Newbie problem with DVD-Video burning concepts

vbimport

#1

Hi all,

I’ve been tasked with a feasability study for a (potential) new project, but after two weeks of fruitless searching I have to admit that my somewhat moderate brainpower is not up to the task…

The supposed project is the creation of an “evolving” DVD, to be written on an incremental basis on a users PC (which may be running Windows 2K/XP or Linux) without access to DVD Authoring software. The basis of this is that a user would be given a blank DVD+/-RW on to which would be written some initial DVD-Video content. This would then be regularly added to to build up a more complete DVD by means of downloading and burning additional content. This DVD is to be playable at all times in a commercially available DVD Player.

If I understand correctly, the VIDEO_TS.IFO is responsible for managing all titles/chapters in the Video content, and therefore any update which added new content (a new VTS_XX_XX.VOB/VTS_XX_XX.IFO?) would have to also overwrite/modify the initial VIDEO_TS.IFO. Is this assumption correct? I also understand that the VIDEO_TS.IFO has to be the first file on a DVD-Video as commercial DVD-Players do not read filesystems but read pointers to offsets of content which are recorded in this file. Is this also correct?

If this is the case, then presumably the initial content would have to include a VIDEO_TS.IFO large enough to be able to cope with all possible future updates. Or could it include pointers to successive IFOs? Even if this was the case, presumably some existing content would have to be overwritten at some point even if only to update pointers?

If I am correct in my assumptions above, the my problem is not just adding incremental content to a DVD+/-RW, but overwriting existing content. Is this possible? Are there tools available that would allow me to do this or would code have to be written to accomplish this?

My apologies if these are stupid questions or if the answer is recorded elsewhere. I have googled and searched on this forum without obvious solution.

Any hints gratefully accepted!

Regards

Julian


#2

If I understand correctly, the VIDEO_TS.IFO is responsible for managing all titles/chapters in the Video content, and therefore any update which added new content (a new VTS_XX_XX.VOB/VTS_XX_XX.IFO?) would have to also overwrite/modify the initial VIDEO_TS.IFO. Is this assumption correct? I also understand that the VIDEO_TS.IFO has to be the first file on a DVD-Video as commercial DVD-Players do not read filesystems but read pointers to offsets of content which are recorded in this file. Is this also correct?
This is correct. The best way to look at it is like .bin and .cue. The cue simply states what the data is how its read, and where to read it. The problem you may have is editing the .ifo, unlike a cue you cant open a readable source using say note/wordpad. Not too mention how complicated the data is.

Are there tools available that would allow me to do this or would code have to be written to accomplish this?
You could try ifoedit. It may be up to the task.


#3

Thanks Pollushon,

You could try ifoedit. It may be up to the task.

It’s not quite the problem with the authoring as such, more a problem of how I would update the content on the DVD…

I assume that to reflect additional content (e.g. a new VOB) the VIDEO_TS.IFO would have to be updated, and therefore I would not only have to append the new VOB to the compilation but also overwrite the original VIDEO_TS.IFO. Unless there is some clever way of setting pointers that would allow additional content to be seen or chained to without changing the initial IFO.

I am struggling to find any software which would allow me to overwrite the original VIDEO_TS.IFO on the DVD with a new one without effectively sucking off the original content and remastering the whole thing!

Regards

Svhog


#4

I could be wrong but my video editing software that came with my burner, Ulead Video Studio, has an option to create a DVD-VR. Reading the help files does lead me to say it is exactly what you are looking for, but at any time during the creation process you can record the progress to disc. I don’t know if this is what you need, but I hope this helps.


#5

I assume that to reflect additional content (e.g. a new VOB) the VIDEO_TS.IFO would have to be updated, and therefore I would not only have to append the new VOB to the compilation but also overwrite the original VIDEO_TS.IFO. Unless there is some clever way of setting pointers that would allow additional content to be seen or chained to without changing the initial IFO.

Tis True, but if you find a way to remaster the VOB, Ifo edit will allow you to create a new IFO to suit.(not on the source level though) So I guess working out how to remaster the VOB is what we need to work out. Here goes Google:)
OK just realised what you said. Adding Vobs is what your saying am I correct. In this case its easy. If you add a new Vob that you wish to put into the project seamlessly, simply move the original ifo away, and using ifo edit create a new one that includes the original vob and the new one.


#6

Pollushon,

OK just realised what you said. Adding Vobs is what your saying am I correct. In this case its easy. If you add a new Vob that you wish to put into the project seamlessly, simply move the original ifo away, and using ifo edit create a new one that includes the original vob and the new one.

Not quite…

I would be given a new VOB and a replacement VIDEO_TS.IFO which includes title/chapter information for the original VOB and the new one…

My problem lies in overwriting the original VIDEO_TS.IFO on the DVD+RW and adding the VOB without extracting the content from the DVD+RW and rewriting it all.

Pacmac,

Yeah, I’ve got the ability to do +/-VR disks with Nero too. But I need to find a way purely to write/append/overwrite data I will be given for my DVD to the DVD+RW… i.e. someone else authors the content and passes it on to me to be appended/overwritten on the DVD+RW.

This is where I’m struggling. DVD+RW is supposed to be Random Access writeable Media, no? But nothing I have seen to date allows me to find a way of overwriting just a specific portion of the DVD without affecting subsequent data.

For example, say the original VIDEO_TS.IFO was created at (guess) 96KB with info for original content. I then get new VOB to be appended and new VIDEO_TS.IFO (still at 96KB) but with updated Video Manager information to replace the original with. So I want to append the VOB to the DVD and overwrite the VIDEO_TS.IFO as I understand this has to be the first physical file to exist on the DVD for it to work in standalone DVD Players…

Sorry if I’m not making things very clear here guys, but thanks for all the help so far!

Svhog


#7

This is where I’m struggling. DVD+RW is supposed to be Random Access writeable Media, no? But nothing I have seen to date allows me to find a way of overwriting just a specific portion of the DVD without affecting subsequent data.
Your thinking of DVD-RAM, which is just a big floppy disc. Nero INCD or some form of Packet writing may help you acheive this.