later became a widely known symbol of IBM. Kettering designed the first cash register powered by a motor in 1906. Within a few years he developed the Class 1000 register which was in production for 40 years, telephone Credit Authorization system for verifying credit in department stores. When John H. Patterson and his brother took over the company, cash registers were expensive, there was little demand for the expensive device, but Patterson believed the product would sell once shopkeepers understood it would drastically decrease theft by salesclerks. He created a team known as the American Selling Force which worked on commissions and followed a standard sales script. The philosophy was to sell a business rather than just a piece of machinery. Sales demonstrations were set up in hotels depicting a store interior complete with real merchandise, the sale prospect was described as the P. P. or Probable Purchaser. Once initial objections were swept aside and the P. P. admitted to internal theft losses, the deal was sealed with a 25 cent cigar. NCR expanded quickly and became multi-national in 1888, between 1893 and 1906 it acquired a number of smaller cash register companies
16.
X Window System
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The X Window System is a windowing system for bitmap displays, common on UNIX-like computer operating systems. X provides the framework for a GUI environment, drawing and moving windows on the display device and interacting with a mouse. X does not mandate the user interface – this is handled by individual programs, as such, the visual styling of X-based environments varies greatly, different programs may present radically different interfaces. X originated at the Massachusetts Institute of Technology in 1984, the protocol has been version 11 since September 1987. The X. Org Foundation leads the X project, with the current reference implementation, X. Org Server, available as free and open source software under the MIT License, X is an architecture-independent system for remote graphical user interfaces and input device capabilities. Each person using a terminal has the ability to interact with the display with any type of user input device. X provides the framework, or primitives, for building such GUI environments, drawing and moving windows on the display and interacting with a mouse. X does not mandate the user interface, individual client programs handle this, programs may use Xs graphical abilities with no user interface. As such, the styling of X-based environments varies greatly. Unlike most earlier display protocols, X was specifically designed to be used over network connections rather than on an integral or attached display device. X features network transparency, which means an X program running on a computer somewhere on a network can display its user interface on an X server running on other computer on the network. The fact that the server is applied to the software in front of the user is often surprising to users accustomed to their programs being clients to services on remote computers. Xs network protocol is based on X command primitives and this approach allows both 2D and 3D operations by an X client application which might be running on a different computer to still be fully accelerated on the X servers display. X provides no support for audio, several projects exist to fill this niche. X uses a model, an X server communicates with various client programs. The server accepts requests for graphical output and sends back user input, a client and server can even communicate securely over the Internet by tunneling the connection over an encrypted network session. An X client itself may emulate an X server by providing services to other clients. This is known as X nesting, open-source clients such as Xnest and Xephyr support such X nesting
17.
Fork (software development)
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The term often implies not merely a development branch, but also a split in the developer community, a form of schism. Free and open-source software is that which, by definition, may be forked from the development team without prior permission without violating copyright law. However, licensed forks of proprietary software also happen, the word fork stems from the Latin word furca, meaning a fork or similarly shaped instrument. Fork in the meaning of to divide in branches, go separate ways has been used as early as the 14th century. In the software environment, the word evokes the fork system call, however, fork was in use in the present sense by 1995 to describe the XEmacs split, and was an understood usage in the GNU Project by 1996. Thus, there is a penalty associated with forking. The relationship between the different teams can be cordial or very bitter and he notes in the Jargon File, David A. Wheeler notes four possible outcomes of a fork, with examples, The death of the fork. This is by far the most common case and it is easy to declare a fork, but considerable effort to continue independent development and support. With a DVCS such as Mercurial or Git, the way to contribute to a project is to first branch the repository. Forks often restart version numbering from 0.1 or 1.0 even if the software was at version 3.0,4.0. An exception is when the software is designed to be a drop-in replacement for the original project. In proprietary software, the copyright is held by the employing entity. This is almost always an economic decision to generate a greater market share, a notable proprietary fork not of this kind is the many varieties of proprietary Unix—almost all derived from AT&T Unix under license and all called Unix, but increasingly mutually incompatible. The BSD licenses permit forks to become proprietary software, and some say that commercial incentives thus make proprietisation almost inevitable, examples include macOS, Cedega and CrossOver, EnterpriseDB, Supported PostgreSQL with their proprietary ESM storage system, and Netezzas proprietary highly scalable derivative of PostgreSQL. Some of these vendors contribute back changes to the community project, while some keep their changes as their own competitive advantages
18.
Audacious (software)
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Audacious is a free and open source audio player with a focus on low resource use, high audio quality, and support for a wide range of audio formats. It is designed primarily for use on POSIX-compatible systems such as Linux, Audacious is the default audio player in Lubuntu and in Ubuntu Studio. Audacious began as a fork of Beep Media Player, which itself is a fork of XMMS, william nenolod Pitcock decided to fork Beep Media Player after the original development team announced that they were stopping development in order to create a next-generation version called BMPx. According to the Audacious home page, Pitcock and others had own ideas about how a player should be designed, which wanted to try in a production environment. Since version 2.1, Audacious includes both the Winamp-like interface known from previous versions and a new, GTK+-based interface known as GTKUI, GTKUI became the default interface in Audacious 2.4. Before version 3.0, Audacious used the GTK+2. x toolkit by default, partial support for GTK+3. x was added in version 2.5, while version 3.0 has full support for GTK+3. x and uses it by default. However, dissatisfied with the evolution of GTK+3. x, MIDI via native OS synthesizer control or TiMidity. CD Audio Audacious owes a large portion of its functionality to plugins, more features are available via third-party plugins. Current versions of the Audacious core classify plugins as follows, Decoder plugins, transport plugins, which are lowlevel and implemented by the VFS layer. General plugins, which provide user-added services to the player Output plugins, visualization plugins, which provide visualizations based on fast Fourier transforms of the wave data. Effect plugins, which provide various sound processing on the audio stream Container plugins. Lowlevel plugins, which provide services to the player core and are not categorized into any of the other plugins.2. Winamp. wsz skin files, a type of Zip archive, can be used directly, the program can use Windows Bitmap graphics from the Winamp archive, although native skins for Linux are usually rendered in Portable Network Graphics format. Audacious 1. x allows the user to adjust the RGB color balance of any skin, Audacious is intended to be a standalone media player and not a server, though it accepts connections from client software, such as Conky. Connection to Audacious for remote control can be done over plain DBus, by using an MPRIS-compatible client, from XMMS to Audacious, The history of a Winamp clone. Official website Audacious on GitHub Audacious plugins on GitHub Bug tracker
19.
Compact Disc Digital Audio
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Compact Disc Digital Audio is the standard format for audio compact discs. The standard is defined in the Red Book, one of a series of Rainbow Books that contain the specifications for all Compact Disc formats. These parameters are common to all discs and used by all logical formats. The standard also specifies the form of audio encoding, 2-channel signed 16-bit Linear PCM sampled at 44,100 Hz. Although rarely used, the specification allows for discs to be mastered with a form of emphasis, the second edition of IEC60908 was published in 1999 and it cancels and replaces the first edition, amendment 1 and the corrigendum to amendment 1. The IEC60908 however does not contain all the information for extensions that is available in the Red Book, such as the details for CD-Text, CD+G, the standard is not freely available and must be licensed. It is available from Philips and the IEC, as of 2013, Philips outsources licensing of the standard to Adminius, which charges US$100 for the Red Book, plus US$50 each for the Subcode Channels R-W and CD Text Mode annexes. The audio contained in a CD-DA consists of two-channel signed 16-bit Linear PCM sampled at 44,100 Hz, the sampling rate is adapted from that attained when recording digital audio on a PAL videotape with a PCM adaptor, an earlier way of storing digital audio. An audio CD can represent frequencies up to 22.05 kHz, the selection of the sample rate was based primarily on the need to reproduce the audible frequency range of 20–20,000 Hz. The Nyquist–Shannon sampling theorem states that a rate of more than twice the maximum frequency of the signal to be recorded is needed. The exact sampling rate of 44, the device that converts an analog audio signal into PCM audio, which in turn is changed into an analog video signal is called a PCM adaptor. This technology could store six samples in a horizontal line. 60 field/s black and white video was required, and in NTSC countries that video signal has 245 usable lines per field, similarly, PAL has 294 lines and 50 fields, which gives 44,100 samples/s/stereo channel. This system could store 14-bit samples with some correction, or 16-bit samples with almost no error correction. There was a debate over the use of 14-bit or 16-bit quantization. When the Sony/Philips task force designed the Compact Disc, Philips had already developed a 14-bit D/A converter, in the end,16 bits and 44.1 kilosamples per second prevailed. Philips found a way to produce 16-bit quality using its 14-bit DAC by using four times oversampling, some CDs are mastered with pre-emphasis, an artificial boost of high audio frequencies. The pre-emphasis improves the apparent signal-to-noise ratio by making use of the channels dynamic range
20.
FLAC
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FLAC is an audio coding format for lossless compression of digital audio, and is also the name of the reference codec implementation. Digital audio compressed by FLACs algorithm can typically be reduced to 50–60% of its original size, FLAC is an open format with royalty-free licensing and a reference implementation which is free software. FLAC has support for metadata tagging, album art. Development was started in 2000 by Josh Coalson, the bit-stream format was frozen when FLAC entered beta stage with the release of version 0.5 of the reference implementation on 15 January 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. Xiph. org is behind other free compression formats such as Vorbis, Theora, Speex and Opus. Version 1.3.0 was released on 26 May 2013, at which point development was moved to the Xiph. org git repository. flac files, the reference implementation is free software. The source code for libFLAC and libFLAC++ is available under the BSD license, and the sources for flac, metaflac, in its stated goals, the FLAC project encourages its developers not to implement copy prevention features of any kind. FLAC supports only fixed-point samples, not floating-point and it can handle any PCM bit resolution from 4 to 32 bits per sample, any sampling rate from 1 Hz to 655,350 Hz in 1 Hz increments, and any number of channels from 1 to 8. Channels can be grouped in some cases, for stereo and 5.1 channel surround. FLAC uses CRC checksums for identifying corrupted frames when used in a streaming protocol, FLAC allows for a Rice parameter between 0 and 16. FLAC uses linear prediction to convert the audio samples, there are two steps, the predictor and the error coding. The predictor can be one of four types, the difference between the predictor and the actual sample data is calculated and is known as the residual. The residual is stored efficiently using Golomb-Rice coding and it also uses run-length encoding for blocks of identical samples, such as silent passages. For tagging, FLAC uses the system as Vorbis comments. The libFLAC API is organized into streams, seekable streams, most FLAC applications will generally restrict themselves to encoding/decoding using libFLAC at the file level interface. LibFLAC uses a compression level parameter that varies from 0 to 8, the compressed files are always perfect, lossless representations of the original data. Although the compression process involves a tradeoff between speed and size, the process is always quite fast and not very dependent on the level of compression
21.
Icecast
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Icecast is a streaming media project released as free software maintained by the Xiph. org Foundation. It also refers specifically to the program which is part of the project. Icecast was created in December 1998/January 1999 by Jack Moffitt and Barath Raghavan to provide an open source audio streaming server that anyone could modify, use, and tinker with. Version 2 was started in 2001, a ground-up rewrite aimed at support and scalability. Icecast requires external programs, called clients, to originate the streams. The source runs typically in the place where the audio is generated, since version 2.4.0 source clients can use plain HTTP standard PUT requests instead of the custom SOURCE method. List of streaming media systems SHOUTcast FreeCast PeerCast Peercasting Edcast Steamcast Official website Icecast Streaming Directory
22.
SHOUTcast
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SHOUTcast is cross-platform proprietary software for streaming media over the Internet. The software, developed by Nullsoft, is free of charge. It allows digital audio content, primarily in MP3 or High-Efficiency Advanced Audio Coding format, to be broadcast to and from media player software, the most common use of SHOUTcast is for creating or listening to Internet audio broadcasts, however, video streams exist as well. Some traditional radio stations use SHOUTcast to extend their presence onto the Web, SHOUTcast Radio is a related website which provides a directory of SHOUTcast stations. Created in 1998, SHOUTcasts streaming protocol uses metadata tags and responses that all start with ICY, Nullsoft was purchased by AOL on June 1,1999. On January 14,2014, AOL sold Nullsoft to Belgian online radio aggregator Radionomy and it uses HTTP as a transport protocol. Although multicast was planned, it was never developed, SHOUTcast servers and clients are available for FreeBSD, Linux, macOS, Microsoft Windows, and Solaris. Client-only versions exist for Android, BlackBerry OS, iOS, Palm OS and webOS, PlayStation Portable, Windows Mobile, Symbian S60 and UIQ, Nintendo DS, and Wii. The output format is supported by multiple clients, including Nullsofts own Winamp as well as Amarok, Exaile, foobar2000, iTunes, Songbird, Totem, XMMS, and Zinf. If the client does not support the SHOUTcast protocol, then the SHOUTcast server sends the stream without the metadata thus allowing it to be heard/viewed in clients like Windows Media Player. SHOUTcast servers are usually linked to by means of playlist files, when that URL is visited in a Web browser which identifies itself as Mozilla-compatible, the server will return a generated SHOUTcast server info/status page, rather than streaming audio. Site visitors can pick a station to listen to and download a playlist file for use in their own SHOUTcast-capable media player, in September 2008, AOL redesigned the SHOUTcast website, which had been roughly the same since 2000. In 2010, SHOUTcast again redesigned it with more of an AOL look, as part of the redesign, the directory and services were rebranded as SHOUTcast Radio, rather than SHOUTcast Streaming Technology. The redesign included a fully functional option to view the site, SHOUTcast said in 2011 that up to 900,000 concurrent listeners could be seen on public streams during peak hours. The audience on private streams is unknown, the maximum and minimum number of listeners fluctuates widely during a day, with roughly three times as many listeners during peak hours as at low use times. This would indicate US-centric use of the platform compared with platforms that have a worldwide audience, as of May 2014 SHOUTcast Radio included over 50,000 stations. Sources, Icecast List of Internet radio stations List of streaming media systems Nullsoft Streaming Video Edcast Official website
23.
Skin (computing)
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As such, a skin can completely change the look and feel and navigation interface of a piece of application software or operating system. Software that is capable of having a skin applied is referred to as being skinnable, and the process of writing or applying such a skin is known as skinning. The most popular skins are for instant messaging clients, media center, some platforms support changing the standard interface, including most using the X Window System. For those that do not, programs can add the functionality, like WindowBlinds for Microsoft Windows and this allows the user to select or design a different skin at will, and also allows for more deep changes in the position and function of the interface elements. The benefit of skinning in user interfaces is disputed, while some find it useful or pleasant to be able to change the appearance of software, a changed appearance can complicate technical support and training. A user interface that has been customized by one person may appear completely unfamiliar to another who knows the software under a different appearance. Some usability practitioners feel that this flexibility requires interaction design expertise that users might not have, many websites are skinnable, particularly those that provide social capabilities. Some sites provide skins that make primarily cosmetic changes, while some—such as H2G2—offer skins that make changes to page layout. Theme Computer wallpaper Look and feel User interface engineering Industrial design Windows Aero Windows XP visual styles
24.
Music tracker
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A music tracker is a type of music sequencer software for creating music. The music is represented as discrete musical notes positioned in several channels at discrete chronological positions on a vertical timeline, the file format used for saving songs is called a module file. A music trackers user interface is usually number based, notes, parameter changes, effects and other commands are entered with the keyboard into a grid of fixed time slots as codes consisting of letters, numbers and hexadecimal digits. Separate patterns have independent timelines, a complete song consists of a master list of repeated patterns, Music trackers like DefleMask and Famitracker are commonly used to make chiptunes. The term tracker derives from Ultimate Soundtracker, the first tracker software, Ultimate Soundtracker was written by Karsten Obarski and released in 1987 by EAS Computer Technik for the Commodore Amiga. Ultimate Soundtracker was a product, but soon shareware clones such as NoiseTracker appeared as well. The general concept of step-sequencing samples numerically, as used in trackers, is found in the Fairlight CMI sampling workstation of the early 1980s. Later, in Rock Monitor 3 and 4 they implemented sample player, however, since the notes were samples, the limitation was less important than those of synthesizing music chips. During the 1990s, tracker musicians gravitated to the PC as software production in general switched from the Amiga platform to the PC. Another sound card popular on the PC tracker scene was the Gravis Ultrasound, for a time, it offered unparalleled sound quality and became the choice of discerning tracker musicians. Understanding that the support of music would benefit sales, Gravis gave away some 6000 GUS cards to participants. Coupled with excellent developer documentation, this gesture quickly prompted the GUS to become a component of many tracking programs. Inevitably, the balance was largely redressed with the introduction of the Sound Blaster AWE32 and its successors, the responsibility for audio mixing passed from hardware to software, which gradually enabled the use of more and more channels. An Amiga tracker called Symphonie Pro even supported 256 channels, as such, hardware mixing did not last. As processors got faster and acquired special multimedia processing abilities and companies began to push Hardware Abstraction Layers, like DirectX, DirectX, WDM and, now more commonly, ASIO, deliver high-quality sampled audio irrespective of hardware brand. There was also a split off from the sample based trackers taking advantage of the OPL2/OPL3 chips of the Sound Blaster series, Adlib Tracker II and many others survive to this day. Tracker music could be found in games of the late 1990s and early 2000s, such as the Unreal series, Deus Ex, Jazz Jackrabbit and Hitman. Some of the early Amiga trackers such as ProTracker and OctaMED have received various updates, ProTracker having resumed development in 2004, with plans for releasing version 5 to Windows and AmigaOS, but only version 4.0 beta 2 for AmigaOS has been released
25.
JACK Audio Connection Kit
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JACK Audio Connection Kit is a professional sound server daemon that provides real-time, low-latency connections for both audio and MIDI data between applications that implement its API. The server is software, licensed under the GNU GPL. JACK can use ALSA, PortAudio, CoreAudio, FFADO and OSS as hardware back-ends, additionally, a dummy driver and an Audio-over-UDP driver exist. It runs on Linux, macOS, Solaris, Windows, iOS, FreeBSD, OpenBSD and NetBSD
26.
OpenMPT
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OpenMPT is an open source audio module tracker for Windows. It originally started out under the name ModPlug Tracker, and was developed by Olivier Lapicque in September 1997, OpenMPT was named by Computer Music as one of the top five free music trackers. Originally called ModPlug Tracker, it was developed as a plug-in named MOD Plugin for Internet browsers. ModPlug Tracker, along with an application named ModPlug Player later evolved from this plug-in. In December 1999, Olivier Lapicque sent the parts of ModPlug Trackers source code to Kenton Varda, under the GPL. The source code was in 2001 released in the domain. This project lay dormant from late 2003 until early 2006, when it was picked up again, today, libmodplug is included in many Linux distributions as a default audio plugin for playing module files and is a part of the popular OpenSource multimedia framework gstreamer. Due to lack of time, Olivier Lapicque discontinued development of ModPlug Tracker itself, the ModPlug Player source code is still closed as of January 2017. Lapicques MPT code was taken up by a group of tracker musicians/programmers and is now known as OpenMPT, also based on the ModPlug code is OpenMPTs sister project Schism Tracker which contributed several backports of bugfixes to OpenMPT. OpenMPT is distributed as software and is, as of November 2015. Until May 2009 OpenMPT was licensed under the Copyleft GNU General Public License, since OpenMPT1.23, OpenMPT is also available as a 64-bit application. This allows musicians to use 64-bit VST plugins and make use of the physical memory on 64-bit systems. OpenMPTs main distinguishing feature is its native Windows user interface, most trackers, even newer ones such as Renoise, have interfaces modelled after the older DOS trackers such as FastTracker II. It supports both loading and saving of IT, XM, MOD, S3M and MPTM files, imports many more module and sample file formats, OpenMPT was also one of the first Trackers to support opening and editing of multiple tracker modules in parallel. OpenMPT supports up to 127 tracks/channels, VST Plugins, VST instruments and has ASIO support, due to limitations of the various mod file formats it is able to save, a new module format called MPTM was created in 2007. However, the format is still in stage and is expected to be changed in the future. OpenMPT had previously introduced non-standard additions to the file formats. For example, one can use stereo samples or add VST Plugins to XM and IT modules, many of these features are gradually removed from IT and XM files and made only available in MPTM files
27.
MP3
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Compared to CD quality digital audio, MP3 compression commonly achieves 75 to 95% reduction in size. MP3 files are thus 1/4 to 1/20 the size of the digital audio stream. This is important for both transmission and storage concerns, the basis for such comparison is the CD digital audio format which requires 1411200 bit/s. A commonly used MP3 encoding setting is CBR128 kbit/s resulting in file size 1/11 of the original CD-quality file, the MP3 lossy compression works by reducing the accuracy of certain parts of a continuous sound that are considered to be beyond the auditory resolution ability of most people. This method is referred to as perceptual coding or psychoacoustics. It uses psychoacoustic models to discard or reduce the precision of less audible to human hearing. MP3 was designed by the Moving Picture Experts Group as part of its MPEG-1 standard, the first subgroup for audio was formed by several teams of engineers at Fraunhofer IIS, University of Hanover, AT&T-Bell Labs, Thomson-Brandt, CCETT, and others. MPEG-1 Audio, which included MPEG-1 Audio Layer I, II and III was approved as a draft of ISO/IEC standard in 1991, finalised in 1992. A backwards compatible MPEG-2 Audio extension with lower sample and bit rates was published in 1995, MP3 is a streaming or broadcast format meaning that individual frames can be lost without affecting the ability to decode successfully delivered frames. Storing an MP3 stream in a file enables time-shifted playback, the MP3 lossy audio data compression algorithm takes advantage of a perceptual limitation of human hearing called auditory masking. In 1894, the American physicist Alfred M. Mayer reported that a tone could be rendered inaudible by another tone of lower frequency, in 1959, Richard Ehmer described a complete set of auditory curves regarding this phenomenon. Ernst Terhardt et al. created an algorithm describing auditory masking with high accuracy and this work added to a variety of reports from authors dating back to Fletcher, and to the work that initially determined critical ratios and critical bandwidths. A wide variety of compression algorithms were reported in IEEEs refereed Journal on Selected Areas in Communications. The genesis of the MP3 technology is described in a paper from Professor Hans Musmann who chaired the ISO MPEG Audio group for several years. The immediate predecessors of MP3 were Optimum Coding in the Frequency Domain, the first practical implementation of an audio perceptual coder in hardware, was an implementation of a psychoacoustic transform coder based on Motorola 56000 DSP chips. Another predecessor of the MP3 format and technology is to be found in the perceptual codec MUSICAM based on an integer arithmetics 32 sub-bands filterbank, driven by a psychoacoustic model. It was primarily designed for Digital Audio Broadcasting and digital TV and this codec incorporated into a broadcasting system using COFDM modulation was demonstrated on air and on the field together with Radio Canada and CRC Canada during the NAB show in 1991. F. As a doctoral student at Germanys University of Erlangen-Nuremberg, Karlheinz Brandenburg began working on music compression in the early 1980s
28.
Mpg123
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Mpg123 is a free and open-source audio player. As the name suggests, it supports MPEG audio formats, including MP3 and it is a console application, meaning that it has no graphical user interface. Builds are only available for Windows, Linux users need to compile mpg123 themselves, mpg123s Assembly code is optimized with SIMD instructions to improve the performance of the iDCT part of the MPEG decoding. Mpg123s decoding library, libmpg123 is used by XMMS and Audacious for MP3 playback and this also led to mpg321, a fork of the program. In 2006, a new maintainer stepped up, reinstating work towards the release of a new official mpg123 package entirely under the LGPL, comparison of audio player software ogg123 madplay Official website
29.
Vorbis
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Vorbis is a free and open-source software project headed by the Xiph. Org Foundation. The project produces an audio coding format and software reference encoder/decoder for lossy audio compression, Vorbis is most commonly used in conjunction with the Ogg container format and it is therefore often referred to as Ogg Vorbis. Vorbis is a continuation of audio compression development started in 1993 by Chris Montgomery, intensive development began following a September 1998 letter from the Fraunhofer Society announcing plans to charge licensing fees for the MP3 audio format. The Vorbis project started as part of the Xiphophorus companys Ogg project, Chris Montgomery began work on the project and was assisted by a growing number of other developers. They continued refining the source code until the Vorbis file format was frozen for 1.0 in May 2000, originally licensed as LGPL, in 2001 the Vorbis license was changed to the BSD license to encourage adoption with endorsement of Richard Stallman. A stable version of the software was released on July 19,2002. The Xiph. Org Foundation maintains an implementation, libvorbis. There are also some fine-tuned forks, most notably aoTuV, that offer better audio quality and these improvements are periodically merged back into the reference codebase. Vorbis is named after a Discworld character, Exquisitor Vorbis in Small Gods by Terry Pratchett, the Ogg format, however, is not named after Nanny Ogg, another Discworld character, the name is in fact derived from ogging, jargon that arose in the computer game Netrek. The Vorbis format has proven popular among supporters of free software and they argue that its higher fidelity and completely free nature, unencumbered by patents, make it a well-suited replacement for patented and restricted formats like MP3. Vorbis has different uses for consumer products, many video game titles store in-game audio as Vorbis, including Amnesia, The Dark Descent, Grand Theft Auto, San Andreas, Halo, Combat Evolved, Minecraft, and World of Warcraft, among others. Popular software players support Vorbis playback either natively or through an external plugin, a number of websites, including Wikipedia, use it. Others include Jamendo and Mindawn, as well as national radio stations like JazzRadio, Absolute Radio, NPR, Radio New Zealand. The Spotify audio streaming service uses Vorbis for its audio streams, also, the French music site Qobuz offers its customers the possibility to download their purchased songs in Vorbis format, as does the American music site Bandcamp. However, by 2014, not many further significant tests had been made, listening tests have attempted to find the best quality lossy audio codecs at certain bitrates. Mid to low bitrates, private tests in 2005 at 80 kbit/s and 96 kbit/s showed that aoTuV Vorbis had a better quality than other lossy audio formats, high bitrates, most people do not hear significant differences. However, trained listeners can often hear significant differences between codecs at identical bitrates, and aoTuV Vorbis performed better than LC-AAC, MP3, due to the ever-evolving nature of audio codecs, the results of many of these tests have become outdated. Listening tests are carried out as ABX tests, i. e. the listener has to identify an unknown sample X as being A or B
30.
Xiph.Org Foundation
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Xiph. Org Foundation is a non-profit organization that produces free multimedia formats and software tools. It focuses on the Ogg family of formats, and the most successful one has been Vorbis, as of 2013, the current development work is focusing on Daala, an open and patent-free video format and codec designed to compete with the patented High Efficiency Video Coding and VP9. These include Speex, a codec designed for speech, and FLAC. The Xiph. Org Foundation has criticized Microsoft and the RIAA for their lack of openness and they also condemn the RIAA for their support of projects such as Secure Digital Music Initiative. In 2008, the Free Software Foundation listed the Xiph. Org projects as High Priority Free Software Projects, chris Montgomery, creator of the Ogg container format, founded the Xiphophorus company and later the Xiph. Org Foundation. The first work that became the Ogg media projects started in 1994, the name Xiph abbreviates the original organizational name, Xiphophorus, named after the common swordtail fish, Xiphophorus hellerii. The name Xiphophorus company was used until 2002, when it was renamed to Xiph. Org Foundation, in 2002, the Xiph. Org Foundation defined itself on its website as a non-profit corporation dedicated to protecting the foundations of Internet multimedia from control by private interests. In March 2003, the Xiph. Org Foundation was recognized by the IRS as a 501 Non-Profit Organization, Ogg – a multimedia container format, a reference implementation, and the native file and stream format for the Xiph
31.
Shorten (file format)
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Shorten is a file format used for compressing audio data. It is a form of compression of files and is used to losslessly compress CD-quality audio files. Shorten is no longer developed and other audio codecs such as FLAC, Monkeys Audio, TTA. However, Shorten is still in use by people because there are legally traded concert recordings in circulation that are encoded as Shorten files. Shorten files use the. shn file extension, some Rockbox applications can play Shorten files without decompression, and third-party Shorten plug-ins exist for Nero Burning ROM, Foobar2000, and Winamp. All libavcodec based players and converters support the Shorten codec, current versions of ffmpeg or avconv support the shorten format. Traders Little helper converts shn to wav among other things etree. org Wiki article, etree. org is a trading site for authorized recordings of live performances, etree formerly used Shorten exclusively but is increasingly using FLAC. Shorten FAQ Lossless audio formats, a comparison of lossless audio formats. A Small SHN and MD5 FAQ Includes a decent list of programs to handle Shorten files
32.
Etree
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Etree, or electronic tree, is a music community created in the summer of 1998 for the online trading of live concerts. Etree pioneered the standards for distributing lossless audio on the net, etree. org was created because collectors and curators of live music recordings historically faced four related problems, First, a problem common to all curators, source material degrades over time. In particular, the audio tape used to make many live audio recordings physically decays and, as it is repeatedly played back. Preserving musical source material, therefore, meant restricting access to it, as a result, archival music may have been preserved, but it was not being heard by anyone. Similarly, individuals who possessed live concert recordings were typically unable to store them appropriately and/or they lacked the ability to make copies for archiving, essentially, the musical history of 20th Century concert performances was being lost, locked up in vaults or decaying in attics and living-room bookcases. Second, copies of analog recordings tend to degrade when copied due to the introduction of hiss or noise inherent to the use of magnetic tape, as a result, no two copies are identical, and each copy, or generation, sounds inferior to the generation preceding it. Even today, historians and collectors find much confusion as to date, venue, setlist, the presence of fraudsters, commercial bootleggers, and other criminals in this area did not help. Archivists, therefore, prefer to distribute copies of material as widely as possible, to reduce the risk that all copies are destroyed. By the late 1990s, mechanisms for capturing or transferring recordings to the domain were well-developed. Copies of such recordings could be made that were exact duplicates of the original recording, thus, today, digital recordings are typically made to DAT, optical disc, or to hard drives, flash memory, and other types of digital storage. This is typically done by generating a checksum of the data in a file, usually in the MD5 format, if the checksums match, the files are identical, if not, then the files are different. Such matching copies are referred to as lossless copies, distribution of lossless audio data became easier as the Internet developed. S. Still, this was slow and liable to fail if a person on the branch of the tree did not follow through. For example, a 74-minute CD holds approximately 640 MB of uncompressed PCM data, transferring a single CD worth of data over a dial-up modem takes approximately seven days. Several developments in technology made the fourth factor, the lossless file transfer over the Internet. First, the Shorten file format was developed by a company called SoftSound, third, mailing lists, e-mail, listservs, etc. allowed collectors and curators to locate each other and material of interest more easily. Once these events happened, the community was formed by members of two highly regarded online music-trading communities, Sugarmegs Audio and PCP. Starting with 10 people, etree. org saw staggering growth rate, by February 2001, there were almost 300 independent FTP servers providing the trunk of etree. org to over 12,000 users
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Amiga
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The Amiga is a family of personal computers sold by Commodore in the 1980s and 1990s. The Amiga provided a significant upgrade from earlier 8-bit home computers, the Amiga 1000 was officially released in July 1985, but a series of production problems meant it did not become widely available until early 1986. The best selling model, the Amiga 500, was introduced in 1987 and became one of the home computers of the late 1980s. The A3000, introduced in 1990, started the second generation of Amiga systems, followed by the A500+, finally, as the third generation, the A1200 and the A4000 were released in late 1992. The platform became particularly popular for gaming and programming demos and it also found a prominent role in the desktop video, video production, and show control business, leading to video editing systems such as the Video Toaster. The Amigas native ability to play back multiple digital sound samples made it a popular platform for early tracker music software. It was also an expensive alternative to the Apple Macintosh. Initially, the Amiga was developed alongside various Commodore PC clones, Commodore ultimately went bankrupt in April 1994 after the Amiga CD32 model failed in the marketplace. Since the demise of Commodore, various groups have marketed successors to the original Amiga line, including Genesi, Eyetech, ACube Systems Srl, likewise, AmigaOS has influenced replacements, clones and compatible systems such as MorphOS, AmigaOS4 and AROS. The Amiga was so far ahead of its time that almost nobody—including Commodores marketing department—could fully articulate what it was all about. Today, its obvious the Amiga was the first multimedia computer, but in those days it was derided as a machine because few people grasped the importance of advanced graphics, sound. Nine years later, vendors are still struggling to make systems that work like 1985 Amigas, Jay Miner joined Atari in the 1970s to develop custom integrated circuits, and led development of the Atari 2600s TIA. Almost as soon as its development was complete, the team developing a much more sophisticated set of chips, CTIA, ANTIC and POKEY. With the 8-bit lines launch in 1979, Miner again started looking at a next generation chipset, Miner wanted to start work with the new Motorola 68000, but management was only interested in another MOS6502 based system. Miner left the company, and the industry, shortly thereafter, in 1982, Larry Kaplan was approached by a number of investors who wanted to develop a new game platform. Kaplan hired Miner to run the side of the newly formed company. The system was code-named Lorraine in keeping with Miners policy of giving systems female names, in case the company presidents wife. When Kaplan left the late in 1982 to rejoin Atari, Miner was promoted to head engineer
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