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Media type | Magnetic cassette tape |
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Encoding | NTSC, PAL, SECAM, ADAT |
Capacity | 50 GB |
Read mechanism | Helical scan |
Write mechanism | Helical scan |
Developed by | Hitachi, JVC, Matsushita, Philips |
Usage | Home movies, Television production |
Extended from | S-VHS |
Released | December 1997 |
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, [1] [2] 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 [3] and was standarized as IEC 60774-5. [4]
As a final effort for VHS, the D-VHS system had significant advantages as a highly versatile domestic recorder (the other tape-based formats are DV and Digital8, which never gained any traction except as camcorder media), but given the wholesale move to DVD and then hard disk drive (HDD) recording, the format failed to make any headway into the video market.
Existing tape media is bulky and more expensive than hard drives. Although cable companies are gradually switching to the H.264 codec, this should not be an issue for D-VHS units since they can act purely as data stores (like a hard drive but using tape instead), and thereby pass the previously recorded H.264 data directly to the Set-top Box or TV (via i.Link/FireWire). Another alternative is a lengthy transfer to a computer for viewing. Finally, since machines are no longer manufactured, maintenance of current recorders may prove difficult.
D-VHS's primary advantage is that it is still the best way to archive encrypted high definition material from cable programming in the US. Cable, satellite companies, TiVo, and PCs equipped with cable card tuners all offered high-definition digital video recorders, but archival has proven to be an obstacle, as proprietary boxes have restrictions on moving encrypted content. Outside of D-VHS, only HD capture devices that use an analog conversion process, such as the Hauppauge HD PVR, have enabled removal of encrypted content off many of the above proprietary boxes. This uses an analog conversion process, producing slightly degraded but still high definition grade recordings. D-VHS, on the other hand, does not need to take advantage of this so-called "analog hole", since D-VHS makes possible a pure bit-for-bit recording with no conversion necessary. This is made possible by compliance with CCI flag values carried by the digital streams, wherein only D-VHS is allowed to digitally move recordings of content originally flagged as Copy Once from a DVR device and onto a D-VHS tape. This programming that complies with the CCI flags then marks such material on the tape such that no second generation copies can be made from the tape itself, though additional copies can still be made directly from the original DVR unit to additional tapes.
Monthly rental fees to cable, TiVo, and satellite were also less with D-VHS.[ clarification needed ]
The only PAL D-VHS model sold in Europe was the JVC HM-DR10000, also sold as the Philips VR-20D, and was standard definition only. This model was not a bitstream recorder, although it did have a FireWire input. Instead it is best thought of as a digital recorder for traditional analog inputs such as domestic analog TV and digiboxes for digital broadcasts. The deck was able to record D-VHS signals onto S-VHS tapes, which made it a cost-effective source of high quality domestic recordings (the US version also allows use of cheaper S-VHS media). Pictures were noticeably superior to S-VHS and were essentially transparent when compared to an off-air source. Using the LS3 mode, approximately 17.25 hours of digital video could be stored on a S-VHS E-240. The deck's biggest shortcomings were the lack of a DV output and, perhaps more crucially, the lack of RGB input via the SCART connector. NTSC versions had component video outputs.
D-VHS VCRs can record at multiple speeds. "HS" is "High Speed", "STD" is "Standard" and "LS" is "Low Speed"; where LS3 and LS5 represent 3 and 5 times the standard length of tape, respectively. High-definition content such as 1920x1080 or 1280x720 is typically stored at 28.2 Mbit/s (HS speed). Standard-definition content such as 720x576 (720x480) can be stored at bit rates from 14.1 Mbit/s down to 2.8 Mbit/s (STD, LS3, LS5 speeds). [5]
The quality of STD speed is actually superior to the average DVD, since this speed has a much higher bitrate (approximately 14 versus 5 Mbit/s average) and suffers few compression artifacts. LS2 speed has a bitrate of 7 Mbits/s. The LS3 speed is roughly equal to an amateur DVD with some visible artifacts in high-action scenes (4.7 Mbit/s), [6] and LS5 appears similar to a medium-quality video download (2.8 Mbit/s). [7] JVC's HM-DH40000U and SR-VD400U were the only units to support LS5 recording.
As a result of all these different speeds, the tape labels are a bit confusing for the consumer. D-VHS was originally a standard definition format that recorded at the STD speed. When High Definition recording and HS speed was later introduced, it required twice the amount of tape. For this reason, a DF-240 will record 240 minutes of standard definition, and 240/2 = 120 minutes of high definition. When reviewing the table, note that the digital speeds HS and STD are equivalent to the older analog speeds SP and LP.
Label | Data storage | Length | Recording time | |||
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HS or VHS-SP | STD or VHS-LP | LS3 | LS5 | |||
DF-240 | 25 GB | 248 m (813 ft) | 120 min (2 h) | 240 min (4 h) | 720 min (12 h) | 1,200 min (20 h) |
DF-300 [6] | 31.7 GB | 314.5 m (1,048 ft) | 150 min (2:30 h) | 300 min (5 h) | 900 min (15 h) | 1,500 min (25 h) |
DF-420 | 44 GB | 433 m (1,420 ft) | 210 min (3:30 h) | 420 min (7 h) | 1,260 min (21 h) | 2,100 min (35 h) |
DF-480 [6] | 50 GB | 500 m (1,640 ft) | 240 min (4 h) | 480 min (8 h) | 1,440 min (24 h) | 2,400 min (40 h) |
In 2002, prerecorded D-VHS cassettes were sold under the brand name D-Theater in the US. While D-Theater is a D-VHS tape, it is incompatible with D-VHS decks not bearing the D-Theater logo. They provide content in both 720p and 1080i as well as at least one Dolby Digital audio track.[ citation needed ] Supported films studios include 20th Century Fox, Artisan Entertainment, DreamWorks, and Universal Pictures.[ citation needed ] D-Theater does have region code restrictions. There are 3 known regions; 1 for the USA, 2 for Japan, and 3 for South Korea.[ citation needed ] There has never been a D-Theater video release in region 2 or 3.[ citation needed ] Region code hacks for Japanese decks have been performed to support playback of US titles.[ citation needed ] The last film available was 20th Century Fox's I, Robot . [8] This title was a surprise to many as there were no prior announcements nor any indication that the title was available. It was originally available only on JVC's D-VHS store in late 2004 and no other distributor had it (not even Fox itself). A couple of weeks later they started trickling out to more distributors after much delay and confusion about its existence. Alien vs. Predator was announced to retailers as also being released on the same day as I, Robot, but Fox later announced that Alien vs. Predator was never shipped to retailers.
Most tapes have built-in copy protection mechanism (DTCP, also known as "5c") (copy never) that disables copying via FireWire. HDNet productions and 2929 Entertainment via Magnolia Entertainment did provide some of their original content on D-VHS but without copy protection. Many of the tapes have an introduction by owner Mark Cuban encouraging the viewer to make copies of the program in order to help distribute them.
Additional tracks may be included on D-Theater in other sound formats such as DTS. However, only the newest D-VHS players, like the JVC HM-DH40000, HM-DH5U, HM-DT100U, and Marantz MV-8300, include alternate audio track capabilities.
There are technical issues with compatibility between recordings from Mitsubishi and JVC D-VHS decks. [9] PAL and NTSC recordings are also incompatible.[ citation needed ]
Very few models were available to the world market and sales of this format have been weak; correspondingly, prices remained high for both VCRs and media, contributing to low demand. In 2000, Sony arranged with JVC to manufacture D-VHS VCRs under the Sony label, marking one of the first collaborations between the two former rivals. [10] The lack of consumer knowledge of D-VHS's advantages and capabilities as well as input limitations led to its eventual demise. The introduction in 2006 of Blu-ray and HD-DVD rendered the format abandoned. [11]
There has been no small-format version of D-VHS equivalent to VHS-C; JVC, the originator of the format, chose to use MiniDV for its digital camcorder lines, and since 2005 has also expanded into tapeless camcorder designs based on hard drive storage (the Everio line). JVC does market the Digital-S format for professional use; while the tapes and technology used are superficially similar to D-VHS tapes, the underlying data format is based on the DV codec and the media formulation is drastically different. Sony's MicroMV format uses the same codec as D-VHS. Therefore, D-VHS capture software can also be used to transfer MicroMV tapes.
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, 25, 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, introduced in 1976 by the Victor Company of Japan (JVC). It was the dominant home video format throughout the tape media period in the late 1970s, 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 the 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.
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.
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 videotape format war was a period of competition or "format war" of incompatible models of consumer-level analog video videocassette and video cassette recorders (VCR) in the late 1970s and the 1980s, mainly involving the Betamax and Video Home System (VHS) formats. VHS ultimately emerged as the preeminent format.
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.
VHS-C is the compact variant of the VHS videocassette format, introduced by Victor Company of Japan (JVC) in 1982, and used primarily for consumer-grade compact analog recording camcorders. The format is based on the same video tape as is used in VHS, and can be played back in a standard VHS VCR with an adapter. An improved version named S-VHS-C was also developed. S-VHS's main competitor was Video8; however both became obsolete in the marketplace by the digital video formats MiniDV and MiniDVD, which have smaller form factors.
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.
XDCAM is a series of products for digital recording using random access solid-state memory media, introduced by Sony in 2003. Four different product lines – the XDCAM SD, XDCAM HD, XDCAM EX and XDCAM HD422 – differ in types of encoder used, frame size, container type and in recording media.
W-VHS (Wide-VHS) is an HDTV-capable analog recording videocassette format created by JVC. The format was originally introduced in January 8, 1993 for use with Japan's Hi-Vision, an early analog high-definition television system. The first W-VHS recorder was the Victor (JVC) HR-W1, released on December 28, 1993.
Digital audio cassette formats introduced to the professional audio and consumer markets:
The first attempt at producing pre-recorded HDTV media was a scarce Japanese analog MUSE-encoded laser disc which is no longer produced.
D-9 or Digital-S as it was originally known, is a professional digital video videocassette format created by JVC in 1995.
A videocassette recorder (VCR) or video recorder is an electromechanical device that records analog audio and analog video from broadcast television or other AV sources and can play back the recording after rewinding. The use of a VCR to record a television program to play back at a more convenient time is commonly referred to as time shifting. VCRs can also play back prerecorded tapes, which were widely available for purchase and rental starting in the 80s and 90s, most popularly in the VHS videocassette format. Blank tapes were sold to make recordings.