Locking LB without a warning

[tartak]

I'm not sure it really qualifies as a bug, but it was sure very unexpected and disconcerting to me when I've run into this problem.

 

I got used to writing DVD-Video from VIDEO_TS. In this mode, before ImgBurn actually starts writing anything, it gives a fair warning, with all the information (label, options and such). This time however, while testing some things, I decided to write from a dvd-9 iso image (no mds). ImgBurn gave me the expected dialog for LB selection. At this point I noticed a button that I had not seen in the similar dialog in the file mode - "Revert to VOBU/ECC search". Intrigued, I clicked on the button. All of a sudden, ImgBurn spins the disk up, and then sits there for a while, seemingly doing nothing. I'm getting concerned and click on Abort. Everything looks fine, the disk is still shown as Empty and available to burn. But there is no position for LB anymore. The reason is obvious - the capacity of the disk is slightly diminished relative to a real blank, and it shows "Changeable: No". So, ImgBurn actually has permanently set the LB (I assume it's in the lead-in, am I right?), without a fair warning, after clicking on a button that does not say anything about burning.

 

PS. The disk was Verbatim +R DL MKM-001

Edited May 12, 2009 by tartak

[LIGHTNING UK!]

The LB box pops up as ImgBurn is about to set the layer break. The layer break has nothing to do with the LeadIn.

 

The setting of the LB position is its own unique command.

 

The LeadIn gets written by the drive once the first 'Write' command has been received.

 

So all in all, there is no 'bug' here, just user error I'm afraid.

[tartak]

Well, as I said, it may be by design. All I'm saying - the Build to device mode is inconsistent in this regard to Write mode. I don't know where and what ImgBurn wrote, but it has. And without a warning, after clicking on a button that the user can't anticipate would initiate any writing to the disk.

 

I sacrificed one more disk and reproduced the "situation" (well, the disk is still empty, I can use it, just not for DVD-Video).

Here is the info before I did anything:

TSSTcorp CDDVDW SH-S203N SB01 (ATA)

Current Profile: DVD+R DL

 

Disc Information:

Status: Empty

Erasable: No

Free Sectors: 4,173,824

Free Space: 8,547,991,552 bytes

Free Time: 927:32:74 (MM:SS:FF)

Supported Write Speeds: 2.4x, 4x

 

DVD

Edited May 12, 2009 by tartak

[LIGHTNING UK!]

So let me get this straight, you clicked the big 'Write' button and now you're saying the user couldn't possibly anticipate ImgBurn would be doing anything to the disc?

 

No offence but, yeah ok!

 

Setting the layer break position is nothing to do with writing data to it. It's perfectly acceptable for a disc to be empty and have a modified layer break.

 

In Build mode, the layer break info has to be figured out so the file system etc can be put together.

 

In Write mode that simply doesn't apply.

 

As Build mode only piggybacks Write mode when the 'Output' is set to 'Device', the LB stuff (where changes to the disc happen) is still being run, just it already has the info and so doesn't need to prompt a second time. Either way, the command sent to the drive to manipulate the physical layer break is still sent at exactly the same time.

 

With some drives, the LB isn't actually moved properly until a write command is sent - in which case you can just eject the disc / reinsert it and it'll look like it's brand new.

 

Now you know how it all works I trust you won't have any more issues with it.

[tartak]

Well, I did click on the big button, yeah

So, I see your point.

It's just that ImgBurn is so intuitive and consistent, and I got spoiled. In the other situations, it starts doing something to the disk only immediately after a click on the Big Button, or after a nice summary dialog, where you'd have OK and Cancel buttons and you need to click OK. That's the only reason I did not expect a physical change in the disk after a click on something other than the Big Write Button or OK button. Seems a bit inconsistent to me, but it could be just me.

 

I'm really curious, where the LB modification resides on the disk? My blank disk is physically changed, I ejected it and put back to verify. You said it's not in leadin zones; so it means one can modify the data zone and the disk is still empty?

 

Oh, and what does that "Revert to VOBU/ECC search" do? I could not find any mention in the guides.

ADDED: I've found the answer to the last question in this post

[LIGHTNING UK!]

Sorry, I don't know exactly what the drive does when a program sends the command to set the LB position - I don't care too much about the inner workings as it's not a level of operation I have to concern myself with.

 

It obviously writes the position to some special area on the disc but it's not in the 'user data' section and hence doesn't change the discs status.

 

Look up 'SEND DISC STRUCTURE' in the MMC specs if you fancy having more of a read.

[blutach]

Use this rule for burning DVD Video - do not use ECC/VOBU method. Reauthor your disc (if necessary) so it is compliant. I mean, why burn a non-compliant DVD that won't play on all players?

 

Regards

[tartak]

LUK!

Thanks for the pointer, I do fancy low-level stuff. Looked it up in MMC-5 r.4 (t10 wants money for it, but it's free on t11 site). The write-up for SEND DISC STRUCTURE with Format 20h does not really say where the info is written, but READ DISC STRUCTURE 20h (p. 445) clearly says that L0 Data Area Capacity is written into Control Data Zone in Lead-in. For one, you were wrong, my god of dvd burning is only human!

 

BTW, the overview on p. 101 says that this user selected L0 capacity is written when the session is closed:

This address is written into the Control Data Zone (in the lead-in) when the first session is closed.

Consequently, if the Host wishes to select an address other than that supplied in the ADIP, that selection shall

be made prior to closing the first session.

Does not this contradict to ImgBurn setting LB before it even starts writing the session?

 

blutach,

I have a great deal of deficiencies, but I would not even imagine using ECC/VOBU method. I was simply testing in some dark corners, in search for an answer to some other question (about the real reasons for "end of the world" situation).

[LIGHTNING UK!]

Hey, I just said it wasn't written as part of the LeadIn or whatever happens when ImgBurn sends its first 'Write' command. Its physical location on the disc is unknown to me and I made that perfectly clear in my last post

 

I also said that some drives don't actually make any physical changes to the media (even LB ones) until the user data area gets burnt... remember, I said you might find it's still changeable if you eject + reinsert the disc?

[tartak]

You did, I remember. It's just I thought you actually have control over when this command (SEND DISC STRUCTURE with Format 20h) gets sent and executed. My drive made the LB non-changeable before any user data was written..

[LIGHTNING UK!]

No, it has to be sent before the burn starts.