What is "create layer break position"? - Imgburn

[Brent.M]

Hello,

I have just converted a .mkv to DVD format with FAVC. It is now ready to be burned on a DVD9 with Imgburn, it is asking of this but I don't understand what it is:



What should I do?

[VegasBud]

Brent.M,

The layer break is where the data starts being written to the second layer of the disk. ImgBurn is asking you where you want to put the layer break.

Of the choices listed, the third one down would be the best in terms of keeping the data as far as possible from the more error-prone outer edge of the disk (approximately equal amounts of data on each of the two layers, with the least amount of padding).

However, since there is always at least a small pause as the player switches layers, you should select a point where there is the least motion, preferably involving a fade to black area of the video. That minimizes, or completely hides the pause at the layer break.

If you click on one of the listed choices, and then the "Preview Selected Cell" button at the bottom of the window, a dialog box will pop up that shows you the video at that location. By viewing each of the choices, you can envision how suitable that location would be.

After checking the available layer break candidates, select the best one. If two (or more) would give similiar results, go with the choice that gives the most compact storage on the disk...in this case the third one in the list is best, followed by the fourth, the second, the fifth, and finally the first.

[Brent.M]

I tried previewing the cells but got this:

The file specified in the 'ImgBurnPreview File Name' option within the settings does not exist.

I took your advice and chose the third one down.

Slightly embarrassing question but how do you know that is the centre of the disk? Because the third, or the one in middle of the list is always the centre?


Thank you for your elaborate response.

[VegasBud]

Brent.M,

The error message you're getting seems to be saying it can't find the ImgBurnPreview program. In the ImgBurn menus, click Tools | Settings. In the dialog box that pops up, on the "General" tab, in the bottom right there is a section that says "ImgBurnPreview File Name". The contents of that box should be the full path to the preview program. On my computer, it's C:\Program Files\ImgBurn\ImgBurnPreview.exe. You can click the folder icon to the right of that box, and a "file open" dialog box should pop up. Go to wherever ImgBurn is installed, and double click "ImgBurnPreview.exe". Hopefully that will fix the preview problem, which should be high on your agenda. Previewing is the only way to pick the smoothest transition point to place the layer break...which is a primary consideration in choosing the best layer break.

As to how I arrived at the ranking of the choices by compactness, I'll explain, but if if it starts hurting your head, let it go for now, use only the preview(s) to select the layer break, and come back to this thread later when you are ready to try this next part again.

The following only refers to the disk you are showing above. You would have to use a similiar procedure for any other disk.

The third potential layer break listed is 50/50 in the "%" column. That means about 50% will be on the first layer, and 50% on the second layer. The "Padding" column shows only 12 blocks/sectors were added to slide that point into the layer break window. In the "LBA" column for that entry, the unshifted start of that spot is 1776884 blocks/sectors, or 3,639,058,432 bytes into your material, which means the size of the entire material is about 7,278,116,864 bytes (or at least that's the "close enough" number we'll use in our calculations).

For each of the potential layer breaks in the list, you can find out the "ballpark" number of bytes in the first layer (always the largest) by multiplying the first % number in the "%" column by the size of the material, and adding the padding bytes (2048 per block).

Doing that, we get the following:
selection #1 = (7,278,116,864*.5)+(572391*2048)=4,811,315,200 bytes
selection #2 = (7,278,116,864*.5)+(272624*2048)=4,197,392,384 bytes
selection #3 = (7,278,116,864*.5)+(12*2048)=3,639,083,008 bytes
selection #4 = (7,278,116,864*.55)+(14*2048)=4,002,992,947 bytes
selection #5 = (7,278,116,864*.59)+(9*2048)=4,294,107,382 bytes

Sorting by size, smallest first, we get:
selection #3 at 3,639,083,008 bytes
selection #4 at 4,002,992,947 bytes
selection #2 at 4,197,392,384 bytes
selection #5 at 4,294,107,382 bytes
selection #1 at 4,811,315,200 bytes

...which is the order I recommended based only on compactness.

Once again, how a layer break choice looks in the preview tells you how seamless the viewing experience will be when the player encounters the layer break, and transitions to reading from the second layer. The more compact the data is on the disk, the more reliable the farthest out part of the data is. It's up to you how you place your priorities. Personally, I always go with viewing experience first, with reliability a secondary consideration.

[LIGHTNING UK!]

It's easier to just multiply the value in the 'LBA' column by 2048 to get the number of bytes in the first layer. (if there's an '->' you use the number after it)

I'm not really sure where that comes in useful though!

[VegasBud]

It's easier to just multiply the value in the 'LBA' column by 2048 to get the number of bytes in the first layer.

In all things ImgBurn related, I'll always go with LIGHTNING UK!'s advice, which completely eliminates the need for any calculations at all. Since the purpose is to determine the relative distance from the hub for each possible layer break choice (the approximate number of bytes in the first layer was just what I was using for a measuring stick), it's much easier to just use the "padding added" "LBA" column values (the ones after the "->", if there is one) directly. Sorting the possible choices by that method, the correct order in this case would be 3, 2, 4, 1, 5 (not 3, 4, 2, 5, 1 as I said earlier). I apologize for providing inaccurate information.

I'm not really sure where that comes in useful though!

In joint studies by NIST, OSTA, and DVDA, they found that most errors occur in the outer 10% of a disk, most significantly in the outer 5% of the disk. They call it the "edge effect". By not putting data in the "edge" area, compatibility was 98%, versus 91% if data was placed in the "edge" area. Given that compatibility on a wide variety of players is a major concern for dvd-video disks, I incorporated their finding into my burning technique when I started burning DL.

With SL, the only way to draw the data back from the edge (without dumping content) is to use more compression, with a reduction in quality. With DL, however, the data furthest from the hub (the layer break area) differs from one layer break choice to the next. In this particular case (going with the extremes), selecting the third choice over the fifth puts the farthest out part of the data nearly 300,000 blocks (slightly less than 600 MB) closer to the hub. That would bring the layer break from deep in the "edge" area, all the way out of the "edge" area. If the two layer break choices would have similiar impact on viewing, it makes sense to go with the one that would be more compatible.

As I mentioned above, I almost always go with the most visually pleasing layer break choice, but the decision is tempered by how "compact" (for lack of a better word) the data placement is on the disk.

[Brent.M]

Saying thanks again for the extremly elaborate responses. Even though most of what you guys said is utter jargon to me, I will give this thread a good read before I do my next conversion.

[lordsmurf]

The "edge effect" is more of a statement of craptastic blank media than anything else.

[VegasBud]

The "edge effect" is more of a statement of craptastic blank media than anything else.

Everyone has their own media quality scale, but personally I would reserve the use of the word "craptastic" (if I used that term at all) to apply to media that skips/fails before 50%, and maybe use the word "bad" to apply to media that skips/fails from 51% to 90% of capacity. It's all how you look at it, I guess. "Craptastic" is certainly much more descriptive, colorful, and entertaining than just using a phrase like "really bad".

I think it is worth noting that in the OSTA DVD Compatibility Committee report I mentioned, using the same burners, readers, and media...changing only whether data was written to the outer 10% or not, compatibility went from 91% to 98%.

In a world filled with players that have widely varying capabilities...each player having a different amount of age/use related "slop" in their mechanisms...I would rather have the added compatibility for a cushion. Considering the "edge effect" when selecting a layer break takes little time, doesn't cost anything, doesn't degrade the video/audio quality in any way, and may make the difference between a disk that has trouble at the layer break area, and one that doesn't. That sounds good to me, which is why it's part of my DL burning technique.