Errors with backup from undecrypted disc image

[kaysee]

I am testing the recovery of imperfect discs and working with optical disc images, but have not gotten MakeMKV to work with disc images.

For example, using a good and new blu-ray, I created an undecrypted copy of it using ddrescue. No errors. The optical drive is LibreDrive enabled, and I first ran MakeMKV to set up the drive for running ddrescue.

The copy via ddrescue yields a disc image that can be mounted in Windows. I can copy the BDMV folder from this and use it together with the other files from the original optical disc that are backed up using MakeMKV "backup" operation without decryption; then proceed with selecting titles and creating MKV files.

The problem I encounter is in using the undecrypted image for making a decrypted backup. MakeMKV sees the virtual drive. However, when I attempt a backup from the disc image, with decryption, I get a series of errors:

Code: Select all

Using direct disc access mode
Loaded content hash table, will verify integrity of M2TS files.
Error 'OS error - The I/O device reported an I/O error' occurred while issuing SCSI command A30..0020..03F to device 'SPTI:\Device\CdRom0'
...
(several similar errors)
...
occasional errors like:
Error 'Scsi error - ILLEGAL REQUEST:CANNOT READ MEDIUM - INCOMPATIBLE FORMAT' occurred while issuing SCSI command AD010..080002400 to device 'SPTI:\Device\CdRom0'
...
Can't read AACS VID from disc - most likely current AACS host certificate is revoked by your drive
Error 'Internal error - Operation was cancelled (140)' occurred while reading 'DVD-ROM Msft Virtual DVD-ROM 1.0' at offset '5308416'
(several similar errors)
...
Saved AACS dump file as C:\*****.tgz
Failed to open disc

[MartyMcNuts]

I am testing the recovery of imperfect discs and working with optical disc images, but have not gotten MakeMKV to work with disc images.

For example, using a good and new blu-ray, I created an undecrypted copy of it using ddrescue. No errors. The optical drive is LibreDrive enabled, and I first ran MakeMKV to set up the drive for running ddrescue.

The copy via ddrescue yields a disc image that can be mounted in Windows. I can copy the BDMV folder from this and use it together with the other files from the original opcitcal disc that are backed up using MakeMKV "backup" operation without decryption; then proceed with selecting titles and creating MKV files.

The problem I encounter is in using the undecrypted image for making a decrypted backup. MakeMKV sees the virtual drive. However, when I attempt a backup from the disc image, with decryption, I get a series of errors:

Code: Select all

Using direct disc access mode
Loaded content hash table, will verify integrity of M2TS files.
Error 'OS error - The I/O device reported an I/O error' occurred while issuing SCSI command A30..0020..03F to device 'SPTI:\Device\CdRom0'
...
(several similar errors)
...
occasional errors like:
Error 'Scsi error - ILLEGAL REQUEST:CANNOT READ MEDIUM - INCOMPATIBLE FORMAT' occurred while issuing SCSI command AD010..080002400 to device 'SPTI:\Device\CdRom0'
...
Can't read AACS VID from disc - most likely current AACS host certificate is revoked by your drive
Error 'Internal error - Operation was cancelled (140)' occurred while reading 'DVD-ROM Msft Virtual DVD-ROM 1.0' at offset '5308416'
(several similar errors)
...
Saved AACS dump file as C:\*****.tgz
Failed to open disc

Disc images do not contain the Volume id, which is stored in a non copyable area of the disc.

If you have the disc, just use it to create the decrypted backup.

[kaysee]

If you have the disc, just use it to create the decrypted backup.

In my message I began with, "I am testing the recovery of imperfect discs...." I did mention ddrescue. That means a direct copy that does not begin with using MakeMKV to decrypt.

How are people using disc images (often described as ISOs) that are encrypted, then opening them in MakeMKV to backup with decryption?

[MartyMcNuts]

If you have the disc, just use it to create the decrypted backup.

In my message I began with, "I am testing the recovery of imperfect discs...." I did mention ddrescue. That means a direct copy that does not begin with using MakeMKV to decrypt.

How are people using disc images (often described as ISOs) that are encrypted, then opening them in MakeMKV to backup with decryption?

What is missing is the discatt.dat file which will be created a few moments after starting an encrypted backup in MakeMKV. This file contains the Volume id. Just start an encrypted backup then stop it once this file is created.

I don't know if adding it to an ISO will help but it does when added to an encrypted folder backup. It may work with an ISO if left unmounted and opened as a folder.

[kaysee]

That specific part of the workflow, making use of discatt.dat for a full decrypted backup from a disc image, is the ambiguous part.

I do have the discatt.dat file, and am familiar with using the partial, undecrypted backup from MakeMKV together with the full BDMV copied from elsewhere, but only to select titles and generate MKV files sourced from folders and files. But getting MakeMKV to open either a disc image file or a mounted disc image (appearing as a virtual optical drive), and make use of discatt.dat to do a full backup with decryption, is where things fall apart.

(Many people have posted about this question and the conversation usually gets derailed regarding cleaning the blu-ray properly, using a better drive, etc. -- not relevant here.)

[MartyMcNuts]

That specific part of the workflow, making use of discatt.dat for a full decrypted backup from a disc image, is the ambiguous part.

I do have the discatt.dat file, and am familiar with using the partial, undecrypted backup from MakeMKV together with the full BDMV copied from elsewhere, but only to select titles and generate MKV files sourced from folders and files. But getting MakeMKV to open either a disc image file or a mounted disc image (appearing as a virtual optical drive), and make use of discatt.dat to do a full backup with decryption, is where things fall apart.

(Many people have posted about this question and the conversation usually gets derailed regarding cleaning the blu-ray properly, using a better drive, etc. -- not relevant here.)

If you can add the discatt.dat file to the ISO then MakeMKV should be able to open it via the index.bdmv file.

It’s easier to work with an encrypted folder backup rather than an ISO file as files can easily be added. Same when using ddrescue. Extract all of the files to a folder from however many copies of the disc you need to, add the discatt.dat file then open the index.bdmv file in MakeMKV.

[kaysee]

I do not see how to do a full backup using that approach.

I can extract anything from the blu-ray image (which is still encrypted, originally created via ddrescue) to files and folders. And can copy from/to that directory tree to include "discatt.dat".

The procedure usually discussed is to begin in MakeMKV an undecrypted backup through the point of saving all the non-media files, canceling while copying a .m2ts file; then copy the BDMV folder obtained elsewhere, undecrypted, into the initial incomplete backup that had been made with MakeMKV. At that point, in MakeMKV: "Open Files" the "discatt.dat" file. This leads to the selection of titles with the active button "Save selected titles".

Using those folders and files, in MakeMKV: instead "Open Files" the "BDMV\index.bdmv" file does the same thing: parses the files and goes to title selection with the active button "Save selected titles".

But the goal is not to select titles and convert to MKV files. It is to create a full decrypted backup. Comparable to clicking the "Backup" button with the decryption checkbox selected and operating on a physical blu-ray disc, to yield a decrypted bundle of folders/files.

I have not tried re-packing the encrypted disc image file into a new disc image with the addition of the "discatt.dat" file. In one of "mike admin"'s infrequent messages he actually mentioned that this would not work, because someone was trying to figure out what we are discussing -- and "mike admin" never clarified what would actually work.

So we are left with the unanswered question (asked many times over years): wouldn't a full nondecrypted copy of a blu-ray plus "discatt.dat" allow for converting to a full decrypted copy in some form (disc image or bundle of files)?

[MartyMcNuts]

I do not see how to do a full backup using that approach.

I can extract anything from the blu-ray image (which is still encrypted, originally created via ddrescue) to files and folders. And can copy from/to that directory tree to include "discatt.dat".

The procedure usually discussed is to begin in MakeMKV an undecrypted backup through the point of saving all the non-media files, canceling while copying a .m2ts file; then copy the BDMV folder obtained elsewhere, undecrypted, into the initial incomplete backup that had been made with MakeMKV. At that point, in MakeMKV: "Open Files" the "discatt.dat" file. This leads to the selection of titles with the active button "Save selected titles".

Using those folders and files, in MakeMKV: instead "Open Files" the "BDMV\index.bdmv" file does the same thing: parses the files and goes to title selection with the active button "Save selected titles".

But the goal is not to select titles and convert to MKV files. It is to create a full decrypted backup. Comparable to clicking the "Backup" button with the decryption checkbox selected and operating on a physical blu-ray disc, to yield a decrypted bundle of folders/files.

I have not tried re-packing the encrypted disc image file into a new disc image with the addition of the "discatt.dat" file. In one of "mike admin"'s infrequent messages he actually mentioned that this would not work, because someone was trying to figure out what we are discussing -- and "mike admin" never clarified what would actually work.

So we are left with the unanswered question (asked many times over years): wouldn't a full nondecrypted copy of a blu-ray plus "discatt.dat" allow for converting to a full decrypted copy in some form (disc image or bundle of files)?

I think you have answered it yourself already. No.

If you want to be 100% sure, try adding the discatt.dat to the ISO and test it.

As far as I was aware, MakeMKV's backup option only works with the original physical disc. You should be able to use the methods discussed to create the mkv file of the movie, though.

[kaysee]

Making a full backup with decryption of an undecrypted blu-ray image can be done. But getting MakeMKV to do it is ridiculously cumbersome, requiring extra steps in which complete copies need to be made. It should be much simpler, with fewer steps, and less re-copying of everything.

Starting with an undecrypted disc image, I created a new disc image that includes everything plus the addition of "discatt.dat". The new image has UDF version 2.5 file system.

In the root directory of the new image:

AACS\
BDMV\
CERTIFICATE\
discatt.dat

If the AACS directory is _not_ included, MakeMKV assumes the source is already decrypted and does not decrypt in the backup/decrypt operation. If the "discatt.dat" file is _not_ included, then MakeMKV will fail with lots of errors in the backup/decrypt operation.

Major missing feature in the software: MakeMKV does not have a way for the user simply to indicate a "discatt.dat" file to accompany the source files of the blu-ray -- an obvious thing to do that is needed. So "discatt.dat" has to be included in the source disc image with the rest of the standard blu-ray files to be used. However, when backing up and decrypting from this new disc image, MakeMKV will show the message 'File "/discatt.dat" was skipped' as if the user had made a mistake instead of working around/compensating for the software's behavior.