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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.
http://www.jvc-victor.co.jp/english/D-VHS/dvhs-e.h tml
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.
Wow, that's an incredibly uninformed "clarification".
In terms of performance/quality, there is no clear difference; they are both digital video formats
Wrong. DVD is 480i (720x480, interlaced), and can be translated into 480p (progressive scan) by the DVD player.
D-VHS supports HDTV resolutions, including 1080i (1920x1080, interlaced; the most common format), and 720p (1280x720, progressive scan). 1080i is over 4x the resolution/quality of a DVD. THAT is the reason people are interested in this.
With D-VHS, there is no easy tape-to-computer interface
Ever heard of IEEE-1394, aka Firewire? That is the interface that the D-VHS VCR's use. I have read reports of people using these with the Linux IEEE-1394 support, and they also work with XP.
This is very close to DIVX
How so? DIVX had all kinds of features to get more money out of viewers, like charging more if you wanted to view the movie again. D-VHS has nothing like this. It only has an encryption to prevent making copies of the movies (as do DVD's, albeit a very weak scrambling method).
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.
That is correct. The JVC D-VHS deck actually supports a range of resolutions - 720x480 (like DVD) and several HD formats up to 1920x1080 ("1080i" HDTV). It is my understanding that D-Theater commercial releases will be encoded at the full 1080i resolution.
It would be insanely cool if the D-VHS deck's MPEG-2 decoder could understand 3:2 pulldown flags, and generate a true 24fps output. With the right projection system you could essentially get the same image quality as a digital cinema movie theater in your own home! (but you'd need to play it at 1080p (60 frames/sec) or 24p (24 frames/sec), which are unfortunately beyond the range of consumer-level HDTV equipment...
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.
Maybe I'm taking this out of context, but the format of the tape is exactly the point. With analog encoding on VHS, the s/n ratio declines as the tape streaches and the signal is corrupted. With digital encoding and CRC's, if a frame is too far out of whack you get nothing. Until then, the video is clean and you don't notice signal problems as you would with analog encoding.
It's a bit like the cell phone technology vs. digial cell phones. The older stuff cracks and pops and fades, while the digital sounds fine right up until the signal strenght is too low to trip the AGC on the tower receiver. Then it looses the channel and it looses the call.
I remember something called OnTrack, a backup system used on an old S100 bus computer. It used VHS video to make backups. You have an "interleave" factor, which was basically how many times the same frame was written to tape. The first frame misses? Don't worry, a copy will be along in a few seconds. I wonder if they are doing that in the new tape format.
And by the bye, the studios can encode all they want, but if it's mag tape, it won't be long before professional copyright violators have duplication machines for it. It will only foil the people that don't want to take the time to make their copies. And yes, it is fair use to make them as long as you don't sell them. IANAL.
Remember, fair use is a state of mind, and technology can't read our minds (thank God!). If someone says they can protect content but preserve fair use, it's not true. Period.
Necessity is the plea for every infringement of human freedom. It is the argument of tyrants; it is the creed of slaves.
"Both are uncompressed and are more than enough to store NTSC/PAL as good as they'll get. There is no need for anything greater unless you're ready to go to HD. (A side note... while Betacam SP is as good as uncompressed analog gets, DigiBeta came about as a lower cost replacement to D1, the original full-quality digital tape -- however D1 decks easily cost $400K+, an hour worth of blank tape - $400. DigiBeta is a dream come true for mid-sized video firms... NTSC as good as it'll get, uncompressed, and ready for the editing/compositing workstation."
Wrong. Neither BetaSP or Digi are uncompressed. Frankly, it's depressing how often I need to disabuse people of this one, but here we go again. BetaSP records it's Luma component at 13.5Mhz, but it's 2 Chroma components at 6.75Mhz ie, half the bandwidth. Digibeta conforms to the 4:2:2 colour subsampling standard where it does the same thing as BetaSP, just in the digital domain. Digibeta aslo uses DCT intra-field compression of the order of 1.8:1. There is only ONE uncompressed tape format available, and that's the Philips Shadow (sometimes called D6) which allows proper 4:4:4 in RGB or Y,Cr,Cb. Panasonics D-5 format allows uncompressed 4:2:2 at 10bit and is also, therefore superior to Digibeta. And, erm, D1 machines certainly do NOT cost $400K - where'd you get that from? I saw a DVR-2100 for £20K the other day.
That was classic intercourse!
Let this retarded concept die. Do not buy!
D-VHS was never intended as a serious consumer tape format. Other than the fact that it is CURRENTLY the only available HD purchase/rental media, it is nothing but a perverse frankenstein reanimation of yesteryear's linear-access mechanical magnetic tape formats with all the disadvantages of inevitable mechanical wear and physical deterioration, and the lame absence of random access play. It seems like a transitional and ultimately short lived technology like Philips' DCC cassettes and Sony's
Digital-8 tapes.
D-VHS offers no substantial value to the user at all in terms of convenience and longevity, and in this enlightened age with widely available random-access technology such as DVD and PVR video decks, who wants to go back to 'please remember to rewind your tape before returning it' ???
Linear access magnetic tapes should at this point in time be relegated to high capacity bulk data backup and professional digital broadcast video formats.
It's more like some kind of experiment to see how many suckers are out there who are willing to pay greedy studios for some kind of frankenstein reanimated tape format and buy it again once the HD-DVDs arrive in one shape or another.
The technology of course exists today for the studios to put a HD movie on a disc the same size as a CD/DVD, but given 1) the ease by which the CSS "copy protection" of the DVD format was broken, and 2) the apparently almost indefinite lifespan of these discs (I have several audio CDs stamped nearly 20 years ago that are playing just fine!), it may be that they feel it is too much of a gamble at present to release a HD-DVD format until they've "tested" the new copy protection scheme on a short lived limited adoption expensive tape format they can take out of circulation should it be proken and the surviving copies will expire eventually like all tapes does in the end.
Another thought: Considering that tapes are "printed" with some kind of bulk linear recording technology, I wold be not at all surprised to learn that Hollyweird is printing digital serial numbers on those D-VHS tapes for tracking them. After all, a high bandwidth HD copy of a movie must be considered a 'valuable' item since a 'dishonest person' (or video enthusiast!) with the right equipment could theoretically create very good quality copies of the movie in any format desired by scaling down to regular broadcast formats.
Consider that even DVD isn't all that - the bandwidth is quite low, and there's many MPEG2 compression artifacts readily visible on a good TV / projector - such as "ringing" around titles and edges. From a HD master such a 'dishonest person' (or video enthusiast) could re-encode a title to a different format perhaps superior to the DVD MPEG2 encoding, and play it back using their computer on a conventional television or projector at substantially better quality than that afforded by conventional DVDs. Just a thought.