Jump to content
IGNORED

Great reference article on CD ripping - comparing various methods with supporting data...


happybob

Recommended Posts

Hi All,

 

Just thought I'd share this useful site I recently ran across - that compares (with lots of data) various CD ripping methodologies (HW and SW).

 

http://www.designwsound.com/dwsblog/?page_id=535

 

Basic bottom line is that you can do an essentially "perfect" or maybe even truly "perfect" CD rip with basic SW like iTunes now (this test was done about 1 year ago and the situation is likely even better now...)

 

Enjoy,

 

-Bob

 

Link to comment

You're quite right, itunes can do a perfect rip, but not all the time, and you don't know when it's done one.

 

Quoting comments following the article:

 

JM: Your data does not show a test on scratched, smudged, damaged, or aged CDs. If you just use a new, crisp CD for your tests then any special features for an exact audio copy or wavelab aren’t going to be used.

 

admin: Hi JM, you are very correct. I have no intention to say that iTunes is better than EAC or Wavelab on CD ripping, it is not. This article is a follow up article to show that bit transparent can be achieved by iTunes, EAC and Wavelab. I guess the Amarra will be the thing for audiophile to playback music.

 

I'm sure itunes is convenient, but it hasn't been designed as an accurate ripper. Some cds of mine are too damaged to be read accurately (and skip in a CD player), some I have managed to rip most tracks, and some, very satisfyingly, dbpoweramp has extracted an accurate rip from after several hours of work. Probably 70% were deemed accurate following the first pass - something only possible with the accuraterip database - and itunes should have ripped these perfectly too. But you don't know which ones it's ripped perfectly ;)

 

Link to comment

Good points you make... and it would be a very nice addition if iTunes could include even an indicator if the rip wasn't perfect...

 

I've given this issue some more thought and I'd like to put things in a different perspective...

 

Let's take your experience (that 70% of discs are fine and the other 30% have defects) as a starting point; Before I go on, I'd say my experience is that only a very small percent (maybe a couple % of my 1000 CDs ever give me any indication of skipping on a CD player - but skipping is an indication that even interpolation on the player isn't working so again we'll run with your 70% number for the moment...). What this would mean is that 3 out of 10 discs has maybe one track that can't be ripped perfectly with iTunes (each track is ripped as a separate file so I'm assuming errors in one track have no effect on other tracks - I assume this is a correct assumption). This then means that only 3 out of 100 tracks (assuming a very rough average of 10 tracks/CD) fail to rip perfectly with iTunes on average. And even then, the "non-perfect" rip portion most likely only effects a very small portion of a given track - say maybe 1% of the time of the track (kind of like a pop and click on a record only likely even less-obtrusive).

 

Back to the "perspective" theme...using the above assumptions, this means that more than 99.97% of the playback time (i.e. 3% of the tracks have an error that effects 1% of that playback time) the disc plays back perfectly with an iTunes rip; the other 0.03% of the time, there is an error which may or may not be audible (and according to an earlier comment by Chris - he has not been able to hear any audible differences in CD rips)... It seems to me that I'm pretty satisfied with that number and not needing to go to a lot of extra efforts to raise 99.97 to 99.999% or 100%. Although again, it would be quite nice if iTunes could let us know when it didn't do a perfect rip just so we could re-rip these discs with other SW that uses database, etc.

 

Now, some would say - isn't this what being an audiophile is all about - going after that last .01%?? I'd say not really; let me explain... To me this issue is similar to the issue of cleaning records vs. the basic sound quality of the record playback. I.e. to what extent to you spend time and effort and $$ to eliminate every last piece of dust on your record (including playback in a dust-free environment) vs. to what extent do you strive to make the overall sound of your record playback better? Personally, I'd put most of my time into making the overall playback sound better and then not worry too much about the very occasional pop or click.

 

In a similar fashion, if we assume we only have so much time and energy to spend on our systems - do we want to spend our time and energy doing perfect rips (to bring the 99.97% up to 100%) or do we want to spend that time and energy improving the overall sound of our playback system? (choosing and optimizing playback hardware, software, analog components, room acoustics, etc.). At this point, I'll choose the latter option of optimizing overall sound vs. eliminating the very occasional glitch (and I'm guessing so will most audiophiles), but I still salute those who do strive to improve ripping accuracy as this only benefits the state of the art - and likely helps companies like Apple fold these techniques into their products...

 

Cheers,

 

-Bob

 

Link to comment

Hi Bob,

 

I agree on the perspective point - I'm not into going OTT for imperceptible benefits. But I don't think your maths is quite right!

 

On the 30% number, that could mean that there is a single erroneous read on 30% of my CDs, which works out at some infinitesimal proportion of total play time, even better than 0.03%. But that's an absolute best case. Absolute worst case, 30% of CDs are completely unreadable in a normal ripper, but can be entirely recovered by a secure ripper. The reality is somewhere in-between, and I'm not sure where, but it's definitely at a level where I would only use a secure ripper.

 

As for convenience - there's no real hassle. dbpoweramp just gets on with it. When I ripped my collection, I put any cds that failed to get an accurate rip into a separate pile from the ones that went straight through. If it was taking a long time over a particular disc, and I wanted to get on with others, I'd cancel the rip and put the CD aside to rip last of the batch (no need to watch it rip). Then the ones that didn't get an accurate rip, I'd clean with soapy water, and try again. Any outstanding failures, you can choose to live with the insecure rip, and if you like, make a note to try to rip from a CD in better condition, from a friend perhaps. I have the list, and still have to get round to sourcing the alternative copies, but I will.

 

The thing about this is get it right once, and it's right forever (long as it's adequately backed up, of course). I'm not sure Apple will ever fold this into itunes. The good rippers are able to securely rip CDs with copy protection, which may be tricky for Apple to get into. And the technology has been around for yonks - the problem of insecure ripping was solved some time ago. Itunes is well integrated in the mac world, yes, but it wouldn't be my choice even if I were a mac man, I think XLD offers secure ripping and accuraterip, and is widely recommended so hopefully it's easy to use (and may I cheekily suggest sticking with Apple when they don't offer the best technology gives them no encouragement to progress...)

 

ZZ

 

 

Link to comment

Hi ZZ,

 

Interesting about the CD ripping percents... I can say that I've literally only had 1 disc out of ~150 so far that I've tried to rip and that would not rip. But as you mention some discs did take a bit longer to rip. Maybe that's the "effective" iTunes indicator - if a disc takes a bit longer than normal to rip, it should be assumed that it needs help. Still would be nice to have true indication though as you say.

 

Regarding using Apple in general, even though their products aren't always state of the art (i.e. your good point about giving them incentive to be mediocre), they still seem to do an amazing job for a growing number of people - of dancing on the edge between upsetting folks due to lack of features and pleasing folks due to good user interfaces. But your point is well taken. In some areas they actually lead the way (pro audio) - and I sense as computer audio takes off, they'll dive in with even better support of the needed features - just to further encourage folks to use Macs instead of PCs...

 

I've tended in the past to be the kind of person who would dig into the details and make things work no matter what; I've got a technical background and can when I set my mind to something usually achieve it. About a year ago, I switched over to the Mac from Windows/PC and while I do often curse the lack of many Windows-supported options (or even the lack options in the standard Apple offerings like OSX, iTunes, etc. that are available in aftermarket SW like dBPoweramp, XLD, etc.) I find myself enjoying the extra time I have to do things since I'm not spending time on my system getting things to work - or figuring out how to get things to work. I sense this is a transition many folks are making and this I believe is why Apple is continuing to be successful. They don't do some things that many folks would want, but what they do do they do (for the most part) with a very easy to use and intuitive fashion. Definitely a trade off...

 

Now shifting gears - I'm very interested in the secure vs. insecure ripping issue you mention for copy protected / encrypted discs... I'm not sure what this entails... Is there really more of a problem ripping a CD that's encrypted then one that's not? I'm showing my ignorance here, but since I've never had a disc not rip (except for one that was badly scratched) I'm not aware of this problem. Thanks for your perspective on that...

 

Cheers,

 

-Bob

 

Link to comment

ok, let me see... this won't be perfect, just indicative...

 

some copy protection mechanisms rely on introducing deliberate errors, which will be corrected by the error correction mechanism built in to CD players, but will not be corrected by CD-ROM drives.

 

Obviously this form of copy protection reduces the potential for genuine errors to be corrected, and part of the uproar at the time involved the argument that CDs using this copy protection were not up to the red book standard.

 

Now I am not sure why, when ripping a CD, one would expect genuine errors (from minor scratches etc.) to continue to be corrected by error correction, while these copy-protection-introduced errors are definitely not resolved - although they would be resolved in a CD player. But, that's the whole point of this copy protection design, which lets you play, but not rip.

 

This CP is on my copy of When It Falls by Zero 7. It plays fine in CD players, but I couldn't get it to play on my PC a few years ago, using a variety of software, without the frequent pops and clicks introduced by the CP. They really do a good job of vandalising the rip. Only when I ripped my collection properly last year did I manage to rip this one.

 

Actually I had better correct my previous post, saying that I could rip this CD securely. Secure ripping has a particular meaning, probably best explained by Spoon's ripping guide onn the dbpoweramp website. With dbpoweramp, When It Falls wouldn't rip correctly in secure mode (dbpoweramp reported errors) and so I ripped again using 'defective by design' mode and got a good rip.

 

So, in my experience, dbpoweramp was the only software able to rip this CD, although I didn't get the confidence of secure ripping. I should ask about it on the dbpoweramp forum, but it's still on my to-do list (the CD is in the naughty pile). Frankly, if itunes manages to rip CDs with this kind of CP, then it has done as well as dbpoweramp did in this case.

 

Edit: Had I got an accurate rip match on the tracks on this CD, this would have provided complete confidence that the rip of those tracks was perfect, but I didn't get an AR match on any tracks. This may be down to my CD, but speculating and with a hazy memory, it may be that dbpoweramp was unable to match the CD to the AR database because of the CP. One for the dbpoweramp forum.

 

Link to comment

Wow, "defective by design", what an appropriate description for CD copy protection!

 

I'm wondering, this disc you have that couldn't rip normally - can it be duplicated via a simple "copy CD" function (i.e. make another optical disc copy of the CD)?? I think this is just a "bits for bits" copy mode, but maybe not...

 

So far, I've not had any experience like this with iTunes (where I literally could not rip a CD), although I'm using iTunes 9 and maybe now these copy-protected discs (if I even have any) might rip with less-than-terrible results, but still not ideal results. So maybe the rips don't have bad pops and clicks, but just don't sound good...

 

I'm wondering why the computer CD Rom drives and associated player SW don't have the same capability to resolve the copy protection? Is there special HW in the CD player to make this happen? If so, then it would seem (and maybe this is the case) that the newer copy-protected discs would not playback on old CD players?

 

-Bob

 

Link to comment

it would seem (and maybe this is the case) that the newer copy-protected discs would not playback on old CD players

 

Quite. There were all kinds of issues, including some people saying that the cds wouldn't work in their cd players. iirc, car stereos were affected worse than home players, as they are sometimes based on cd-rom type transports. All very hazy recollection, these, but it wasn't a very clever move by the industry. Of course, the industry tried to deny there was an issue, but then there was the Sony rootkit fiasco, which got Sony into serious hot water and helped to put proponents of CP onto the back foot.

 

There is a difference between CD-ROM and cd players, I'm vague on what it is, but this is a difference which secure rippers seek to bridge (plus more, like re-reads etc.) If the software can tell the CD-ROM drive to behave as a CD-player, and yet rip an ISO image, then yes, perhaps it's then possible to duplicate to a CD-R, but then I don't think that gets you any closer to ripping to a file, as the duplicate still has the CP. So that at least keeps the CD off file-sharing sites, but stops us from playing them on our PCs...

 

Link to comment

I remember the Sony rootkit fiasco... Yikes, what a mistake that was! I haven't had any discs that I can't play on old players, but then again, I haven't tried many of my newer discs on my old player... In any case - as you say even if complete dupes can be made of these discs, it still doesn't help in achieving a ripped file...

 

Thanks for all the info/perspective on this... I think I'll be investigating XLD as a backup means if/when things don't rip quickly, well or at all on iTunes...

 

Thanks again,

 

-Bob

 

Link to comment

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


×
×
  • Create New...