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Could CDRW Disks Replace Videotapes?
NewtonsLaw asks: "I'm in the process of building a TiVo-like PC that uses off-the-shelf technology to implement video timeshift, MPEG recording, MP3 recording, etc along with Net-radio functionality. Over the past two months I've effectively replaced VHS video tapes with CDRW disks. Once a program has been captured on the PC in (S)VCD MPEG format, I can either watch it by playing back the recorded file or dump it onto a CDRW and watch it on my DVD player, before blanking the disk and returning it to the 'empty' pile. What I've noticed is that most of the CDRWs I've tried only last about 30-40 rewrites before they start showing significant data dropouts (almost always at the start of a recording). Since disks in (S)VCD format don't carry the same level of error-checking/correction as disks written in regular data format, such dropouts are more noticeable than they would otherwise be (of course the up-side is that you get to store 805MB on a 700MB CDR/RW without overburn).
What I want to know is -- how many rewrites do most people expect from their CDRW media? I seem to recall seeing a figure of a thousand rewrite cycles being touted by some manufacturers. Is this realistic? Thirty rewrites makes a $2.50 RW disk an economic medium for this purpose but it seems a hell of a long way short of 1,000."
"I've tried CDRW disks from several manufacturers and they're being used in a new Sony CDRW drive which seems to function just fine. I've also encountered a slightly shorter lifetime for CDRW media when used for (S)VCD disks and written by a slightly older HP CDR/RW drive.
And before anyone asks 'Why don't you just play directly from the HD?', I should point out that I have to share the TV gear in this house with the rest of the family so it's just easier to burn their stuff to disk and let them use the DVD player than to fight over access to the TiVo-clone."
Just get more hard drives. They have the lowest $/mb and are theoretically supposed to last a long time.
I just use CDRs since they're so cheap. Given up on CDRWs - all of my older ones are no longer readable.
I find that the video quality of MPEG-1/VCD to be too low for enjoyment. Perhaps if you could reimplement this with DVD-RAM/DIVX (with one of those new DivX capable DVD-players, e.g. the Kiss DP-450, then we'd be talkin.
Figure $5 for a pack of 50, so $0.10 each -- you can't re-record on them, but it shouldn't cost you more than CD-RWs that start failig at 15 uses or so. Plus, this way you have the ability to create instant archives of your favorite shows, or just discard the used disks.
How did you build a tivo-clone? I for one would be interested in the hardware and software choices you made and how you configured it.
Insert disk and hit record, for a price point of $200.00 when it is in volume. And 2.40 for a CDRW?!? Just jump to DVD(+-) RW. They are only $6.00, and getting cheaper, and would hold about as much as a long video cassette at similiar quality. Also, tapes are not reliable either. They are only good for about 100 plays.
The law is a weapon of the government, not a protection for the likes of you. Surely you understand that.
You are correct that the 700MB limit sucks. However, I have had some good experiances with an Apex 3 disk model. That way you can split a Replay Tv'ed mini-series into three svcd disks and take them with you to a friends house to watch and there is just a slight pause between the disks. It worked well for me.
... when is this guy going to do a big ol' write up of his experiences building such a thing and share it with his in-awe peer group? This sounds like a REALLY neat thing and I'd love to give it a try myself sometime in the future if I have the cash to try it.
I don't doubt the quoted figures of "1000 rewrites" for CD-RW media, for the reason that the crystalline substrate which stores the data proper should last around that much, chemically. In my experience, it's the physical disc which fails- scratches from handling, pitting on the reflective aluminum layer, etc.
CD-RWs reflect around 25% of the read laser, as opposed to CD-Rs which reflect around 75%, and pressed CDs which reflect close to 100%. When the signal-to-noise ratio is this low, the A/D circuitry has a hard time keeping up even with minor defects- fingerprints and dust are much more deadly on a CD-RW than on a CD-R.
In my experience, the first burn to a virgin CD-RW delivers CD-R-like readability, but once you rewrite it even once, the drive has to work a lot harder. I used to treat my CD-RWs like floppies, carrying them between the lab and my home, playing with them while waiting for an operation to complete, etc. and got maybe 4-5 rewrites on average. I then started keeping them inside jewel cases at all times, exposing them for a few seconds to put into the drive, and immediately got 20+ rewrites out of them.
Also, we were using really bad drives at the lab (some early HP CD-RW burners which often rejected discs) and when we upgraded the machines (to better HP burners, in late 2001) rewritability literally doubled for me to about 40+ rewrites. So the type of drive makes a difference as well IMHO.
Wrists killing you? Not in 2 weeks. Learn Dvorak.
If you ever watch a VCR tape and a VCD on a low-end TV (no HD now) you will probably be happier with the VCD quality. I even drop the VCD quality to about half the bit rate and I still can't see the difference on the crappy TV, except that VCDs don't bounce around.
Of course my computer monitor is a completely different story.
In the past 5 years since I puschased a DVD player, I have watched a VCR tape on average 3 times a year. Mostly becasue corporate videos came to me that way, and of course Lucas.
In the past years since I purchased TiVo, I have never recorded a tape, unless I was lo-teching for an unfortunate friend.
I still think that CD-R's are a more reliable medium, and still, in most cases a faster medium. But if you get right to it, what happens when you recorded a video on a tape, over and over and over. Or watched the same tape over and over and over, the picture quality gets worse and worse.
Phillips is now selling a DVD-RW for such purposes, so It does look like the video tape has one more nail in it's coffin.
To make a TiVo clone would be cool, but to make one that will output to CD's, CDRW's, or DVD's would be great. (But still it's a waste of time to dupe a DVD if you can't get DTS ot Dolby Digital on it...)
"This is you left and that's your left. This is your right and that's your right. You're gonna die!
I seem to remember reading that the VCR has already begun to be phased out. Circut City doesnt even carry them any more. I remember reading that one of the major makers has already started to slow production of them. I think that with things like DVRs and DVD-R/RW/ect options comming just around the corner ($300 or less) VCD's are just not really going to be an industry supported medium. What do u guys think? I am writting this question in extreme hast as my professor is about to start bitching at my for not paying attention (I love campus wide wi-fi =] ) Got to dip!
I have a divx version of "Legally Blonde" (yes, I own a copy of the dvd) which is almost indistinguishable from the dvd. That divx encode is stored on a bright pink 700 Meg CDR.
Now before you go around saying that quality is subjective, and I don't know what to look for, I'd like to mention that I work in the video capture and compression industry (coding drivers for various products, including mpeg-2 [en|de]coders). I'm familiar and, generally, fairly sensitised to the various artifacts resulting from DCT and wavelet compression, interlaced video, scaling, etc.
It sounds like you are used to seeing poor quality encodes. There is an art to getting the best quality out of the bandwidth allocated.
-SpeedBump
PS: I should concede, though, that the "Legally Blonde" divx that I have probably benefitted from the ability to do multi-pass encoding.
Bizarre. I care about quality, which is probably why I'm not interested in using CD-R for video recording. I've been experimenting lately with recording video from my WinTV card to my harddrive, and in order to get reasonable quality I need to record at around 640x480 streaming at somewhere around 4 Mbps. That results in about 2 Gigs for a one hour program.
Can you fit 2 Gigs on a single CD-R? Didn't think so. What I could fit on a CD-R would look like crap on my 51" HDTV set.
As far as the Microsoft comment. The sad thing is, as poor quality as software is these days Microsoft software is higher quality then the competition.
I don't bother with CD-RW, I just use CDR. I only buy them when they're "free after rebate," which between OfficeMax, Staples, BestBuy, and Compusa, is about every other week.
I didn't go with (S)VCDs because my DVD player (XBox, actually) doesn't play them.
The cost of entry is higher, but the quality is far superior than VHS (unless you're trying to record off of the local Fox station, but that's their fault).
Boobies never hurt anyone. - Sherry Glaser.
Last year, I've written my thesis work about recording VCDs in real time. I have a simple command line tool you can run to record analog TV (with small changes probably from any source) to your CD writer. The code is GPL, based on VCDImager and somewhere in the VCDImager repository.
The thesis text is a bit dated by now but you can still find it at http://users.evitech.fi/~arndb/project/htmlmain/
Arnd Bergmann
That scared me off using them for 3 or 4 years, but I recently started using them again and they dont seem to have these problems now.
Religion is a gateway psychosis. -- Dave Foley
One question -- why are people in this discussion using the term DivX when they mean MPEG4? Sure, DivX is one available MPEG4 codec, but there are several others that are at least as widely distibuted (like, say, the MPEG4 codec's in QuickTime and Windows Media). So I can understand why DivXNetworks wants to blurr the distinction between their product and the standard it's based on, I'm not why anybody else would.
... offers 7-10 times greater compression than MPEG-2 technology" are all crazy. There's no such thing as a "DivX Video" -- it's an MPEG4 video!
For example "it takes no more CPU to encode DivX format as it does to do a *good* job of multi-pass MPEG encoding" doesn't make sense. Perhaps you meant "it takes no more CPU to encode MPEG4 format as it does to do a *good* job of multi-pass MPEG2 encoding"? Or perhaps "it takes no more CPU to encode MPEG4 using the DivX codec as it does to do a *good* job of multi-pass MPEG2 encoding using TMPGEnc"?
As another example, nobody sane would want a "DivX(TM) Compatible DVD Player" (see the headline onthe announcement of the KiSS DP450) -- why would I want a player that only played video encoded with a proprietary codec -- but an MPEG4 Compatible DVD player is very cool! Also, the terms "DivX certified" and "full compatability with all versions of DovC video" and claims like "DivX video compression technology
And people say that Apple's marketing is over the top! At least they know the difference between a standard and an implementation...
What I like most about this question is premise must strike fear in the hearts of the MPAA and other big media goons that are reading it. The premise is a recipe for a p2p video experience. The MPAA and the perpetrators of the DTV fiasco are hoping to eke out some more life for themselves by trying to convince people they need better quality and they want to pay more money for it, oh, ignore the chains that come with it.
But your question demonstrates that you don't value what those hucksters are trying to sell you, you want flexibility. And it just so happens that flexibility means you can download video in a reasonable amount of time and store it on cheap media, ala mp3.
I had a Dr Who hankering the other day, hadn't watched it in years. I don't own a TV, I probably watch a sitcom every 3 months or so and am blown away by the crap on TV, I've never been in a household with cable. I downloaded maybe 15 vhs-ish quality Dr Who episodes as divx over a couple nights and watched them over the course of a week, haven't felt the need to watch them or other movies since. Now that's an experience that big media has no interest in providing me.
Not to mention MythTV... already has a nice program guide, interface conducive to using with a remote and irxevent, etc... It can record to an extremely hacked NuppelVideo codec or some mpeg4 codec. Check it out if you haven't.
Restating the obvious since nineteen aught five.