Video tape formats
Valdemar Poulsen in 1898 with his Telegraphone demonstrated the ability to make magnetic recording of electrical signals. Like its more sophisticated successor the Magnetic Tape Recording, the technique involves the use of a medium that can be magnetically affected and which can be moved with a constant speed through a recording head. An electrical signal is fed to the recording head, inducing a pattern of magnetization proportional to the intensity of the signal. A playback head later can pick up the changes in the magnetic field from the tape and convert it back into the original electric signal. The Magnetic tape is just an information storage medium consisting of a coating suitable to be affected by a magnetic field on a thin plastic strip and nearly all types of recording tapes are manufactured under this principle whether their use will be for video, audio or data storage.
There are many tape formats that has been popularized through the years, lets explore some of the most successful standards:
Betacam is the family of a half-inch professional videotape format developed by Sony from 1982 onwards. The cassettes come in two sizes, S and L (small and large). The shell and case for each Betacam cassette is colored differently depending on the specific format for visual identification. There is also a mechanical key that allows the video tape recorder to tell which format has been inserted in the cassette compartment. In 1986 Betacam SP was developed increasing the horizontal resolution to 340 lines. Beta SP (for "Superior Performance") became the industry standard for most TV stations and high-end production houses until the late 1990s.
Digital Betacam (commonly abbreviated to Digibeta or d-beta) was launched in 1993. It outperformed both Betacam and Betacam SP for its recording quality and reliability 
while costing significantly less than the D1 systems. The Digital Betacam format records a DCT-compressed component video signal at YUV 4:2:2 sampling and 4 channels of uncompressed 48KHz PCM-encoded audio. A 5th audio track is available for cueing, and a linear time code track is also used on the tape. Some Digital Betacam equipment can also read Betacam and Betacam SP tapes and the designers kept the physical size of the cassettes for easy upgrading and compatibility. Other key element that helped the fast acceptance of the format was the Sony's implementation of the Serial Digital Interface (SDI) coaxial digital connection on Digital Betacam decks. Facilities could begin using digital signals on their existing coaxial wiring without having to commit to an expensive re-installation.
Betacam SX is a digital version of Betacam SP introduced in 1996 positioned as a cheaper alternative to Digital Betacam. It stores video using MPEG 4:2:2 Profile@ML compression, along with 4 channels of 48 KHz 16 bit PCM audio. Betacam SX cassettes are easily identifiable for its bright yellow color.
MPEG IMX is a 2001 development of the Digital Betacam format that uses the MPEG compression algorithm at a higher bit rate than Betacam SX. The IMX format allows for a CCIR 601 compliant video signal, with 8 channels of audio as well as cue and time code tracks. With its new IMX video tape recorders, Sony introduced some new technologies including SDTI and e-VTR: SDTI allows for audio, video, time code, and remote control functions to be transported by a single coaxial cable, while e-VTR technology extends this by allowing the same data to be transported over IP by way of an Ethernet interface on the VTR itself. IMX recorders such as the MSW-2100M are capable of playing back Digital Betacam cassettes as well as analog Betacam SP cassettes, but can only record to their native IMX cassettes. MPEG IMX cassettes are coded with its characteristic muted green color.
U-matic is the name of a videocassette format developed by Sony in 1969. It was among the first video formats to contain the videotape inside a cassette, as opposed to the various open-reel formats of the time where the tape was rolled in a reel.The videotape was 3/4" wide - and the format was often known as 'three-quarter-inch'. The 'original' U-matic format became known as 'Low-band' when in the early 1980s Sony introduced the semi backwards-compatible High-band or BVU (Broadcast Video U-matic) format. U-matic is no longer used as a mainstream production format.
Sony's D1 format was the first major professional digital video format, introduced in 1987.
D1 stored uncompressed digitized component video, encoded at YUV 4:2:2 using the CCIR 601 raster format, along with PCM audio tracks as well as time code. Uncompressed component video uses enormous bandwidth, and a simpler D2 system soon followed. It used a 19mm (3/4") cassette tape format, and also stores PCM audio tracks as well as time code. D1 was notoriously expensive and the equipment required very large infrastructure changes in the facilities that decided to implement the format. Early D1 operations were plagued with difficulties, though the format quickly stabilized and was renowned for its superlative image quality. D1 was still in some usage as of 2003, and many of the technologies introduced with this format are still common to more recent digital videotape formats.
Panasonic's D5 format has similar specifications, but was introduced much later.
D2 is a professional digital video format, created as a lower-cost alternative to D1. The format still used no digital compression, but saved bandwidth and other costs by sampling a fully encoded NTSC or PAL composite video signal and storing that directly on to tape, rather than sampling component video. This is known as digital composite. D2 used 19mm (3/4") tape loaded into cassettes. PCM-encoded audio and timecode are also recorded on the tape. The tapes are similar to the more popular D1 format, though they are not interchangeable. D2 has always had a mild stigma associated with it, and as of 2003 only a handful of broadcasters were using it, and even then only to access materials recorded when the format was more popular. D3 is the equivalent Panasonic format.
D5 is a professional digital video format introduced by Panasonic in 1994. Like Sony's D1, it is an uncompressed digital component system, but uses the same half-inch tapes as Panasonic's digital composite D3 format.
HD D5 uses standard D5 videotape cassettes to record HD material, using a intra-frame compression with a 4:1 ratio. HD D5 supports the 1080 and the 1035 interlaced line standards at 60 Hz and 59.94 Hz field rates, all 720 progressive line standards and the 1080 progressive line standard at 24, 25 and 30 frame rates. Four uncompressed audio channels sampled at 40 kHz, 20 bits per sample, are also supported.
HD material also is often captured for post production of film projects, especially on lower budget films, from the Super 16mm film format (15:9 aspect ratio crops well to 16:9 HDTV widescreen ratio) whereby the HD D5 scanning equipment is cheaper by the hour than a full resolution 2K film scan. Most importantly the 1920x1080 resolution at 24 progressive frames per second, with MPEG-2 or MPEG-4 compression, can be edited on high-end desktop computers since 2004.
DV is a video format launched in 1996, which encodes video onto tape in digital format with intraframe compression, making it straightforward to transfer the video onto computer for editing. DV tapes come in two formats: MiniDV and DV.
There is a high-definition variant of DV (and MiniDV) called HDV.
As a curious fact we can refer that the Digital video standard D4 does not exist and will probably never do, at least in the Asian electronics market. This is due because the number 4 in Eastern cultures has similar bad connotations to the number 13 in Western cultures. Specifically, the Chinese character for four is shi, which also sounds like the word for death.
Many traditionally minded Chinese car owners refuse to accept license plates for their new cars that end with the number 4. So much so that the authorities in China have bowed to public demand and do not issue such license plates, much to the chagrin of reform-minded Chinese who wish to get rid of old superstitions. Just a funny note to end a lengthy and very introductory exploration to the multiple world of professional tape formats.