Video technology was first developed for cathode ray tube television systems, but several new technologies for video display devices have since been invented. Standards for television sets and computer monitors have tended to evolve independently, but advances in computer performance and digital television broadcasting and recording are resulting in a convergence of standards and use of content. Computers can now display television and film-style video clips and streaming media, encouraged by increased processor speed, storage capacity, and broadband access to the Internet. General purpose computing hardware can now be used to capture, store, edit, and transmit television and movie content, as opposed to older dedicated analog technologies.

The term video ("video" meaning "I see", from the Latin verb "videre") commonly refers to several storage formats for moving pictures: digital video formats, including Blu-ray Disc, DVD, QuickTime, and MPEG-4; and analog videotapes, including VHS and Betamax. Video can be recorded and transmitted in various physical media: in magnetic tape when recorded as PAL or NTSC electric signals by video cameras, or in MPEG-4 or DV digital media when recorded by digital cameras.

Quality of video essentially depends on the capturing method and storage used. Digital television (DTV) is a relatively recent format with higher quality than earlier television formats and has become a standard for television video. (See List of digital television deployments by country.)

3D-video, digital video in three dimensions, premiered at the end of 20th century. Six or eight cameras with realtime depth measurement are typically used to capture 3D-video streams. The format of 3D-video is fixed in MPEG-4 Part 16 Animation Framework eXtension (AFX).

In the United Kingdom, Estonia, Australia, Netherlands, Finland, Hungary and New Zealand, the term video is often used informally to refer to both Videocassette recorders and video cassettes; the meaning is normally clear from the context.

Frame rate, the number of still pictures per unit of time of video, ranges from six or eight frames per second (frame/s) for old mechanical cameras to 120 or more frames per second for new professional cameras. PAL (Europe, Asia, Australia, etc.) and SECAM (France, Russia, parts of Africa etc.) standards specify 25 frame/s, while NTSC (USA, Canada, Japan, etc.) specifies 29.97 frame/s. Film is shot at the slower frame rate of 24photograms/s, which complicates slightly the process of transferring a cinematic motion picture to video. The minimum frame rate to achieve the illusion of a moving image is about fifteen frames per second.

Video can be interlaced or progressive. Interlacing was invented as a way to achieve good visual quality within the limitations of a narrow bandwidth. The horizontal scan lines of each interlaced frame are numbered consecutively and partitioned into two fields: the odd field (upper field) consisting of the odd-numbered lines and the even field (lower field) consisting of the even-numbered lines. NTSC, PAL and SECAM are interlaced formats. Abbreviated video resolution specifications often include an i to indicate interlacing. For example, PAL video format is often specified as 576i50, where 576 indicates the vertical line resolution, i indicates interlacing, and 50 indicates 50 fields (half-frames) per second.

In progressive scan systems, each refresh period updates all of the scan lines. The result is a higher spatial resolution and a lack of various artifacts that can make parts of a stationary picture appear to be moving or flashing.

A procedure known as deinterlacing can be used for converting an interlaced stream, such as analog, DVD, or satellite, to be processed by progressive scan devices, such as TFT TV-sets, projectors, and plasma panels. Deinterlacing cannot, however, produce a video quality that is equivalent to true progressive scan source material.

The size of a video image is measured in pixels for digital video, or horizontal scan lines and vertical lines of resolution for analog video. In the digital domain (e.g. DVD) standard-definition television (SDTV) is specified as 720/704/640×480i60 for NTSC and 768/720×576i50 for PAL or SECAM resolution. However in the analog domain, the number of visible scanlines remains constant (486 NTSC/576 PAL) while the horizontal measurement varies with the quality of the signal: approximately 320 pixels per scanline for VCR quality, 400 pixels for TV broadcasts, and 720 pixels for DVD sources. Aspect ratio is preserved because of non-square "pixels".