Hashcheck errors request/suggestion

[jack123]

I have a bluray here that fails on hashcheck half way through at the same place
every time. (cleaning doesnt help - the disc is obviously damaged)
When makemkv encounters this and can't recover it throws the error and notes the failure.
This leave a short unplayable MKV file.

However - when the relevant section plays back on a (cheap) bluray player it pauses a second then continues
(presumably just past the error)

The question is:
Would it be possible for makemkv to just report the hard failure but continue to process past it to
produce a playable file? I assume some code re-writing would be needed.

thanks
jack

[mike admin]

It can be done now in various ways.

You can try making a disc backup (not MKV) to get raw decrypted M2TS, then convert M2TS file to MKV either with MakeMKV, or if it fails - with any other tool. For this MakeMKV has a hidden setting to ignore read errors. Or you can just play the m2ts file.

If you have a LibreDrive-enabled drive, there is another way. First, you have to "bless" the disc (makemkvcon info), and after that you can make an ISO image with imgburn or ddrescue. This iso image can be turned into (encrypted) backup. You might be able to get mkv file from this backup with MakeMKV.

The hashcheck error by itself is not an error that would stop the conversion. The garbage data forces MakeMKV to error out.

[kilomeki]

It can be done now in various ways.

You can try making a disc backup (not MKV) to get raw decrypted M2TS, then convert M2TS file to MKV either with MakeMKV, or if it fails - with any other tool. For this MakeMKV has a hidden setting to ignore read errors. Or you can just play the m2ts file.

If you have a LibreDrive-enabled drive, there is another way. First, you have to "bless" the disc (makemkvcon info), and after that you can make an ISO image with imgburn or ddrescue. This iso image can be turned into (encrypted) backup. You might be able to get mkv file from this backup with MakeMKV.

The hashcheck error by itself is not an error that would stop the conversion. The garbage data forces MakeMKV to error out.

nice. thanks a lot

[jack123]

Thanks mike I'll give that a go.

jack

[jack123]

Some feedback:
(I have libraDrive fully patched latest version from here)
Windows version makeMKV

I was able to create an ISO using imageburn (V2.5.8.0)
I then ran:
makemkvcon64 --decrypt backup disc:c:\temp\disc.ISO d:\temp
which reported hash errors but completed (with a failed message)

I was then able to playback the corrupt 00002.m2ts file on mpc-hc player and the file played
and displayed the corrupt data at the correct location and continued to play ok to the end.
all I have to do now is edit the corruption out of the m2ts file (about 2 seconds worth) and I'm good to go.

The fun part is I had the AC3 conversion done at the same time using the AC3 profile from the other day.
If anyone is interested I added in <extraArgs> -r 48000 -b 640k -f volume=+9db </extraArgs> to my AC3 profile,
which all seems to work as far as I can tell.

Many thanks to mike and the MKV team.

jack

[npdude]

I've used the techniques mentioned here and bits from some other threads to read a problem BD. I now have a decrypted and playable mt2s file for the main title. There is one tiny catch. It doesn't have any chapter information. I can easily remux to a mkv container and add chapters with MKVToolNix. And I can see the chapters somewhat by pointing the MakeMKV GUI at the backup. The only problem is, it only shows the chapters down to the seconds, not sub-seconds. makemkvcon doesn't seem to show chapter information at all. Can anyone point out a way to get more accurate chapter information from the backup folder? Thanks.

[stephon1024]

Some feedback:
(I have libraDrive fully patched latest version from here)
Windows version makeMKV

I was able to create an ISO using imageburn (V2.5.8.0)
I then ran:
makemkvcon64 --decrypt backup disc:c:\temp\disc.ISO d:\temp
which reported hash errors but completed (with a failed message)

I was then able to playback the corrupt 00002.m2ts file on mpc-hc player and the file played
and displayed the corrupt data at the correct location and continued to play ok to the end.
all I have to do now is edit the corruption out of the m2ts file (about 2 seconds worth) and I'm good to go.

The fun part is I had the AC3 conversion done at the same time using the AC3 profile from the other day.
If anyone is interested I added in <extraArgs> -r 48000 -b 640k -f volume=+9db </extraArgs> to my AC3 profile,
which all seems to work as far as I can tell.

Many thanks to mike and the MKV team.

jack

Hey jack123,

Thanks for posting this, really helpful. One question on using imageburn. Did you have to tell imageburn to ignore the read errors when making the ISO? Mine is getting tripped up (assuming) in the same spots as makemkv is...

Thanks or the help!

Steve