Scratched Bluray

[Lazlow]

Ok, so I have got a few blurays that have seen better days. Doing a regular makemkv fails, using handbrake produces a shortened version.

With a fair amount of experience recovering dvds, I thought ddrescue. I understand that makemkv needs the discattd.dat file to handle an encrypted iso. So here is my proposed procedure:

1. Backup the bluray with makemkv WITHOUT breaking the encryption. (in most cases it stops somewhere on main title). Making certain that the discattd.dat file is in place.

2. Apply ddrescue to the bluray generating the iso (this can be days, with varied success).

3. Mount the iso.

4. Copy the main title(assuming that is where the backup failed) mts from the mounted iso to the backup (overwriting the existing, smaller, file).

5.Open Makemkv files section, point it at the index.bdmv in the backup, and decrypt as normal.


Does this sound about right? Hate to waste a few days with ddrescue (never done a bluray before) and find out I missed something.

Thanks
Lazlow

[Woodstock]

The only issue might be that the drive will enforce the AACS access to the data if it doesn't have an access key. Will ddrescue bypass that?

[Lazlow]

I THINK ddrescue uses direct (low level) access to the drive. This makes an exact(?) copy of what it sees on the drive. With DVDs this makes a good copy(iso) with the "protection" intact. Which you can then decrypt and rip. This can be REALLY handy on older discs that one cannot simply decrypt and rip (due to damage).

[Woodstock]

However, a DVD drive is not as aggressive about enforcing access. If a BD drive detects that there is a BD in it that has AACS protection, it will return SCSI errors for any reads that are not done with the proper access key in place.

It would be an interesting experiment, in any case.

[Lazlow]

Well it works, sort of. After six days of ddrescue running (94% recovery), I put it through the process(above). Makemkv got about half way through and errored out. So I tried Handbrake. Handbrake ended at roughly the same place but it did save the file(unlike Makemkv). The file played perfectly up until it stopped (halfway through the film).

I did run into one odd thing. While Handbrake was running (off the backup not the disk), I tried to restart ddrescue. While handbrake was running ddrescue identified the bluray as a dvd. Thus the iso was corrupted. Tried a fresh start(deleting iso and mapfile) with ddrescue and it still identified the bluray as a dvd(handbrake still running). I removed the disk while handbrake was running (after ddrescue dvd thing) to make certain that Handbrake was not accessing the drive. It was not. After Handbrake finished running, ddrescue properly identified the disk as bluray. Not sure if the conflict was due to with the disk and the backup being the same was the source of the issue, if it would occur if they were mismatched, or it it was just some fluke glitch.

[thetoad]

1) I do this all the time and have posted about it here.

2) If you blu-ray drive has bus encryption, it wont work. need a blu-ray drive without bus encryption

3) for non bd+ encrypted discs, it's easy (use some tools from doom9 to both get the VUK and decrypt the disc)

4) for bd+ discs (I haven't had the issue with them yet), it be nice if makemkv worked and was able to make a backup de'aac'ing and de'bd+'ing it as well.

[thetoad]

For DVD's I found it easy to authenticate the drive to the disc (just run lsdvd, it does the css handshake)

As mentioned I haven't had an issue with blurays with my drives

But, it be great if there was a method with makemkvcon to authenticate the drive to the disc, let us run ddrescue (or even have a ddrescue like mode built in for generating an iso) and then able to decrypt said iso using the VUK it calculated when the disc was inside. It make my life more of a one stop shop then having to rely on multiple tools.