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Topic: Extracting Wav files or copying cd image 1:1 (Read 4059 times) previous topic - next topic
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Extracting Wav files or copying cd image 1:1

Hello. I have a few questions for you audiophiles out there. I am interested in backing up some of my cd's. One in particular has scratches on it that managed to rip in EAC. I'd like to back it up on a CD-R. I wasn't sure what is more effective, either extracting the WAV files with EAC (in secure mode) or copying/burning a image/cue file with EAC, Blindwrite, Clone CD etc. Are the wav files the same exact quality as if you copied the cd 1:1? It seems to me it's less work to just extract audio cd tracks with EAC in secure mode. Lastly, is there generation loss if the following occur:  copying a cd 1:1? or extracting the wavs from my original cd and burn them with NERO on a cd-r? I have heard that while a 1:1 copy with Nero or CloneCD or Alcohol would seem to be lossless, the fact is that all CD burners generate miniscule data errors during the burn process. Most of the time, a CD-ROM's read-error correction will fill in the gaps. Is this still considered generation loss? Any help is greatly appreciated.

Extracting Wav files or copying cd image 1:1

Reply #1 –
As far as I know the best way how to make a backup of your audio CD is to use EAC in secure mode (if the CD is not copy protected).
It doesn't matter if you use extract tracks or make a image but you must have a proper cue-sheet to your wave files / image to rebuild the CD as it was on original.
The CD copy is lossless if you use EAC in secure mode and there are no errors introduced during the extraction.
Other interesting thing is to have EAC properly set-up eg. offset correction, caching, C2 errors, drive read command...
and also a write offset correction if you want to use EAC for burning.
I'm highly recommending you this option!
So when you have all these issues solved right your backup will be the same as original.
PS: You can extract image of the original and copy and compare them in EAC and they should be bit-by-bit identical...
Sorry for my poor English, I'm trying to get better... ;)
"The greatest trick the Devil ever pulled, was convincing the world he didn't exist."

Extracting Wav files or copying cd image 1:1

Reply #2 –
IF you burn from flac files you have the option to add CD text with album and track names which would make it better than the original.  Most of my original CD's do not have CD text. 

The effort is usually very low as my burner program picks up the text from tags which the ripper fills in automatically from on-line databases.

Edit: a correctable error would not be considered a generation loss.

Extracting Wav files or copying cd image 1:1

Reply #3 –
Quote
The CD copy is lossless if you use EAC in secure mode and there are no errors introduced during the extraction.

...

So when you have all these issues solved right your backup will be the same as original.
PS: You can extract image of the original and copy and compare them in EAC and they should be bit-by-bit identical...
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IMO it's imperitive that this comparison is done, otherwise you can't say that you have a 1:1 copy (the same goes for data).

The burned CDR should always be tested.
daefeatures.co.uk

Extracting Wav files or copying cd image 1:1

Reply #4 –
EAC's "copy image and create cue sheet" is useful especially for newbies and if there's no wish for changing the audio data (deleting some tracks ect.) An image created by EAC will always be as secure as "copy selected tracks" (same read mode, options ect.) Images created by other programs are normally non-secure !
"copy image" doesn't offer CRC comparison, so maybe you want to perform the same extraction twice in order to compare the resulting images (use EAC's "compare wavs"; no message means everything's OK)
as for the loss issue:
A copy is lossless if it is bit-by-bit identical. Maybe a 1 is written as a 0,9 onto the CD and during reading it becomes a 0,8 but is still considered as being 1 and written as a 1 again on HDD. So after comparing you see there's nothing like "generation loss".
Take a word *.doc file. Copy it. Make a copy from the copy. Make a copy from the copy of the copy....
The file will never have a wrong character somewhere or a lost word ect. It's in principle the same for all digital data.
So as long as you don't get an error "file unreadable" or whatever there's no loss at all.
Perhaps you should ask some C1 error expert here (I think Pio could help).
I know that I know nothing. But how can I then know that ?

Extracting Wav files or copying cd image 1:1

Reply #5 –
I don't pretend to know alot about digital data, but I'm pretty sure when data is written, it is either a 1 or a 0.  There is no in between.  I think the errors are in reading the data, i.e. the device reads something where it isn't.

For example, 2 bits in sequence--01.  Perhaps the device reads the 2nd bit thinking it is the first one, and then reads the second one.  The result would be 11, when it is really 01.

Extracting Wav files or copying cd image 1:1

Reply #6 –
Quote
Maybe a 1 is written as a 0,9 onto the CD and during reading it becomes a 0,8 but is still considered as being 1 and written as a 1 again on HDD.

You shouldn't take this all exactly true-to-the-words...
I know that I know nothing. But how can I then know that ?

Extracting Wav files or copying cd image 1:1

Reply #7 –
When you RIP a CD to WAV, it's totally lossless and remains bit-for-bit identical.
The only difference is that WAV adds a RIFF header, which basically tags the file that as 44100Hz, 16bit, stereo. A CD player can only run at 44.1/16/Stereo, so headers are not needed. Only the raw PCM data is stored.

An Audio CD only holds a table of contents then a really, really,really long array of 16 bit, byte flipped, signed integers. Which is n00b terms is a number between -32768 and 32767.

Extracting Wav files or copying cd image 1:1

Reply #8 –
[double post removed]

Extracting Wav files or copying cd image 1:1

Reply #9 –
Quote
Which is n00b terms is a number between -32768 and 32767.

What about 32767 ? Perhaps it's only a mistake...
I noticed that CEP can't create +32768-samples during editing (in 16bit), but  it can display them. Also on some (LAUD) audio CDs I've already seen samples with value 32768.
2^15=32768; the last bit for positive/negative ? or the channel ?
I know that I know nothing. But how can I then know that ?