DVD 9

[m baqar]

What are the benifits of DVD 9. Can it be palyed on DVD players as well.

[guns1inger]

DVD9 is the pressed version of dual layer. The advantage is the capacity - 7.8GB as opposed to 4.38 for a standard disc. The downside is that there is only one consistently good manufacturer, and older players can have more problems with these discs. Also, most burning programs do not burn DL discs correctly or well.

[dadrab]

Also, most burning programs do not burn DL discs correctly or well.

True, but IMGBurn is free and does a helluva good job. The vast majority of everything I burn is DL (Verbatim only) and I only burn coasters when I make a mistake.

Now I might open up a can of worms here, but I burn to the slowest speed the media will accept - which is 2.4x for most DL Verbatim discs. I firmly believe that helps. If you're in such a hurry that you can't be bothered with a slow burn, may the coasters be with you.

Even the finicky-as-Hell DVD player in our 2002 van plays my DL discs with no problems (knocking on some wood because of the obvious).

[Seeker47]

DVD9 is the pressed version of dual layer. The advantage is the capacity - 7.8GB as opposed to 4.38 for a standard disc. The downside is that there is only one consistently good manufacturer, and older players can have more problems with these discs. Also, most burning programs do not burn DL discs correctly or well.

A couple questions here. Why can't they get at least up to 8.2 or 8.3GB of storage, out of the supposed 8.5 ? (I'm pretty sure I recall seeing some pro discs that reported themselves as having 8GB on them, when I checked.) Since a lot of the commercial releases are on DL, unless the studios routinely use the Verbatim DL blanks, it must be that in pressing -- rather than burning -- reasonably good results are much more easily obtainable with lesser quality blank media ?

[jman98]

A couple questions here. Why can't they get at least up to 8.2 or 8.3GB of storage, out of the supposed 8.5 ? (I'm pretty sure I recall seeing some pro discs that reported themselves as having 8GB on them, when I checked.) Since a lot of the commercial releases are on DL, unless the studios routinely use the Verbatim DL blanks, it must be that in pressing -- rather than burning -- reasonably good results are much more easily obtainable with lesser quality blank media ?

Well, the problem is that guns1inger is using a different scale than you are. He is using what is actually abbreviated as GiB and you are using GB. You are talking about the same thing, but the values are different.
7.9 GiB = 8.5 GB
It's what I call the old "When is a byte not a byte?" question. Does a megabyte mean 1000 bytes or 1024? It's a complicated thing caused by binary numbers - humans prefer to deal with round numbers (1000) when the actual computer value is a power of 2 (1024).

There's no real capacity difference between home burned DL and pressed DL. The "differences" you see are differences of scale.

The layer change somehow causes you to lose some data space, so DL discs are less than double a single layer disc no matter what your scale is.

[VegasBud]

The layer change somehow causes you to lose some data space, so DL discs are less than double a single layer disc no matter what your scale is.

While it is true that the Middle Zones (on DL only) account for part of why dual layer isn't twice the capacity of single layer (8.5 "GB" instead of 9.4 "GB" (4.7 "GB" x 2)), the main reason is the difference in "channel bit length" between SL and DL. The average "channel bit length' in the Data Zone (normal capacity of the disk) is 133.3 nm for SL versus 146.7 nm for DL.

(133.3/146.7) * 9.4 = 8.54 (approximately)

For anyone who hasn't run across the term "channel bit length" before, it's just the distance the read/write head has to move (while following the data spiral) to cover one bit of data. To offset the drawbacks of dual layer, the "channel bit length" is about 10% longer than is needed for single layer.