Some simple questions about DVD ripping (no encoding involved)

[Matthew]

I posted in this forum, because some of what I ask specifically relates to DVD2SVCD, and double posting is gay.

Anyway, on with the questions:

1. If I copy the VOB files to the HD before ripping can I be confident they are undamaged even if the DVD is scratched? As I understand it, a CRC check is performed during the copying process.

2. If the vob files are damaged after copying to the HD, when I move onto ripping off the HD, will there be error messages in the DVD2SVCD log?

[markrb]

It is inaccurate to say the files are copied to the hard drive. When you rip a DVD the files are processed and the copy protection is removed along with the FBI warning etc...
You should always rip to the hard drive and not attempt a straight copy.

If you are concerned that the VOB files might be damaged open DVD2AVI manually and using the slider bar check to make sure they look ok. If so they are most likely fine.
If a DVD is is damaged the files won't be able to be ripped in the first place and if they are chances are they are fine.

I have only had VOB files damaged for two reasons. The first is that my hard drive was not working right and it corruted the files.
The second is that I closed a program while it was working on the VOB files and caused an error. Even though thry are open read only it does happen.

In both cases simply opening up DVD2AVI and checking the files there will alert you if there is a problem. If the video is blocky or looks wrong then they are most likely damaged.

Mark

[Matthew]

"It is inaccurate to say the files are copied to the hard drive. When you rip a DVD the files are processed and the copy protection is removed along with the FBI warning etc...
You should always rip to the hard drive and not attempt a straight copy."

Umm, no it's not inaccurate because I am talking about copying to the HD, then ripping from that. There's nothing wrong with this, I've read dvd2svcd himself say it's fine.

"If you are concerned that the VOB files might be damaged open DVD2AVI manually and using the slider bar check to make sure they look ok. If so they are most likely fine.
If a DVD is is damaged the files won't be able to be ripped in the first place and if they are chances are they are fine."

I'm talking about small scratches which lead to distortions in playback at a certain point. So viewing the video won't help short of watching the whole film, and I imagine the vobs can be ripped if the scratch is small (this is the case form what I've read).

So I still need both my questions answered!

[Faceman101]

damn you are pretty cocky. he went out of his way to help you.

1. Just copying to your HD will result in macrovision on your VOBs and then you have 4-8gigs of useless 0s and 1s. You need to use a program that will demacrovision them.

Are you trying to say your DVD is scratched and afraid by copying the data you may loose some bytes (hense scenes) in the transfer? If so this is a disc problem and not a DVD2SVCD problem. If it copies to your HD fine, you may not worry about that.

Next time when someone trys to help you, try to be alittle more nice.

[markrb]

#1 If you know so much why bother asking?

If the VOB files are damaged they will not work in DVD2AVI correctly if at all. Like I said load them into DVD2AVI and check manually yourself to see if the video is blocky a damaged file will be very obvious.
Or you can try to play the files in WinDVD or PowerDVD in file mode.
I have never tried this and do not know how to do it.

If you attempt to do a straight copy and not a rip on a windows system 99% of DVD's you will get a file system error. It is part of the disks copy protection. You need a special program like a DVD ripper that can get around the copy protection.

If you are successful with a straight copy the file is most likely not copy protected(an example would be Dawn of the Dead directors cut), but these are rare, about 1% of motion pictures.

I tried to give you the simple answer, but I guess you don't like simple.

When a DVD player (even computer based) shows distortion or blockyness in a video you are watching this is due to the real time decoding needed. There is no real error detection and correction, there is no time to re-read a section. In this case the errors are passed to the screen or the DVD stops. When you copy or rip a file it is subject to windows error detection and if a sector is not readable it will attempt to do so until it either 1 is succesful or 2 errors out and will not continue the copy or rip. This guarantees the read, but not the write. In 90% of computers today error detection on the write, except for fatal errors, is not used to speed system usage and because for the most part is not needed.
In your case the DVD is the item in question and thus the read. Read errors that get passed onto the final write do happen, but are rare.
So in this case if you are succesful copying a file to the hard drive and there are errors the most likely causes are
1. data corruption on the Hard Drive
2. Bad original file
3. Form of copy protection.
4. Ouput of ripping program
5. Bad hardware
6. Virus
7. other reasons possible, but each one is less likely then the next

For the most part if your copy is succesful your file is just like the original.

If you are going to completely blow off an answer I would suggest you get some facts before calling the answer bull.

I don't appreciate the way you posted. I was only trying to help. Even if I was wrong do you expect people to help you with a reply like that?

Mark

[Matthew]

First up, I apologise if I sounded rude or cocky, it wasn't intended that way. Granted it was definately blunt, I tend to go all in when I disagree with someone (it's nothing personal but can appear that way sometimes).

Now some clarifications, because it seems I worded my original (late night) post rather badly. When I say ripping I do not mean encoding to SVCD (hence the "no encoding involved" in the title). I mean ripping from VOB to VOB. So what I am doing is copying the protected vobs to the HD then ripping to unprotected VOBS then encoding to SVCD. As opposed to just copying over the vobs and disabling dvd ripping in DVD2SVCD.

It seems you are saying that a straight copy of VOBs from a DVD to an HD may lead to corrupt VOBs if the disc is scratched (assuming there are no problems with the HD, etc), have I got this right? Faceman seemed to say I needn't worry if the vobs copied correctly :confused: One reason for copying across the unprotected VOBs was to make myself feel better about the integrity of the VOBs. I thought ripping from the DVDROM drive to the HD would be less likely to produce warnings about any errors that exist.

Now say for arguments sake as a result of a scratched disc I've got some damaged protected VOBs sitting on my HD. If I rip these to unprotected vobs using DVD2SVCD will the log show errors, or isn't that a feature of the program?

Thanks for any help and please accept my apologies ;)

[Labersack]

With most DVDs you won't be able to just copy the VOBs to HD. They are protected, explorer will give you an error.
Almost all time with CSS,a digital-copy-protection. Many of them also with Macrovision, a analog-copy-protection. You don't have to worry about Macrovision, it's only a problem if you try to copy to (s)vhs via analog tapes etc, it won't protect anything on SVCD.
But the CSS will prevent copying to HD. So you have to use a ripper. It can remove both protections while it is copying the files to disk.
You can leave Macrovison in the VOBs, it won't give you any problems, but you have to remove CSS, so your HD-VOBS aren't the same as your DVD-VOBs.

[Kedirekin]

If you use the vStrip option, I'm pretty certain you won't get any errors in the dvd2svcd log. I'm not sure when using the internal routines, but I wouldn't be surprised if you don't get any log messages then either.

In my opinion, you don't need to worry about it too much. DVDs are pretty resistant to scratches. You should see some of the discs I get from NetFlix - they look like someone buffed them with 80 grit sandpaper. I'd only worry if the scratch is more of a gouge, and only then if it's tangential.

Besides, I've heard dvd2avi isn't very forgiving of corrupt vob files. If a vob is damaged (whatever the source of the damamge), it's probably more likely that encoding will simply fail than that you'll get a damaged encode. No guaranties though - I've had two encodes where macroblock errors snuck through.

If in doubt, I'd use SmartRipper or DVDDecrypter to rip the vobs to the hard drive first, then use DVD2SVCD from there. That is what I do.

PS. It is possible to copy the encrypted vobs in explorer after the disc has been authenticated (by a ripper or a software DVD player, for example). I do not recommend copy to HD, then rip from there. I always rip to HD, then re-rip from there.

[markrb]

Thanks Kedirekin I did not know that. I just tried it and you are right. If I run PowerDVD and leave it running I can do a straight copy. I will file that one away with all the other things I have learned here.

Matthew actually what I meant, and turned out I was wrong about, was that you couldn't do a straight copy with copy protected VOB files at all. There shouldn't be any file corruption in either case. I don't know enough to know if the IFO file will still work if straight copied. You will still need to rip the files to de-encrypt them and remove macrovision although this is not absolutely needed. Most people just do it because you can and then copying to VHS is easier an it doesn't hurt the quality so why not.

Basically if a rip or a copy is succesful the chances of the files being damaged is very slim. If it is there will definately be noticable errors in DVD2AVI, because if the file is damaged the video will be as long as the audio, most likely anyway.
If the DVD is not read correctly Windows will attempt to read it until it is happy that it has it correct. If that does not happen windows will error and stop the copy or rip.
Have you ever tried to copy a file off a floppy and hear the heads moving back and forth fast, then moving on? This is an error reading the file and the following attempt to get the correct data. If it doesn't move on it will fail. It is the same with all media although not as obvious.

Mark

[Matthew]

Thanks all, I feel better now ;)