Copy = Original ?

[Mr.Green]

Could anybody tell me if there is any difference between the original and copied DVDs in the case of copying 1:1, without any compression. I copy a 4.7Gb DVD to hard drive with the use of DVDShrink in "no compression" mode, make image without compression (the title is small), then burn it by Alcohol 120.

Should I expect to notice with my critical eye any difference as a result of such procedure? What is the cause of it, if any?

Thank you

[jimmalenko]

One is burnt (copy), region-free (dvdshrink default).

One is pressed (original).


That's about it. Apart from that there should be no visible or audible difference.

[Mr.Green]

Maybe you heard the statement that "any Copy is always worse than the Original". I was not sure about posting my question for it is difficult to explain and prove that NO difference is to be expected.

I wonder if there is any explanation on what stage we can theoretically get losses. I personally understand the only thing - vibration of PC and DVD drive. They should somehow effect the process of burning, its accuracy.

What else?

[jimmalenko]

Maybe you heard the statement that "any Copy is always worse than the Original". I was not sure about posting my question for it is difficult to explain and prove that NO difference is to be expected.

In the ANALOG domain it is certainly hard if not impossible to reproduce a copy 1:1 with no losses. However in the digital domain it's all 1's and 0's, so there's no alternative but a perfect copy, every time.

[RDS1955]

Just like Jimmalenko says, the only difference is the actual media itself... One (the copy) is a laser burned copy, the other (Original) is a pressed copy. if you want to get down to the finite microscopic details, I'm certain you can probably find something, but if it doesn't affect the viewing or listening, then it's all moot.

[ROF]

What about when a burn is successful and yet the copy won't play in certain players? Or the burn is successful and towards the end of the data readback the data is unreadable, a movie skips, or locks up? There are differences between an original and a copy. With an original if any of the above occur you can return to your retail store of purchase and exchange for another original.

[jimmalenko]

They're problems with media and/or the burn process. I'm talking strictly audio and video "quality" here, since the OP mentioned "critical eye".

[Mr.Green]

I gave in in the similar argument about original CD and its copy. In a quiet room after a while my ear detected that the copy lacked the richness of the original. Many people wouldn't hear it.

Anyway, thank you.
Though, I still don't know how to win in this argument about DVD copying
The fact that I personally enjoy the copy exactly as I enjoy the original doesn't satisfy the counterpart of the argument.

[thecoalman]

I gave in in the similar argument about original CD and its copy. In a quiet room after a while my ear detected that the copy lacked the richness of the original. Many people wouldn't hear it.

You probably ripped as MP3 or some other lossy format or sent it through some type of conversion and then created new disc. If you do an exact copy of the original disc it can't be different, it's impossible unless you alter it such as converting it to another format. As mentioned above it's just a bunch of 1's and 0's, they don't change when you make an exact duplicate even if you made a 1,000,000 copies each from the preceding one.

You can't win this argument as it's a fact

[Mr.Green]

I don't deal with the lossy formats whether it is audio CD or video DVD.
Or else this conversation would be incorrect.

[thecoalman]

Then your ears were playing tricks on you.

[jimmalenko]

I think it may have been to do with the way the CD player in question is able to read burnt media vs pressed media. I have noticed with some audio CDs that the Bass seems to be a little "chunkier" on the original and I did a copy to disc image then burn from disk image with CloneCD.

I know the theory states that this must be utter bullshit , but I must confess that I too have experienced this and I certainly don't have superhuman hearing. I've never experienced this with DVDs though.

[jtoolman2000]

If you take 1000110111010100010111010101 and copy it to a new piece of paper number for number it will still be 1000110111010100010111010101.

The same goes for anything digital. Now,,,, whether the copying / burning process actually burns a perfect pit for each #1 and leaves a corresponding area blank to represent a #0 is another ???

The way the computer reads / interprets a binary code for say the character " A " is simmilar to the way our brain recognizes that same character. Everyone has a diferent way or style to write the letter A but most people will recognize it as an A no matter if it is slanted crooked or perfectly written. Even if the lines that make up the letter A have slight gaps in them, we still know it is an A. The drive and PC will read the code and interpolate for any minute mistakes in the written code. If it exceeds a certain threshold than you get a read error. Maybe I am completely off on this but it seems to make sense to me.

[ROF]

Is there a difference if no compression / no re-encoding is involved and a completely successful non-error producing reproduction for a 1:1 video copy is made from a pressed DVD to burnt DVD?

No!

I agree on the CD Audio bit that in some cases there is an audible difference but since that's not the subject here and because that subject always seems to bring those people out who think they know it all or who want to belittle those who know they hear an audible difference I will just say that the answer to the OP's question is there is no difference when all things are considered equal.

[Mr.Green]

One of the factors that wasn't mentioned is mechanic vibration coming from the PC fan and the DVD drive itself.
In case of CD recording I heard recommendations to use the drive externally to avoid extra vibrations.

I wonder if it can really have any visible effect in the DVD recording situation.

Can this sort of vibration be a culprit?

[InXess]

No-compression reencoding takes original VOB's as they are and places them in a new DVD structure (they are copied not reencoded).

[greymalkin]

when you copy a word document from your computer to a data cd do you expect to pull up a different word document on the cd?
Do you expect the characters to be out of place??
or the font to be harder to read??

No,
No,
and No.

It either works or you get a message saying "whoops your file is corrupted, here's the trash we recovered". It's hit or miss, on or off, bit error or no bit error. Error correction schemes (CRC with dvd's?) will do it's best to correct the bit errors it receives but otherwise, see above.

[BobK]

I agree on the CD Audio bit that in some cases there is an audible difference but since that's not the subject here and because that subject always seems to bring those people out who think they know it all or who want to belittle those who know they hear an audible difference

I don't think I know it all, and I wouldn't belittle those who think they hear an audio difference. I would question if they hear the audio difference when they know whether it's a copy or an original playing and wonder if they'd still be able to hear a difference in a double-blind test.

[cpotoso]

IN fact, copies in this case are better than originals for the following reason:

Normally dvddecrypter (or other rippers) remove stupid restrictions like region coding, prohibited user operations (i.e. they force you to see a commercial before the film), etc.

So, what is better: a movie with no restrictions or one with them?

[slimpickins]

so true, i love that my back-ups go straight to menu, commercial dvd's take loads of button pushing and alot of waiting , i think sg atlantis volumes its a ten minute wait to get to the dvd