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D-VHS is a digital video format developed by JVC, in collaboration with Hitachi, Matsushita and Philips. The "D" in D-VHS is for Data, not Digital. It uses the same physical cassette format and recording mechanism as VHS, and is capable of recording and displaying both standard definition and high definition content. The content data format is in MPEG-2 Transport stream. The format was introduced in 1998.
The JVC D-VHS deck, released in the UK, was not a bitstream recorder, although it did have a DV input. Instead it is best thought of as a digital recorder for traditional analogue 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. 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 out and perhaps more crucially the lack of RGB input via the scart (PAL territories only as the NTSC versions had component outs).
As a last "hurrah" for VHS, the D-VHS system was terrific as a domestic recorder (The only comparison at the time being the DV format) but given the wholesale move to DVD and then HDD recording, the format failed to make any headway into the video market.
Tape Length
HD content is stored at 28.2 Mbit/s, while SD content can be stored at bit rates from 14.2 Mbit/s down to 2.0 Mbit/s. The tape labels are a bit confusing for HD as D-VHS was originally a standard definition format that recorded at the "STD" speed. When HD was introduced it required double the amount of tape. So that's why a DF-300 will only record 150min and not 300min. High Definition can only be recorded at the "HS" speed.
| Tape Label | Data storage | Tape Length | Rec. Time | |||
|---|---|---|---|---|---|---|
| HS | STD | LS3 | LS5 | |||
| DF-240 | 25gig | 240m | 120min (2 hrs) | 240min (4hrs) | 720min (12hrs) | 1,200min (20hrs) |
| DF-300 | 31.7 gig | 300m | 150min (2 1/2 hrs) | 300min (5hrs) | 900min (15hrs) | 1,500min (25hrs) |
| DF-420 | 44 gig | 420m | 210min (3 1/2 hrs) | 420min (7hrs) | 1,260min (21hrs) | 2,100min (35hrs) |
| DF-480 | 50 gig | 480m | 240min (4hrs) | 480min (8hrs) | 1,440min (24hrs) | 2,400min (40hrs) |
Issues
There are technical issues with compatibility with recordings from Mitsubishi and JVC D-VHS decks. PAL and NTSC recordings are incompatible too. Very few models are available to the world market and sales of this format have been weak.
D-Theater
In 2002, prerecorded D-VHS cassettes are sold under the brand name D-Theater in the US. They provide content in both 720p and 1080i as well as at least one Dolby Digital audio track. Supported movies studios include 20th Century Fox, Artisan Entertainment, DreamWorks and Universal Pictures. D-VHS provides much more video quality than previous formats (VHS and DVD), but has since been displaced by newer format such as Blu-ray Disc or HD DVD. The last movie available was 20th Century Fox's i,Robot. This title was a surprise to many as there were no prior announcements or any indication that the title was even available. It was originally only available on JVC's D-VHS store and no other distributor had it not even Fox themselves. A couple of weeks later they started trickling out to more distributors after much delay and confusion of it's existence.
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 do provide some of their original content on D-VHS but without copy protection. Many of the tapes have an introduction by the owner Mark Cuban encouraging you to make copies of the program.
A link to a list of all the D-Theater movies that have been released: http://archive2.avsforum.com/avs-vb/showthread.php?t=313242
DTS
Additional tracks may be included on D-Theater in other sound formats such as DTS. However, only the newest D-VHS players like JVC HM-DH40000, HM-DH5U, HM-DT1000, and Marantz MV-8300 include alternate audio track capabilities.
DTS D-Theater D-VHS tapes. * means dts was not mentioned on the package.
See also
External links
Video storage | VHS | High-definition television | 1998 introductions
"D-VHS"