"If it can be written, or thought, it can be filmed..." STANLEY KUBRIC
From Encyclopedia PRO
D-VHS (Data-VHS) is a digital recording and playback format for high definition material developed and launched by JVC in 1998. D-VHS 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 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.
D-VHS uses the same cassette format as standard VHS. It can record and playback both standard definition and high-definition. Digital video is encoded with MPEG-2. High-definition content is recorded at 28.2 Mbit/s. Maximum recording time is 3.5 hours of high definition and up to 49 hours of standard definition.
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.
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.
[Correction: High Definition can also be recorded at STD speed, IF the bit stream is CBR (Constant Bit-Rate) at 14.1 MBit/sec or less, OR is VBR (Variable Bit-Rate) with no peaks exceeding 14.1 MBit/sec. Somewhat confusingly, "STD" does not refer to "Standard Def", but "Standard Speed", for high definition. "HS" is "High Standard".]
|Tape Label||Data storage||Tape Length||Rec. Time|
|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)|
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 is a brand name for distributing pre-recorded D-VHS tapes. D-Theater supports 720p and 1080i resolution and Dolby audio.
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. 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.
Only D-Theater equipped D-VHS players will be able to play back D-Theater movies on tape. But all D-VHS decks also allow you to record (via MPEG-2 encoding) high definition broadcasts off the air as well as current NTSC analog signals (PAL format decks have yet to be announced) . The decks are fully backwards compatible with all existing VHS formats, including S-VHS. Currently only one manufacturer (JVC) is supporting the D-Theater platform, but others are already making D-VHS decks and are likely to adopt it in the future (Panasonic, Mitsubishi, Hitachi and Toshiba are all supporting the basic D-VHS format currently in Japan.
D-Theater/D-VHS supports full Dolby Digital 5.1 soundtracks at a bit rate of 576Kbps (higher than DVD's 448Kbps rate). Both the manufacturer and the studios say the format will support DTS multi-channel surround sound as well through the deck's optical digital audio output (one studio already has plans to include DTS on future D-Theater titles), although it's not entirely certain whether the existing hardware will be able to handle it without modification (expect this to get ironed out quickly - the belief is that existing players should work with future DTS-encoded tapes). The HD videos are all pre-recorded in the 1080i format, with an average video bit rate of about 23Mbps (the format max is 28Mbps, some of which is taken up by audio, DVD bit rate on average is 9mbps). As far as features go D-VHS supports multiple audio channels and chapter stops (with obvious limitations given the linear tape format).
The HM-DH5U defines the home theater performance. With its HDMI™ (High Definition Multimedia Interface) connect to newest HDTV and hi-res projector systems. It enables full enjoyment of prerecorded D-Theater movies, and keeps you in touch with the analog video library you've built over the years. So go beyond video. Experience High Definition Video for the age of HDTV.
- Digital Set-top box ready with Digital-to-Digital connection via i.Link (IEEE 1394) terminal
- D-Theater compliant with the advanced D-VHS security system
- HDTV Digital Broadcast Bitstream Recording/ Playback
- Built-in MPEG2 Decoder for Direct Connection to HDTV via Y/Pb/Pr or HDMI™ (High Definition Multimedia Interface)
- Can Record Any Type of Broadcast including HD, SD or Analog HS mode (28.2 Mbps) for up to 4 hours* HDTV recording STD Mode (14.1 Mbps) for up to 8 hours* SD recording LS3 Mode (4.7 Mbps) for up to 24 hours* long-time recording * and LS5 mode for up to 40 hours* long-time recording Per DF-480 cassette
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.