If you want to ensure your DVD-9 will be within the DVD specification and want precise control over the layer break and assure general compatibility with set-top DVD players, then the only sure-fire way to do this is with submiting DDPs on DLTs or DDPs on DVDs to the replicator.


General replicator policy holds no responsibility for any manufacturers recordable media masters submitted on DVD-DL media, and the authoring application's Layer Break placement. The absolute best method for supplying a DVD-9 master to your replicator is on 2 DLT tapes (1 tape per layer) or DDPs on 2 DVD-R 5s. DLT tapes contain DDP (Data Description Protocol) files, a file format utilized by disc manufacturers to make a glass master. The DDP contains all the assets and information about the DVD including region codes, copy protection, and layer break information -- something a DVD-DL will not contain.

I don't have DVDA Pro, but the manual has relevant information. Search for 'title order' and 'master'.

Thanks for the info TOG62 - searching in the DVDA help did not bring it up, but skimming through the .pdf manual did (page 38): so simple, yet I missed the option somehow: File>Order Titles... I wonder why right clicking a media asset doesn't open the same option?

The mastering info DVDA provides is helpful relative to defining some of the mastering parameters, but it doesn't really give me a complete answer.

It seems the best way to find solutions with this program is to search, ask (if needed), ponder, then experiment. Again your simple but practical suggestion has lead me to a solution in locating a non-intuitive function of DVDA - thanks again. I seriously need to start reading manuals more!

I've also been testing and experimenting with the layer placement of video assets and I've made what I believe to be an important discovery.

I will share what I have come across - the next guy may find it useful...or not should I dare to commit yet more egregious sins in my explanation.

When I spin the DVD+DL disc in my set top player, the disparity in seek times from any link (regardless of hierarchical order - links and/or media assets) is imperceptible in practical terms (no need for a stopwatch). When I run the disc in a brand new portable player however, I discovered that links to assets in the upper 2/3 of the hierarchy load slightly faster than those further down. This is also evidenced by the audible mechanical groans the player makes when seeking: 4 groans for the upper assets / 6 for the lower. This is a clear indication that the player's laser is switching layers looking for the assets stored on layer 2 - adding to the seek time (exactly what I want to avoid as much as possible and the reason for my original query). While the difference in seek times is not earth-shattering, I think it best to restructure my asset pool, squeezing as many video assets onto layer 1 as possible. I should add that DVD+DL can be tough on some players (from what I've read).

Now that I have regained control over "title order" (as the DVDA manual specifies it!) I'll restructure my hierarchy, squeezing as many video assets onto layer 1 as I can. I'll have to keep my eye on the amount of disc space used as I go and I'll place the lengthiest clips at the bottom of the list { (4) 5-8 minute-long routines, and the introduction/program use chapter - approx. 12 mins. long}. If necessary, I'll also add some of the loops that I feel will be watched the least (simplest exercise movements most end users won't need to watch repeatedly to learn) at the bottom. According to my current file size calculations, all of my loops and 1-4 minute segments should accrue to 4.1GB and should all fit on layer 1 - I tink. To be safe (as mentioned above) I'll move what I feel are the least popular loop clips to the bottom of the heap in company of the bigger files - just to play it safe. I will burn a couple of DL discs and see if I can discern a difference having the "unpopular" loops at the bottom verses ostensibly stored in layer 1.

My thinking is that the viewer will find the slightly longer seek times the layer 2 assets impose less objectionable if the clips themselves are longer in duration and /or will not be viewed in a back to back fashion - such as the (58) 8-20 second-long loops or the (33) 1-4 minute-long segments.

VITG - your suggestions about DLT are valid, but not practical for my project at this time. I don't own a DLT drive; they're pretty expensive and hard to find - not to mention I'll probably never use the thing a second time after mastering this project. If the product itself takes off I'll explore DLT after my first 1000 discs are out the door - then money will no longer be a concern. In this project, it's not the $1000.00+ for the DLT tape drive that's the issue, it's the $100,000 that was spent before it!!

I may however look further into the DDP on 2 disc approach if I find any meaningful advantage to that method as I learn more about it. From what I've read so far, DVD+DL (as a mastering medium) by default permits all region codes (fine by me) but does not permit layer break specification or CSS. I'm not concerned at this time about CSS (if this disc were copied, it serves no purpose without the accompanying tangible device anyway) or region codes - the only possible concern is specifying the layer break. I'll have to find out how precisely DVDA allows me to designate the break. If it is only as precise as bumping ahead to the next available sector past the end of the closest chapter, I honestly don't see the advantage of the 2 DDP discs for my project. I'll have to experiment further, unless someone is willing to share that info.

My primary objective now is to finish this project in the most painless way possible so I may release the first 1000 discs for test marketing. I've also entertained having a DVD 10 replicated; while this disallows artwork on the disc itself, it would theoretically spare me from potential compatibility issues with DVD 9 for a wide release. I realize that the viewer has to flip the disc, but this segmented project would be just fine in that instance - intro and segments on side 1 / loops and routines on side 2. Just a thought...

Thanks all.
Steve M.

The layer break point is the place where a dual layer DVD switches from the first layer (layer 0) to the second layer (layer 1). DVDs are laid out in sectors (each sector contains 2048 bytes of content), starting with sector 0 (zero). The break point is the sector address of the first sector on the second layer. This number also represents the number of sectors on layer 0.

It is important to keep in mind that although your DVD-9 title has 2 layers, it is not 2 discs. The DVD player software will see only one disc, with one ISO/UDF file system, and one set of files. The DVD drive that plays back the disc will have to know where the layer break occurs, so it can refocus to layer 1 when it reaches the break point, or whenever any content is requested that is beyond the break point. The drive will read the layer break point in the control data, a small file at the start of the disc (in the lead-in).

The position of the layer break is important. It can also be called the layer split point, because it splits the contents of the disc into 2 layers. So, the position of the layer break determines how the contents of the whole disc is divided into 2, and how much content ends up on each layer. A dual layer DVD can only hold about 4 Gigabytes of data on each layer. If the total size of the DVD is 7 Gigabytes, for instance, and the layer break was set too far from the halfway point, one layer might end up with more data than the disc can hold. You must have software that checks the layer break point that you enter, to make sure that it doesn't cause this problem.

At this time, all dual layer recordable DVDs are oriented with Opposite Track Path. This means that the first layer (0) is recorded in a spiral track from the inside to the outside of the disc, and the second layer (1) is recorded in a spiral track from the outside (at the same diameter where the first layer finished recording), back towards the inside of the disc. For all Opposite Track Path DVDs, the layer break point must be at a sector address that is at least halfway through the total number of sectors. This insures that layer 0 is larger than layer 1. If layer 0 was not larger than layer 1, the disc would run out of room when it records layer 1, since it starts at the end of layer 0 and records back to the inside.

DVDs are encoded with a sophisticated scheme that scrambles groups of 16 sectors, in order to minimize the visibility of any errors that occur during playback. These groups are called ECC blocks (Error Checking and Correction). The layer break must occur at the start of a new ECC block, so that an ECC block is not written on 2 separate layers. So, the layer break must occur at a sector address that is evenly divisible by 16.

When the DVD is being played back, it will reach the end of layer 0 at the layer break point. The player will refocus the laser to layer 1, which is behind layer 0. While this layer transition usually takes only a fraction of a second, the player's data buffer may run dry during this time, and the video and audio will appear to freeze for a moment or two. This is normal, but DVDs are designed to try to minimize this problem.

DVD Video programs consist of up to 99 Video Title Sets (a VTS) each with a possible 99 titles. The audio and video content of each program is arranged in Video Objects (VOBs). Each Video Object is broken up into files that are 1 Gigabyte or less, but really the video object itself can be as large as 8 Gigabytes. DVD Video discs have an Information file (IFO file) for each Video Title Set. A spare backup (BUP) copy of this information file is also stored on the disc, in case the information file is unreadable.

The content within each VOB is organized into cells. Each cell is a segment of video (or a still picture), along with the audio. In order for the video decoder on a DVD player to function correctly, the layer break for DVD Video titles must occur at the start of a cell. To find the location of cells, you can use a tool called IFOEdit.