CD in the context of Digital media

A library is a collection of books, and possibly other materials and media, that is accessible for use by its members and members of allied institutions. Libraries provide physical (hard copies) or digital (soft copies) materials, and may be a physical location, a virtual space, or both. A library's collection normally includes printed materials which can be borrowed, and usually also includes a reference section of publications which may only be utilized inside the premises. Resources such as commercial releases of films, television programmes, other video recordings, radio, music and audio recordings may be available in many formats. These include DVDs, Blu-rays, CDs, cassettes, or other applicable formats such as microform. They may also provide access to information, music or other content held on bibliographic databases. In addition, some libraries offer creation stations for makers which offer access to a 3D printing station with a 3D scanner.

Libraries can vary widely in size and may be organised and maintained by a public body such as a government, an institution (such as a school or museum), a corporation, or a private individual. In addition to providing materials, libraries also provide the services of librarians who are trained experts in finding, selecting, circulating and organising information while interpreting information needs and navigating and analysing large amounts of information with a variety of resources. The area of study is known as library and information science or studies.

The Roud Folk Song Index is a database of around 250,000 references to nearly 25,000 songs collected from oral tradition in the English language from all over the world. It is compiled by Steve Roud. Roud's Index is a combination of the Broadside Index (printed sources before 1900) and a "field-recording index" compiled by Roud. It subsumes all the previous printed sources known to Francis James Child (the Child Ballads) and includes recordings from 1900 to 1975. Until early 2006, the index was available by a CD subscription; now it can be found online on the Vaughan Williams Memorial Library website, maintained by the English Folk Dance and Song Society (EFDSS). A partial list is also available at List of folk songs by Roud number.

Optical disc packaging is the packaging that accompanies CDs, DVDs, and other formats of optical discs. Most packaging is rigid or semi-rigid and designed to protect the media from scratches and other types of exposure damage.

MPEG-4 is a group of international standards for the compression of digital audio and visual data, multimedia systems, and file storage formats. It was originally introduced in late 1998 as a group of audio and video coding formats and related technology agreed upon by the ISO/IEC Moving Picture Experts Group (MPEG) (ISO/IEC JTC 1/SC29/WG11) under the formal standard ISO/IEC 14496 – Coding of audio-visual objects. Uses of MPEG-4 include compression of audiovisual data for Internet video and CD distribution, voice (telephone, videophone) and broadcast television applications. The MPEG-4 standard was developed by a group led by Touradj Ebrahimi (later the JPEG president) and Fernando Pereira.

Loud music is music that is played at a high volume, often to the point where it disturbs others and causes hearing damage. It may include music that is sung live, played with musical instruments, or with electronic media, such as Radio broadcasting, CD, MP3 players or even on phones and streaming services.

Playing loud music that can be heard by others in nearby properties is considered rude by many societies in many settings, and may result in loss of respect and legal action under the nuisance ordinance. In certain contained settings, such as nightclubs or concerts, music is often played very loudly, but is viewed as acceptable. Headphones allow loud music to be enjoyed without annoying neighbors, though leakage is an issue with headphones, and the listener will still get hearing damage.

Cover art is a type of artwork presented as an illustration or photograph on the outside of a published product, such as a book (often on a dust jacket), magazine, newspaper (tabloid), comic book, video game (box art), music album (album art), CD, videotape, DVD, or podcast. Cover art can include various things such as logos, symbols, images, colors, or anything that represents what is being sold or advertised. The art has a commercial function (i.e., to promote the product it is displayed on), but can also have an aesthetic function, and may be artistically connected to the product (such as with art by, or commissioned by, the creator of the product).

Optical engineering is the field of engineering encompassing the physical phenomena and technologies associated with the generation, transmission, manipulation, detection, and utilization of light. Optical engineers use the science of optics to solve problems and to design and build devices that make light do something useful. They design and operate optical equipment that uses the properties of light using physics and chemistry, such as lenses, microscopes, telescopes, lasers, sensors, fiber-optic communication systems and optical disc systems (e.g. CD, DVD).

Optical engineering metrology uses optical methods to measure either micro-vibrations with instruments like the laser speckle interferometer, or properties of masses with instruments that measure refraction.

Live PA (meaning live public address or live personal appearance) is the act of performing live electronic music in settings typically associated with DJing, such as nightclubs, raves, and more recently dance music festivals.

In a performative context, the term was originally used to refer to live appearances, initially at rave events in the late 1980s, of studio based producers of electronic dance music who released music using fixed media formats such as 12-inch single, CD, or music download. The concept of the live PA helped provide a public face for a scene that was criticized as "faceless" by the mainstream music press. The trend was quickly exploited by a music industry desperate to market dance music to a popular audience.

Physical media refers to the physical materials that are used to store or transmit information in data communications. These physical media are generally physical objects made of materials such as copper or glass. They can be touched and felt, and have physical properties such as weight and color. For a number of years, copper and glass were the only media used in computer networking.

The term physical media can also be used to describe data storage media like records, cassettes, VHS, LaserDiscs, CDs, DVDs, and Blu-ray discs, especially when compared with modern streaming media or content that has been downloaded from the Internet onto a hard drive or other storage device as files.

The Nintendo GameCube is a home video game console developed and marketed by Nintendo. It was released in Japan on September 14, 2001, in North America on November 18, 2001, in Europe on May 3, 2002, in Australia on May 17, 2002, in Brazil on August 23, 2002, and in South Korea on December 14, 2002. It is the successor to the Nintendo 64. As a sixth-generation console, the GameCube primarily competed with Sony's PlayStation 2, Sega's Dreamcast, and Microsoft's Xbox.

Nintendo began developing the GameCube in 1998 after entering a partnership with ArtX to design a graphics processing unit. The console was formally announced under the codename "Dolphin" the following year and was released in 2001 as the GameCube. It is based on PowerPC. It is Nintendo's first console to use its own optical discs instead of ROM cartridges, supplemented by writable memory cards for saved games. Unlike its competitors, it is solely focused on gaming and does not play mass media like DVD or CD. The console supports limited online gaming for a few games via a GameCube broadband or modem adapter and can connect to a Game Boy Advance with a link cable for exclusive in-game features using the handheld as a second screen and controller. The GameCube supports e-Reader cards to unlock special features in a few games. The Game Boy Player add-on runs Game Boy, Game Boy Color and Game Boy Advance cartridge games.

Dither or dithering is an intentionally applied form of noise used to randomize quantization error, preventing large-scale patterns such as color banding in images. Dither is routinely used in processing of both digital audio and video data, and is often one of the last stages of mastering audio to a CD.

A common use of dither is converting a grayscale image to black and white, so that the density of black dots in the new image approximates the average gray level in the original.

In information theory and coding theory, Reed–Solomon codes are a group of error-correcting codes that were introduced by Irving S. Reed and Gustave Solomon in 1960.They have many applications, including consumer technologies such as MiniDiscs, CDs, DVDs, Blu-ray discs, QR codes, Data Matrix, data transmission technologies such as DSL and WiMAX, broadcast systems such as satellite communications, DVB and ATSC, and storage systems such as RAID 6.

Reed–Solomon codes operate on a block of data treated as a set of finite-field elements called symbols. Reed–Solomon codes RS(n, k) are able to detect and correct multiple symbol errors. By adding t = n − k check symbols to the data, a Reed–Solomon code can detect (but not correct) any combination of up to t erroneous symbols, or locate and correct up to ⌊t/2⌋ erroneous symbols at unknown locations. As an erasure code, it can correct up to t erasures at locations that are known and provided to the algorithm, or it can detect and correct combinations of errors and erasures. Reed–Solomon codes are also suitable as multiple-burst bit-error correcting codes, since a sequence of b + 1 consecutive bit errors can affect at most two symbols of size b. The choice of t is up to the designer of the code and may be selected within wide limits.

Digital Audio Tape (DAT or R-DAT) is a discontinued digital recording and playback medium developed by Sony and introduced in 1987. In appearance it is similar to a Compact Cassette, using 3.81 mm / 0.15" (commonly referred to as 4 mm) magnetic tape enclosed in a protective shell, but is roughly half the size at 73 mm × 54 mm × 10.5 mm. The recording is digital rather than analog. DAT can record at sampling rates equal to, as well as higher and lower than a CD (44.1, 48, or 32 kHz sampling rate respectively) at 16 bits quantization. If a comparable digital source is copied without returning to the analogue domain, then the DAT will produce an exact clone, unlike other digital media such as Digital Compact Cassette or non-Hi-MD MiniDisc, both of which use a lossy data-reduction system.

Similar to most formats of videocassette, a DAT cassette may only be recorded and played in one direction, unlike an analog compact audio cassette. Many DAT recorders had the capability to embed program numbers and IDs into the recording which can be used to select an individual track like on a CD player.