[Enovikoff]

Is that data CDs have checksums which can be used for error correction, and Redbook CDs do not: they are simply a stream of bits. This means that when you read a Redbook CD, you don't know if you are getting the information that the original creator put on the CD. In many ways, it's just a digital version of a vinyl LP. I guess this was all they could do with the technology back in the 80s when it was invented, but it's woefully inadequate for assuring good copies.

 

[erin]

Quote:

Originally Posted by Enovikoff /img/forum/go_quote.gif In many ways, it's just a digital version of a vinyl LP. I guess this was all they could do with the technology back in the 80s when it was invented, but it's woefully inadequate for assuring good copies.

Thats not correct.
Im not going to explain the whole thing, but the data on redbook CD's is not an exactly linear stream of data. It has error correction data on the CD, and the data is arranged so that a scratch wont render the CD unreadable.
Its actually really very good, and a terrific effort considering when they began designing it in the late 1970's.

People should take better care of their CD's anyway.
Why do people treat them poorly and then complain that it wont play, and they cant get a good rip. How silly!

 

[Currawong]

I can't find it now, but there used to be a usenet faq (for alt.cd-rom?) which included info about how CDs work. Considering they are designed to transfer data bit-perfectly, as long as error correction is on, then, unless there are severe scratches, data should be transferred perfectly. I gather the issue with ripping is that drive firmware sometimes doesn't use (necessary) error correction when ripping, which EAC forces to be used.

 

[DWi]

Here is a brief rundown on how EAC works.

When the drive's C2 is not used (unchecked), EAC reads a chunk of data, then goes back to re-read it. It then compares both chunks to see if they match. If it matches, then it goes to the next chunk. If it does not match, it goes back and keeps trying until it gets two consecutive matching reads.

Nb. When C2 is not used, EAC already reads the entire disc twice (or more), so doing Test and Copy is really unnecessarily. I've seen No C2 + T&C result in mis-matching CRCs, but I think that is a bug in EAC. It is difficult to prove, since there is no resulting .wav file during the Test read. However, if you think that there is a reasonable probability that EAC will read the data incorrectly the exact same way twice in a row, then you should use Test and Copy. Me, I won't worry about the miniscule chance of an error that I won't hear even if I listen to it 100x with headphones.


When the drive's C2 is used (checked), EAC reads once and relies on the drive's C2 ability to detect errors.


EAC does not correct errors! (Although in an older version, there was an option to use C2 to correct errors, but due to German laws regarding circumventing copy-control, this feature was removed. In any case, the consensus is that since the majority of drives have poor C2 abilities, this is an undesirable feature.)


An important thing to note is that even if EAC gets two consecutive reads in a row, this is no guarantee that the rip is error-free! This is why you should use AccurateRip. If possible, use a CD drive (not DVD), as CDs drives are better than DVD drives at reading CDs, in general. The possible exception are Plextor-made drives.

Kudos to the guy who uses Plextools to rip. It often gets passed over when discussing secure rippers. The only real con of Plextools is not having AccurateRip.

 

[Currawong]

DWi: Thanks for the description. What I still don't get though is that, unless a CD is seriously scratched, why error correction simply wont provide an accurate rip, since CDs are designed with error correction.

 

[qusp]

excellent link on XLD its fantastic. finally an accuraterip for OSX works great

 

[MusicallySilent]

Sbooth has now put Rip into beta stages which is a AccurateRip using program for Mac OSX Rip from sbooth.org I was wondering if anyone tried this.

Probably around december I want to put my entire CD collection into flac but I was finding Max with MusicBrainz a bit difficult to get correct tags for everything. So i was thinking of maybe trying rip.

Can rip embed album art into Flac and is this possible (I thought I read somewhere it wasn't)

Also I want to then trascode the Flac into MP3 for portable use, would max do this fine and keep the tags and art intact?

What is a good (free) app for media tagging with album art in osx.

Finally should I maybe consider ripping in windows in dbpoweramp? If dbpoweramp i that much better should I use it over rip and then just come back to max for the transcoding?

I am also sorta considering buying DBPowerAmp

 

[cerbie]

Quote:

Originally Posted by Currawong /img/forum/go_quote.gif DWi: Thanks for the description. What I still don't get though is that, unless a CD is seriously scratched, why error correction simply wont provide an accurate rip, since CDs are designed with error correction.

Audio CDs are not data CDs. They specifically allow for some data loss to be acceptable. We're talking the 70s, here, when a many-KB buffer was $$$. CD audio has ECC in the stream, but if there is not enough, it tries to guess what should be there, so you don't hear that there was a problem (you can have losses on a pristine CD, when playing it for the first time!). Rereading an area of the disc was a last resort option. Data CDs have better ECC built in, and checking designed for perfect transfer at a lower speed, rather than lower data fidelity at the same speed.

Digital never guarantees a set of bits is transferred perfectly, just that the data exists as digits. The ability for perfect transfer relies on specific storage and transfer mechanisms being designed and implemented with that as a requirement. Audio CDs took playback with a small buffer, reading only once if possible, as a higher priority than perfect data transfer.

Modern readers have forsaken quality CD reading, as well. My old 8X HP burner was a flawless performer. I found out how bad things generally were only after it died. Just a sacrifice for commoditization of the technology, I guess.

 

[krmathis]

Quote:

Originally Posted by MusicallySilent /img/forum/go_quote.gif Sbooth has now put Rip into beta stages which is a AccurateRip using program for Mac OSX Rip from sbooth.org I was wondering if anyone tried this.

Rip has actually been in beta stage since last year.
I have been using it since beta 1, and it has matured a lot during the 6-7 months it has been in development. To a stage where it now feels quite stable, secure and user friendly.

Until December I am sure it has come even a way further.

 

[Currawong]

Quote:

Originally Posted by cerbie /img/forum/go_quote.gif Audio CDs are not data CDs. They specifically allow for some data loss to be acceptable. We're talking the 70s, here, when a many-KB buffer was $$$. CD audio has ECC in the stream, but if there is not enough, it tries to guess what should be there, so you don't hear that there was a problem (you can have losses on a pristine CD, when playing it for the first time!). Rereading an area of the disc was a last resort option. Data CDs have better ECC built in, and checking designed for perfect transfer at a lower speed, rather than lower data fidelity at the same speed. Digital never guarantees a set of bits is transferred perfectly, just that the data exists as digits. The ability for perfect transfer relies on specific storage and transfer mechanisms being designed and implemented with that as a requirement. Audio CDs took playback with a small buffer, reading only once if possible, as a higher priority than perfect data transfer. Modern readers have forsaken quality CD reading, as well. My old 8X HP burner was a flawless performer. I found out how bad things generally were only after it died. Just a sacrifice for commoditization of the technology, I guess.

Thanks for the explanation. Some time after I wrote my post, I found out that the error correction in Redbook was only very basic and not the same as the error correction in data CD's.

 

[leeperry]

Quote:

Originally Posted by cerbie /img/forum/go_quote.gif Modern readers have forsaken quality CD reading, as well. My old 8X HP burner was a flawless performer. I found out how bad things generally were only after it died. Just a sacrifice for commoditization of the technology, I guess.

definitely! you can get a 8X dvdrom Hitachi GD7000 for $10 on ebay...it doesn't cache audio, has fully working C2 correction and does wonderful rips! most recent burners are just a hit and miss at audio extraction

 

[MusicallySilent]

Quote:

Originally Posted by krmathis /img/forum/go_quote.gif Rip has actually been in beta stage since last year. I have been using it since beta 1, and it has matured a lot during the 6-7 months it has been in development. To a stage where it now feels quite stable, secure and user friendly. Until December I am sure it has come even a way further.

I will take your word for it, I swear i looked at their full site and didnt find it earlier this year.

So question, how is it in the tagging department is it pretty accurate? (I have found musicbrainz to be a bit lacking if im not mistaken rip doesnt use that)

What about album art? can it embedd art into files too?

 

[krmathis]

Quote:

Originally Posted by MusicallySilent /img/forum/go_quote.gif I will take your word for it, I swear i looked at their full site and didnt find it earlier this year. So question, how is it in the tagging department is it pretty accurate? (I have found musicbrainz to be a bit lacking if im not mistaken rip doesnt use that) What about album art? can it embedd art into files too?

That is because it has been closed beta until recently, only available to those granted access.
You have three sources for metadata, FreeDB, MusicBrainz and iTunes. So far not ran into any CD either of them have not found.

Embedding artwork seems to work fine as well. Just provide the picture (drag and drop) and it will embed it into the files.

 

[MusicallySilent]

Ok cool, I noticed musicbrainz could be lacking at times so having a second source would be nice. I noticed itunes didnt embed album art which became a problem with apps such as boxee.

Not sure if you ever do so but for transcoding to mp3 for portable devices, should max do the trick fine?

 

[krmathis]

Quote:

Originally Posted by MusicallySilent /img/forum/go_quote.gif Not sure if you ever do so but for transcoding to mp3 for portable devices, should max do the trick fine?

I would guess so.
Even if I have not encoded to MP3 in years, and know for certain.