D-VHS
Digital Video Home System, or D -VHS is a digital video format introduced in 1998 as the successor to VHS or S- VHS; a medium and standard for recording video on magnetic tape in a cassette with the VHS form factor. The recording is done digitally as MPEG -2 transport stream. Apart from the usual television resolutions NTSC and PAL D -VHS dominated the recording of HDTV movies. The format was developed by JVC, in collaboration with Hitachi, Matsushita and Philips.
The "D" in D -VHS originally stood for Data VHS, since the beginning it was planned to use the system for the storage of computer data of any kind. For this reason, the capacity was on D -VHS cassettes usually listed in gigabytes. After this, however, was never implemented and the system commonly referred to as Digital VHS, it was officially renamed later by JVC.
D -VHS was to create at the time of introduction beside DV the only affordable for home use, digital video system with the possibility of self- shots, where D -VHS as opposed to DV, which is mainly in mobile camcorders was used exclusively in the form of stationary Video recorders became available for home use.
Recording format and cassettes
D -VHS supports several different shooting modes with different tape speeds. European devices support only the two modes "SD" (standard) and " LS3 " ( low-speed, three times the playing time per band ), sometimes simply called SP and LP respectively. SD uses a bit rate of 14.1 Mbit / s and therefore provides a higher quality than DVD. LS3 with 4.7 Mbit / s on the other hand allows a term of up to 24 hours per cartridge, the quality is still moving at the level of an average DVD. There are also "HS" ( high-speed ) for HDTV recordings with a bitrate of 28.2 Mbit / s, but this mode only support Japanese and American models, with the usual there 60 Hz ( 60i or 30p ). More originally planned modes are LS2 and LS7, but these came to any device used, LS5 (2.8 MBit / s) was only supported by a single model.
D -VHS recorders are backward compatible to VHS, all devices also support recording and playback in the ordinary analog VHS format, some speak additional S-VHS.
Cassettes are available in lengths of 300, 420 and 480 minutes, the duration of in each case based on the SD mode. In addition, it is also possible with some devices to use of ordinary S- VHS tapes for digital recording. However, this is with a higher error rate ( drop-outs ) can be expected than when using D- VHS tape. The specified term of S- VHS tapes extended if the recording in D -VHS something on a 240 - minute cassette tape fit into D -VHS SD approximately 330 minutes.
D -Theater
Under this brand prerecorded buy D- VHS tapes were offered with movies. These can be stored in two resolutions ( 720p and 1080i) and have at least one sound track ( in Dolby Digital). Subsequently, it was also another sound standard, DTS, supported. However, only D- VHS players newer design can process this and switch between multiple audio tracks. In addition, these bands are equipped with copy protection technology that prevents read-out via Firewire. In D -Theater prerecorded cassettes were only available in the U.S. and in Japan and can not on European models, simply because of the lack of HDTV support be reproduced. The last published in D- theater movie was I, Robot in 2004.
Market situation
In Europe, only three different models were offered a total of: The JVC HM- DR10000, the (almost identical ) Philips VR - 20D and finally a model of Thomson, the DVH- 8090th In the U.S. and Japan in the selection of equipment was a bit bigger.
D -VHS could not prevail on the market. Initially the devices were still very expensive, with the advent of DVD and hard disk recorders lost D -VHS ultimately important. Production was stopped meanwhile, are only sporadically D -VHS recorder and tapes offered as a residual item.
- Videotape format
- Digital storage medium