I finally burned my first dual layer ISO file that didn't have a .MDS file associated. The image was created by CloneDVD.
I used the ISO tool to see what were acceptable layer break points and ImgBurn only indicated that cell 25 was acceptable, though the previous cell would have been preferable for me, as that was the beginning of a scene change with fade out. Cell 25 was during a scene. Judging from the final burned disc which put 57.72% of the sectors in layer 0 (42.28%) and the short time between chapters (avg 5 minutes) it should have been possible to put the flag on cell 24.
However, ImgBurn modified the ISO file to insert the flag in the VTS_01_0.IFO and burned fine, and compared fine, so that is not the bug.
The bug is that ImgBurn did not make the same change in VTS_01_0.BUP, which is supposed to be indentical to VTS_01_0.IFO and used in case VTS_01_0.IFO cannot be read for some reason. I recommend that this change be implemented in future releases.
I was alerted to this difference by creating CRCs of the files on the original image mounted as a drive and also for the modified image mounted as a drive. By doing this, I found that the CRCs of TWO files differed between the original and modified images:
VTS_01_0.IFO (as desired with the flag inserted, but VTS_01_0.BUP remained the same as original)
AND
VTS_01_3.VOB
Now, why did ImgBurn modify the VTS_01_3.VOB file? The video where the layer break flag corresponds to is actually contained within VTS_01_4.VOB, but even then there is no need to modify a VOB at all when setting a layer break flag - correct?
Here is the file compare log between the .SFV CRC files for both images:
***** Files_Image_Orig.sfv
VTS_01_0.BUP 2A4C6EE0
VTS_01_0.IFO 2A4C6EE0
VTS_01_0.VOB C7EBDAE0
***** FILES_IMAGE.SFV
VTS_01_0.BUP 2A4C6EE0
VTS_01_0.IFO B7667004
VTS_01_0.VOB C7EBDAE0
*****
***** Files_Image_Orig.sfv
VTS_01_2.VOB 145425D8
VTS_01_3.VOB 0EB4222A
VTS_01_4.VOB ABF4D22F
***** FILES_IMAGE.SFV
VTS_01_2.VOB 145425D8
VTS_01_3.VOB C62DF9EB
VTS_01_4.VOB ABF4D22F
*****
So, is ImgBurn actually corrupting my video files when it modifies the .ISO image?
I've attached zip files with the IFO and BUP files from both the original and modified images. However I cannot of course include the VOB file, though I would be curious to find out what change was made to it...
Thanks,
fordman
EDIT: I did some more research and found the the ImgBurn modified ISO had changed the VTS_01_3.VOB quite dramatically! Beginning at address 08E15000 the VTS_01_03.VOB had large sequences of bytes changed - mostly from actually values to 00 (null)! This is not good, so I will likely extract the ISO files and burn with a program like RecordNow Deluxe 7.3 to ensure I have an uncorrupted copy. For example, here is an example of one such range, and I even truncated this one for brevity's sake (The first column is the hex address, the second is the byte value in the original VOB at the address, and the third column is the ImgBurn modified value):
08E16814: 81 00
08E16815: 00 01
08E16817: 0B 2D
08E16818: 30 00
08E16819: E0 01
08E1681A: 33 00
08E1681B: 8C 2E
08E1681C: 1F 00
08E1681D: 20 01
08E1681E: 69 00
08E1681F: 2B 2F
08E16820: 23 00
08E16821: 16 00
08E16822: DC 00
08E16823: 09 00
08E16824: 27 00
08E16825: EC 00
08E16826: AE 00
08E16827: 07 00
08E16828: 55 00
08E16829: 62 00
08E1682A: 33 00
08E1682B: 37 00
08E1682C: 56 00
08E1682D: 4E 00
08E1682E: 51 00
08E1682F: FC 00
08E16830: 3C 00
08E16831: 79 00
08E16832: CD 00
08E16833: 06 00
08E16834: E6 00
08E16835: 0D 00
08E16836: 42 00
08E16837: 5F 00
08E16838: 67 00
08E16839: 5A 00
08E1683A: BE 00
08E1683B: 55 00
08E1683C: 9F 00
08E1683D: 5D 00
08E1683E: 41 00
ModdedImage_VTS.zip
OrigImage_VTS.zip