Windows Media Audio
Windows Media Audio is a series of audio codecs and their corresponding audio coding formats developed by Microsoft. It is a proprietary technology. WMA consists of four distinct codecs; the original WMA codec, known as WMA, was conceived as a competitor to the popular MP3 and RealAudio codecs. WMA Pro, a newer and more advanced codec, supports high resolution audio. A lossless codec, WMA Lossless, compresses audio data without loss of audio fidelity. WMA Voice, targeted at voice content, applies compression using a range of low bit rates. Microsoft has developed a digital container format called Advanced Systems Format to store audio encoded by WMA; the first WMA codec was based on earlier work by Henrique Malvar and his team, transferred to the Windows Media team at Microsoft. Malvar was a senior researcher and manager of the Signal Processing Group at Microsoft Research, whose team worked on the MSAudio project; the first finalized codec was referred to as MSAudio 4.0. It was officially released as Windows Media Audio, as part of Windows Media Technologies 4.0.
Microsoft claimed that WMA could produce files that were half the size of equivalent-quality MP3 files. The former claim however was rejected by some audiophiles. RealNetworks challenged Microsoft's claims regarding WMA's superior audio quality compared to RealAudio. Newer versions of WMA became available: Windows Media Audio 2 in 1999, Windows Media Audio 7 in 2000, Windows Media Audio 8 in 2001, Windows Media Audio 9 in 2003. Microsoft first announced its plans to license WMA technology to third parties in 1999. Although earlier versions of Windows Media Player played WMA files, support for WMA file creation was not added until the seventh version. In 2003, Microsoft released new audio codecs; these codecs were Windows Media Audio 9 Professional, Windows Media Audio 9 Lossless, Windows Media Audio 9 Voice. All versions of WMA released since version 9.0 - namely 9.1, 9.2 and 10 - have been backwards compatible with the original v9 decoder and are therefore not considered separate codecs. The sole exception to this is the WMA 10 Professional codec whose Low Bit Rate mode is only backwards compatible with the older WMA Professional decoders at half sampling rate.
Full fidelity decoding of WMA 10 Professional LBR bitstreams requires a WMA version 10 or newer decoder. A WMA file is in most circumstances contained in the Advanced Systems Format, a proprietary Microsoft container format for digital audio or digital video; the ASF container format specifies how metadata about the file is to be encoded, similar to the ID3 tags used by MP3 files. Metadata may include song name, track number, artist name, audio normalization values; this container can optionally support digital rights management using a combination of elliptic curve cryptography key exchange, DES block cipher, a custom block cipher, RC4 stream cipher and the SHA-1 hashing function. See Windows Media DRM for further information. Since 2008 Microsoft has been using WMA Professional in its Protected Interoperable File Format based on the ISO Base Media File Format and most used for Smooth Streaming, a form of adaptive bit rate streaming over HTTP. Related industry standards such as DECE UltraViolet and MPEG-DASH have not standardized WMA as a supported audio codec, deciding in favor of the more industry-prevalent MPEG and Dolby audio codecs.
Each WMA file features a single audio track in one of the four sub-formats: WMA, WMA Pro, WMA Lossless, or WMA Voice. These formats use different codes that are mutually incompatible; each codec is further explained below. Windows Media Audio is the most common codec of the four WMA codecs. Colloquial usage of the term WMA in marketing materials and device specifications refers to this codec only; the first version of the codec released in 1999 is regarded as WMA 1. In the same year, the bit stream syntax, or compression algorithm, was altered in minor ways and became WMA 2. Since newer versions of the codec have been released, but the decoding process remained the same, ensuring compatibility between codec versions. WMA is a lossy audio codec based on the study of psychoacoustics. Audio signals that are deemed to be imperceptible to the human ear are encoded with reduced resolution during the compression process. WMA can encode audio signals sampled at up to 48 kHz with up to two discrete channels.
WMA 9 introduced variable bit rate and average bit rate coding techniques into the MS encoder although both were technically supported by the original format. WMA 9.1 added support for low-delay audio, which reduces latency for encoding and decoding. Fundamentally, WMA is a transform coder based on modified discrete cosine transform, somewhat similar to AAC, Cook and Vorbis; the bit stream of WMA is composed of each containing 1 or more frames of 2048 samples. If the bit reservoir is not used, a frame is equal to a superframe; each frame contains a number of blocks, which are 128, 256, 512, 1024, or 2048 samples long after being transformed into the frequency domain via the MDCT. In the frequency domain, masking for the transformed samples is determined, used to requantize the samples; the floating point samples are decomposed into coefficient and exponent parts and independently huffman coded. Stereo information is mid/side coded. At low bit rates, line spectral pairs and a form of noise codin
A music genre is a conventional category that identifies some pieces of music as belonging to a shared tradition or set of conventions. It is to be distinguished from musical form and musical style, although in practice these terms are sometimes used interchangeably. Academics have argued that categorizing music by genre is inaccurate and outdated. Music can be divided into different genres in many different ways; the artistic nature of music means that these classifications are subjective and controversial, some genres may overlap. There are varying academic definitions of the term genre itself. In his book Form in Tonal Music, Douglass M. Green distinguishes between form, he lists madrigal, canzona and dance as examples of genres from the Renaissance period. To further clarify the meaning of genre, Green writes, "Beethoven's Op. 61 and Mendelssohn's Op. 64 are identical in genre – both are violin concertos – but different in form. However, Mozart's Rondo for Piano, K. 511, the Agnus Dei from his Mass, K. 317 are quite different in genre but happen to be similar in form."
Some, like Peter van der Merwe, treat the terms genre and style as the same, saying that genre should be defined as pieces of music that share a certain style or "basic musical language." Others, such as Allan F. Moore, state that genre and style are two separate terms, that secondary characteristics such as subject matter can differentiate between genres. A music genre or subgenre may be defined by the musical techniques, the style, the cultural context, the content and spirit of the themes. Geographical origin is sometimes used to identify a music genre, though a single geographical category will include a wide variety of subgenres. Timothy Laurie argues that since the early 1980s, "genre has graduated from being a subset of popular music studies to being an ubiquitous framework for constituting and evaluating musical research objects". Among the criteria used to classify musical genres are the trichotomy of art and traditional musics. Alternatively, music can be divided on three variables: arousal and depth.
Arousal reflects the energy level of the music. These three variables help explain why many people like similar songs from different traditionally segregated genres. Musicologists have sometimes classified music according to a trichotomic distinction such as Philip Tagg's "axiomatic triangle consisting of'folk','art' and'popular' musics", he explains that each of these three is distinguishable from the others according to certain criteria. The term art music refers to classical traditions, including both contemporary and historical classical music forms. Art music exists in many parts of the world, it emphasizes formal styles that invite technical and detailed deconstruction and criticism, demand focused attention from the listener. In Western practice, art music is considered a written musical tradition, preserved in some form of music notation rather than being transmitted orally, by rote, or in recordings, as popular and traditional music are. Most western art music has been written down using the standard forms of music notation that evolved in Europe, beginning well before the Renaissance and reaching its maturity in the Romantic period.
The identity of a "work" or "piece" of art music is defined by the notated version rather than by a particular performance, is associated with the composer rather than the performer. This is so in the case of western classical music. Art music may include certain forms of jazz, though some feel that jazz is a form of popular music. Sacred Christian music forms an important part of the classical music tradition and repertoire, but can be considered to have an identity of its own; the term popular music refers to any musical style accessible to the general public and disseminated by the mass media. Musicologist and popular music specialist Philip Tagg defined the notion in the light of sociocultural and economical aspects: Popular music, unlike art music, is conceived for mass distribution to large and socioculturally heterogeneous groups of listeners and distributed in non-written form, only possible in an industrial monetary economy where it becomes a commodity and in capitalist societies, subject to the laws of'free' enterprise... it should ideally sell as much as possible.
Popular music is found on most commercial and public service radio stations, in most commercial music retailers and department stores, in movie and television soundtracks. It is noted on the Billboard charts and, in addition to singer-songwriters and composers, it involves music producers more than other genres do; the distinction between classical and popular music has sometimes been blurred in marginal areas such as minimalist music and light classics. Background music for films/movies draws on both traditions. In this respect, music is like fiction, which draws a distinction between literary fiction and popular fiction, not always precise. Country music known as country and western, hillbilly music, is a genre of popular music that originated in the southern United States in the early 1920s; the polka is a Czech dance and genre of dance music familiar throughout Europe and the Americas. Rock music is a broad genre of popular music that originated as "rock and roll" in the United States in the early 1950s, developed into a range of different styles in the 1960s and particular
An artist is a person engaged in an activity related to creating art, practicing the arts, or demonstrating an art. The common usage in both everyday speech and academic discourse is a practitioner in the visual arts only; the term is used in the entertainment business in a business context, for musicians and other performers. "Artiste" is a variant used in English only in this context. Use of the term to describe writers, for example, is valid, but less common, restricted to contexts like criticism. Wiktionary defines the noun ` artist'. A person who makes and creates art as an occupation. A person, skilled at some activity. A person whose trade or profession requires a knowledge of design, painting, etc; the Oxford English Dictionary defines the older broad meanings of the term "artist": A learned person or Master of Arts One who pursues a practical science, traditionally medicine, alchemy, chemistry A follower of a pursuit in which skill comes by study or practice A follower of a manual art, such as a mechanic One who makes their craft a fine art One who cultivates one of the fine arts – traditionally the arts presided over by the muses The Greek word "techně" translated as "art," implies mastery of any sort of craft.
The adjectival Latin form of the word, "technicus", became the source of the English words technique, technical. In Greek culture each of the nine Muses oversaw a different field of human creation: Calliope: chief of the muses and muse of epic or heroic poetry Clio: muse of history Erato: muse of love or erotic poetry and marriage songs Euterpe: muse of music and lyric poetry Melpomene: muse of tragedy Polyhymnia or Polymnia: muse of sacred song, lyric and rhetoric Terpsichore: muse of choral song and dance Thalia: muse of comedy and bucolic poetry Urania: muse of astronomyNo muse was identified with the visual arts of painting and sculpture. In ancient Greece sculptors and painters were held in low regard, somewhere between freemen and slaves, their work regarded as mere manual labour; the word art derives from the Latin "ars", although defined means "skill method" or "technique" conveys a connotation of beauty. During the Middle Ages the word artist existed in some countries such as Italy, but the meaning was something resembling craftsman, while the word artesan was still unknown.
An artist was someone able to do a work better than others, so the skilled excellency was underlined, rather than the activity field. In this period some "artisanal" products were much more precious and expensive than paintings or sculptures; the first division into major and minor arts dates back at least to the works of Leon Battista Alberti: De re aedificatoria, De statua, De pictura, which focused on the importance of the intellectual skills of the artist rather than the manual skills. With the Academies in Europe the gap between fine and applied arts was set. Many contemporary definitions of "artist" and "art" are contingent on culture, resisting aesthetic prescription, in much the same way that the features constituting beauty and the beautiful cannot be standardized without corruption into kitsch. Artist is a descriptive term applied to a person. An artist may be defined unofficially as "a person who expresses him- or herself through a medium"; the word is used in a qualitative sense of, a person creative in, innovative in, or adept at, an artistic practice.
Most the term describes those who create within a context of the fine arts or'high culture', activities such as drawing, sculpture, dancing, filmmaking, new media and music—people who use imagination, talent, or skill to create works that may be judged to have an aesthetic value. Art historians and critics define artists as those who produce art within a recognized or recognizable discipline. Contrasting terms for skilled workers in media in the applied arts or decorative arts include artisan and specialized terms such as potter, goldsmith or glassblower. Fine arts artists such as painters succeeded in the Renaissance in raising their status similar to these workers, to a decisively higher level; the term may be used loosely or metaphorically to denote skilled people in any non-"art" activities, as well— law, mechanics, or mathematics, for example. Discussions on the subject focus on the differences among "artist" and "technician", "entertainer" and "artisan", "fine art" and "applied art", or what constitutes art and what does not.
The French word artiste has been imported into the English language. Use of the word "artiste" can be a pejorative term; the English word'artiste' has thus a narrower range of meaning than the word'artiste' in French. In Living with Art, Mark Getlein proposes six activities, services or functions of contemporary artists: Create places for some human purpose. Create extraordinary versions of ordinary objects. Record and commemorate. Give tangible form to the unknown. Give tangible form to feelings. Refresh our vision and help see the world in new ways. After looking at years of data on
An album is a collection of audio recordings issued as a collection on compact disc, audio tape, or another medium. Albums of recorded music were developed in the early 20th century as individual 78-rpm records collected in a bound book resembling a photograph album. Vinyl LPs are still issued, though album sales in the 21st-century have focused on CD and MP3 formats; the audio cassette was a format used alongside vinyl from the 1970s into the first decade of the 2000s. An album may be recorded in a recording studio, in a concert venue, at home, in the field, or a mix of places; the time frame for recording an album varies between a few hours to several years. This process requires several takes with different parts recorded separately, brought or "mixed" together. Recordings that are done in one take without overdubbing are termed "live" when done in a studio. Studios are built to absorb sound, eliminating reverberation, so as to assist in mixing different takes. Recordings, including live, may contain sound effects, voice adjustments, etc..
With modern recording technology, musicians can be recorded in separate rooms or at separate times while listening to the other parts using headphones. Album covers and liner notes are used, sometimes additional information is provided, such as analysis of the recording, lyrics or librettos; the term "album" was applied to a collection of various items housed in a book format. In musical usage the word was used for collections of short pieces of printed music from the early nineteenth century. Collections of related 78rpm records were bundled in book-like albums; when long-playing records were introduced, a collection of pieces on a single record was called an album. An album, in ancient Rome, was a board chalked or painted white, on which decrees and other public notices were inscribed in black, it was from this that in medieval and modern times album came to denote a book of blank pages in which verses, sketches and the like are collected. Which in turn led to the modern meaning of an album as a collection of audio recordings issued as a single item.
In the early nineteenth century "album" was used in the titles of some classical music sets, such as Schumann's Album for the Young Opus 68, a set of 43 short pieces. When 78rpm records came out, the popular 10-inch disc could only hold about three minutes of sound per side, so all popular recordings were limited to around three minutes in length. Classical-music and spoken-word items were released on the longer 12-inch 78s, about 4–5 minutes per side. For example, in 1924, George Gershwin recorded a drastically shortened version of the seventeen-minute Rhapsody in Blue with Paul Whiteman and His Orchestra, it ran for 8m 59s. Deutsche Grammophon had produced an album for its complete recording of the opera Carmen in 1908. German record company Odeon released the Nutcracker Suite by Tchaikovsky in 1909 on 4 double-sided discs in a specially designed package; this practice of issuing albums does not seem to have been taken up by other record companies for many years. By about 1910, bound collections of empty sleeves with a paperboard or leather cover, similar to a photograph album, were sold as record albums that customers could use to store their records.
These albums came in both 12-inch sizes. The covers of these bound books were wider and taller than the records inside, allowing the record album to be placed on a shelf upright, like a book, suspending the fragile records above the shelf and protecting them. In the 1930s, record companies began issuing collections of 78 rpm records by one performer or of one type of music in specially assembled albums with artwork on the front cover and liner notes on the back or inside cover. Most albums included three or four records, with two sides each, making six or eight compositions per album; the 12-inch LP record, or 33 1⁄3 rpm microgroove vinyl record, is a gramophone record format introduced by Columbia Records in 1948. A single LP record had the same or similar number of tunes as a typical album of 78s, it was adopted by the record industry as a standard format for the "album". Apart from minor refinements and the important addition of stereophonic sound capability, it has remained the standard format for vinyl albums.
The term "album" was extended to other recording media such as Compact audio cassette, compact disc, MiniDisc, digital albums, as they were introduced. As part of a trend of shifting sales in the music industry, some observers feel that the early 21st century experienced the death of the album. While an album may contain as many or as few tracks as required, in the United States, The Recording Academy's rules for Grammy Awards state that an album must comprise a minimum total playing time of 15 minutes with at least five distinct tracks or a minimum total playing time of 30 minutes with no minimum track requirement. In the United Kingdom, the criteria for the UK Albums Chart is that a recording counts as an "album" i
Sound recording and reproduction
Sound recording and reproduction is an electrical, electronic, or digital inscription and re-creation of sound waves, such as spoken voice, instrumental music, or sound effects. The two main classes of sound recording technology are analog 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 magnetic tape recording, the sound waves vibrate the microphone diaphragm and are converted into a varying electric current, 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 bigger loudspeaker diaphragm causing changes to atmospheric pressure to form acoustic sound waves. Digital recording and reproduction converts the analog sound signal picked up by the microphone to a digital form by the process of sampling.
This lets the audio data be transmitted by a wider variety of media. Digital recording stores audio as a series of binary numbers representing samples of the amplitude of the audio signal at equal time intervals, at a sample rate high enough to convey all sounds capable of being heard. A digital audio signal must be reconverted to analog form during playback before it is amplified and connected to a loudspeaker to produce sound. Prior to the development of sound recording, there were mechanical systems, such as wind-up music boxes and player pianos, for encoding and reproducing instrumental music. Long before sound was first recorded, music was recorded—first by written music notation also by mechanical devices. Automatic music reproduction traces back as far as the 9th century, when the Banū Mūsā brothers invented the earliest known mechanical musical instrument, in this case, a hydropowered organ that played interchangeable cylinders. According to Charles B. Fowler, this "...cylinder with raised pins on the surface remained the basic device to produce and reproduce music mechanically until the second half of the nineteenth century."
The Banū Mūsā brothers invented an automatic flute player, which appears to have been the first programmable machine. Carvings in the Rosslyn Chapel from the 1560s may represent an early attempt to record the Chladni patterns produced by sound in stone representations, although this theory has not been conclusively proved. In the 14th century, a mechanical bell-ringer controlled by a rotating cylinder was introduced in Flanders. Similar designs appeared in barrel organs, musical clocks, barrel pianos, music boxes. A music box is an automatic musical instrument that produces sounds by the use of a set of pins placed on a revolving cylinder or disc so as to pluck the tuned teeth of a steel comb; the fairground organ, developed in 1892, used a system of accordion-folded punched cardboard books. The player piano, first demonstrated in 1876, used a punched paper scroll that could store a long piece of music; the most sophisticated of the piano rolls were hand-played, meaning that the roll represented the actual performance of an individual, not just a transcription of the sheet music.
This technology to record a live performance onto a piano roll was not developed until 1904. Piano rolls were in continuous mass production from 1896 to 2008. A 1908 U. S. Supreme Court copyright case noted that, in 1902 alone, there were between 70,000 and 75,000 player pianos manufactured, between 1,000,000 and 1,500,000 piano rolls produced; the first device that could record actual sounds as they passed through the air was the phonautograph, patented in 1857 by Parisian inventor Édouard-Léon Scott de Martinville. The earliest known recordings of the human voice are phonautograph recordings, called phonautograms, made in 1857, they consist of sheets of paper with sound-wave-modulated white lines created by a vibrating stylus that cut through a coating of soot as the paper was passed under it. An 1860 phonautogram of Au Clair de la Lune, a French folk song, was played back as sound for the first time in 2008 by scanning it and using software to convert the undulating line, which graphically encoded the sound, into a corresponding digital audio file.
On April 30, 1877, French poet, humorous writer and inventor Charles Cros submitted a sealed envelope containing a letter to the Academy of Sciences in Paris explaining his proposed method, called the paleophone. Though no trace of a working paleophone was found, Cros is remembered as the earliest inventor of a sound recording and reproduction machine; the first practical sound recording and reproduction device was the mechanical phonograph cylinder, invented by Thomas Edison in 1877 and patented in 1878. The invention soon spread across the globe and over the next two decades the commercial recording and sale of sound recordings became a growing new international industry, with the most popular titles selling millions of units by the early 1900s; the development of mass-production techniques enabled cylinder recordings to become a major new consumer item in industrial countries and the cylinder was the main consumer format from the late 1880s until around 1910. The next major technical development was the invention of the gramophone record credited to Emile Berliner and patented in 1887, though others had demonstrated simi
Automotive head unit
An automotive head unit, sometimes referred to as a deck, is a component of an automotive infotainment, which provides a unified hardware interface for the entire system. Antiquated names for head unit are receiver, in-dash dash stereo; the head unit is the centerpiece of the car's information system. Located in the center of the dashboard, modern head units are densely integrated electronic packages housed in detachable face plates; as high-end head units are common targets for theft, many head units are integrated into the vehicle's alarm system. Head units give the user control over the vehicle's information and entertainment media: AM/FM radio, satellite radio, DVDs/CDs, cassette tapes, USB MP3, Dashcams, GPS navi, Bluetooth, WiFi etc. Many audio-only head units afford the user precise control over detailed audio functions such as volume, frequency, speaker balance, speaker fade, treble, EQ and so on. Several OEMs such as General Motors are integrating more advanced systems into vehicle's head units such that they can offer vehicle data such as trouble warnings.
In as much as head units are a central part of a car's decor, they vary as in aesthetics as they do in functionality. With the advent of dashcams, GPS navi and DVDs, head units with video screens are on the market. Voice control and gesture recognition are used for them; the most standard sizes for car audio head units and enclosures is ISO 7736: Single in Europe, South America and Australasia Single Din Features: More compact and fits in the dashboard, DVD player with no video access, no option for a rearview camera. And Double in Japan, the UK and North America. Double DIN is written as 2 DIN and double din. Double Din Features: Requires more space to fit, DVD player capable of playing videos, cell phone can be accessed via large screen. ISO 10487 is the standard for connectors for the head unit to the car's electrical system. Most manufactures offer DIN headunits and standard connectors, including Pioneer, Alpine, Eclipse, JVC, Dual, Visteon and Blaupunkt. Aftermarket Android Auto CarPlay Connectors for car audio Vehicle audio MPT 1362 UK code of practice for the installation of mobile radio and ancillary equipment in land based vehicles.
Federation of Communications Services Industry, November 2005. 2 Din In-Dash Headunit