What's the best way to verify rip integrity?

[Zangmonkey]

When using "Rip To Image" and leaving all protections intact, how should I verify the integrity of the rip?

I found a few older threads about the integration of hash checks in AnyDVD but nothing definitive.

Today what I'm doing is ripping with AnyDVD HD, then opening the ISO with MakeMKV and checking for hash errors.

Is this appropriate or necessary to verify rip integrity? Is there a better way?

As an additional interesting note, if I then use the same ISO and have AnyDVD rip again, from it, to remove protections... Then MakeMKV hash checks still pass. This surprised me as I would have presumed that removing encryption would adulterate the files and make hash checks fail.

 

[DeepSpace]

As an additional interesting note, if I then use the same ISO and have AnyDVD rip again, from it, to remove protections... Then MakeMKV hash checks still pass.

That depends on what AnyDVD uses to create the hash. I would assume that it is smart enough to ignore protection specific things.
But since I never used it and haven't seen people talking about, I cannot help you, that guess aside.

 

[coopervid]

When using "Rip To Image" and leaving all protections intact, how should I verify the integrity of the rip?

I found a few older threads about the integration of hash checks in AnyDVD but nothing definitive.

Today what I'm doing is ripping with AnyDVD HD, then opening the ISO with MakeMKV and checking for hash errors.

Is this appropriate or necessary to verify rip integrity? Is there a better way?

As an additional interesting note, if I then use the same ISO and have AnyDVD rip again, from it, to remove protections... Then MakeMKV hash checks still pass. This surprised me as I would have presumed that removing encryption would adulterate the files and make hash checks fail.

There are several layers of encryption. If ripped to encrypted ISO the bus encryption has to be defeated first. So you rip it with a friendly drive or you need Makemkv installed to rip it with an official drive. If you just copy the folders or files no program can decrypt it later. Such ISOs can then later be decrypted by AnyDVD or Makemkv if the key is known. Bus encryption needs to be removed for anything that can be decrypted later.

 

[Zangmonkey]

There are several layers of encryption. If ripped to encrypted ISO the bus encryption has to be defeated first. So you rip it with a friendly drive or you need Makemkv installed to rip it with an official drive. If you just copy the folders or files no program can decrypt it later. Such ISOs can then later be decrypted by AnyDVD or Makemkv if the key is known. Bus encryption needs to be removed for anything that can be decrypted later.

I understand that but I'm not sure I'm making my question clear.


I can make rips in various ways.

I'm trying to make a 1:1 perfect ISO and then I want to verify the ISO I've created.

 

[coopervid]

Why? If there are no error messages just assume it's OK. Since the source is encrypted and the destination is not encrypted - compare to what?

 

[Zangmonkey]

Why? If there are no error messages just assume it's OK. Since the source is encrypted and the destination is not encrypted - compare to what?

I have a source UHD disc.
I want to create a bit perfect 1:1 iso from it. I do this using the "Keep Protection" option in AnyDVD HD


So now, given that ISO, I want to verify it.

In the "olden times" we used to do this by making multiple rips, then creating a hash of each of them and comparing them.

For comparison, tools like dbPowerAmp have AccurateRip, which compares my hash against other users submitted to a DB.

This isn't really available or needed for movies since they include hashes on the disc to check against.

My understanding is that MakeMKV checks these when it opens a disc.

So I deduced from that, if I want to verify the integrity of an ISO I make, that I can use MakeMKV to check it.


All I'm trying to do is verify my rip.
Is there a better way to do this?

 

[coopervid]

You are way too paranoid. Rip to disc and if you don't get an error message it's Ok. I have never seen an issue w/o an error message.

 

[Zangmonkey]

You are way too paranoid. Rip to disc and if you don't get an error message it's Ok. I have never seen an issue w/o an error message.

Yeah maybe. Drives have error correction behaviors, though. So I feel like there ought to be a way to check this.

With CDs it was very common to need to re-rip a track because its hash didn't match.


I am assuming that AnyDVD HD doesn't create its own new hashes when it rips with protection in place.... Or does maybe only CloneBD do this?

I figure I want to be certain about data at the archival point lest I find out months later that my rip was bad. This used to happen with DVDShrink a lot

 

[coopervid]

So. No warning but also no problem.

 

[WayToGo]

With CDs it was very common to need to re-rip a track because its hash didn't match.

Not technical on this stuff, but I think the process of ripping/copying audio CDs, is VERY different from ripping/copying DVD/BD/UHDs. The latter contain data -even if encrypted- which can be read and are compatible with, well, computers.

Audio CD's do not contain such data, only tracks. There's no actual file system and a form of conversion is required - hence the increased need for verification.

 

[ryley]

So now, given that ISO, I want to verify it.

I have used MakeMKV in the past to check rips for errors. AnyDVD can also verify protected ISO files if you mount and re-rip them, but the last I read on the matter indicated that verification was only done when ripping to a decrypted ISO/folder output (Link). This may have changed in the months since that post was made.

 

[Zangmonkey]

I have used MakeMKV in the past to check rips for errors. AnyDVD can also verify protected ISO files if you mount and re-rip them, but the last I read on the matter indicated that verification was only done when ripping to a decrypted ISO/folder output (Link). This may have changed in the months since that post was made.

So I conducted an experiment.

I made three rips:

One ISO with protection intact using AnyDVDHD "rip to image"

One ISO with protection removed using AnyDVDHD "rip to image"

One ISO with protection removed using AnyDVDHD to unlock the disc and CloneBD to create the ISO (totally uncompressed)


MakeMKV was able to open all three no problem, so their hashes must match.

But when I compared the actual file hashes the two decrypted ISOs we're different.


So which is bit perfect to the disc?


The link you posted actually seems to imply that "keep protection" ISOs are *not* necessarily valid even though no errors are raised

 

[DQ]

Personally speaking, anything I create/rip/backup etc I will play it to be sure it came out ok. Just a few moments here or there to see the video, hear the audio and make sure they line up ok. But that is just me.

 

[ryley]

MakeMKV was able to open all three no problem, so their hashes must match.

I'm not sure whether MakeMKV (or AnyDVD) verifies the content of decrypted discs. My recollection is that the content hashes are calculated using the encrypted, rather than decrypted data, but I could be mistaken.

One ISO with protection intact using AnyDVDHD "rip to image"

In the absence of bus encryption, I would expect this rip to match the output of other tools, such as ImgBurn.

One ISO with protection removed using AnyDVDHD "rip to image"

One ISO with protection removed using AnyDVDHD to unlock the disc and CloneBD to create the ISO (totally uncompressed)

I think this circumstance came up recently on this forum. As part of the re-authoring process AnyDVD performs when decrypting many Blu-ray discs, several files are modified. The date and time of this in-place modification is recorded in the resultant ISO file as it contains filesystem metadata as well as disc content. If you were to use AnyDVD multiple times to create a decrypted ISO, I would expect a different hash for each ISO file.

So which is bit perfect to the disc?

The protected ISO can be considered bit-perfect.

The link you posted actually seems to imply that "keep protection" ISOs are *not* necessarily valid even though no errors are raised

That was my understanding at the time. The only reference I can see to integrity checks in the AnyDVD changelog seems to confirm that only unprotected backups are verified (8.2.5.0).

 

[kufo]

What about to open the ISO in CloneBD? If there is something wrong with your file CloneBD will tell you that it would fail to process this. If there is no warning you can be pretty sure that your file is okay. I really did a lot of UHD rips and allways went fine with doing so.

 

[James]

When using "Rip To Image" and leaving all protections intact, how should I verify the integrity of the rip?

You rip it with AnyDVD removing protection. This will do sanity checks.

 

[James]

I'm not sure whether MakeMKV (or AnyDVD) verifies the content of decrypted discs.

AnyDVD does.

 

[Zangmonkey]

You rip it with AnyDVD removing protection. This will do sanity checks.

Thanks.
So actually there is no way to get a verified bit-perfect rip?

But making a rip removing protection is the "closest" approach to a verified rip?

That's good info, and it's the opposite of my assumption. I think something about this might be useful in the faq.


Will it be sufficient to re-rip unprotected from the protected ISO? Or should I go back to the disc?

 

[coopervid]

I repeat myself. Don't be so paranoid. What are you worrying about?

 

[Zangmonkey]

I repeat myself. Don't be so paranoid. What are you worrying about?

Well, I understand your perspective but just look at the things we've learned in this thread.

We've learned that rips keeping protection *do not* verify against the source media.

We've also leaned that rips keeping protection can be corrupted even when no errors are raised. So this point is the nature of my paranoia.

I create my rip from the virgin cleaned disc fresh from the package. If I subsequently damage the disc I want to have a perfect backup. So what I was doing, which was keeping protection in order to seek 1:1 bit perfect copies was *actually* the worst thing to do, since it's actually the most risk-prone and unverified method.