I pray not. I love my DVD player and own 50 movies already.
Anyway, I read an article recently about digital VHS (D-VHS) that says this format, presented on digital tape, provides far better picture quality than DVD. However, the only TVs that can take advantage of this are years away from being affordable.
But what happens when they are? I’m not sure. If D-VHS is a tape format, that means:
You still have to rewind.
You have to manually fast forward to particular chapters or special features.
The medium is subject to more physical deterioration than DVDs.
The medium is larger in size than DVD.
So, from what I can tell, the only edge D-VHS has is picture quality. But, won’t DVDs catch up as compression technology improves? My DVD players says it’s “feature upgradable” which I assume is referring to such advances.
So, is DVD going to be obsolete, or will it beat out a challenge from D-VHS?
Ease of use has as much to do with it as picture quality. I imagine that the format that eventually replaces DVDs will have to be just as easy to use, and not a tape.
It seems likely that D-VHS, like DATs, will only be used extensively in professional situations.
Tapes will always have higher quality, simply because the surface area (and thus amount of data) is enormous. But they will always be more expensive to produce because they have moving parts. And as noted, random access is not possible for tapes. Considering the huge head start made by DVDs, I think DVDs will be around for a while.
There probably is a market for higher quality recordable systems. Still, I’d bet on the recordable DVDs. There are already a few on the market (right?) and Hitachi even makes a DVD video camera. Random access is useful for recording as well as playback - you don’t have to find the blank space before recording. All you need to do is check if there’s enough space left on the disk.
I have to disagree. The method of data propagation on a medium such as a tape is entirely different than a CD. Tape is a magnetic medium; CD is optical. Surface area is moot with regards to a CD.
Someone might hand my ass back to me on this point, but I don’t recall that it was ever established that DAT was of better quality than CD. DAT lends itself well to professional audio because it’s easy to record on and re-useable. However mini-disks made a certain amount of headway in filling that gap, and are far more affordable.
Also if you’ve ever used a DAT machine, you’d notice that the tape is very easy and fast to cue. Not as fast as a non-linear medium like CD, but still pretty good, so unless it’s comparitively expensive like DAT technology is, then D-VHS might be a good alternative.
OK, I guess I oversimplified. Optical media do have much higher data density, and I agree direct comparison is meaningless. Still, there is a limit on the density, and surface area does play a role. Don’t laser disks hold more data than DVDs, despite having lower data density?
Also, if you compare disks and tapes of the same period, I think you’ll find that tapes have usually had more capacity for comparable size. A few years ago, a 3.5" magneto-optical disks held 640MB while DAT tape held 2GB. Now, DVD-RAM disks hold about 5 GB, while data backup tapes hold over 20 GB.
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I don’t know about this, but I didn’t think so.
This is true, but I think it’s the case for the same reason that hard drives are now capable of holding so much data. Without getting physically larger, they’re able to produce heads on HDs that read incredibly small differences in the magnetic medium, so your magnetic 1s and 0s are much closer together, while still being readable, than they were in the past. I’m guessing they can apply this technology to tape drives too.
As far as I understood about optical media, instead of squashing data closer together, the data is actually layered ( like on the Z axis ) , so the method for increasing the capacity is still different.
Anyway all that to say that I believe the issue between CD and digital tape isn’t a quality one.
Anyway, the main point for D-VHS is the quality. I think this is 1080p (1080 scan lines, progressive), which is the quality of HDTVs. However, the technology already exists for DVDs to store 1080p movies, and some progressive scan DVD players are already out there, just rather expensive. DVDs haven’t switched to 1080p simply because there’s no demand. In short, I think the entire point is moot, and DVDs other advantages mean that the medium is here to stay.
Also, as far as compression goes, the Motion Pictures Expert Group has released MPEG 4 (whereas DVDs are MPEG 2) which gives you DVD quality video for about 1/4 the file size. It’s anyone’s guess what effect this will have on the industry down the line (there’s no reason DVHS couldn’t use this), but it’s something that could be interesting.
I’m fairly sure that you’re wrong, but only because I know of no way that you could record analog data onto an optical medium. How did this work, exactly?
As for the OP, I’d agree with the DAT/CD argument. DAT (which, IIRC, could be recorded as high as 24 bit, compared to CD’s 16 (I could be wrong)) never replaced CD in the consumer market because of 3 reasons: Cost, ease of use, and the “Tape? Eww…that’s soooo 80s” factor. Never underestimate consumer confusion as a way to kill a product. People will look at this new format and ask “Didn’t we just throw out our VCR? I’m not buying in on this again.”
Also, remember that Betamax had higher quality than VHS, as well. It never caught on, either.
No, laserdiscs have pulse frequency modulated analog video.
If I remember correctly, unlike a CD where a pit (or absense of a pit) indicates a 0 or 1, the length of the pits vary on laserdiscs. I wish I could remember the details better — I used to have a bookmark for a pioneer web page that described the mastering process, but I seem to have lost it. I wasn’t able to find it after a brief web search, but I did find many copies of laserdisc FAQs that confirmed that the video was analog.
Laserdisc
Laserdisc audio could be analogue OR digital. See section 2.3 of the laserdisc FAQ.
I seem to remeber that the video was stored as pits of varying length on the disc. The LD FAQ does not come right out and say that the video on a LD is analogue, but given that section 1.1 of the Laserdisc FAQ states that
and section 2.2 states that
it’s hard to see how it could have been digital at that early date.
DAT
My impression is that DAT never made it big in the consumer market in North America because of the whole copy-protection/pirating controversy. One mode of DATs is IDENTCAL to normal CDs (16-bit uncompressed stereo audo sampled at 44.1 kHz); DATs were often used as sources for CD production.
Over time the disadvantages of the serial access tape format outweigh any advantages it may possess relative to random access optical media. Whatever advantages tape may have with respect to it’s larger media surface will be outweighed by the more complex requirements of handling and reading (and storing) tape media relative to optical media.
When DVD (and any future optical media) finally have a mature and mass market affordable recordable format, tape will vanish entirely. D VHS is interesting but that’s all it is. By 2010 (or sooner) future DVD extensions that increase the information density will make HDTV quality DVDs an affordable, everyday item.
Do most people really need a recordable video format? I can see a future where a person has 1 read-only format for pre-recorded video, 1 read/write format for video cameras (which already exists anyway in Hi-8) and a Tivo-like box that has a hard-drive to record TV programs.
DAT’s failed as a commercial medium for the reasond listed above, ease of use, cost, and the dreaded implimentation of SCMS (serial copy management system). But in my line of work (soudn design) I still use DAT’s frequently and fondly, sometimes for mastering, and particularly for field recording. They are far more stable in field conditions than something like a hard disc redorder or a minidisc recorder. And for high end applications, yes, they can record at 24/48 in contrast to the CD standard of 16/44.1 (bit’s/freq.). And they are uncompressed (unlike minidiscs). The other high end advantage is the ability to record SMPTE time code, thus making DAT a really excellent option for location recoring that requires time sync to video.
cj
Seeing as how I’ve never seen a full length movie on a single laser disc, I don’t think so.
As for picture quality, I don’t think that more is really all that much better. Unless you have a really expensive TV, you’re not going to notice the difference between DVD and D VHS, and even then it’s marginal. Beside which, detail does not depend on medium, it depends on the standards associated with that medium. If there is a demand for higher detail, DVD manufacturers will just dedicate more bits to each frame. If what Sunspace says is true, frame resolution could be increased by an order of magnitude without sacrificing space for all the extras we’ve gotten useful.
Pretty much the only use for a medium that holds on the order of one terabyte is to have a bunch of your favorite movies on one disk, so you don’t have to change movies as often. But if you’re doing that, random access is going to be really important. Can you imagine having to fast forward through ten hours of movies you don’t want to watch until you get to the one you do?