HydrogenAudio

CD-R and Audio Hardware => CD Hardware/Software => Topic started by: gnik61 on 2012-04-19 13:24:02

Title: EAC says burned CD (offset-corrected) and original are different; why?
Post by: gnik61 on 2012-04-19 13:24:02
After having followed all the instructions and setting the writer offset (+30 for matshita UJ-220) I tried to comopare the wav's . The message is that the original and my rip are -different samples. I went through the whole process again and again but nothing. Am I missing something?
Title: EAC says burned CD (offset-corrected) and original are different; why?
Post by: pdq on 2012-04-19 14:03:24
How many samples does EAC say they are offset? Does it say there are samples missing at the beginning or end? Do you have the correct read offset?
Title: EAC says burned CD (offset-corrected) and original are different; why?
Post by: burnett_s on 2012-05-02 01:37:54
How many samples does EAC say they are offset? Does it say there are samples missing at the beginning or end? Do you have the correct read offset?


Something similar happened to me yesterday trying to setting the correct value for my HL-DT-STDVDRWBD CT30N.

I followed 2 guides:

The FIRST (http://blowfish.be/eac/Burn/burn.html) guide tells that "Missing samples" for the CDR-sourced file equals a negative offset value. If the report had said "repeated samples", the offset value would be positive instead.
So, after comparing the original and the cdr sourced file, EAC told me there were "30 missing samples". I wrote "-30" and saved setting.
But just to check if this value was really right, I burnt yet another audio CD from original rip from the retail CD with the correct offset "-30". The comparison between wave files showed "60 missing samples this time". 

The SECOND (http://filesharefreak.com/tutorials/how-to-find-your-cd-drives-write-offset-in-eac/) guide shows how to ‘Create Offset Test CD’, so I did.
I got +132, this is the sum of my Read and Write offset combined. Now I know from AccurateRip that my drives Read Offset is +102, which must make my Write Offset +30 (+102 + +30 = +132).
Now with a new CD-R, I repeated the process this time with the correct Read and Write offsets. After making a new Offset Test CD, went back to the Offset / Speed tab and ‘Detect read sample offset correction…’, I got the correct value, +102.

Conclusion

With a value of -30, Accurate Rip told me No tracks could be verified as accurate. You may have a different pressing from the one(s) in the database
With a value of +30, Accurate Rip told me All tracks accurately ripped.

The correct write offset value of my drive is +30. 

P.S: I'm using EAC (V1.0 beta 3). When it says "missing samples" maybe it means that you should put a posite value instead of negative like old versions? 

Manufacturer - HL-DT-ST (LG)
Type - DVDRWBD
Model - CT30N
Accurate Stream - YES
Caching - NO
C2 Error Info - NO
Read Command - MMC 1
Gap Detection Mode: A, Secure
Read Offset Correction - +102
Overread - ONLY IN
HTOA - YES
Write Offset - +30
Write UPC/ISRC - YES
Write CD-Text - YES
Firmware - 1.01
Title: EAC says burned CD (offset-corrected) and original are different; why?
Post by: psycho on 2012-05-02 10:39:31
Try this. (http://www.hydrogenaudio.org/forums/index.php?s=&showtopic=93391&view=findpost&p=786416)
Title: EAC says burned CD (offset-corrected) and original are different; why?
Post by: greynol on 2012-05-02 15:41:52
Yes, follow my post (http://www.hydrogenaudio.org/forums/index.php?s=&showtopic=93391&view=findpost&p=786419) in that thread, not the previous one! This discussion has made it readily apparent that going by repeated samples/missing samples is unreliable.

combined read/write samples offset correction = read samples offset correction + write samples offset

...where combined read/write samples offset correction is determined by creating an offset test CD with the write samples offset set to 0 and the read samples offset correction is determined by AccurateRip.  So long as you make sure you don't perform an arithmetic error then this will always give you the correct answer.  Determining the write samples offset is simple subtraction, just make sure you pay attention to the signs of your numbers.  There is no need to concern yourself with what is missing, what is repeated or the meaning of the words ahead or behind.

Plug and chug, baby!