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Proper way to extract audio tracks from a CD.
1loser
post Jul 4 2002, 23:35
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Is it wrong to just extract the tracks from an audio CD to my hard drive with Isobuster and than use lame to convert them to a mp3? Are the tracks digital and when I use Isobuster do they stay digital?

I tried CDex and it works pretty good but is it really necessary to use a program like that to get good results?


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Pio2001
post Jul 6 2002, 23:03
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Two short remarks :

If I remember well, Alt Preset Fast Standard is not necessarily worse in quality. I think it is very slightly more unstable : sometimes a tiny bit worse, sometimes a tiny bit better than the regular APS.

As everyone will tell you here, joint stereo is better. The idea of regular stereo being better is a old myth started with a bug in the Fronhaufer encoder, and now perpetuated like a dogma by some traders who require 192 CBR stereo MP3s (while Alt Preset Standard, or even Alt preset 192 are much better).

More info : http://www.hydrogenaudio.org/forums/showth...s=&threadid=759

(hey ! This is in the beta FAQ ! When will it be online, and how will we Moderators know it, since for us it is already online ?)

Audio extraction basics

Computers CD ROM drives are mainly made for reading... CD ROMs !
A CD ROM contains files, like the hard disc of the comlputer, and they can be copied from the CD ROM to the Hard Disc.
Audio CDs don't contain files. The data is stored a bit differently. A computer can recognize an audio CD. When you play an audio CD with Windows Cd Player, Windows doesn't read the CD, it just sends an internal "play" command to the drive. The the drive, plugged into the soundcard, plays the CD by itself. The audio data are not read by the computer in this process.

But for audio processing purposes, programs were made that can perform a "Digital Audio Extraction" (DAE). They read the audio data, and convert it (without changing it) into files for computers. These are WAV files.

Any burning program : Nero, EasyCD, etc can perform a DAE. At the beginning, not all CD ROM drives were capable of DAE ! Now, more and more multimedia players (Windows Media Player 7, Winamp 3 ...) play audio CDs performing a DAE and sending the data to the soundcard internally, without cable, instead of asking the drive to play the CD with a sound quality that could vary from drive to drive.

But for a reason I couldn't explain because I don't know it (Laziness ? Patented algorithms ?), Audio extraction programs don't reproduce the playback of CD Players.
During this playback, three levels of error correction occurs :
The C1 level is quite active, and corrects the erroneous raw data, that is not readable error free. The presence of this error correction level allows to store much more data on a CD than if the raw data was required to be read reliably without error correction.
The C2 level is less active, it corrects the errors that couldn't be corrected in the C1 level.
Last, when the C2 level fails, the original data can't be guessed any more. Then the player "fills the gap" with some interpolated (=guessed) data.

This last step is not performed by audio extraction programs !

This step occurs very rarely on brand new CDs in good players. Usually never. So when you rip a CD, the result is often perfect.
But if your original CD is not perfect, if it is a CDR that was poorly burned, if it has scratches, or fingerprints, or if it's old and no more in perfect state, the last error "concealment" process is required for getting good sounding results.
Otherwise, and it is the case in computers, there are audible clicks in the extracted file.

EAC was developed to detect these clicks during the extraction, and trying to read again and get a proper result for the faulty data. Other programs have some options of this kind, like CD EX, or CDP32, but they don't match EAC, that is very complete and has a lot of advanced options for audio error detection and recovery.
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Posts in this topic
- 1loser   Proper way to extract audio tracks from a CD.   Jul 4 2002, 23:35
- - iwod   CDex and EAC both support some technique of readin...   Jul 5 2002, 03:56
- - clintb   There's nothing at all wrong to extract on your hd...   Jul 5 2002, 04:07
- - 1loser   QUOTE Originally posted by iwod CDex and EAC both...   Jul 5 2002, 06:17
- - Pio2001   QUOTE Originally posted by 1loser - Better Error ...   Jul 5 2002, 21:48
- - 1loser   QUOTE Originally posted by Pio2001 It seems to be...   Jul 6 2002, 00:42
- - theduke   QUOTE Originally posted by 1loser I don't even kn...   Jul 6 2002, 14:15
- - 1loser   QUOTE Originally posted by theduke Ripping or gr...   Jul 6 2002, 17:00
- - theduke   QUOTE Originally posted by 1loser Thx for the inf...   Jul 6 2002, 18:05
- - Case   Since nobody knew how IsoBuster extracts audio, I ...   Jul 6 2002, 19:37
- - 1loser   QUOTE Originally posted by theduke Encoding will ...   Jul 6 2002, 21:44
- - SometimesWarrior   QUOTE Originally posted by 1loser I did a compari...   Jul 6 2002, 22:07
- - Pio2001   Two short remarks : If I remember well, Alt Pres...   Jul 6 2002, 23:03
- - 1loser   Comparison using a "Sting" album --vbr-new -V 2--...   Jul 6 2002, 23:14
- - theduke   QUOTE Originally posted by Pio2001 [b]Any burning...   Jul 7 2002, 00:35
- - daniel   QUOTE I read in a Besweet document that you should...   Jul 7 2002, 00:40
- - Pio2001   QUOTE Originally posted by theduke What is the re...   Jul 7 2002, 01:57
- - 1loser   QUOTE Originally posted by daniel That was true ...   Jul 7 2002, 02:50
- - William   Just in case somebody doesn't know, vbr-new = vbr-...   Jul 7 2002, 03:55
- - greenirft   I persoanlly make an image file of an audio cd usi...   Jul 7 2002, 03:58
- - William   QUOTE Originally posted by Pio2001 If I remember...   Jul 7 2002, 04:01
- - Pio2001   QUOTE Originally posted by greenirft I haven't fo...   Jul 7 2002, 20:54
- - DSPguru   QUOTE Originally posted by 1loser I read in a Bes...   Jul 9 2002, 00:04
- - 1loser   QUOTE Originally posted by DSPguru the Only BeSwe...   Jul 9 2002, 01:04


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