An audio format is a medium for sound recording and reproduction. The term is applied to both the physical recording media and the recording formats of the audio content—in computer science it is often limited to the audio file format, but its wider use usually refers to the physical method used to store the data. Note on the use of analog compared to digital in this list; the definition of digital used here for early formats is that which is represented using discrete values rather than fluctuating variables. A piano roll is digital as it has discrete values, that being a hole for each key, unlike a phonograph record which is analog with a fluctuating groove.
A Dictaphone cylinder for voice recordingAnalog, the Ediphone and subsequent wax cylinders used in Edison's other product lines continued to be sold up until 1929 when the Edison Manufacturing Company folded.
1894
Pathé cylinder
The vertical-groove pathé cylinderMechanical analog; vertical grooves, vertical stylus motion
Edison's "gold moulded" black wax cylinder recordMechanical analog; vertical grooves, horizontal stylus motion - made from hard black wax - 160rpm standard - 100 threads per inch
Indestructible Record cylinder, vertical groove. Constructed of black celluloid on a cardboard core with metal bands at each endMechanical analog; vertical grooves, vertical stylus motion - made from black celluloid with cardboard and inner metal bands
The Edison "Amberol" cylinder record, vertical grooveMechanical analog; vertical grooves, vertical stylus motion - made from hard black wax - 160rpm standard - 200 threads per inch
The Edison vertical-groove "diamond disc"Mechanical analog; vertical grooves, vertical stylus motion - made from Bakelite or china clay
Blue Amberol cylinder record
The Edison vertical-groove "Blue Amberol" cylinderMechanical analog; vertical grooves, vertical stylus motion - made from blue celluloid with plaster of paris core - 160rpm standard - 200 threads per inch
Studio master tape reelAnalog; magnetization; AC "bias" dramatically increases linearity/fidelity, tape speed at 30 ips, later 15 ips and other refined speeds: 7½ ips, 3¾ ips, 1⅞ ips
Mechanical analog; electrically cut from amplified microphone signal, high fidelity sound, lateral or vertical grooves, horizontal or vertical stylus motion, most discs 16" at 33⅓rpm
Green, vertical groove Sound Scriber disks Mechanical Analog; vertical groove, 4–6 inch discs, it recorded sound by pressing grooves into soft vinyl discs
Analog, medium consisting of a thin, plastic belt 3.5" wide that was placed on a cylinder and rotated like a tank tread, developed by the Dictaphone company in 1947
Analog, with preemphasis and other equalization techniques (LP, RIAA); lateral grooves, horizontal stylus motion; discs 7", 10" and 12" at 33⅓rpm, 1st LP Columbia ML 4001 Milstein, Mendelssohn Violin Concerto
A stand-alone Tefifon player with cartridge loadedElectro-mechanical analog, vinyl belt housed in a cassette, used an embossing technique using a stylus to imprint the information, was the first thing to resemble a modern audio cassette
Minifon cassetteAnalog, magnetic wire on reel, 30cm/s or about 11.8ips was quickly adopted by many governments as being the ultimate "spy" recorder of its day
An early stereo record labelAnalog, with pre-emphasis and other equalization techniques. Combination lateral/vertical stylus motion with each channel encoded 45 degrees to the vertical
Dictet
Cassette for the Dictaphone Dictet dictation machineAnalog, ¼ tape, 2.48 in/s, (3" reels housed 5.875 × 3 × .4375 inch cassette), developed by the Dictaphone Corp
The cassette format created by RCAAnalog, ¼ inch wide tape (stereo & mono), 3¾ in/s & 1.875 in/s, one of the first attempts to offer reel-to-reel tape recording quality in a convenient format for the consumer market
The cartridge known as a "Fidelipac"Analog, ¼ inch wide tape in cartridge, 7½ in/s & 15 in/s, Introduced in 1959 by Collins Radio, the cart tape format was designed for use by radio broadcasters to play commercials, bumpers and announcements
The micro pack recording system, intended for dictation ¼ inch wide tape housed in a transparent cartridge measuring 2.6 × 2.9 × 1.9 inches, tape was stored on two reels residing atop one another, keeping the cartridge compact
DC-International cassetteAnalog cassette format introduced by Grundig, Telefunken and Blaupunkt: 120 × 77 × 12mm cassette with ¼ inch wide tape run at 5.08cm per second.
A comparison of sizes for the Microcassette and Minicassette Analog, ⅛ inch wide tape, used generally for note taking, mostly mono, some stereo (developed in the early '80s). 2.4cm/s or 1.2cm/s
This audio format famously caused controversy among recording companies when released due to the potential of perfect digital copies to increase piracy[2]
A Digital Compact CassetteDigital, ⅛ inch wide tape, 1⅞in/s, introduced by Philips and Matsushita in late 1992, marketed as the successor to the standard analog compact cassette
Magnetic tape is a medium for magnetic storage made of a thin, magnetizable coating on a long, narrow strip of plastic film. It was developed in Germany in 1928, based on the earlier magnetic wire recording from Denmark. Devices that use magnetic tape could with relative ease record and playback audio, visual, and binary computer data.
Data storage is the recording (storing) of information (data) in a storage medium. Handwriting, phonographic recording, magnetic tape, and optical discs are all examples of storage media. Biological molecules such as RNA and DNA are considered by some as data storage. Recording may be accomplished with virtually any form of energy. Electronic data storage requires electrical power to store and retrieve data.
Video is an electronic medium for the recording, copying, playback, broadcasting, and display of moving visual media. Video was first developed for mechanical television systems, which were quickly replaced by cathode-ray tube (CRT) systems which, in turn, were replaced by flat panel displays of several types.
An optical disc is a flat, usually disc-shaped object that stores information in the form of physical variations on its surface that can be read with the aid of a beam of light. Optical discs can be reflective, where the light source and detector are on the same side of the disc, or transmissive, where light shines through the disc to the be detected on the other side.
MiniDisc (MD) is an erasable magneto-optical disc-based data storage format offering a capacity of 60, 74, and later, 80 minutes of digitized audio.
Digital audio is a representation of sound recorded in, or converted into, digital form. In digital audio, the sound wave of the audio signal is typically encoded as numerical samples in a continuous sequence. For example, in CD audio, samples are taken 44,100 times per second, each with 16-bit sample depth. Digital audio is also the name for the entire technology of sound recording and reproduction using audio signals that have been encoded in digital form. Following significant advances in digital audio technology during the 1970s and 1980s, it gradually replaced analog audio technology in many areas of audio engineering, record production and telecommunications in the 1990s and 2000s.
Sound can be recorded and stored and played using either digital or analog techniques. Both techniques introduce errors and distortions in the sound, and these methods can be systematically compared. Musicians and listeners have argued over the superiority of digital versus analog sound recordings. Arguments for analog systems include the absence of fundamental error mechanisms which are present in digital audio systems, including aliasing and associated anti-aliasing filter implementation, jitter and quantization noise. Advocates of digital point to the high levels of performance possible with digital audio, including excellent linearity in the audible band and low levels of noise and distortion.
Analog recording is a category of techniques used for the recording of analog signals. This enables later playback of the recorded analog audio.
Mastering, a form of audio post production, is the process of preparing and transferring recorded audio from a source containing the final mix to a data storage device, the source from which all copies will be produced. In recent years, digital masters have become usual, although analog masters—such as audio tapes—are still being used by the manufacturing industry, particularly by a few engineers who specialize in analog mastering.
In signal processing, a signal is a function that conveys information about a phenomenon. Any quantity that can vary over space or time can be used as a signal to share messages between observers. The IEEE Transactions on Signal Processing includes audio, video, speech, image, sonar, and radar as examples of signals. A signal may also be defined as any observable change in a quantity over space or time, even if it does not carry information.
Direct Stream Digital (DSD) is a trademark used by Sony and Philips for their system for digitally encoding audio signals for the Super Audio CD (SACD).
Digitization is the process of converting information into a digital format. The result is the representation of an object, image, sound, document, or signal obtained by generating a series of numbers that describe a discrete set of points or samples. The result is called digital representation or, more specifically, a digital image, for the object, and digital form, for the signal. In modern practice, the digitized data is in the form of binary numbers, which facilitates processing by digital computers and other operations, but digitizing simply means "the conversion of analog source material into a numerical format"; the decimal or any other number system can be used instead.
D-VHS is a digital video recording format developed by JVC, in collaboration with Hitachi, Matsushita, and Philips. The "D" in D-VHS originally stood for "Data", but JVC renamed the format as "Digital VHS". Released in December of 1997, it uses the same physical cassette format and recording mechanism as S-VHS, but requires higher-quality and more expensive tapes and is capable of recording and displaying both standard-definition and high-definition content. The content data format is in MPEG transport stream, the same data format used for most digital television applications. It used MPEG-2 encoding and was standarized as IEC 60774-5.
In library and archival science, digital preservation is a formal endeavor to ensure that digital information of continuing value remains accessible and usable. It involves planning, resource allocation, and application of preservation methods and technologies, and it combines policies, strategies and actions to ensure access to reformatted and "born-digital" content, regardless of the challenges of media failure and technological change. The goal of digital preservation is the accurate rendering of authenticated content over time. The Association for Library Collections and Technical Services Preservation and Reformatting Section of the American Library Association, defined digital preservation as combination of "policies, strategies and actions that ensure access to digital content over time." According to the Harrod's Librarian Glossary, digital preservation is the method of keeping digital material alive so that they remain usable as technological advances render original hardware and software specification obsolete.
Electronic media are media that use electronics or electromechanical means for the audience to access the content. This is in contrast to static media, which today are most often created digitally, but do not require electronics to be accessed by the end user in the printed form. The primary electronic media sources familiar to the general public are video recordings, audio recordings, multimedia presentations, slide presentations, CD-ROM and online content. Most new media are in the form of digital media. However, electronic media may be in either analogue electronics data or digital electronic data format.
etree, or electronic tree, is a music community created in the summer of 1998 for the online trading of live concert recordings. etree pioneered the standards for distributing lossless audio on the net and only permits its users to distribute the music of artists that allow the free taping and trading of their music.
The term born-digital refers to materials that originate in a digital form. This is in contrast to digital reformatting, through which analog materials become digital, as in the case of files created by scanning physical paper records. It is most often used in relation to digital libraries and the issues that go along with said organizations, such as digital preservation and intellectual property. However, as technologies have advanced and spread, the concept of being born-digital has also been discussed in relation to personal consumer-based sectors, with the rise of e-books and evolving digital music. Other terms that might be encountered as synonymous include "natively digital", "digital-first", and "digital-exclusive".
Pulse-code modulation (PCM) is a method used to digitally represent sampled analog signals. It is the standard form of digital audio in computers, compact discs, digital telephony and other digital audio applications. In a PCM stream, the amplitude of the analog signal is sampled at uniform intervals, and each sample is quantized to the nearest value within a range of digital steps.
A digital signal is a signal that represents data as a sequence of discrete values; at any given time it can only take on, at most, one of a finite number of values. This contrasts with an analog signal, which represents continuous values; at any given time it represents a real number within a continuous range of values.
A video format is a medium for video recording and reproduction. The term is applied to both the physical recording media and the recording formats. Video is recorded and distributed using a variety of formats, some of which store additional information.
↑ Demetris, Jordan (1990-01-01). "The challenge of introducing digital audio tape technology into consumer markets". Technology in Society. 12 (1): 91–100. doi:10.1016/0160-791X(90)90031-7. ISSN0160-791X.
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