DVDA - Mastering for DLT

Giroud Francois · September 15th, 2009, 02:57 PM

you need to understand how CSS works to properly handle DVD mastering.

CSS is encrypting the content of the files on DVD (the VOB files) and for this needs two things.

The track at the center of the disk that is not available on DVD-R. This track will contain part of the key used to scamble content. That is why you need something like a special "DVD-R for Authoring" and a burner that can handle this.

The second that CSS require is a sector size on disk that is a bit larger than the one used on DVD-R, even if left empty at time of authoring, it is required, because for example it will cause the layers to cut at a different place. So you cannot use DVD-R for this reason.

Additionally, DVD-R is written using a lossy scheme. Data are written by the laser on disk as a "cloud" of data, with some redundancy, to make sure in case of dust, the reading is still possible. Unfortunately, video DVD and mpeg use error correction allowing some data to be lost without being noticed. So there is no real way to guarantee that a video DVD is 100% correct. If you use it to master a DVD, chance are the data could be corrupted on the final disk (with or without effect on playability).
So the best way is to make a DATA image (or also called Tape image ) of your DVD, you still can burn it on a DVD-R, but this time it will be seen as a data DVD, where each bit is set for sure. Some companies do not want to deal with such media and request DLT tapes , because the DLT format also include redundancy and error correction, so there is absolutely no place for mistake.

Another care for example is to stick to standard. If you edit a very simple DVD, the information for the menu for example will be very small. DVD standard include backup files (the .BUP files) for each .IFO file. If you burn it on a DVD-R with nero for example, if these .IFO and .BUP are very small, they could be recorded in the same sector on disk.

That is pretty useless to have the data and its backup in the same sector, because if sector cannot be read, the purpose of the backup is defeated and disk is useless.

Some burning application like IMGBurn are managing this (not NERO) and can pad (put enough blank space after each file) to make sure they will not be written in same sector.

This kind of mistake is not fatal, meaning you can burn a mishaped DVD and have no problem.

But many companies will return you the DVD-R reporting they cannot burn it like that.

Kevin Kimmell · September 16th, 2009, 09:21 AM

Jason,

I've worked with Discmakers and two other nationwide replication houses on projects that didn't require DLT/Macrovision, etc. and in all instances at their recommendations sent them 2 or three copies of finished DVDs that I was able to view on a variety of playback devices.

They will glass master from that copy and press your silvers based on that. It's the least troublesome thing that you're likely to deal with. Getting the art copy to them in a perfect format poses more problems if you're not savvy in that area.

Good luck!

-Kevin

p.s. I never used the "master" option for my products and we've sold somewhere in the neighborhood of 2000 discs with very few problems.

September 16th, 2009, 09:21 AM	#17
Kevin Kimmell Major Player Join Date: Feb 2004 Location: Akron, OH Posts: 209	Jason, I've worked with Discmakers and two other nationwide replication houses on projects that didn't require DLT/Macrovision, etc. and in all instances at their recommendations sent them 2 or three copies of finished DVDs that I was able to view on a variety of playback devices. They will glass master from that copy and press your silvers based on that. It's the least troublesome thing that you're likely to deal with. Getting the art copy to them in a perfect format poses more problems if you're not savvy in that area. Good luck! -Kevin p.s. I never used the "master" option for my products and we've sold somewhere in the neighborhood of 2000 discs with very few problems. __________________ Kevin Kimmell http://www.yurplebliss.com/

September 15th, 2009, 02:57 PM	#16
Giroud Francois Inner Circle Join Date: Feb 2004 Location: switzerland Posts: 2,133	you need to understand how CSS works to properly handle DVD mastering. CSS is encrypting the content of the files on DVD (the VOB files) and for this needs two things. The track at the center of the disk that is not available on DVD-R. This track will contain part of the key used to scamble content. That is why you need something like a special "DVD-R for Authoring" and a burner that can handle this. The second that CSS require is a sector size on disk that is a bit larger than the one used on DVD-R, even if left empty at time of authoring, it is required, because for example it will cause the layers to cut at a different place. So you cannot use DVD-R for this reason. Additionally, DVD-R is written using a lossy scheme. Data are written by the laser on disk as a "cloud" of data, with some redundancy, to make sure in case of dust, the reading is still possible. Unfortunately, video DVD and mpeg use error correction allowing some data to be lost without being noticed. So there is no real way to guarantee that a video DVD is 100% correct. If you use it to master a DVD, chance are the data could be corrupted on the final disk (with or without effect on playability). So the best way is to make a DATA image (or also called Tape image ) of your DVD, you still can burn it on a DVD-R, but this time it will be seen as a data DVD, where each bit is set for sure. Some companies do not want to deal with such media and request DLT tapes , because the DLT format also include redundancy and error correction, so there is absolutely no place for mistake. Another care for example is to stick to standard. If you edit a very simple DVD, the information for the menu for example will be very small. DVD standard include backup files (the .BUP files) for each .IFO file. If you burn it on a DVD-R with nero for example, if these .IFO and .BUP are very small, they could be recorded in the same sector on disk. That is pretty useless to have the data and its backup in the same sector, because if sector cannot be read, the purpose of the backup is defeated and disk is useless. Some burning application like IMGBurn are managing this (not NERO) and can pad (put enough blank space after each file) to make sure they will not be written in same sector. This kind of mistake is not fatal, meaning you can burn a mishaped DVD and have no problem. But many companies will return you the DVD-R reporting they cannot burn it like that.