Todd Hochard

Because for many titles, the space is needed. Single layer DVD is 4.7GB, but a dual layer is 8.5GB (somewhere around there). If all films, complete with multiple surround formats and languages, were required to be jammed into single-layer discs, they wouldn't look very good. The video bitrate would have to be held too low, leaving you with lots of artifacts. You can look at some of the early releases that were single layer (from 1997), and see just this.
Not all DVDs are dual layer, but many are, out of necessity.

Sure, you could go dual sided instead, but "flippers" are pretty much universally reviled among the DVD crowd.

Contact and Ghostbusters still working here. Denon DVD-2500 player (circa 1999). I'll take a look at the 3rd and 4th discs of FTETTM.

I haven't had a single rot issue yet, among about 500 titles.

It could still be a player issue. The optics on the pickup must be in good shape to correctly do a read-through. For those that say "you don't watch enough," I say that could still be the player- heavy use issue- there are going to be a finite number of operating hours a player will work. And, it seems I keep seeing the name brand names pop up. What player do you have, Todd?

Todd

I love to singa, about the moon-a, and the june-a, and the springa...
-Owl Jolson

Todd Robertson

My DVD/Film Library
dvd folders under construction:wink:

Todd Hochard

Standing offer-

Since I seem to have the best luck ever, anyone can send me their defective DVDs, and I'll try them on my apparent miracle player. I'll try it, and send it back. As a long-time HTF member, I promise not to stiff anyone.

Seriously. Email me if you like. I'm not trying to belittle anyone's situation. I'm a troubleshooter for a living, and one of my peeves is the manner in which many engineers I've dealt with over the years will instantly declare the source of the problem, without having done any sort of real isolation. The sky might be falling- we just need to wait until it gets closer, so we can see it.

Have you tried any DVD-Rom players?

My Denon is based on the Panasonic A120 chassis. Most Denon players to this day use the optics from Panasonic. And, generally speaking, with Panasonic optics, they work right, or they don't. No glitches in between- they're either good, or the player is basically dead (and, back in the A110 era, many did die). That's my take from this and other boards.

I don't think you get better error correction, necessarily, from spending more money. But, based on the size of your DVD collection, ponying up $600 for a player ought to be a drop in the bucket, eh?

What sort of display are you using, or intending to use in the near future?

I love to singa, about the moon-a, and the june-a, and the springa...
-Owl Jolson

Todd Robertson

My DVD/Film Library
dvd folders under construction:wink:

GlennH

Todd H., I'd gladly send you one of my problem discs if I still had them. But they've all been replaced now.

Come to think of it, doesn't the fact that the replacement discs I've gotten play fine tend to speak against the "it's always the player" theory. If a player is having trouble with a particular DVD release and the DVD is fine then why wouldn't said player have problems with *any* copy of said DVD?

By the way, this was the case with the problem I mentioned earlier with Disney titles on my old Toshiba player. It was repeatable with a different disc of the same title.

Todd Hochard

I didn't say it was always the player- I'm just saying it's not always the discs.

Or, maybe I am just really lucky.

I love to singa, about the moon-a, and the june-a, and the springa...
-Owl Jolson

Todd Robertson

My DVD/Film Library
dvd folders under construction:wink:

Todd Hochard

Todd,

The Pioneer 643-HD5 at Costco has to be one of the best deals going. $2599 at my local store, for 64" widescreen. This has the fantastic Elite ProHD-x10's PureCinema line doubler in it, which is among the best in any RPTV. If I were getting a RPTV today, this would be on a very short list.
I've had the Elite Pro-510HD (53") for a little over two years now. It's been great.

Todd

I love to singa, about the moon-a, and the june-a, and the springa...
-Owl Jolson

Rohan_B

Hi folks,

I'm in Australia and have had a couple of Region 4 discs go belly-up on me post layer change (tested in several players). I also happen to work in a failure analysis laboratory, so I have been able to do some independent research on the problem.

Extensive examination of my 'problem' discs using high-magnification optical microscopy has revealed the presence of multitudes of black spots in the reflective metallic coating of the second layer, corresponding to the approximate locations of the content I am having trouble playing back. I have several images you can view at my website here: www.andraste.org/discfault/discfault.htm

I am currently in discussions with a local (Melbourne based) replicating plant regarding the issue and they have also had a look at these discs. They have taken the issue up with some local distributors and informed me that I have managed to 'stir the pot' somewhat.

I have also been in independent contact with some of the local distributors. Columbia-Tristar have taken particular interest and told me they are forwarding the information on to 4 Australian pressing plants and their head plant in Austria for comment.

As to what I *think* is happening ... the problem appears to be unique to dual-layer DVDs and is probably related to the resin used to bond the layers together.

The polycarbonate substrates of dual layer discs are bonded using a 'free radical UV curing' resin. The resin is applied in liquid form and UV light hardens it to a strong bond. It is my belief that if the bond resin is not quite cured correctly, excess reactive chemicals may still be present within the disc. These chemicals will diffuse around looking for something the react with.

The reflective coating used for the first layer of a dual layer disc is usually gold, sometimes silicon. Gold and silicon are pretty much inert to everything. The reflective coating used for the second layer of a dual layer disc is aluminium. Aluminium is extremely reactive under the right conditions. The rate controlling factor would then be the time it takes the active chemicals to diffuse to the aluminium and react with it. This may be of the order of many months after original purchase and may explain why problems are usually not apparent when the discs are newly manufactured.

Finally, how do these tiny black spots affect playback? It is my belief that each of the spots generates a read error. The large number of spots probably result in read errors that exceed the error correction capabilities of most dvd players.

Hope this was of interest.

Rohan.

Matt Everett

When my copy of "Amarcord" died (no scratches, warpage, cloudiness or cracks at all) I posted my experience in this forum. Many of the replies insisted that it was a player error, despite the fact that I tested the disc in two players prior to posting, and both failed in the exact same manner. I tested it in two MORE players and had the same result. I doubt that 4 players were enough to please everyone, however.

Previous posters are correct in saying some people are in denial. I'm not happy that this is happening to anyone, but more and more I see that I am not alone.

I still defend the DVD format since I've only had one disc do this. If others start failing, I will be concerned.

steve jaros

I've owned a copy of the 'sweet hereafter' since when it came out in 1998. I played it about a month ago with no problems.