DVD lasts longer than portable hard drives or not?

[lingyi]

Forgot an important DO:

DO:

Verify your data when copying/moving. Teracopy can do this with hard drives and flash drives. Someone who knows how to verify an optical disc rip or burn, please advise.

[Cornucopia]

ImgBurn, and many others, can do a sector-by-sector verify after burning (if checked in prefs), but this kind of verification usually only works with session-at-once or disc-at-once burn types so DLA/packet-writing types are more difficult. Best if you create file checksums ahead of time, then you can use a generic file checksum compare, post burning. And that works with any burn type.
Scott

[johnmeyer]

Someone who knows how to verify an optical disc rip or burn, please advise.

There are several programs, although you must have a drive that supports the ability to read the raw, uncorrected data (many Lite-On drives do). The one I use was originally included with Nero and called CD-DVD Speed. I think it may now be called DiscSpeed, and if you click on that link you'll be taken to this site's software download page.

The "Disc Quality" tab is the one you want. It will list the total number of both correctable and uncorrectable errors on your disc, and at the end of the test will give you a single "figure of merit" number (100 is perfect) to indicate the quality of the burn. You can repeat this test years later to see if the disc has degraded.

[tntroy]

Yes, the 2 Windows XP computers I had, both came with Nero burning systems installed. The place I got them from installed the program on all their computers back then. But I do remember it asking either before or after the burn, do you want to verify the burn? Which I always clicked Yes on, even if it took the burn a bit longer. I don't know if the burner on my Gateway either does that automatically or doesn't do it at all. I just know I never get asked that question.

I don't really like the burner on here much at all. But the one it came with is what I got, lol. It has Cyberlink Expresso on it, which sounds familiar to Nero for some reason. ( But No, Cyberlink isn't Nero. ) I don't know what the actual burner is. They say Cyberlink is better of the 2 but, when you grew up computer wise, using a Nero.

[johnmeyer]

Verifying a burn is a totally different thing. It is also much less useful. Basically, all it does is tell you if you have a "coaster." The program I recommended gives you a lot of insight into whether the disc will be readable in 20-30 years, not just now.

All media will degrade, and with DVDs, that degradation will increase the number of read errors. Up to a point, the redundant bits burned on the DVD will be able to reconstruct the original data perfectly and you won't notice any problems. However, once it degrades beyond a certain point, you'll start to get errors.

The better the initial burn, the longer it will take to get to the point where you start to have read problems.

Even if the disc has 100x the number errors of a "good" burn, it will probably still verify just fine.

[lingyi]

On the other end, how do you verify that rip is okay? For audio, EAC notes errors during ripping. Is there anything like this for video other than the rip failing?

[johnmeyer]

It has always been my understanding that a "rip" of a DVD is simply a copy that removes CSS. I guess the decryption could fail, but when that happens, it doesn't copy at all.

So, I've never felt the need to verify a rip.

[lingyi]

A rip of a DVD or CD is supposed to be an exact bit for bit (less protection) of the disc. Non-copy protected discs can be ripped. However, I wonder if there's some measure of error correction allowed. I've never seen anything like EAC for audio discs which shows a screen (and slows down) when the ripped track(s) don't have the same hash as the original.

Edit: DVD Passkey and I believe DVDFab can be set to leave CSS, AACS and Region Lock on the disc.

I also assume that if there were no errors if the program (e.g. DVDFab, DVD Decrypter, etc), but we know how dangerous it is to assume! Not something I worry about, just curious.

There can definitely be errors ripping a DVD or Blu-Ray, that's where something like ISObuster comes in and keeps trying to recover the bad parts of the disc, but even then sometimes it's not 100% complete. I've also had rips that have errors on playback and when I play the original disc and the errors are the same on the original disc, so the rip was accurate, warts and all.

Also, MakeMKV will sometimes fail to rip a disc on the first try, but will work on the second or third. I suspect there's a log somewhere in ripping programs that show what's going on, be interesting to see.