The following is a guide to analog and digital video formats, including many that are now extinct or obsolete. A selection of online resources for identifying current and obsolete media formats is also included.
1" IVC-700/800/900 - 1967-? (extinct). An open-reel format using 1" videotape, adopted by commercial and semi-professional producers, as well as the U.S. military.
1" SMPTE Type A - 1965-? (extinct). An open reel format using 1" videotape. This was the first one-inch wide format to be standardized by the Society for Motion Picture and Television Engineers (SMPTE--hence the name.) It was not considered broadcast-quality, and was used in corporate and industrial applications.
1" SMPTE Type B - 1975-? (extinct). Introduced by the German company Bosch, this format is visually similar to the other 1" SMPTE tapes. It was not widely used outside Europe.
1" SMPTE Type C - 1978-1990s (obsolete). An open-reel format using 1" tape, Type C was the most widely-adopted of the 1" SMPTE formats. It largely succeeded 2" quad tape in broadcast outlets.
1/2" Open Reel - 1965-late 1970s. An open-reel format using 1/2" tape. These were the first genuinely portable videotape recorders, and were widely adopted by artists, educators, and community activists. Most 1/2" open reel tapes fall into one of two categories: CV (Consumer Video/Commercial Video); and AV (EIAJ Type 1). Though the tapes look the same, the decks are not compatible.
2" Quad - 1956-1980s (extinct). An open-reel format, 2" quad (or simply, "quad") was the first successful videotape format. Introduced in 1956, it was the broadcast-television standard through the early 1980s. Because the equipment was large and expensive, it was limited to broadcast operations. Quality was excellent and the tapes are relatively durable. Over the years, there were differing types of 2" Quad--low-band, high-band, and super high-band--but most transfer houses that deal with 2" can handle them all.
2" Quad Video Cartridge - 1969-? (extinct). These small cartridges used standard 2" tape and were developed for television stations in order to allow for automated playback of videotaped commercials.
3/4" U-matic - 1971-1990s (obsolete). A cassette format using 3/4" tape, U-matic (often referred to simply as '3/4"') was widely used by broadcast, corporate, and educational institutions. It was also commonly used in newsgathering.
3/4" U-matic SP - 1986-1990s (obsolete). Though appearing identical to standard U-matic cassettes, these higher-quality tapes are generally labeled on the cassette body with the letters "SP." They can be played on standard 3/4" decks, though at lower quality; standard U-matic tapes can play on SP decks.
8mm - See Video8.
Audiocassette - 1963-present. An unidentified audio cassette with a strange signal on it may in fact hold a recording from a Pixelvision camera.
Betacam - 1982-1990s (extinct). This cassette format, utilizing 1/2" tape, appears identical to the consumer Betamax format, and in the beginning, the tapes were used interchangeably, but the recordings themselves were not compatible. It was the first in the Betacam family of tapes, and was widely used by broadcast outlets for newsgathering.
Betacam SP - 1986-present. A cassette format using 1/2" tape, Betacam SP was widely adopted by professional broadcast outlets. The cassettes come in small and large sizes; small cassettes can record up to 30 minutes of video; the larger, up to 90 minutes. It is generally considered a high-quality, stable format.
Betacam SX - 1996-present. A cassette format using 1/2" tape, Betacam SX is mainly used as a newsgathering format; a higher compression ratio allows for longer record times. Cassette housings are yellow. Because of the heavy compression, SX is not considered an archival format.
Betamax - 1975-mid-1980s (extinct). A cassette format using 1/2" tape, Betamax was developed by Sony for the consumer market, and despite its superior quality, it lost out to JVC's VHS format. Similar in appearance to the other Beta-family tapes.
Blu-Ray - 2006-present. Blu-Ray (so named because of the blue-violet laser used in playback) is one of two competing High Definition playback formats currently fighting for dominance. The format was developed by the Blu-ray Disc Association, with the corporate backing of Sony. Because of this conflict, and the accompanying potential for obsolescence, use of Blu-Ray should be approached with caution.
CD (audio) - 1982-present. The Compact Disc was originally designed as a digital format for the playback of audio. Standard CD audio uses 16-bit samples and a 44.1 khz sample rate, with a potential disc capacity of 74 minutes of audio. Although the format is universally used and record/playback machines are ubiquitous, the long-term stability of the physical medium remains in question. Additionally, other digital audio storage formats can offer higher-quality sound. For this reason, CDs are a less-than-ideal archival medium.
CD-ROM (data) - 1985-present. CD-ROM discs (the acronym stands for "Compact Disc Read-Only Memory") are visually identical to audio Compact Discs, but are used for the storage of digital data rather than the playback of audio. Standard CD-ROMs can hold 700 mebibytes (just over 700 megabytes) of data. Although the format is very widely used and record/retrieval drives are ubiquitous, the long-term stability of the physical medium remains in question. For this reason, CD-ROMs are a less-than-ideal archival medium.
D2 - 1988-present. D2 is a cassette-based digital videotape format, which records an uncompressed composite video signal on 3/4" tape. Developed for the broadcast industries, D2 tapes and equipment are quite expensive, leaving them out of reach for most not-for-profit or smaller institutions. D2 cassettes come in three different sizes, generally marked as D2 in the upper-right corner. The format is not currently in wide use, and is in danger of becoming quickly obsolete—but because of the format's relative newness and high quality, extant D2 tapes are not generally considered to be at high risk for preservation purposes.
D3 - 1991-present. D3 is a cassette-based digital videotape format, which records an uncompressed composite signal on 1/2" tape. D3 was originally introduced as a rival to the earlier D2 format for high-end broadcast use, offering longer cassette run times and somewhat lower cost. Because of their relative newness, D3 tapes are not generally considered to be at high risk for preservation purposes.
Digital 8 - 1999-present. This cassette format, utilizing 8mm wide tape, was created primarily as a consumer format. The cassettes are identical to those used by Hi8 decks, and Hi8 tapes will play on Digital8 equipment. Digital8 can record on regular 8mm tapes, but the quality can be compromised.
Digital Betacam - 1993-present. A digital version of the Betacam format that offers 2:1 compression in a component format. Commonly known as "Digibeta," these tapes are at present (2006) a standard archival remastering format, due to their high quality, durability, and the widespread availability of playback equipment.
DV - 1995-present. DV, originally known as DVC (for Digital Video Cassette) uses 1/4" videotape to record a digital video signal. The acronym DV is also frequently used as a generic term encompassing related compact digital videocassette formats, including MiniDV (which is a DV variant using identical technology in a smaller cassette), DVCAM, and DVCPRO. Despite its relatively high quality, the small size of the cassettes and the thinness of the tape mean that DV is not an acceptable archival format.
DVCAM - 1995-present. Widely used both by independent videomakers and artists, as well as broadcast television outlets, DVCAM is also used as a master format due to its ability to record lengthy programs. It is not, however, used as an archival format.
DVCPro - 1996-present. DVCPro is a DV variant developed by Panasonic for high-end production, including newsgathering, field production, and industrial use. Has recently been declining in popularity relative to other small digital formats.
DVD - 1996-present. DVD is currently the most widely-used display format for media art. Identical in size and appearance to audio and data CDs, DVDs (the letters have variously stood for for Digital Video Disc and Digital Versatile Disc--officially, the name is simply "DVD") generally use the MPEG-2 standard for compressing video and audio. Because of this compression, and because the long-term stability of the discs remains unclear, DVDs are not recommended as an archival video format.
DVD-ROM - 1996-present. A read-only disc format for storage of digital data. Visually identical to Compact Discs or DVDs, DVD-ROMs can hold between 4.7GB and 17GB of data. DVD-ROM drives are backwards-compatible with CD-ROMS; many can also play back standard video DVDs. DVD-ROMs cannot be read in conventional DVD players.
HD-DVD - 2006-present. HD-DVD is the disc format for playback of High Definition television signals developed by a group of electronics companies, led by Toshiba. As of this writing, it is competing with the Blu-Ray format for control of the market. Because of this conflict, and the accompanying potential for obsolescence, use of HD-DVD should be approached with caution.
HDCAM/HDCAM-SR - 1997-present. HDCAM is a digital HDTV cassette format. Some HDCAM machines can play back older Betacam tapes. HDCAM-SR, introduced in 2003, offers a higher bitrate than HDCAM and thus can provide higher fidelity. HDCAM tapes are black with orange cassette doors; HDCAM-SR tapes are black with blue cassette doors.
Hi8 - 1975-2000. A higher-quality version of Video8, Hi8 was widely used by independent documentarians, video artists, and community organizations; it has largely been supplanted in that realm by MiniDV. The tape is extremely thin and fragile.
Laserdisc - 1987-present. A playback-only analog disc format developed by Pioneer. Laserdiscs were 30cm in diameter, resembling large audio CDs. The discs could be easily cued to a single frame anywhere in the program; this interactive capability was used both in educational and technical applications and artists’ video. Laserdiscs were most commonly recorded in one of two formats: CAV (Constant Angular Velocity), which allowed for freeze-frame, reverse playback, and other special effects; and CLV (Constant Linear Velocity), which did not allow these special features. Most commercially produced laserdisc titles were CLV discs. See also RCA Videodiscs/SelectaVision.
M-II - 1986-1990s (extinct). This 1/2" cassette format was developed for broadcast outlets by Panasonic. A competitor to Betacam, MII (pronounced "m-two") was not as widely adopted and eventually failed. Among its main users were NBC in the United States, and NHK in Japan.
MiniDV - 1995-present. MiniDV is one of the most commonly used formats in the consumer and educational markets, as well as among artists and independent video makers. Its quality is relatively high and the tapes (and equipment) are relatively small. However, that small size does make the cassettes vulnerable to damage and deterioration. MiniDV should not be considered a format for long-term retention.
Selectavision/RCA VideoDisc - 1975-1985. A playback-only analog disc format, originally in competition with the more popular Laserdiscs, RCA Videodiscs can be identified by the plastic enclosure in which the discs are held; the discs are only exposed within the Videodisc player. See also Laserdisc.
Pixelvision (PXL-2000) - 1987-1990s (extinct). Introduced as a children's toy, Pixelvision used standard audiocassettes, but moved the tape at a much higher speed, resulting in a recording time of only about 10 minutes on a 90-minute cassette. Now highly collectible, the original cameras have been modified by enthusiasts so that they can output composite video into another recording device.
S-VHS - 1987-present. Outwardly identical to VHS, S-VHS tapes offer higher picture and audio quality. Generally, S-VHS decks are backwards-compatible and will play regular VHS tapes. S-VHS did not achieve wide market penetration.
VHS - 1976-present. VHS (Video Home System) was the most successful home videocassette format by far, and soundly defeated its rival Betamax, despite the latter's higher quality. The miniaturized VHS-C is for use in home camcorders; it plays in home VCRs with an adapter.
Video8 (8mm) - 1984-present. Video8 was developed as a consumer format, and offered quality similar to that of VHS. Its small size allowed for equally small camcorders, which helped it in the consumer market. The tapes, however, are relatively unstable.
Video CD - 1993-present. Video CD (or VCD) is a disc format utilizing MPEG-1 encoding; its quality is quite low—generally lower than VHS. A higher-quality variant, Super Video CD (SVCD) uses MPEG-2 encoding. Primarily popular in Asia, and frequently utilized in the distribution of pirated movies. Most modern DVD players can also play Video CDs.

Format Resources

VidiPax: Magnetic Tape Preservation
The Web site of Vidipax, a magnetic media preservation facility, offers a video format guide, an audio format guide, and a virtual museum showcasing old wire recorders, reel-to-reel audio decks, and video recorders. The basics of magnetic tape preservation are explained with sections devoted to tape composition, problems with magnetic tape, storage, reformatting, and restoration.

Texas Commission on the Arts Videotape Identification and Assessment Guide
This online guide was created by the Texas Commission on the Arts to assist custodians of video materials with the care and preservation of these materials. The guide includes detailed descriptions of different video formats, instructions for condition assessment, and an evaluation of the factors that can affect the materials' longevity. The 55-page Videotape Identification and Assessment Guide is available for download as a pdf.

LabGuy's World
This Web site tracks the history of video tape recorders before Betamax and VHS. LabGuy's World features a virtual museum of extinct video recorders and video cameras, a catalog of extinct video equipment and related documentation, and information on key pioneers in VTR history.