Dvdisaster

Blank Media Disc Testing Methods and Software
#1

Tried out dvdisaster for the first time www.dvdisaster.com
I took a disk which had previously given me a quality score of 99% and using dvdisaster made an error correction file. Then I damaged the disk slightly – scan number 1. Then ran thu the dvdisater procedure - burned another disk ---- scan2.

What can I say ? a great free program.

Another point of interest though - I was able to watch the movie ( scan 1) with a Pioneer 2750 so maybe “clean” damage ( I just scratched the DVD with a set of keys) is easier to restore than longer term DVD decay ?

#2

Very interesting. Thanks for going to the trouble, that was rather clever. :cool:

#3

Sorry to say but I don’t think the second scan proves much. All it shows is that the disc is in good condition, not the content of the files. Would be better if you included a file compare with the original source (as in the files you burned onto the first dvd before you scratched it). I’m not saying that the program doesn’t work, I’m pretty sure it does what it claims, and does it well.

Q.

#4

The program that I use is Beyond Compare 2 from www.scootersoftware.com

There were several points behind showing the scans.

(1) I never cease to be amazed just how bad they can get - and yet still play.
(2) The second scan was simply to show the end product. A simulated failing of a disk being corrected by dvdisaster and allowing the burning of a new disk with a better scan.

Unfortunately the output from Beyond compare 2 is not very exciting:

CRC Comparison of <E:&gt; to <D:&gt;
8 files in 1 folders

8 files match exactly

VIDEO_TS\VIDEO_TS.BUP
VIDEO_TS\VIDEO_TS.IFO
VIDEO_TS\VTS_01_0.BUP
VIDEO_TS\VTS_01_0.IFO
VIDEO_TS\VTS_01_1.VOB
VIDEO_TS\VTS_01_2.VOB
VIDEO_TS\VTS_01_3.VOB
VIDEO_TS\VTS_01_4.VOB

Anyway as far as I can tell data on the new dvd is the same as on the pre scratched dvd. Rather than burn and just do a DVD speed scan (or any other scan for that matter) I would suggest that if the data is important that consideration be given to using a program like dvdisaster. Making multiple copies is perhaps even safer but with a requirement of only 14% the making of error correction files makes sense to me.

#5

Yeah, I agree about that. :slight_smile: I was just asking for the complete picture, so to speak. I’m certainly going to look more into this prog. Too bad it wont help me with the 150 unreadable discs I’m trying to salvage. :frowning:

edit: I find the compare quite exciting actually, it proves that the program was able to recreate the disc 100%. :clap:

Q.

#6

Do you know anyone who has a Lite on 16P9S ? I picked one up a few days ago and was amazed to discovery that it could read ( with some errors) that my BenQ’s and Plextors could not

#7

I’m actually planning on buying a Liteon next week just for that purpose. Haven’t decided yet which model, I was thinking of a dvd-rom actually. Already got 3 burners, BenQ 1640, Nec 3520 and one other not worth mentioning. It starts with P, that’s all there is to say about it. :stuck_out_tongue:
Well to be honest it’s not working anymore since it attempted to fly and fell 3 stories to the ground, not that it worked much better before that either. Just keeping it so I can show it to the other burners before putting them to work. You know, inspiration. :slight_smile:
(The BenQ is safe, but the Nec is getting nervous. I think it’s afraid of heights)

Q.

#8

Hi Harry, it’s really great that you damaged a disc in the name of science and all, but unfortunately it wasn’t a very good test. As Qyngali has already pointed out it is file comparision that’s important, but unfortunately it still is not a real test if the damaged DVD was still readable. That is the point of the DVD’s own inbuilt error correction, to allow you to accurately reconstruct the data despite some degree of damage or media degradation. Sorry to say that this would only have been a real test of DVdisaster if the original damaged disc was unreadable. That is to say that if no regular programs could extract the data from the original DVD to the harddrive. Your post does not make it clear that this was the case, infact it suggest the damaged DVD was still readable and hence copyable by normal means. Could you please clarify this point.

In the mean time I’m now scouring my DVD collection to find either a Princo or Ritek G05’s that is no longer readable but which has been backed up to better media before failure. I have quite a few of these (ie where I have two copies. one on good media and one on crook and dying media). I’m sure if I look hard enough I’ll find one that’s unreadable with CRC errors and then I’ll make an ECC file from the good copy and see how DVDisaster goes at patching up the unreadable disc with just that bad disc and the ECC file.

BTW. I’ve also been using DVDisaster for about a month or more to make ECC files of my most important DVD’s. So far I’ve not had to use it to patch any failures becuase I’m only using good media now (no more Princo or Ritek). Naturally I want to see how well this program works when the time comes that one of these ECC files is actually needed for recover, I want to know that I’m not just wasting my time making the things. Anyway that how I came to search for this thread, I was looking for someone who’d actually used the program for recovery, this thread was the closest I could find.

#9

Yes I agree - unfortunatley the disk was still readable. I will keep it and test it again in a few months.

At the moment I burning another DVD ( will use a Ritek so as not to waste anything ) and will make an ecc file and then use a marker pen ensuring that the disk is unplayable in any of 5 dvd writers and 3 DVD players. Then I will see what Dvdisaster can do and report back.

I wish I could be so confident about Quality disks lasting. I have one of two yudens about 6 months old and they are not looking good.

Anyway - every disk that I burn has an ecc file. If anyone knows of a better way I’d be interested to know

#10

OK Uart see if this helps

(1) Made a DVD
(2) ran it thru dvdisaster to make an error correction file
(3) used marker pens to make the dvd unreadable.
when I tried in in players it played, froze and died
copy and paste failed, dvd shrink no go, dvd decrypter I gave up after 500 errors.

In totoal 322496 sectors were corrected.
Clearly it would not be difficult to made a disk which could not be restored but
I’m convinced that it is worth the effort to protect burns which hopefully will not be as bad even as this one.

untitled3.PNG788x584 45 KB

quality.png641x532 48.7 KB

#11

Nice result.

How big are the error correction files?

This looks like it could be an indespensible utility…

#12

Good stuff Harry. While you were doing that I finally managed to find a DVD that was unreadable in my collection. It was kind of surreal as I was going through all my old Princos and cursing and swearing because they were all still readable, the opposite of normal behavior :). Well they all worked because a few months ago I went through my whole collection and threw out anything where the media was too crappy.

Finally good old Ritek G05’s crappiness came to the rescue and I found a movie that was completely unreadable on both my DVD burners. Both direct file copy and dvdshrink failed with ecc errors, basically if I didn’t have a backup copy of this disc I would have been screwed.

Now normally of course you’d make the ecc correction file beforehand but in this case I was able to make the ecc file right now from a second good copy of the same disc. Not the way you’d normally do it but the principle is exactly the same.

The results: Well the program was a little slower than I expected, it took 2hrs to reconstruct the iso from the combination of the damaged disc and the ecc file, but it was successful and the movie that was burnt from the reconstructed iso file played without a hitch. BTW I did the reconstruction on my second computer that’s only a slowish Duron 1000 with 20G drive, it may run faster on a better computer.

At least the readback of the damaged DVD was not too much hassle, once I read the manual and placed the readback in “adaptive read mode” as recommended then it quickly read the damaged DVD skipping over the damaged areas and reconstructing them from the ecc file. In fact when it got to 90% I was expecting it to take ages as most of the worst degradation was in the last 10% of the disc, but I was pleasantly surprised when it simple skipped the read of the whole last 10%. It appears that the “adaptive read” mode must tell it to not try and read any more of the damaged DVD than it really needs to. As it knew it had enough info in the ecc file to cover all of the last 10% it seemed to just skip it entirely, terminating with the message that it had enough data to fully reconstruct and just waiting for confirmation to proceed.

It was only in this last part that the program seemed a little inefficient, taking a little over 2 hours to reconstruct a 4.1GB ISO file from the partial ISO it had already made and the existing ecc file. Since all this stuff was already on the hard-drive (the DVD drive didn’t even appear to be accessed during this time), I expected it to take more like 15 or 20 minutes, but hey it worked so I cant really complain about the time.

BTW.How long did you reconstructions take Harry?

#13

BTW. One thing I forgot to add to the last post that may be of interest. For the last month or so I’ve been making these ECC files but only at 10.4% reduncacy instead of the default 14+ percent. So to make this a good test for the ecc files I’ve been making I only used that same 10.4% redundancy level in the ecc file I made to do the above test reconstruction.

I’m sure the more redundancy the more damaged the media you’ll still be able to repair. Anyway I choose 10.4% when I started out because I wanted to fit up to 10 ecc files on the one DVD. So it was quite reassuring to see that it was able to fully reconstruct my failed DVD from only a 10.4% ecc file. :slight_smile:

#14

The size of the correction files varies - depends up size of the original and %
correction file size chosen.

So far I have only used the default size of 14.3% and have an average size of
550,428 meg. with a full original DVD I get 664,998 meg.
I think the idea is that for every 8 DVD’s you will need an extra DVD for the correction files.

You could make them smaller ( see uart posts ) or much larger ( up to 64.5%)

I know of only one other program like this www.quickpar.org.uk which is supposed to be stronger but for me dvdisater is much easier to use.

Anyone know of any alternative or better solutions ?

#15

This time reconstructing the ISO took a long time - perhaps 40 mins to 1 Hour. Sorry I didn’t time it. Yes “adaptive” mode is essential.

With my marker pen I did originally manage to damage the disk so that the first effort to correct did not work. I then cleaned the disk a little and ran again. So it is still possible to have disks which 14.3% can not correct. But is
65% worth it ? Its a trade off. Beyond a certain point you might as well make 2 copies ?

The reconstruction did take a long time - all of the chart was red 100%.
with Real damage using better disks and picked up earlier the correction is no doubt much faster. My first test only took a fraction of the time - I had not done so much damage.

#16

Just tried Isobuster on my damaged DVD. I must admit I’m not too sure how it is supposed to work but I get the feeling that very slow progress and hanging my machine are not what is intended. Perhaps it could eventually restore most or even all of the DVD but I doubt it

#17

I find dvdisaster is superior for restoring, no silly max 50 retry limit every other program seems to have. Just set it to adaptive and drag the stopping when unreadable intervals slider to 0. Let it run and check it once in a while. :slight_smile: I wish the author could implement a timed pause though, reading 4 days non stop isn’t healthy for the reader…

BTW, I found a Litey 401S in one of my piles of misc old hardware. It’s read back all of the discs with some effort, except 1. Been running this last disc for… about a week now. Most of my other drives couldn’t even read the TOC, while the litey is missing 11504 sectors as of now.

I think I’ll get a 1693. :slight_smile:
Q.

#18

11481 missing sectors, 23 sectors per day. I’m blinded by the speed. :stuck_out_tongue: Toothpaste for a couple of hours maybe…

Q.

#19

I not sure what you are doing here. Are you using dvdisaster to restore or Liteon and something else ? At 23 sectors per day HD TV and Blue Ray will be obsolete by the time you are finished.

Looked at a couple of Cds from 1995/96 and found a few minor errors ( 97% good, 3% recoverable). Then I looked at the content of the CDs ---- 3DFX drivers and other such useful files. Perhaps at my age 100 years may not be necessary after all :doh:

#20

Well it’s down to 11350 missing sectors now, so going a bit faster again. :slight_smile: Yes, I’m using the liteon with dvdisaster to read to image one of my Samsung BeAll 4x dvd-r discs. 99.5% total recoverable as of now. I’m not really doing this out of neccessity(sp?), but more as a test of readers. I’ve tried this disc in 12 different drives now, and the LDW-401S is the best so far.

One issue I got though, almost all the drives detect the size of the disc differently? Irritating when you run the image with a drive that detects a larger size than the original reader, and you want to switch back later on… Now what, which drive do you trust… of course the program warns you when the image is larger than what the drive detects, but not the other way around.

Edit: 11348 :slight_smile:

Q.