ripping time

[jtwrace]

Why do some Cd's take a lot less time to rip? I've noticed that some take much longer then others...it doesn't seem to have anything to do with the age or condition. Thoughts?

 

[The Computer Audiophile]

Hi JWTrace - My first guess was all about the condition of the CD, but you blew that one out of the water. Once in a while my ripping will be very slow until I reboot my Mac. Very weird. What about the disc itself? Do the slow ones conform to the redbook standard? Some DualDiscs are not really redbook even though they play in most CD Players.

 

[jtwrace]

Yes, they do conform to the std. I've only been ripping the max 30 per day. It doesn't seem to change from the first one to the last one.

 

[jb8312]

I was wondering the same thing. When I copy a disc via my MacBook, it takes about 3:30 per disc. When I copy on my PC at work, it takes about :45 secs.

 

Both are Apple Lossless.....

 

Anyone?

 

[Roseval]

Don’t use a Mac so a bit of guess work.

If a CD is damaged error correction is applied (interpolating).

This is a property of the drive.

Ripping software often has the option to by pass the error correction of the drive. In case of an error the same sector is read over and over (EAC does this up to 80 times) and tries to find the most likely combination of bits.

This slows ripping substantially but might yield a more accurate result.

Probably you can choose in iTunes to en/disable the error correction of the optical drive.

 

 

[BEEMB]

 

In my experience condition. Ripped a new CD yesterday which was done ridiculously quickly. Some of older CD's took a little longer I'm guessing due to surface marks and minor scratches.

 

Matt.

 

[PeterSt]

I never found a reason. A brand new CD can rip slow or "normal". I guess this has to do with the general readability of a CD, and the one reads better than the other. I think EAC can slow down when it finds it can't read that well, and after that it is unrelated to error correction IMO. Slower reading is just more reliable.

 

Btw, any rip which goes in 45 seconds is suspect to a not good rip. This is unrelated to the CD, but related to the settings (of EAC etc.). Anyway with EAC any net speed above 3.5x-4.0x is no good. Just my experience.

Note this is unrelated to the drive, which may do 52x or more.

 

Also note that with EAC anyway, you just can see it is reading errors (the red squares). If they appear, the speed is obviously (and very much) influenced by that.

When EAC shows no errors, errors will be there anyway (I wrote a glitch detect program, so I can visualize it to a certain extend).

 

2c

Peter

 

[jtwrace]

Anyway with EAC any net speed above 3.5x-4.0x is no good

 

 

Peter,

 

Do you think this is true with itunes as well?

 

[PeterSt]

Sorry, But I have no idea.

 

In due time I will write some ripping software myself. Maybe I get some clues from that. :-)

 

[jtwrace]

what does this mean? It is next to "Time remaining" when ripping in itunes.

 

(3.6x) I noticed it changes as well depending on the CD...

 

[markr]

... it more closely, I think that you will see that it changes from song to song, and even during the song. I believe that this is the indicator that tells you how much faster than real time playback (1.0x) your rip is proceeding.

 

- markr

 

[jtwrace]

ahh. That makes sense.

 

[jb8312]

For a follow up: First, maybe 45 sec was a bit of an exaggeration, but it does take about 1:30 on my office computer. Second, both computers' iTunes are set up the same way (lossless and Correction on) and the age/condition of the CD makes no difference at all.

 

Whether it is an online purchase shipped to my office or a 10 year old disc from my collection, the comparative rip times are the same. About 1:30 at the office to about 3:30 on the MacBook. This fact alone caused me to get a back up HD too. I am NOT going to go through the endless weeks of ripping my collection again!

 

Any comments are welcome and encouraged!

 

[jtwrace]

I've got about 630 done....my backup HD will be here on Wednesday. This is not fun at all IMO. To help my mini I've put a fan blowing on it.

 

[markr]

First, remember that the amount of audio data on one CD can vary greatly from the amount on another CD, resulting in different rip/burn times from disc to disc. If you want to really get scientific about this, then you need to use the same disc when comparing one system to another. Just to be sure that you are comparing 'apples to apples', as it were.

 

Having said that, what speed is your macbook's optical drive rated at for CD's? The current macbook is rated to burn at 10x. No 'CD read' stat is given for it. Then, at what speed is the optical drive in your PC desktop rated? I think that there is where you will find your answer. Most laptops do not have particularly fast optical drives in them. Most desktops do.

 

I have noticed this with my hardware:

Macbook Pro:

- using the internal optical drive (probably the same drive as yours - I know it isn't a fast one) takes about what yours does,~3-4 minutes to rip a CD

- using the external FW400 optical drive I have - 24x -, it is typically less than 2 minutes to rip a CD

 

MacPro:

- w/32x optical drive takes about 1.5 minutes

 

PC Desktop:

- w/48x optical drive takes about 1.5 minutes. Usually less.

 

Not a mystery really. Just hardware limitations or specifications I suspect. I'm not sure why you mention the slower ripping speed of the Macbook causing you to buy a backup HD, but it is probably a GREAT idea to have a backup hard drive. Enjoy that "safer" feeling! If you plan on keeping the macbook for some time, I'd recommend that you do what I did and ALSO get a backup external optical drive - one that is better designed to take the wear and tear than any internal optical drive on a laptop. But that last part could just be my paranoia, and might not be the first choice of most audiophiles.

 

markr

 

 

 

 

[ldolse]

I can think of 2 things that might make a difference:

1. Different pressings can have varying quality levels. This is most obvious if you've ever bought a brand new CD and taken it home to find it skips all over the place without a scratch, but I don't see why it couldn't create a situation where there are no errors, but reading is a bit more difficult.

 

2. Balance - being mass produced, most CDs aren't perfectly balanced - that's why some CDs sound like a jet engine when you stick them in a laptop drive. Out of balance CDs are more difficult to read accurately than well balanced ones, so this can slow down ripping.

 

[markr]

Sorry JB, I see that it is jtwrace who has the backup HD coming. Getting a backup HD should definitely be on your agenda as well if it isn't already though.

 

Jtwrace, I understand your fear of the possibility of having to possibly re-rip those CD's in the future. That is a LOT of time spent at a truly tedious task. Good job on seeing that fact and doing something about it.

 

markr

 

[glt]

- Rip speed depends on h/w generation. e.g. 12X, 48X, 52X, etc.

- Rip speed depends on whether you have s/w correction on or off

- Rip speed depends also on the error correction capability of the drive. With iTunes s/w error correction off, the rip can take anywhere from 1X to 33X speed. According to tests in CDRInfo CD Drives have different capabilities to correct for errors. Some do better than others. There are some drives that are "best" in audio extraction.

- Balance: If the CD is out of balance, your drive will vibrate. If it sounds like a jet engine is because the disk is spinning really, really fast.

- Error correction is based on Reed Solomon: I didn't have the patience to figure out how it works in detail. but it is a mathematical formula. If presented with corrupted data, the software error corrector either is able to correct it or it is not. If it can't, then it may interpolate or do other guessing. Maybe some software can guess better than others, but I don't know.

- if the hardware does error correction (and some kind of guessing if it can't correct), then I would suppose that the software can't detect any error. Here you can use AcurateRip (from EAC) and leverage the large database to compare your results. The only solution then is to clean the disk or buy a new disk

- Brand new CDs can have built-in errors during the manufacturing. These will rip slower. But Typically I can get 20+X rip speed with new CDs.