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D-VHS to Hit The Market This Week
An Anonymous Coward writes: "Yahoo News is has an article stating that D-VHS is hitting the market this week. The upside: D-VHS supports full high-definition picture quality. The down side: $35 - $45 per movie (although available for less) and $2k for a player. Seems to me you'd lose a lot of that HD picture after a few viewings too. 4 studios are supporting it: 'JVC persuaded Fox, Universal, DreamWorks and Artisan to support the format after developing a new copy-protection standard it calls D-Theater to prevent unauthorized copying of the high-definition movies'."
D-Theater is an option (feature) on D-VHS tape decks. There are already decks on the market, especially in Japan, that are D-VHS but not D-Theater.
D-Theater is a content encryption system. D-VHS is a recording format (MPEG-2 aparently). A D-VHS recorder would allow you to record any HDTV broadcast directly - up to 4 hours of it in fact. Also, D-VHS supports full Dolby Digital 5.1 soundtracks at a bit rate of 576Kbps (higher than DVD's 448Kbps rate). This is being touted as the VHS for the HDTV generation.
Also, while the titles are listed at 35-40 USD Buy.com and BestBuy have them listed at 25-29 USD, so they aren't terribly more expensive than DVDs. Even so, DVDs have market edge on D-VHS (and a few other technological advantages including durability). It seems as if D-Theater is unimportant, but take notice of D-VHS.
The problem with VHS degradation over time has nothing to do with the data format on the tape. The problem is with the medium itself: flexible magnetic storage.
On the contrary, data format matters a lot, as it tells you how sensitive the content will be to medium degradation.
A (binary) digital tape - one with two levels of data per sample - can tolerate far more noise than an analog tape that stores a large number of levels per sample. Error correction codes can be applied to digital data, which allows you to correct one (or several) corrupted bits per code in the data stream. Analog encoding doesn't let you do this. In many other ways, digital encoding lets you map content space into signal space so that you can have large amounts of signal noise/degradation without the content degrading much.
Digital encoding also lets you reconstruct _perfectly_ the original content when only moderate degradation has occurred - letting you copy a worn tape on to a pristine one with no content loss. This isn't possible with analog video encoding.
So, data format does matter.
Some of the currently-available D-VHS decks support FireWire I/O. This allows one to record and play video to the deck with a computer (the streams can be recorded from the deck - e.g. for PVR-style timeshifting of HDTV - or generated and encoded yourself).
Several people at avsforum.com have already gotten this working using MPEG2-over-FireWire support built into Windows XP.
Dan Dennedy and I are working on a Linux driver that will provide the same functionality as Windows XP. (it will appear at linux1394.sourceforge.net; it's not ready for release yet though).
D-VHS is a truly versatile format. The deck I have experience with (JVC) can record and play MPEG-2 streams at a wide variety of bitrates (up to 29MBit/sec) and formats (720x480 NTSC up to 1920x1080 HDTV)... The encoding is standard MPEG-2, so you can make and play your own HDTV content (I've done it already), and you could probably also do things like record a DVD to tape without re-compressing the video.
Note however that Windows XP and my drivers can only handle cleartext MPEG-2 streams (either home-made or recorded from broadcast/satellite HDTV). The new "D-Theater" standard is basically like DVD's CSS; the MPEG-2 streams will come in a scrambled format that is "impossible" to read without a licensed decoder.
Manufacturer's suggested retail price: $1999.95
JVC's upcoming HDTV-capable Dish Network receiver will also have a IEEE 1394 (FireWire) connection so it can transfer content directly to the D-VHS box.
Wow, there's a lot of FUD floating around here..
D-VHS is currently the only format that allows true High Definition resolutions in a removable format. It allows you to record HD content from a HDTV Set Top Box (if the HD receiver is equipped with a firewire port). It also allows playback of pre-recorded movies at 1080i resolution.
DVD's don't have the storage capacity to hold an HDTV movie. Broadcast HDTV is about 9GB per hour. Pre-recorded movies on D-VHS will be even more than that, up to twice the bit rate of broadcast HDTV.
DVD's are at best 480p (720x480), the D-VHS VCR supports HD resolutions, 720p (1280x720) and 1080i (1920x1080). The HD movies are over four times the resolution/quality of DVD's. The difference is very dramatic.
This variant of D-VHS, D-Theater, includes an encrpytion, to stop the pre-recorded movies from being copied (much like CSS was supposed to do with DVD's). That is the only restriction that this format has, which is a welcome change from all the other attempts to control HD content.
The JVC unit also has analog component video outputs, allowing 1080i playback on all existing HDTV's. This capability is one that Hollywood has been threatening to disable in HD receivers (block the "Analog Hole").
If you look at the statistics for HD capable TV's sold vs. HDTV Set Top Boxes, you'll see that most people with the nice 16:9 HD-Capable TV's are not using the full capabilies of their TV's. They are just using them for DVD's. D-VHS could be the first chance for them to really use their HDTV.