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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."
My personal experience is that a nice quality video doesn't fit on a 700MB cd-rw. Not unless there is significant amount of compression and then the quality suffers. That is my only bitch, IMO CD-RW's are easy to create, play, and store. Not quite as convienant as tape, but in the future it very well could be!
Hold up, wait a minute, let me put some pimpin in it
There are basically two reasons to save:
1 You don't have the time to watch while the program is being broadcast. Save it on the TIVO hard drive and see it later that night or two days after or whatever. Then delete.
2 You have a genuine interest in the program and want to save it for the future. Then save it on a disc, and don't overwrite it.
Tor
One of the small-town grocery stores nearby actually sells CD-Rs and CD-RWs at pretty decent prices, and place them next to the blank VHS tapes in the store. Seeing as to how they're becoming more ubiquitous, and devices like the Terapin VCD Recorder (at http://www.thinkgeek.com/electronics/video/57a6/) are starting to appear, perhaps CD-RWs could give VHS a run for its money, with comparable video and audio quality, as well as interoperability with a computer. For instance, you just missed Everybody Loves Raymond, so you hit KaZaA and somebody uploaded a VCD for you. So yeah, they've got their merits.
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And the Angel said unto me, "These are the cries of the carrots! The cries of the carrots!"
Can MPEG really replace VHS? I know, VHS is pretty crappy too, but MPEG seems lossier than VHS.
I use VCDs quite often, so I'm not dissing MPEG format by any means. I just don't see the attraction of replacing magnetic tape with a lossy format.
The real solution is cheap DVD-RW.
There is no reasonable defense against an idiot with an agenda
:wq
The CDR will never replace vidoetapes for the same reason HDTV is only just starting to bloom and cassette tapes were EVER on the market.
People don't care about quality! If people cared about quality Microsoft would be out of business, Airlines would have decalred bankupcy years ago, and NO ONE would eat fast food.
Unfortuately people care about how little effort they have to excert to get something done. People don't want to deal with CD-R's because, despite an overall decrease in effort required, short term effects are minimal.
On a side note: CDRs would be a great alternative to video tapes. Tape media sucks
Help I'm a rock.
Are you sure the discs are not getting dirty w/fingerprints, dust, etc.? Such things can cause a lot of the problems misattributed to media failure...
.13$ a CD-R, and you get to keep it forever.
well i know that the specs claim for many many more rewrites that 30 or 40.
but I am also amazed that you have even actually used any of your discs that much. I would expect that if your using the CDs that much - they'd get scratched up and ruined long before you killed them via to much burning.
I know that all my CDs are treated as a trash commodity that i just toss out when it starts getting bad. or I pre-emptively burn another copy of anything that is getting a lot of use - and throw out the other when its scratched up enough.
How much watching do you do to get 30 or 40 burns on a single RW?
Anyone examined a magnetic video tape's quality after 30-40, let alone 1000 rewrites? It's not too great either.
There's 10 types of people in this world, those who understand binary and those who don't.
Nice quality video isn't achievable below some bitrate. 700 MB isn't a bitrate, it's a bitcount. Your claim would only make sense if you phrased it as "more than X minutes of nice quality video doesn't fit on a 700MB cd-rw". You didn't give a value of X and you got score 4 insightful??
how many rewrites do most people expect from their CDRW media
Zero. Actually, I find that CDRW are actually CDW. I can write to them, but I never expect to be able to read back from them. I've tried on dozens of CDRW drives, and I've never had luck archiving for a month or more on CDRW. Sure, "most" of the time it works - but it falls far short of my expected success ratios.
I've learned not to trust CDRW. I always use CDR instead.
Education is the silver bullet.
The one exception I can see to this is if you're using the CD as a data transport mechanism, between your PC in the office with the fast data connection and your DVD player in the living room.
Bill Stewart
New Fast-Compression-only CPR http://preview.tinyurl.com/dy575ks
Unless your device supports capturing of original closed captioning information onto the CD-RW's - meaning you preserve the information present including the stuff in the vertical blank interval and replay it on playback - you will never be allowed to bring this device to market as a consumer VCR replacement. As far as I know the SVCD format does not have any built in mechanism for this. There are certain things you need to do to meet FCC requirements before this device will be allowed to be sold in the USA market. Same rules applies to closed captioning decoders being required in all TV's 13" or larger.
CDRWs are too unreliable and have too little storage per disk. Hard drives are very reliable (compared to CDs) and can hold very large files.
Price/Performance comparison:
CDRW disks - $30 for 50 700MB 10x disks - $0.857 per GB - 1.458 MB/s transfer rate (assuming 10x)
Hard drives - $141 for 120GB 5400RPM drive - $1.175 per GB - 40 MB/s transfer rate
Replace your CDs once and it has already paid to use hard drives instead. As an added bonus, you also get a transfer rate equivalent to 274x in a CD drive. All you need is a video card with TV-out.
And yes, I've written and pointed this out to my reps. :-)
When companies talk about MTBF, or number of re-writes, or anything like that you have to remember these few rules:
1. They were done under ideal conditions and not your normal, everyday, household conditions.
2. They count every time they were actually able to do whatever. (Like in being able to write to the CDRW disk they will count even partial writes in order to boost their numbers.)
3. They don't care if they make outrageous statements. It takes a very long time to prove them otherwise. (Take the cigarette industry - PLEASE! Look how long it's taken to prove them wrong. [And they are STILL fighting it in the courts.])
It used to be that if you cut whatever the company said in half you could be close to what the actual figures were. Now it's about a tenth of what they say. Not that all companies are like this. But there are quite a few.
Someone put a black hole in my pocket and now I'm broke.
Ah, yes, where you actually PAY a lot more and then have to mail in a coupon to get a refund mailed to you after X weeks.
Show me a place where I can go in a dump a $5 on the counter and carry out a decent 50-pack.
If you mod me down, I *will* introduce you to my sister!
Wow... amazing how people don't get it.
If it's on a CD in SVCD format then you can take it to nearly any DVD player, stick it in, and watch. That's it.
If you're limited to a computer then you're paying 4-10x the money for the playback device and you can't transport it. Want to record something for someone else, or to take to a friend's house and watch? Too bad. Want to send a recording of an important TV show to family or friends? Nope. Can't do.
Not to mention that labeling a CD as "Junkyard Wars, Season 5, Episode 3" makes it a whole lot easier for a non-techie to deal with than some obscure location on a poorly integrated HTPC.
Perhaps he wants to keep form tossing a CD-R into the landfill every time he burns a [S]VCD. If he's getting 30-40 burns per CDRW before tossing it, that's 29-39 fewer disks of plastic, aluminum and die that end up on the trash heap.
This way, if his family member (who he's burning the shows for) wants a "permanent" archive, he can still reburn to a CDR and put the CDRW back on the blank stack.
What I want to know is which DVD player he's using to view the [S]VCD's. I recently bought a GoVideo DVD+VCR combo for my folks, and out of curiousity, tried burning some SVCD's & VCD's and playing them. I'll have to take GoVideo/SonicBlue at their word that it will play "commercially produced" [S]VCDs, as it sure couldn't play the ones I burned to CDRs.
I'm the guy who posted the story and I'm documenting my experiences and the project at aardvark.co.nz/pvr/.
:-)
What you say has some merit -- SVCD is certainly streets ahead of VCD in terms of image quality.
However, DivX is not quite the ogre you make it out to be.
For a start, it takes no more CPU to encode DivX format as it does to do a *good* job of multi-pass MPEG encoding.
On a 1.8GHz P4, TMPGenc takes around 6-8 hours to encode a 100 minute movie into an MPEG2 file to SVCD standards using multipass variable-bit-rate encoding.
You can get faster multi-pass MPEG2 encoders but they are *expensive* -- TMPGEnc is free for MPEG1 encoding and costs (from memory) just $49 for the version with MPEG2 capabilities.
By comparison, the same machine usually does a multi-pass DivX encoding in just a fraction that time.
In respect to playback, the DivX codec is quite nice insomuch as it allows some optimizations and post-processing to be performed as the video is played. This means you can create a video file that is able to be played back on a variety of different machines with different CPU-powers -- such that the faster machine will produce a better result but the slower machine will still play without pauses or stuttering.
In the past couple of months I've downloaded and evaluated hundreds of MB of applications, drivers, documentation, etc for all manner of commercial and freeware PVR solutions. These will all be compared on my site shortly.
I'm also about to publish my findings on the Haupaugge PVR card which does hardware-based MPEG1 and MPEG2 encoding -- thus freeing up the PC's CPU and allowing more "headroom". This is important when you're trying to do things such as timeshift or concurrent record/playback.
Linux-based software solutions are also being evaluated but unfortunately (damn it!) there are only two or three that appear to have much merit.
Given Microsoft's agenda to hog-tie all video and audio with DRM I'd really like to come up with a Linux based (and preferably OSS) option that is reliable, functional and ergonomic.
The truth will (eventually) be revealed
Why are you using re-writes at all? You can get a spindle of CDR's nowadays for $16.00 CDN on sale. (Must be $10 US?) That's 10 cents a disc, and you get to *keep* them. You are meanwhile spending 2.50 on a CDRW that you say can only be burnt 30 times, or 8.3 cents a burn. Seems to be it just isn't economical at all, when you could be spending pretty much the exact same amount and archiving all yoru movies instead of wiping them.
Let's run down some numbers for media costs:
The average CDRW blank costs 2-3 bucks. The average CDR blank costs 15 cents. Therefore you can burn 13-20 CDRs for the cost of one CDRW. If the video data you're recording is worth burning, then it might be worth collecting too (entire star trek series or something). My suggestion is to source a truckload of cheap CDR discs (think 2000+ qty, get a discount). CDRW is flaky, slow and unreliable. You can burn a CDR in about 2 minutes with the latest 48x burners, while CDRW is still stuck at 10-12x. This one's a no-brainer.
-Billco, Fnarg.com