Quality of copied CD's?
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mikeliao

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Pirated CD's are a fact of life around China and most of Asia. Even if you wanted to buy a "real" CD, the choices are extremely limited. I'm curious if the quality of the pirated disks (stamped kind) are different from original factory CD's.

Also if you make CDR's from original CD's, does the CD writer and quality of the disk affect the quality of the music? Or is it all just a bunch of 0's and 1's?
 
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chadbang

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Some people contend that you lose a bit of data here and there when you make a copy, and you wind up with a poor reproduction of the original.

Maybe, but I don't buy it, personally.

I may be wrong, and those more computer-oriented please correct me, but I have plenty of software that's been copied and spread around the world as copies. It would seem to me that losing bits of data would also have to occur this way. Wouldn't a piece of software be rendered unusable with the loss of just a tiny bit of code? A copied song might theoretically lose a bit of data and play with less fidelity, but wouldn't software just fail to function if it lost data?

I've very rarely encountered a program where this has happened.
 
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fewtch

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Music data on a CD isn't software though. IME there's a slight potential drop in SQ when copying a Redbook CD, depending on what kind of drives, software and etc. are used for the copy. Likely that it's not going to be audible if it's done well.

P.S. one possible risk of pirated CD's is that they're made from MP3's... there would be no way to tell before buying one.
 
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chadbang

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So the information stored on a redbook cd is more complex than just a data stream?



That's true about the MP3s. When I first got to Thailand a copy of a cd was a copy of a cd. Post-Napster, now there's all these weird "collections" turning up, that I know are made from MP3s. You can just hear it. Even if you only lost a buck and half, it's still annoying.

But the great bargains are the MP3 only cds. They rip and encode whole collections of albums onto cds. You can get every Beatles' album, or Dylan album on one cd in MP3 form. For non-audiophiles it's a dream for 2 bucks.
 
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Stephonovich

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Theoretically, it should be a 1:1 copy. Practically, (as with Fewtch, this is IMO) this never happens. Little things like burning software, whether or not you use a CUE sheet and/or subcode data, media quality, offsets, laser strength... it all adds up to tiny errors. Can you hear any difference? I highly doubt it, and I challenge anyone who says they can to a blind test. (this includes people who think that burning to a black CD-R improves the quality)

That being said, I still make sure offsets are corrected, sub-codes are extracted, CUE sheets are used, and high quality media is purchased


EDIT: No, it's still one continous data stream (tracks do not physically exist; the index tells the CDP where to seek for the next 'track'), just like any other. In theory, making a copy of, say, a game will also give you slight errors, however error correction fixes these problems. As I said, you're not going to be able to hear a difference, unless something's REALLY fux0red up.

(-:Stephonovich:)
 
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halcyon

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CD-ROM data has a different error correction and synchronisation mechanism than CD Audio.

You cannot compare them to each other on that level.

Possible problems with cd audio copies:

1) Source used for the copy is a low quality mp3/mp4/etc or otherwise digitally manipulated (i.e. copied badly, normalized, from copy protected source, etc) => Data is lost => Audio quality suffers

2) Resulting burn / pressing is bad quality (the disc itself is bad) = Readability/Compatiblity suffers => More uncorrectable errors in reading => Audio quality suffers

It's impossible to say what kind of quality the copies are. They can be better quality than pressed original discs (very rare) or they can be much, much worse.
 
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jefemeister

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the market needs to start *demanding* an audio format that is more CD-ROMish in nature. Ie, it can be read perfectly every time by a $15 mechanism. I'll take that over the new hi-rez formats any day.
 
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fewtch

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Quote:

Originally Posted by jefemeister
the market needs to start *demanding* an audio format that is more CD-ROMish in nature. Ie, it can be read perfectly every time by a $15 mechanism. I'll take that over the new hi-rez formats any day.


An excellent idea... something like storing tracks as .WAV files (or .raw data files) in a data CD format. This would be dead simple to implement, and better than redbook (transport quality would likely not matter at all anymore). Unfortunately it'll probably never happen because of piracy fears and such, even though redbook CD is already simple to pirate.
 
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Stephonovich

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All brilliant ideas are shot down by the copyright lawyers


Using this method, you could drag and drop the .WAVs into a folder; no DAE required. Of course, who's to say they wouldn't put some new copy protection on it? (that would be broken after 2 hours, mind you)

(-:Stephonovich:)
 
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Data stored on a redbook disc is in the form of zeroes and ones. Assuming you have a program with good error checking (EAC, for instance), there should be absolutely no loss in data; just as with copying a piece of software (both are zeroes and ones, period).

There's no logical or possible reason for "small errors" to occur that affect the sound; with a digital recording, either the errors are automatically corrected by error correction firmware on the CDROM, or they cause a "skip" in which the data is considered unreadable. It works the same as with software: WITH SOFTWARE, EVERY SINGLE BIT (0 or 1) MUST BE EITHER READABLE OR CORRECTED FOR BY THE FIRMWARE, OR SOFTWARE ON A DISC IS UNREADABLE.

This is NOT like vinyl, which has bumps, ticks, etc., and all are read because the read device is in the form of a needle.

If all of these things occur like people say they do, then why do copies of software work perfectly or not at all? Is the method for reading data different here? If you can rip a piece of software and it works to 100% functionality off of the copied disc, doesn't that put a hole in these unproven theories about "some" data being miscopied when burning a redbook CD? According to what happens with a data disc, any problems should be automatically corrected by error correcting utilities.

Simply put, I can't see a way for it to happen.

Cheers,
Geek

Cheers,
Geek
 
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fewtch

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It would work well for standalone CDP's too (at least "new and improved" ones). Since .WAV is a container format, they could also include song titles, additional info, whatever you want.

Heck while we're at it, why not use lossless files instead... fit nearly twice as much music onto a single "CD". Given how cheap dedicated processors are these days it would add nearly nothing to the cost of the new/improved CD player.

Any way you cut it, redbook is seriously out of date...
 
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fewtch

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Quote:

Originally Posted by Geek
If all of these things occur like people say they do, then why do copies of software work perfectly or not at all? Is the method for reading data different here?


In a word, yes.
Quote:

If you can rip a piece of software and it works to 100% functionality off of the copied disc, doesn't that put a hole in these unproven theories about "some" data being miscopied when burning a redbook CD?


In a word, no.
 
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Stephonovich

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I know, it doesn't make sense. Bit == 1 || 0. Nothing in between. However, offsets DO make sense to me. My burner (I use for ripping, since it's in better shape than my main drive) has a +685 read offset. Since there's 44,100 samples to a second in Redbook, that's about 1/64 of a second. Not much, granted, but it's not a 1:1 copy anymore, since the lost data is filled up with null to make up for it.

(-:Stephonovich:)
 
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kaitsuburi

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I wouldn't imagine pirates in China are using Taiyo Yuden media burned at 4X


I don't know about you, but I am always paranoid about CD copying....

-kaitsuburi
 
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markl

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Obviously, your CDs do not contain little one's and zeroes that fly through your CD-ROM to your hard drive. They are pits in the sufrace of the CD that must be read by the laser. The problem as I understand it is with timimg errors. From what I've read, for a computer software program it doesn't matter *when* the data gets there so long as it gets there, but with music, when there is jitter in the signal, timing errors occur, and timing matters for music. How audible these minute little fluctuations may be, who knows? But we can hear even stranger things (like differences between copper cables), so I'm open to the idea that these things may be audible.
 
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