how are dual layer dvds read?

[dblake2]

Anyone know exactly what the process is?

I ask cause my sony ns75h has started acting up after 1 1/2 years, it frequently will freeze when reading dual layer, its ok with single layer.

Recently I've been watching discs with 4 episodes per side & it will freeze one or more times on 2 or 3 episodes so I'm wondering if there are multiple layer changes, or whats going on. The sony is going to be retired & used as an experimental guinea pig.

[redwudz]

Do you mean commercial pressed discs or burned double layer discs?

For pressed discs: http://electronics.howstuffworks.com/dvd2.htm

For double layer DVD discs: http://en.wikipedia.org/wiki/DVD%2BR_DL Also if they are burned DL discs, I would use Verbatim DL+ and ImgBurn for the best reliability.

For commercial discs, you could try cleaning the laser lens on your player, but with the price of players at present, I would consider replacing it if cleaning doesn't help.

[VegasBud]

What redwudz said, plus:

You should also check the non-label side of the disk(s) for fingerprints, debris, scratches, etc. which can cause playback problems like you're describing.

Dual layer disks have only one layer break (change) where the laser refocuses from the first layer to the second layer. On commercial disks, or well prepared dvd-rdl disks, it should be undetectable.

[dblake2]

the freezes are all with commercial pressed discs & they have no visible marks/scratches etc.

excellent link. from what i've read there's only one layer change per disc

i did pull the cover off but getting at the laser is going to be difficult. looks like i'll have to remove the drive.

i'll wait til the replacement comes.

it would be nice, with all the dvd high tech around, if someone could make a player that didn't start freezing discs after a year or so. I was able to access the service menu of the thing & it said the laser had 1668 hours of use. the cleaning disc i have doesn't do anything.

[jman98]

it would be nice, with all the dvd high tech around, if someone could make a player that didn't start freezing discs after a year or so. I was able to access the service menu of the thing & it said the laser had 1668 hours of use. the cleaning disc i have doesn't do anything.

You are fighting the trends my friend. The US consumer, if not the world consumer, has told the electronics industry 2 things.
1) It has to cheap if they want to sell a lot of them.
2) Thinner is better, but not at the expense of being cheap.

Both of these things are a dream come true to the electronics manufacturers. Why? To keep costs down, they have to use inferior parts. Inferior parts break sooner. Breaking sooner means replacing sooner, which means buying a new one (repair costs exceed the price of any DVD player that sells for $70 US or less). Thinner is also great because it means that heat buildup is more of a problem, which means components can get damaged sooner from heat, which also means replacement, which means buying a new one. So you see that the problem is that your fellow consumers have told the industry that they don't care if it lasts, as long as it's cheap.

If you want something that might last, you'll have to pay for it. Oppo (http://www.oppodigital.com) makes some relatively expensive (compared to almost everybody else at least) DVD players that are well regarded here that use high quality components. They might last.

[Noahtuck]

What redwudz said, plus:

You should also check the non-label side of the disk(s) for fingerprints, debris, scratches, etc. which can cause playback problems like you're describing.

Dual layer disks have only one layer break (change) where the laser refocuses from the first layer to the second layer. On commercial disks, or well prepared dvd-rdl disks, it should be undetectable.

That's not completely accurate, I have seen several commercial pressed disc's that even say you may notice a slight pause on the layer break right no the back of the cover.
Regardless of the SA player.
I notice it a lot on store bought disc's, they usually hide it well at some transitional spot but i have even noticed it on many new releases.

[redwudz]

I suspect some commercial DVDs want to squeeze that last bit onto the discs, with extras, etc. The layer break position and how it affects playback is probably a minor concern.

Sometimes it's not only the laser that wears out. The mechanism that moves the laser lens can also be sticking or the feedback mechanism that focuses and aligns the laser may be having problems.

What a CD laser assembly looks like. A DVD assembly is similar:

[harishkumar09]

I suspect some commercial DVDs want to squeeze that last bit onto the discs, with extras, etc. The layer break position and how it affects playback is probably a minor concern.

Sometimes it's not only the laser that wears out. The mechanism that moves the laser lens can also be sticking or the feedback mechanism that focuses and aligns the laser may be having problems.

What a CD laser assembly looks like. A DVD assembly is similar:

Thanks for the diagrammatic description of the anatomy of a laser assembly. It was sexy !

[lordsmurf]

That's not completely accurate, I have seen several commercial pressed disc's that even say you may notice a slight pause on the layer break right no the back of the cover.

No, it's accurate.
The bigger issue is the hardware in use. Not all players are seamless.
If either disc or player is not seamless, then there is a detectable pause at the layer change.

[jman98]

Thanks for the diagrammatic description of the anatomy of a laser assembly. It was sexy !

harishkumar09 - Don't grave rob old threads, moron. Nobody needed to see your post. Leave old threads alone and don't dig them up just to add pointless comments like this.

lordsmurf - Kind of late to this party, dude. See my comments above. Plus, you actually agree with Noahtuck. Re-read what he said. NOTHING he said disagrees with your comments. You just basically rephrased what he already said.

[lacywest]

I'm putting my 2 cents in this thread ... and jman98 ... if you don't like it ... too bad. Yes ... he resurrected an old thread with a comment that did not have any useful info for a person to use.

But for you to come back with "harishkumar09 - Don't grave rob old threads, moron. Nobody needed to see your post. Leave old threads alone and don't dig them up just to add pointless comments like this " ... not good neither.

There are nicer ways to scold someone for posting old threads ... so give it a try and be nice.

And to add some useful info ... I use Verbatim DVD+R DL disks ... bought at Best Buy back in 2007 and I have not bought anymore since ... I still have about 10 blank disks left. I use Cyberlink Power2go 6 to burn a 7.5 - 8GB ISO file ... I use CloneDVD2 to make the ISO file.

I also get by just fine using ... DVD+R or DVD-R disks ... and I use DVD Rebuilder 1.28 Pro with the Cinema Craft Encoder SP v2.70.02.12 encoder ... and if I want to ... I will let it do 10 Passes ... even if some folks say ... here at this website ... that anything past 4 Passes is a waste.

I hope everybody here in the USA enjoyed ... 4th of July ... remember folks ... its the war of 1776 ... that Americans won their independence. And during ... 1812 - 1815 ... another war took place ... hence the song ... "The Battle of New Orleans" ... do a wikipedia ... some good reading there ... laters