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Topic: AccurateRip Test #2 (Read 9857 times) previous topic - next topic
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AccurateRip Test #2

Reply #25 –
it got the same result, +12, as EAC with my liteon 24102b burner anyways.

AccurateRip Test #2

Reply #26 –
yeah, same here, but I have also had it to reccognize discs that were actually not the correct pressing and were offsetted, thereby finding the wrong offset.  I think what spoon is saying is that this won't happen with his program.
WARNING:  Changing of advanced parameters might degrade sound quality.  Modify them only if you are expirienced in audio compression!

AccurateRip Test #2

Reply #27 –
Could someone who knows Andre approch him and ask how EAC finds the offests? how it identifies a known disc and the mechanism used to find the offset on that known disc.

I think AccurateRip should be immune to different pressings, at least I hope so - there are two things in its favour - It recognises a disc on the TOC, different pressings should have different TOCs, even if they do not to find the offset it will search up and down about 2 sectors for 1 sector it knows the CRC for (50 seconds into the track), if the disc was different it shouldn't match.

AccurateRip Test #2

Reply #29 –
What if someone finds out, that his rip is not accurate (regarding to the info in the database)? What should he do? Shoot himself? What if the rip in the database is not accurate? Who wins?

AccurateRip Test #2

Reply #30 –
I don't see why different pressings would necessarily have different TOCs. The same album issued worldwide will be a loss less copy of the masters sent to the factories, but each factory will release a CD with a different offset.
At the beginning, mismatching offsets were blamed on the fact that EAC users were using american CDs while EAC's database was based on european pressings. But we realized that the offsets mistmatched even in europe, even in Germany. It is even common (see EAC mailing list) to find CDs that have the same pressing number on the inner ring (same factory etc), but different offsets.

Thinking about it, I realized that it was still possible to find the right offset using several CDs because there was more possible offsets (several thousands) than possible pressings (several ones). Thus when two offsets from two different CDs are matching, it is much more probable that they are both the same pressing as the one referenced in EAC's database, than they have both the same offset.
I should retry to detect manually my offsets (http://pageperso.aol.fr/Lyonpio2001/offset.htm). When I had the Yamaha 6416S, I found the same offset three times, that looked different from the ones reported at SatCPs for all the other drives of the same kind (4416, 8416...).
If they are still different from SatCP's on my new drives, it means that either SatCP's database is wrong (due to users relying on wrong results to calculate their offsets), either there are matching offsets that are different from the reference one. In the later case, we'd have to trade reference CDRs in order to build the database.

AccurateRip Test #2

Reply #31 –
I am ready to trade reference cd's when you are...I frankly don't think its such a bad idea.  Someone could possibly even make a small amount of donation money or even charge a small fee (which would be fine) and burn hundreds of these to cheap CMC Media and send them out to whomever needed one in the community.  CMC media would do fine, as it is the cheapest usually, and these test cds just have to last long enough to test one's drive  .  I guess he or she could charge more for Taiyo Yuden Test cds!
WARNING:  Changing of advanced parameters might degrade sound quality.  Modify them only if you are expirienced in audio compression!

AccurateRip Test #2

Reply #32 –
Quote
It is even common (see EAC mailing list) to find CDs that have the same pressing number on the inner ring (same factory etc), but different offsets.


Depending how EAC is working out the offsets - if it is pretty much the same method I will try to locate two such CDs - one of them would have to be Andres CD, another one off a user.

AccurateRip Test #2

Reply #33 –
I've nearly got two of them.
Lisa Gerrard - The mirror Pool (CAD 5009 CD - England)
Lisa Gerrard - The mirror Pool (7243 8 40592 2 4 - France)

Copy image and create cuesheet, then compare wav gives :
/1476 repeated samples at 0:00:01.062
Different samples 1:08:13.552 - 1:08:13.853 / 1:08:13.586 - 1:08:13.886
0:00:00:040 longer /

Thus they are offsetted by 1476 samples, the binary content is the same, exept the very end.

FC cuesheets gives :

Quote
Comparaison des fichiers virgin\CDImage.cue et 4ad\cdimage.cue
****** virgin\CDImage.cue
   PERFORMER "Unknown Artist"
   INDEX 00 43:15:55
   INDEX 01 43:16:07
 TRACK 13 AUDIO
****** 4ad\cdimage.cue
   PERFORMER "Unknown Artist"
   INDEX 00 43:15:42
   INDEX 01 43:16:05
 TRACK 13 AUDIO
******

****** virgin\CDImage.cue
   PERFORMER "Unknown Artist"
   INDEX 00 51:59:53
   INDEX 01 52:00:35
 TRACK 15 AUDIO
****** 4ad\cdimage.cue
   PERFORMER "Unknown Artist"
   INDEX 00 51:59:52
   INDEX 01 52:00:32
 TRACK 15 AUDIO
******


Thus the TOC only differs in tracks 12 and 14.

AccurateRip Test #2

Reply #35 –
Quote
Could someone who knows Andre approch him and ask how EAC finds the offests? how it identifies a known disc and the mechanism used to find the offset on that known disc.

As a user, you identify a known disc by reading a long list of CDs for which the data has been contributed, finding a title that you have, and checking to see if it matches the number on your pressing.  Repeat 100 times to find a couple matches.  The identity of the disc is not detected by EAC automatically for drives with unknown offsets.

I believe the database was created by users with known offsets who submitted data for CDs in their collection.

Presumably if you have a known pressing for which you have data, calculating the offset is not difficult (assuming away the issue Pio noted about different pressings having the same ID number).

AccurateRip Test #2

Reply #36 –
just noticed, the test rip method still creates directories in the output directory. Wondered why I had a crapload of directories in there and then I noticed there were no files.

AccurateRip Test #2

Reply #37 –
The next release of AccurateRip (test #3) will solve that small bugget

I have been in contact with Andre, he was most helpful, but it leaves me in two minds if there are discs out that that can upset accuraterip.

A new site accuraterip will be on line in the next few days - the goal for this site is 3 fold:

Provide AccurateRip database / resource
All drive - automatically collected and updated drive offset database
A resource for beating CopyProtected CDs - free exchange of information between developers.
 

AccurateRip Test #2

Reply #38 –
Quote
just noticed, the test rip method still creates directories in the output directory. Wondered why I had a crapload of directories in there and then I noticed there were no files.

yeah, I noticed that as well and posted something about it on the dBpoweramp board last week.

Quote
A new site accuraterip will be on line in the next few days - the goal for this site is 3 fold:

Provide AccurateRip database / resource
All drive - automatically collected and updated drive offset database
A resource for beating CopyProtected CDs - free exchange of information between developers.


I like the second one, I hadn't even thought of using AccurateRip to do that.  Great idea, because with AccurateRip, it can be verified. 
WARNING:  Changing of advanced parameters might degrade sound quality.  Modify them only if you are expirienced in audio compression!