DVD-RAM Media: Speed question

[Johnny_Deep_Down_Below]

Hello!

I just got my Panasonic DMR-ES 10 EC-K recorder, which should have a great quality and many features.
The most interesting feature is time-shifting, which is only available when recording on DVD-RAM.

As I never used DVD-RAM before, I wonder whether you could share your experiences with me.

What I already know:
-I want single sided media (4.7 GB)
-It should be in a catridge
-It has to be removable (otherwise I can't read it out in my PC)

The most important question is: What about the speed?
According to the manual, the recorder supports DVD-RAM v2.0, v2.1, v2.2. The last one supports 2x - 5x.
Do I need such high-speed media for time-shifting, or are 2x - 3x DVD-RAMs sufficient?

Is there anything else to obey?

Could you recommend me some DVD-RAM media?


Thanks!

[Joe Fenton]

First, does your PC's DVD support DVD-RAM? Not many do. Second, DVD-RAM rarely comes in a cart anymore, but I've seen them sold seperately. Third, it's not a matter of which DVD-RAM media is best, it's a matter of can you even find it at all. I had one DVD-RAM come with a LG DVD SuperMulti, but that's the only DVD-RAM I've ever seen.

For people who don't know what DVD-RAM is, it's an old rewriteable optical media based on magneto-optics instead of phase-change dyes. As such, it takes a special drive to write it, and most readers won't read it. Only one of the four DVD writers I have had could read or write DVD-RAM. It's just not very popular anymore.

[Johnny_Deep_Down_Below]

It has the big advantage that you can read and write it at the same time (time-shifting) and is much safer than DVD-R(W) (due to the catridge).

My Toshiba-DVD-ROM supports reading DVD-RAMs (but only without catridge). There are many discs available on the net, just have a look.

[Joe Fenton]

If you have to take the DVD-RAM out of the cart to use it on your PC, it's no safer than DVD+-R(W).

While you can find DVD-RAM on the net, at more than $3 a pop, it's FAR less expensive to use DVD+-R(W). I suppose you might get a couple and see how much you like time-shifting, but I certainly wouldn't get more than a couple. You could have one in the machine while using the other on the PC, and swap when needed.

[Shinigami-Sama]

wow
I've seen them in future shop a few times, $20/1opack I thought it was a bad seal, but $3USD sounds worse than my $2CAD, intersting, I was wonding why you could timeshift and know I know :)

[Joe Fenton]

I checked several places online where I normally get DVDRs. $3.50 each was the lowest price I found, and that was for crappy generic discs. Good name brands were $6 to $10 each. If you see $20 for a ten pack, you'd best snap it up. DVD-RAM is only slightly less expensive than DL media. :)

[Shinigami-Sama]

strange, I guess theres more taxes on them down in the USA, becuase I saw them in a flyer not to long ago for $2CAD each, for mid grade disks

[Johnny_Deep_Down_Below]

I bought a few high quality Panasonic DVD-RAMs for 3.33€ - that seems quite a fair price.

The drive's internal error-protection and the hard-sectored disc make DVD-RAM a lot safer than other DVD-recordables, plus it supports writing and reading at the same time.

[Joe Fenton]

Let us know how that works out... I'm interested in whether I should look into that "time shifting" feature on a DVR or not. I plan to go DVR shopping later this summer.

As to price, DVD-RAM is old and getting older, so look for prices to go up, not down. Also, there is nowhere near the demand for DVD-RAM compared to DVD+-R(W).

[Atamido]

For people who don't know what DVD-RAM is, it's an old rewriteable optical media based on magneto-optics instead of phase-change dyes.From Wikipedia (http://en.wikipedia.org/wiki/DVD-RAM): It is a common misconception that DVD-RAM uses magneto-optical (MO) technologies: DVD-RAM is a pure phase change medium. DVD-RAM drives used to be cool many years ago, but I hadn't seen any computer drives that supported DVD-RAM until a year ago when some (http://www.lge.com/catalog/prodmodeldetail?actType=search&page=1&modelCategoryId=CTG1000658&categoryId=CTG1000500&parentId=CTG1000439&modelPrefix=400000&globalCode=GSA-4082B&globalSuffix=000000&model=NOTHING) newer DVD+-R/W drives started to add support for it.

[Joe Fenton]

That's the problem with Wikipedia - it's written by normal people, often spreading misinformation they "heard somewhere" without verifying it. If they had simply followed one of their own links, they'd have found this:

"DVD-RAM, with an initial storage capacity of 2.58 billion bytes, later increased to 4.7, uses phase-change dual (PD) technology with some magneto-optic (MO) features mixed in."

So no, it's not 100% magneto-optic, but to say it's "pure" phase-change is just as wrong. In particular, the writing uses magneto-optic methods to trigger the phase change. It's just the reading which is "pure" phase-change.

That's what allows DVD-RAM to do the "time shifting" - seperate read and write heads. The read head is pretty much a standard optical reader, while the write head is pretty much a magneto-optic head.

[Atamido]

I couldn't find any mention of any sort of magnetic property in the ISO/IEC 16824:1999 (http://isotc.iso.org/livelink/livelink/fetch/2000/2489/Ittf_Home/PubliclyAvailableStandards.htm) specs. It appears to be completely optical based, although I may have missed something as it goes well over my head at times.

If I had to guess wildly, I would say that the "magneto-optic (MO) features" being mentioned are it's method of using fixed sector locations instead of the continuous round track used by every other CD/DVD+-R/W media. But I just don't know enough to say for sure what they were refering to as they (http://www.dvddemystified.com/dvdfaq.html#4.3.4) never go into more detail than that vague comment.


As far as Wikipedia goes, I find it to be pretty accurate with any article related to basic technical info that has been edited several times. Things such as political or historical topics that tend to have multiple conflicting viewpoints should be taken with a large helping of salt.

[Joe Fenton]

That's mighty weird... it certainly doesn't match the tech docs I got back in college. Unfortunately, I can't find anything else on it either.

[Atamido]

Let's just say it uses "black magic (http://wombat.doc.ic.ac.uk/foldoc/foldoc.cgi?black+magic)" and call it even.

[Joe Fenton]

Sounds good to me. :D

Anywho, I'd still like to hear how well that time-shifting works. As I said, I am looking at DVRs this summer and if it's a good feature, I'll try to make sure I consider that as I check various models.

[alge66]

I own a Panasonic DMR-E50 and time shifting works well for me. You can record and watch on the same disc, at the same time. Also if you begin to record a progamme, and say after 20 minutes, you decide to watch it, you can while it's still recording.
I also own a LG-GSA 4040 super multi, but I have found compatability issues when I try to watch recordings from the TV on my PC. Something about UDF reader and unknown format. Personally, if you got the hard drive space and the set up, use something like WinTV, Showshifter or AverTV to record directly from your aerial/cable onto your PCs hard drive.

[Joe Fenton]

Thanks for the 411.

[Atamido]

I'll just make a quick DVR comment here that is non-DVD-RAM. I set up a MythTV box a few weeks ago and have pretty good success with it. I'm using a PVR-500 which has two tuners so I can record two shows at the same time while watching an already recorded show. Ditto about watching recordings in process. The card has MPEG-2 encoders so it uses very little CPU to record. It has built in re-encoding so you can have it convert to MPEG-4 in the background to save space.

Biggest drawback is that it takes a few seconds to change channels so no channel surfing. I just use the built in channel guide so it isn't a big issue to me.

If you've got money to burn, MythTV has a really cool modular design. You can put a server in the basement that only records stuff and then some light PCs next to your TVs that stream the video over the network. I saw a guy putting together a system with 16 cards for his backend. :cool: