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Audio disk ripping tools


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Well, it all depends on what you are looking for, and how much you want to involve yourself in getting the maximum fidelity from your CDs.

The problem with redbook audio CDs is that the disc data structures they use are not too tuned for perfect data preservation and perfect reading.

A CD's surface is addressed by sectors which are 2352 bytes each. That's common to any CD format, but the way they are used varies completelly.

On a redbook audio CD (your standard audio cd) all the data is used for audio samples. at 44100hz 16 bit (2 bytes) stereo, each sector contains 1/75 of a second of audio data exactly:

44100samples * 2channels * 2bytes = 176400 bytes

176400/75 = 2352

So, an audio CD is all audio data, except for the initial area in which the TOC (Table Of Contents) is written, which says how many tracks there are and where they all start and end. But there's no tracking or synchronizing information or some other important things to allow for good error detection, even less correction. This is because PCM audio can be reasonably reproduced with some jitter, ie, some bits being incorrectly read and not causing a big quality loss most of the times.

 

For CD-ROM, a single incorrect bit can be disastrous. CD-ROM is designed to carry any possible kind of computer data, and it cannot accept that uncertainty about how it will reproduce. It should allways read correclty, and if not, try to fix the error or at the very least, report it to the host computer.

For that end, CD-ROM uses part of those 2352 bytes for what its called "the subchannel", whic is a fixed quantity of NON USER DATA with error correction codes, cheksums, seeking information, etc. This all allows for a much more robust and resilient data storage, which is vital for its integrity.

 

Now, after this explanation.

 

There are many CD audio extractors.

What they try to do is recover the digital PCM data from a redbook disc as reliably as possible, but given that the format doesn't quite colaborate for that end, its a really complex task, and for now, nobody has it PERFECT UNDER ALL CIRCUMSTANCES. Its a really difficult subject and I don't have all the answers. Sometimes I even get a bit depressed when I try to impose myself with making such PERFECT rips, but then I can't be really sure if I succeed or not. If the program says there was an error, you can be sure there was, but if it says all went perfect... you can't be absolutelly sure that's the case, which is a bit of discouraging if you are like me.

The selection of the ripper/grabber/extractor to use should be done depending on your taste and a vague idea of the "secureness" level you feel comfortable with.

AFAIK, no pogram has it perfect. I used to think that of EAC, but if you read a bit in hydrogenaudio.net, you'll soon discover that things are not so clear cut.

 

There are many good ripping engines in many programs. Normally they talk about "secure ripping" in their specs. I'm not quite sure what exactly does that imply, but now I know it is no guarantee of a perfect rip. More advanced rippers, such as EAC, and dbpoweramp and some other I don't remember it's name, have a lot of settings and tweaks which are meant for EXPERTS, or, rather, magicians.

The more I understand them, the less comfortable I feel seeing how all that work doesn't guarantee perfection by any means.

 

CDex should be good, as should be foobar2000 or EAC with "normal settings".

 

Hope you found this useful. Knowledge is fear... but don't be too afraid

Edited by Radorn Keldam
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Good post Radorn Keldam. I agree that EAC is good for those who do not know how to tweak the settings. I prefer dbpoweramp and tweaking it a bit. I know that the setting can be confusing to those novice users out there but I have played around with it for a few years and come to find it is the best. For those that are not sure just play around with the setting till you get it to the taste you like.

Edited by Jitway
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There are many good ripping engines in many programs. Normally they talk about "secure ripping" in their specs. I'm not quite sure what exactly does that imply, but now I know it is no guarantee of a perfect rip. More advanced rippers, such as EAC, and dbpoweramp and some other I don't remember it's name, have a lot of settings and tweaks which are meant for EXPERTS, or, rather, magicians.

The more I understand them, the less comfortable I feel seeing how all that work doesn't guarantee perfection by any means.

 

CDex should be good, as should be foobar2000 or EAC with "normal settings".

 

Normally, CD security relates to the checking that the ripper uses, to make sure the data it rips, is exactly the same that is outputed. Often this is in the form of running checksums on data sectors to see if they match. And if not, the ripping engine will re-extract the data until its perfect. foobar2000 supports up to scanning 4 times each sector and supports offset correction, so it is a real competitor to EAC and dbpowerAMP's ripper.

 

From my personal experience, anything without sector level checking (or "secure mode") ripping, should be avoided. CDex gave me nothing but hell. EAC and foobar2000 do just about the same job. ;) Heck, there was actual tests done on the accuracy of fb2k's ripper.

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