Digital Video Home System
Digital Video Home System , or D-VHS for short , 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 tapes in a cassette with the VHS form factor. The recording is digital as an MPEG- 2 transport stream . In addition to the usual NTSC and PAL television resolutions , D-VHS can also record HDTV films. The format was developed by JVC in collaboration with Hitachi , Matsushita and Philips .
The “D” in D-VHS originally stood for Data-VHS, since it was initially planned to use the system for storing computer data of all kinds. For this reason, the capacity in gigabytes was usually stated on D-VHS cassettes . However, after this was never implemented and the system was generally referred to as digital VHS, it was later officially renamed by JVC.
At the time of its introduction, D-VHS was the only affordable digital video system for home use with the ability to create your own recordings, in addition to DV , whereby D-VHS, in contrast to DV, which was mainly used in mobile camcorders, was exclusively in the form of stationary VCRs for home use was available.
Recording format and cassettes
D-VHS supports several different recording modes with different tape speeds . European devices can only handle the two modes "SD" (standard) and "LS3" (low-speed, 3 times the playing time per tape), sometimes simply referred to as SP and LP. SD uses a bit rate of 14.1 Mbit / s and thus offers a higher quality than DVD. LS3 with 4.7 Mbit / s, on the other hand, enables a runtime of up to 24 hours per cassette, whereby the quality is still at the level of an average DVD. There is also "HS" (high-speed) for HDTV recordings with a bit rate of 28.2 Mbit / s, but this mode is only supported by Japanese and American models with the 60 Hz (60i or 30p) that are common there. Other originally planned modes are LS2 and LS7, but these were not used in any device, LS5 (2.8 Mbit / s) was only supported by a single model.
D-VHS recorders are backwards compatible with VHS, all devices also support recording and playback in the usual, analog VHS format, some also support S-VHS.
Cassettes are available in lengths of 300, 420 and 480 minutes, the running time in each case being based on the SD mode. In addition, with some devices it is also possible to use normal S-VHS cassettes for digital recording. However, a higher error rate ( drop-outs ) is to be expected here than when using D-VHS cassettes. The specified running time of S-VHS cassettes is slightly longer when recording in D-VHS, around 330 minutes fit on a 240-minute cassette in D-VHS SD.
D theater
D-VHS cassettes prerecorded with films were offered under this brand. These can be stored in two resolutions (720p and 1080i) and have at least one sound track (also in Dolby Digital ). Another sound standard, DTS , was also subsequently supported. However, only newer D-VHS players can process this and switch between several audio tracks. In addition, these tapes are equipped with copy protection, which prevents reading via Firewire . Cassettes recorded in D-theaters were only available in the USA and Japan and cannot be played on European models due to the lack of HDTV support. The last film released in D-Theater was I, Robot in 2005.
Market situation
In Europe, only three different models were offered: the JVC HM-DR10000, the (almost identical) Philips VR-20D and, most recently, a model from Thomson , the DVH-8090. In the USA and Japan, the selection of devices was slightly larger.
D-VHS could not establish itself on the market. In the beginning, the devices were still very expensive, but with the advent of DVD and hard disk recorders , D-VHS finally lost its importance. The production has meanwhile been stopped, only a few D-VHS recorders and cassettes are offered as remaining stock.