Layer Breaks for Consumers

[Xesdeeni]

Now that dual layer drives are available (albeit with limited media available), how do we consumers go about setting layer breaks?

If I use something like DVDMaestro, I understand it can support the break. But is this hard-wired to DLT writing, or is the info in the VOBs. If the latter, can Nero or another burning software recognize this flag? Can DVD-Lab or another reasonably priced/available authoring tool do this as well?

Xesdeeni

[Xesdeeni]

I'm still unclear on where the layer break support needs to be. Can an authoring tool put the flag in the VOBs (or IFOs) and the burning software uses it to organize the burn?

Xesdeeni

[Dimmer]

Someone around pointed out these news (http://www.nero.com/en/632164078246694.html) from Nero about being "ahead" of the others in this area. Apparently, no need to worry about the layer break.

[Xesdeeni]

Perhaps its my natural paranoia showing, but "...automatically modifies video content..." and "...the optimum layer break location...will be detected by analyzing video signal and navigation structures..." seem a bit scary to me. What if Nero gets it wrong?

Plus, it seems the players have to support the "...caching and playback optimization necessary...." And we all know how little conformance there is beyond the basics of the standard.

Having this as an option is great, but I still think it would be useful for the user to be able to adjust if desired. Maybe I'll have to contact Ahead and/or Media Chance.

Xesdeeni

[mpucoder]

I'm going out on a limb here, not having seen what Ahead did. But if I were trying to analyze the files for the best location of the layer break (there is only one) I wouldn't go any further than satisfying two requirements
1) there must be more data on the first layer than the second layer - this means start looking at the midpoint of all data (ifo, bup, and vob) for...
2) the layer break must occur between cells.

Of course there may be a choice of locations somewhere after the midpoint, but before the maximum size of the first layer. In that case the best place would be the one with the lowest bitrate. This would allow the greatest time for the player to refocus and start tracking the second layer.

It would still be nice to choose the point ourselves, but there is no mechanism that I know of to denote the break other than iso images or two tapes/disks. Maybe someone will read this and support a 2 folder mechanism?

[Xesdeeni]

The above-referenced quote seems to indicate Ahead balances the data evenly between the layers. I think this makes sense, since it means the head doesn't have to move as it changes layers, given that the end of the first layer is right at the start of the second. The DVD-ROM reviews I've seen with dual layer read graphs seem to show this type of arrangement.

I would assume that the first place to put a layer break would be between files. DVDs with episodic TV shows would be easy to split.

After that, then I can see the analysis you mention being handy. But I think I'd look for fades to black and no sound first. Looking for cell boundaries is an interesting idea as well. That way it'd at least be on a chapter boundary.

If there isn't an indicator of the break in the data, what are the DVD backup tools (http://www.google.com/search?hl=en&lr=lang_en&ie=UTF-8&c2coff=1&as_qdr=all&q=DVD+remove+layer+break&btnG=Search&lr=lang_en) looking at?

Xesdeeni

[MrWGT]

Hi...

in the german magazine c't 11/2004 (2004-05-17) there's a test of a beta Philips DVDR885P. They write a few lines about duplicating a DVD-9 (roughly translated):

...To make sure that the layer break occures on the right place the original layer break from the source disc is taken...

Comment: They copied a unprotected DVD-9 (probably with "copy 1:1 DVD") so there should be no need to change the layer break.

and:

...Nero Express will set the layer break into the middle of your self made film...

...if the layer break is more to the end (comment from me: e.g. layer 0 is 4 GB, layer 1 is only 2 GB) there would be unwritten range on the inner side of the second layer. This unwritten range might confuse some dvd players during seeking the lead in if they would (by mistake) focus on the unwritten second layer...

Conclusion(s):

1) Nero seems not to modify the layer break on a 1:1 copy
2) Nero Express sets the layer break into the middle of the film
3) Nero must rearrange the layer break if the VOB files are on hdd to make sure that the layer break is near the middle of the dvd because
a) the order of the files might be changed,
b) the vobs might be smaller now (some content removed e.g. wb trailer) or
c) the dvd rom content is now missing.

Regards,

Gerd

[mpucoder]

The 2 points I made were in respect to the specs. It's true that you don't want any unrecorded data on the inner part of the second layer, which is the filler space Nero talks about. But the second layer is also at a slightly lower bit density, so splitting in exactly the middle isn't possible. The requirement for the first layer to be larger than the second is due to both the layer capacities and the fact that to perform the layer switch you don't want to reposition the pickup at all. Therefore it can't move out to find the start of the second layer.
The other part is the requirement that a cell not span layers. If Nero is ignoring this there may be problems with some players, although from a technical standpoint, the requirement makes little sense. What does make sense is that you don't span a layer break with multi-angle or seamless branching material, they are demanding enough in themselves.
As for not altering 1:1 data, it only makes sense if the same criteria is used by both the original and Nero to locate the break.
It's not clear to me what manipulation of data Nero is performing. I would hope nothing more than playing with the padding, as anything else could lead to a reduction in video/audio quality.

[MrWGT]

Hi...

i've burned my first DL dvd today and watched the tracks around the layer break with my standalone (Grundig GDP6150) and on the PC. I noticed that the track after the layer break has no audio.

A quick view with ifoedit showed why:

1) A new cell was inserted at end of track 6 for the layer break. This cell has "illegal fps"
2) The follwing track has now also "illegal fps" (instead of 25 fps) and therefore the duration was around 25min showed in standalone instead of about 3 min.
3) The audio status 1-8 was totally destroyed. There where "random" numbers in audio status 1-8 instead of 0x8000 for audio status 1 an 0x00 for the rest.

Conclusion: At the moment you cannot burn valid dvd dl with nero 6.3.1.15

Regards,

Gerd

PS: I've send a detailed error report to techsupport of nero.

[waterdd]

Has anyone successfully backed up a DVD-9 to a DL (and what software did you use)?

[hendrix]

Originally posted by waterdd
Has anyone successfully backed up a DVD-9 to a DL (and what software did you use)?
reading the post...probably used nero 6.3.1.15