Read/Write Offset Correction - What Are the Proper Settings? - Digital-Inn

Audiophizzle · 09-02-2008

I've followed some instructions on how to adjust the read/write offset correction for my drive but I'm still a little confused. I went to EAC -> Drive Options -> Writer (tab) and created an Offset Test CD with a brand new disc, I then went to Drive Options -> Offset / Speed (tab) and detected the Read Sample Offset Correction Value. For my DVD-ROM Drive (MAD DOG MD-16XDVD9) the read sample offset correction was +66.

So what am I supposed to type in the Write Sample Offsets field? I checked the AccurateRip database and found that my DVD-ROM drive's "Correction Offset" is +48, does this mean that the Write Sample Offset should be +18? I'd appreciate any help on this.

greynol · 09-02-2008

You have it exactly right.

Audiophizzle · 09-02-2008

OK cool, I knew that this would be the right forum to ask. Hydrogenaudio Forums why won't you accept my account already!?. Sorry about that little rant.

Another thing: I'm trying to create a tutorial which include proper settings for Offset Correction. So what would be the math on this? Would it be something like:

Create Offset Test CD -> Detect Read Sample Offset Correction -> Find your CD/DVD-ROM drive Correction Offset at Accuraterip.com -> add that value to the Read Sample Offset Correction Value field -> type the difference of the Read Sample Offset Correction Value and Accuraterip's Correction Offset to the Write Sample Offset field.

Example:
Detected read sample offset correction: +66
(Accuraterip) Correction Offset: +48
Read Sample Offset Correction Value = +48
Write Sample Offset = +18

Doesn't this sound a little confusing or am I just overcomplicating things?

greynol · 09-02-2008

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

Audiophizzle · 09-02-2008

Again:

Thanks.

Audiophizzle · 12-02-2008

So should I be worried that I burned most of my CDs without any write sample offset? I guess they're not 100% bit-accurate are they.

Well at this point it doesn't seem practical to re-burn all of those CDs just to gain 18 extra samples.

wyhiwyg · 12-02-2008

> So should I be worried that I burned most of my CDs without any write sample offset? I guess they're not 100% bit-accurate are they.

No, you shouldn't be worried.

Depends how you define bit-accurate. It's pretty much going to be the same bits (with the possibility of a difference in lead-in/lead-out), just shifted slightly.

Does it matter to you if the disc is:
0 0 (74min of music) 0 0 0 0 0 0
when it should be
0 0 0 0 (74min of music) 0 0 0 0?
We're talking in the range of 0.001s difference here.

Audiophizzle · 13-02-2008

OK thanks, I'm more at ease.

RolloTomasi · 13-02-2008

I just wrote a guide on determining the write offset just the other day on another forum [not HA]. This guide is from a slightly different approach, and more fool proof, IMHO.

Quote:

Easy way to determine your Write Offset in EAC

This short guide makes the assumption that you have already correctly determined and set your drives READ offset, either by using the AccurateRip CD Drive Offset Page or by another approved method.

Using any commercial CD, rip all individual tracks [the entire CD] to WAV [F6] in EAC and make a non-compliant cue file [Actions > Create Cue > Mult WAVs with Gaps (Non-Compliant)].

When finished ripping, check that your current Write Samples Offset is set to ZERO [F10 > Writer tab].

Open EAC's CD-Writer [Alt+W] and load the non-compliant cue file you made above, and burn a copy of the CD.

When finished, close the CD-Writer module.

Select any single track from the CDR copy and rip to WAV [F6], being careful not to overwrite the files you made from the original disc [i.e. burn to a different folder]. Alternately, you can rip the entire disc.

Using the WAV compare tool [Ctrl+W], first open a WAV file from the rip of the original disc, then open the corresponding WAV file of the same track from the ripped CR-R. It is important that you open the original WAV first and the CDR WAV second.

The result tells you what your offset is. If the original WAV [left two columns] has missing samples OR if the CDR WAV [right two columns] has repeated or extraneous samples, then the offset is a positive number.

On the other hand, if the original WAV has repeated or extraneous samples OR if the CDR WAV has missing samples, the offset is a negative number. For example, if the original wav has 85 missing samples, then your offset is +85. If the original wave has 85 repeated samples, then your offset is -85.

In the first illustration shown below for my writer, the track 2 CDR WAV [info shown in right columns] shows missing samples, so my write offset is negative 30.

The second illustration is for track 1, and the Original WAV [info shown in left columns] shows repeated samples in that instance.

wyhiwyg · 10-03-2008

Instead of ripping + burning a CD, once you know the read offset, you can just burn the EAC Test CD and use that to determine the write offset.

- with write offset at 0, burn test CD
- pop that CD back in, test read offset correction (drive's write offset wll be opposite of this value)

loubat · 30-03-2008

So am I the only one that doesn't have a "Writer" tab in EAC V0.99pb4? I was interested in using it to make "more perfect" rips, but can't find anywhere to enter the value. *scratches head*

greynol · 30-03-2008

The writer tab won't show up for drives that cannot write.

loubat · 30-03-2008

Yeah, you think I would have realized that before I posted this, but nope. Alas. Thanks for the reply anyway!

Rollin · 05-04-2008

In accuraterip database my drive has offset +12. But if i create test CD by EAC and try to detect offset, then result is +1700. What may be reason of such difference?

greynol · 05-04-2008

Most drives introduce an offset upon writing.

09-02-2008	#1
Audiophizzle Registered User Junior Member Join Date: Feb 2008 Location: NJ Posts: 70 Abgegebene Danke: 2 Erhielt 2 Danke für 2 Beiträge	Read/Write Offset Correction - What Are the Proper Settings? I've followed some instructions on how to adjust the read/write offset correction for my drive but I'm still a little confused. I went to EAC -> Drive Options -> Writer (tab) and created an Offset Test CD with a brand new disc, I then went to Drive Options -> Offset / Speed (tab) and detected the Read Sample Offset Correction Value. For my DVD-ROM Drive (MAD DOG MD-16XDVD9) the read sample offset correction was +66. So what am I supposed to type in the Write Sample Offsets field? I checked the AccurateRip database and found that my DVD-ROM drive's "Correction Offset" is +48, does this mean that the Write Sample Offset should be +18? I'd appreciate any help on this.

12-02-2008	#7
wyhiwyg Registered User Senior Member (Board-Inventar) Join Date: Sep 2003 Location: vancouver.bc.ca Posts: 560 Abgegebene Danke: 0 Erhielt 0 Danke für 0 Beiträge	> So should I be worried that I burned most of my CDs without any write sample offset? I guess they're not 100% bit-accurate are they. No, you shouldn't be worried. Depends how you define bit-accurate. It's pretty much going to be the same bits (with the possibility of a difference in lead-in/lead-out), just shifted slightly. Does it matter to you if the disc is: 0 0 (74min of music) 0 0 0 0 0 0 when it should be 0 0 0 0 (74min of music) 0 0 0 0? We're talking in the range of 0.001s difference here. Last edited by wyhiwyg on 12-02-2008 at 08:32

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09-02-2008	#2
greynol Registered User Senior Member (Board-Inventar) Join Date: Aug 2006 Location: Sunny California Posts: 1.107 Abgegebene Danke: 0 Erhielt 26 Danke für 25 Beiträge	You have it exactly right.

09-02-2008	#5
Audiophizzle Registered User Junior Member Join Date: Feb 2008 Location: NJ Posts: 70 Abgegebene Danke: 2 Erhielt 2 Danke für 2 Beiträge	Again: Thanks.

13-02-2008	#8
Audiophizzle Registered User Junior Member Join Date: Feb 2008 Location: NJ Posts: 70 Abgegebene Danke: 2 Erhielt 2 Danke für 2 Beiträge	OK thanks, I'm more at ease.

10-03-2008	#10
wyhiwyg Registered User Senior Member (Board-Inventar) Join Date: Sep 2003 Location: vancouver.bc.ca Posts: 560 Abgegebene Danke: 0 Erhielt 0 Danke für 0 Beiträge	Instead of ripping + burning a CD, once you know the read offset, you can just burn the EAC Test CD and use that to determine the write offset. - with write offset at 0, burn test CD - pop that CD back in, test read offset correction (drive's write offset wll be opposite of this value)

30-03-2008	#11
loubat Registered User Board-Frischling Join Date: Sep 2006 Location: Google Posts: 2 Abgegebene Danke: 0 Erhielt 0 Danke für 0 Beiträge	So am I the only one that doesn't have a "Writer" tab in EAC V0.99pb4? I was interested in using it to make "more perfect" rips, but can't find anywhere to enter the value. scratches head

05-04-2008	#14
Rollin Registered User Board-Frischling Join Date: Apr 2008 Location: Russia/Saint-Petersburg Posts: 8 Abgegebene Danke: 0 Erhielt 0 Danke für 0 Beiträge	In accuraterip database my drive has offset +12. But if i create test CD by EAC and try to detect offset, then result is +1700. What may be reason of such difference?

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