Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[rjm]

For years I have encountered mp3s ripped by other people that have defects such as pops and skips.
Because I have never created such an error when ripping a cd, and because I could not imagine how these errors were created, I often said under my breathe, "what a bonehead".

Well tonight I'm the bonehead and I'm hoping someone can educate me.

I ripped a cd using MC with the Lame codec and the Copy Mode set to Normal and the Read Speed set to Max. When complete, I tagged the tracks and found a few that had pops, skips, and repeats.

The probable cause of the problem is that I was doing some other heavy lifting (video encoding) at the same time. This is something I do not normally do but today I was in a rush. I also confirmed that the cd is not physically damaged and plays fine.

My assumption has always been that ripping is a fundamentally digital process. By that I mean if the cd is physically damaged I assume the drive will retry and if unsuccessful will abort and report an error. I also assume that if the computer is busy doing other things, the rip process will slow down but that there is no risk of introducing a rip error since it is just a digital calculation and not dependent on any real-time constraints.

Apparently my understanding of how ripping works is wrong. Would someone please educate me on the way rip errors can occur and how to prevent them?

Jumping ahead to possible conclusions: If I use the Secure Copy Mode, will this always prevent errors? Is it safer to Analyze Audio after the rip has completed rather than using the option to analyze during the rip? Should I avoid running other heavy tasks simultaneously?

Thanks in advance.

[rjm]

I think I figured it out.

The cd did have several tracks that were hard to read. Apparently in Normal Copy Mode disc errors are ignored which results in a bad mp3 with no warning to the user.

I tried Secure mode and it correctly reported the error.

I will be using Secure mode from now on.

[dcwebman]

I tried Secure mode and it correctly reported the error.

I will be using Secure mode from now on.

Thanks for doing that little verification test. I have been using Secure mode because that's what others have recommended. I'm glad to see it really is true. I guess I'm still back in the old days when you could only do one task at a time because the computer couldn't handle it. When ripping, video encoding, etc., I still make sure that's the only thing being done just to avoid any problems.

[tunetyme]

I've run into similar problems from time to time.  I think, I have zeroed in on the mouse as the primary culprit.  If I rip and try to do other things with my computer then I seem to get skips.  I have a wheel mouse and I think the wheel is the primary cause.  My solution is to rip and store as an APE file.  I make a copy of the folder to another location and convert back to a WAV file format.  If I don't have an error I have a good rip.  So far this has been true.  When I go back and re-rip the file, it is clean.  I don't use the secure mode.

[glynor]

I tried Secure mode and it correctly reported the error.

I will be using Secure mode from now on.

Secure Mode == Good   

Also... Dual Core CPU with a good, high-quality optical drive is key.  Unless the disc is damaged, I very rarely get bad rips (even while doing LOTS of other things with my computer at the same time).  I regularly rip while playing games and watching videos.

[rjm]

In my opinion, it is a mistake for any rip mode to ignore errors on a bad cd without notifying the user. I think Normal mode should report the error and give the user a choice of ignoring the error or deleting the track. Secure mode, which does more retires upon encountering an error and reports uncorrectable errors, works as it should. The problem is that Secure mode is significantly slower than Normal mode.

Please consider changing Normal mode to report errors.

[rjm]

I've run into similar problems from time to time.  I think, I have zeroed in on the mouse as the primary culprit.  If I rip and try to do other things with my computer then I seem to get skips.  I have a wheel mouse and I think the wheel is the primary cause.  My solution is to rip and store as an APE file.  I make a copy of the folder to another location and convert back to a WAV file format.  If I don't have an error I have a good rip.  So far this has been true.  When I go back and re-rip the file, it is clean.  I don't use the secure mode.

I can understand how a mouse (or any other device that generates a lot of real-time interrupt activity) could cause a rip problem if and only if you were using an Analog Copy Mode. In analog mode I think the cd wav data is output as an analog signal which is then digitized in real time before encoding. Any activity that steals cpu cycles could cause a bad rip because the computer must keep up with the analog data streaming off the cd.

Normal and Secure mode, on the other hand, are digital processes meaning that data comes off the cd in a digital format. Any other task that uses cpu cycles will slow the ripping process but should not introduce errors.

[tunetyme]

First, I do not use MC to rip.  I use EAC or Plex Tools on a Plextor Premium drive.  I can't explain why the mouse creates problems.  But I can play with the wheel on my mouse and the volume on MC goes up or down. 
I have an Itel board and I think it is a problem with the board not MC.  I haven't gone back to Intel because the last time I followed their trouble shooting procedures I ended up spending a week trying to recover from their ultimate solution of "re-install all your software".  Of course this didn't fix a thing.

So, when I rip, I don't do anything else on the computer.

Tunetyme
"living with it"

[rjm]

In my opinion, it is a mistake for any rip mode to ignore errors on a bad cd without notifying the user. I think Normal mode should report the error and give the user a choice of ignoring the error or deleting the track. Secure mode, which does more retires upon encountering an error and reports uncorrectable errors, works as it should. The problem is that Secure mode is significantly slower than Normal mode.

Please consider changing Normal mode to report errors.

I was thinking some more about this. I'll bet it's not so simple to detect errors on audio cds. Just guessing, but in the early days of cds, the players probably did not have the smarts to do error correction/detection. Hence audio cds do not have error correction/detection data added to the wav files. Hence the need for Secure mode to read multiple times and compare to confirm a good read. Hence the strange report produced by Secure mode which says x out of y reads were the same (but does not say with certainty that the rip was perfect). Hence Secure Mode is slower. Hence Normal mode cannot report errors even if it wanted to.

Can someone confirm this hypothesis?

[horse]

http://teamcombooks.com/mp3handbook/15.htm

http://www.treworgy.com/cdr/test.html

http://web.ncf.ca/aa571/daefaq.htm

There are some great discussions regarding jitter and DAE. Never had time to prove the above, but both my PC's use Plextor drives as I've found them to be worth the little extra and after reading the articles make me feel a little better that within reason I got the best extraction I could.

Disclosure - I don't have shares or work at Plextor :-)

[rjm]

http://teamcombooks.com/mp3handbook/15.htm

http://www.treworgy.com/cdr/test.html

http://web.ncf.ca/aa571/daefaq.htm

There are some great discussions regarding jitter and DAE. Never had time to prove the above, but both my PC's use Plextor drives as I've found them to be worth the little extra and after reading the articles make me feel a little better that within reason I got the best extraction I could.

Disclosure - I don't have shares or work at Plextor :-)

Interesting, thanks. These articles indicate that audio cds do have some error correction code, yet it is still possible to get rip errors due to seek inaccuracies of drives. I did not have time to sort out the inconsistency between these two points.

[Matt]

We believe MC has the best secure ripping system available.

If you do not use secure mode, there's no way for MC to know reliably if a read contained a possible error.  This is the whole point of secure mode -- to (at least) double-check reads and make sure it gets a bit-perfect copy.

Of course, with a disc in nice shape with a good drive, secure mode may be overkill.  Personally I like the warm fuzzy of overkill for things like this.