Optical disc in the context of "CD player"

Video is an electronic medium for the recording, copying, playback, broadcast, and display of moving-image 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.

Video systems vary in display resolution, aspect ratio, refresh rate, color reproduction, and other qualities. Both analog and digital video can be carried on a variety of media, including radio, magnetic tape, optical discs, computer files, and network streaming.

Digital cinema is the digital technology used within the film industry to distribute or project motion pictures as opposed to the historical use of reels of motion picture film, such as 35 mm film. Whereas film reels have to be shipped to movie theaters, a digital movie can be distributed to cinemas in a number of ways: over the Internet or dedicated satellite links, or by sending hard drives or optical discs such as Blu-ray discs, then projected using a digital video projector instead of a film projector.

Typically, digital movies are shot using digital movie cameras or in animation transferred from a file and are edited using a non-linear editing system (NLE). The NLE is often a video editing application installed in one or more computers that may be networked to access the original footage from a remote server, share or gain access to computing resources for rendering the final video, and allow several editors to work on the same timeline or project.

Digital distribution, also referred to as content delivery, online distribution, or electronic software distribution, among others, is the delivery or distribution of information or materials through digital platforms. The distribution of digital media content may be of digitized versions of analog materials, as well as other materials offered in a purely digital format, such as audio, video, e-books, video games, and other software.

The term is generally used to describe distribution over an online delivery medium, such as the Internet, thus bypassing physical distribution methods, such as paper, optical discs, and VHS videocassettes. The term online distribution is typically applied to freestanding products, with downloadable add-ons for other products are more commonly described as downloadable content. Content distributed online may be streamed or downloaded, and often consists of books, films and television programs, music, software, and video games. Streaming involves downloading and using content at a user's request, or "on-demand", rather than allowing a user to store it permanently. In contrast, fully downloading content to a hard drive or other forms of storage media may allow offline access in the future.

Home video is recorded media sold or rented for home viewing. The term originates from the VHS and Betamax era, when the predominant medium was videotapes, but has carried over to optical disc formats such as DVD and Blu-ray. In a different usage, "home video" refers to amateur video recordings, also known as home movies.

Released in 1978, LaserDisc (LD) is another home video format, which never managed to gain widespread use on North American and European retail markets due to high cost of the players and their inability to record TV programs (unlike the VHS), although it retained some popularity among videophiles and film enthusiasts during its lifespan; the format had greater prevalence in some regions of Southeast Asia such as Japan, Hong Kong, Singapore and Malaysia where it was better supported. Film titles were released in LD format until 2001, production of LD players ceased in 2009.

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.

Data storage in a digital, machine-readable medium is sometimes called digital data. Computer data storage is one of the core functions of a general-purpose computer. Electronic documents can be stored in much less space than paper documents. Barcodes and magnetic ink character recognition (MICR) are two ways of recording machine-readable data on paper.

Disc and disk are both variants of the English word for objects of a generally thin and cylindrical geometry. The differences in spelling correspond both with regional differences and with different senses of the word. For example, in the case of flat, rotational data storage media the convention is that the spelling disk is used for magnetic storage (e.g., hard disks) while disc is used for optical storage (e.g., compact discs, better known as CDs). When there is no clear convention, the spelling disk is more popular in American English, while the spelling disc is more popular in British English.

DVD (digital video disc or digital versatile disc) is a digital optical disc data storage format. It was invented and developed in 1995 and first released on November 1, 1996, in Japan. The medium can store any kind of digital data and has been widely used to store video programs (watched using DVD players), software and other computer files. DVDs offer significantly higher storage capacity than compact discs (CD) while having the same dimensions. A standard single-layer DVD can store up to 4.7 GB of data, a dual-layer DVD up to 8.5 GB. Dual-layer, double-sided DVDs can store up to a maximum of 17.08 GB.

Prerecorded DVDs are mass-produced using molding machines that physically stamp data onto the DVD. Such discs are a form of DVD-ROM because data can only be read and not written or erased. Blank recordable DVD discs (DVD-R and DVD+R) can be recorded once using a DVD recorder and then function as a DVD-ROM. Rewritable DVDs (DVD-RW, DVD+RW, and DVD-RAM) can be recorded and erased many times.

Blu-ray (Blu-ray Disc or BD) is a digital optical disc data storage format designed to supersede the DVD format. It was invented and developed in 2005 and released worldwide on June 20, 2006, capable of storing several hours of high-definition video (HDTV 720p and 1080p). The main application of Blu-ray is as a medium for video material such as feature films and for the physical distribution of video games for the PlayStation 3, PlayStation 4, PlayStation 5, Xbox One, and Xbox Series X. The name refers to the blue laser used to read the disc, which allows information to be stored at a greater density than is possible with the longer-wavelength red laser used for DVDs, resulting in an increased capacity.

The polycarbonate disc is 12 centimetres (4+3⁄4 inches) in diameter and 1.2 millimetres (1⁄16 inch) thick, the same size as DVDs and CDs. Conventional (or "pre-BDXL") Blu-ray discs contain 25 GB per layer, with dual-layer discs (50 GB) being the industry standard for feature-length video discs. Triple-layer discs (100 GB) and quadruple-layer discs (128 GB) are available for BDXL re-writer drives.