 | |
| Media type | Magnetic tape cassette |
|---|---|
| Encoding | 1035i or 480i (1125-line baseband) |
| Developed by | JVC |
| Usage | Home movies, Home video, Video production |
| Extended from | VHS |
| Released | 1994 |
W-VHS (Wide-VHS) is an HDTV-capable analog recording videocassette format created by JVC. The format was originally introduced in 1994 for use with Japan's Hi-Vision (aka MUSE), an early analog high-definition television system.
The Japanese language uses "W", as an ideogram meaning "double", the original Japanese name of the system refers to a doubling of resolution seen on W-VHS system.
By the time the system was being prepared for a western market, JVC had retrofitted the "W" name as "Wide-VHS" and coined four marketing points based on the "Wide" moniker. [1]
W-VHS VCRs can record a high-definition video signal (1035i, stored internally as an 1125-line signal similar to Hi-Vision) via the analog Y/Pb/Pr component interface, a standard-definition signal (480i), or two simultaneous standard-definition signals, for 3D video. [2]
The recording medium of W-VHS is a 1⁄2-inch double-coated metal particle tape stored in a cartridge similar to VHS. Some W-VHS VCRs are capable of playing and recording VHS and S-VHS media.
Unlike normal VHS, which uses a single head to record video fields as a series of parallel standalone tracks, W-VHS uses a dual-head design to record each video field as two parallel tracks storing a component video signal. The signal is recorded using a method called "time compression integration" in which the luminance signal is divided into two sets of lines, which are then split and recorded across both tracks. After the luminance signals are recorded, the two color signals are recorded, one on each track, in a time-compressed form. Recording these signals sequentially rather than side by side prevents crosstalk between the luma and chroma components. [3] [1] [4]
Because the video signals are recorded in component form instead of e.g. the "color-under" method used by S-VHS, standard-definition image quality for W-VHS is typically much higher, due to the lack of noise caused by a chroma sub-carrier. Audio is stored as a digital PCM stream.
Due to its high cost, W-VHS equipment and media was distributed in the United States through JVC's professional video and broadcast equipment division and was primarily marketed for industrial and commercial applications such as medical imaging. [5]
Currently, it is very difficult to find either W-VHS VCRs or tapes. If W-VHS media is not available, JVC recommends the use of tapes intended for the D-9 or Digital-S digital video format. [6]
The running time between W-VHS and Digital-S is not the same; a Digital-S tape with a length of 64 min is approximately 105 min when used with W-VHS.
Digital video is an electronic representation of moving visual images (video) in the form of encoded digital data. This is in contrast to analog video, which represents moving visual images in the form of analog signals. Digital video comprises a series of digital images displayed in rapid succession, usually at 24, 30, or 60 frames per second. Digital video has many advantages such as easy copying, multicasting, sharing and storage.
Video is an electronic medium for the recording, copying, playback, broadcasting, and display of moving visual 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 of several types.
The VHS is a standard for consumer-level analog video recording on tape cassettes, invented in 1976 by the Victor Company of Japan (JVC). It was the dominant home video format throughout the tape media period in the 1980s and 1990s.
DV is a family of codecs and tape formats used for storing digital video, launched in 1995 by a consortium of video camera manufacturers led by Sony and Panasonic. It includes the recording or cassette formats DV, MiniDV, DVCAM, Digital8, HDV, DVCPro, DVCPro50 and DVCProHD. DV has been used primarily for video recording with camcorders in the amateur and professional sectors.
Videotape is magnetic tape used for storing video and usually sound in addition. Information stored can be in the form of either an analog or digital signal. Videotape is used in both video tape recorders (VTRs) and, more commonly, videocassette recorders (VCRs) and camcorders. Videotapes have also been used for storing scientific or medical data, such as the data produced by an electrocardiogram.
S-VHS (スーパー・ヴィエイチエス), the common initialism for Super VHS, is an improved version of the VHS standard for consumer-level video recording. Victor Company of Japan introduced S-VHS in Japan in April 1987, with their JVC-branded HR-S7000 VCR, and in certain overseas markets soon afterward. By the end of 1987, the first S-VHS VCR models from other competitors included Hitachi VT-2700A, Mitsubishi HS-423UR, Panasonic PV-S4764, RCA VPT-695HF, and Toshiba SV-950. It has been standardized as IEC 60774-3 and IEC 60774-4.
Chroma subsampling is the practice of encoding images by implementing less resolution for chroma information than for luma information, taking advantage of the human visual system's lower acuity for color differences than for luminance.
Betamax is a consumer-level analog recording and cassette format of magnetic tape for video, commonly known as a video cassette recorder. It was developed by Sony and was released in Japan on May 10, 1975, followed by the US in November of the same year.
D-1 or 4:2:2 Component Digital is an SMPTE digital recording video standard, introduced in 1986 through efforts by SMPTE engineering committees. It started as a Sony and Bosch – BTS product and was the first major professional digital video format. SMPTE standardized the format within ITU-R 601, also known as Rec. 601, which was derived from SMPTE 125M and EBU 3246-E standards.
A camcorder is a self-contained portable electronic device with video and recording as its primary function. It is typically equipped with an articulating screen mounted on the left side, a belt to facilitate holding on the right side, hot-swappable battery facing towards the user, hot-swappable recording media, and an internally contained quiet optical zoom lens.
Betacam is a family of half-inch professional videocassette products developed by Sony in 1982. In colloquial use, Betacam singly is often used to refer to a Betacam camcorder, a Betacam tape, a Betacam video recorder or the format itself.
A video tape recorder (VTR) is a tape recorder designed to record and playback video and audio material from magnetic tape. The early VTRs were open-reel devices that record on individual reels of 2-inch-wide (5.08 cm) tape. They were used in television studios, serving as a replacement for motion picture film stock and making recording for television applications cheaper and quicker. Beginning in 1963, videotape machines made instant replay during televised sporting events possible. Improved formats, in which the tape was contained inside a videocassette, were introduced around 1969; the machines which play them are called videocassette recorders.
The 8mm video format refers informally to three related videocassette formats. These are the original Video8 format and its improved successor Hi8, as well as a more recent digital recording format known as Digital8. Their user base consisted mainly of amateur camcorder users, although they also saw important use in the professional television production field.
A DVD recorder is an optical disc recorder that uses optical disc recording technologies to digitally record analog or digital signals onto blank writable DVD media. Such devices are available as either installable drives for computers or as standalone components for use in television studios or home theater systems.
U-matic or 3⁄4-inch Type E Helical Scan or SMPTE E is an analogue recording videocassette format first shown by Sony in prototype in October 1969, and introduced to the market in September 1971. It was among the first video formats to contain the videotape inside a cassette, as opposed to the various reel-to-reel or open-reel formats of the time. The videotape is 3⁄4 in (19 mm) wide, so the format is often known as "three-quarter-inch" or simply "three-quarter", compared to open reel videotape formats in use, such as 1 in (25 mm) type C videotape and 2 in (51 mm) quadruplex videotape.
D-VHS is a digital video recording format developed by JVC, in collaboration with Hitachi, Matsushita, and Philips. The "D" in D-VHS originally stood for "Data", but JVC renamed the format as "Digital VHS". Released in December 1997, it uses the same physical cassette format and recording mechanism as S-VHS, but requires higher-quality and more expensive tapes and is capable of recording and displaying both standard-definition and high-definition content. The content data format is in MPEG transport stream, the same data format used for most digital television applications. It used MPEG-2 encoding and was standarized as IEC 60774-5.
MII is a professional analog recording videocassette format developed by Panasonic in 1986 in competition with Sony's Betacam SP format. It was technically similar to Betacam SP, using metal-formulated tape loaded in the cassette, and utilizing component video recording.
D-9 or Digital-S as it was originally known, is a professional digital video videocassette format created by JVC in 1995.
MUSE, commercially known as Hi-Vision was a Japanese analog high-definition television system, with design efforts going back to 1979.