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EAC Option: Fill up missing offset samples with silence?, Yes or No?
eiko
post Mar 17 2009, 02:52
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What is your opinion?

Under what circumstances does this option have any effect?

Thanks
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greynol
post Mar 17 2009, 03:12
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http://wiki.hydrogenaudio.org/index.php?title=Main_Page


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Synthetic Soul
post Mar 17 2009, 10:12
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QUOTE (greynol @ Mar 17 2009, 02:12) *

biggrin.gif I think greynol is making the point that the first place to start is to take the time to explore the wiki.

I'm either being more kind, or just encouraging you to be lazy. I hope it is the first. wink.gif

http://wiki.hydrogenaudio.org/index.php?ti...ions#Extraction


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eiko
post Mar 17 2009, 23:35
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I've read it, not enough details though... I want to know the implications for making an "exact" copy. Is that not possible due to read offsets?

Should people be "overreading" if they can? All the setup guides I've seen say to disable it.

I have a rip of the last track using both settings. With "fill missing samples" EAC says it is 0:00:00.001 longer than without it. (offset = +48)

And what are the implications if you rip from CD, then burn the ripped files to a new CDr? I guess they will both be slightly different... what one is closer to the original?

Thanks for any info....

This post has been edited by eiko: Mar 17 2009, 23:48
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greynol
post Mar 18 2009, 02:39
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QUOTE (eiko @ Mar 17 2009, 15:35) *
I've read it, not enough details though...
Nonsense.

QUOTE (eiko @ Mar 17 2009, 15:35) *
I want to know the implications for making an "exact" copy. Is that not possible due to read offsets?
Depending on how "exact" you want, maybe not. With a drive that can overread it still may not be possible.

QUOTE (eiko @ Mar 17 2009, 15:35) *
Should people be "overreading" if they can? All the setup guides I've seen say to disable it.
I think it's fair to say that most of those guides are just playing monkey-see, monkey-do. Most of their authors simply plagiarize each other without even the faintest idea about how some of the settings work. Read the guides in the HA wiki, ignore anything else you've read and you'll be ok.

I rarely give external links but here's one that might help make things more clear for you:
http://users.fulladsl.be/spb2267/offsets/offsets.htm


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eiko
post Mar 18 2009, 03:30
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Thank you greynol for that link, very interesting read.


Now I have one last question about this topic.

I just re-ripped a CD with overread enabled. (The last rip had no overread, and filled missing samples with silence.) My read offset correction is +102. I compared the WAVs of the first and last tracks and they were exactly the same. Does this indicate that the last 102 samples on the last track were silence anyways, so it was coincidentally the same? Or is there something else going on here?

This post has been edited by eiko: Mar 18 2009, 03:47
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greynol
post Mar 18 2009, 04:24
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It was coincidentally the same.

If your drive can't overread and you rip with the overreading setting enabled, one of these days you might encounter a disc where the samples from the area on the disc that your drive thinks is the lead-out are not silent and EAC will tell you there was an error. The resulting rip will have thousands of samples that were nulled out which otherwise would not have been if you had your drive configured as not being able to overread. I wish EAC handled this situation more elegantly, but unfortunately it doesn't.

How to test:
http://wiki.hydrogenaudio.org/index.php?ti...p#Drive_Options
QUOTE
Overread Lead-In and Lead-Out : Press the button that says "Detect read sample offset correction". Enable this setting if it says your drive can overread from both the Lead-In and Lead-Out or if it says Lead-Out and your offset correction is positive or if it says Lead-In and your offset correction is negative. Otherwise disable it.


This post has been edited by greynol: Mar 18 2009, 04:44


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eiko
post Mar 18 2009, 04:56
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I tested and EAC says my drive overreads both lead-in and lead-out. However I just re-ripped the last track on 8 CDs (with overreading) and I can't find ANY difference on any of them.

Should there be a difference in the last track simply by virtue of the read offset correction being positive as seems indicated here?
("Offset correction tells your drive to read a little away from its normal position. For the first or last track that implies reading out of the drive's normal read range, also called overreading."...)

Or does the CD need to be special, as seems indicated here?
("You must find a CD with audio noise running before first track and after last track."...)

For practical purposes I suppose it's rare that these CDs from the 90s & 00s don't have silence in the last 102 samples. But I'm still not 100% sure if, say, the CD's last track contained music right to the end rather than going silent, I would notice a difference between overreading and not. :-S

This post has been edited by eiko: Mar 18 2009, 04:58
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greynol
post Mar 18 2009, 05:21
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QUOTE (eiko @ Mar 17 2009, 20:56) *
However I just re-ripped the last track on 8 CDs (with overreading) and I can't find ANY difference on any of them.
...because the last 102 samples were null samples.

You need a CD where any of the last 102 samples aren't null for there to be a difference in the last track depending on whether overreading is enabled.

QUOTE
But I'm still not 100% sure if, say, the CD's last track contained music right to the end rather than going silent, I would notice a difference between overreading and not. :-S

I'm 100% sure you will never encounter a single instance where you would.


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eiko
post Mar 18 2009, 05:39
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Thanks for the info.

I guess I'm still confused what filling missing samples does then. I just ripped the last track again without filling missing samples with silence, but with overreading enabled, and the last 26 samples are different according to EAC.

The link you provided indicated to me that if you overread, there should be no difference, but this appears to be incorrect, so I'm back wondering why everyone suggests to fill missing samples with silence and what is actually filled. huh.gif

This post has been edited by eiko: Mar 18 2009, 05:56
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greynol
post Mar 18 2009, 05:54
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If overreading is enabled, the fill up offset samples with silence option is not supposed to do anything.

If overreading is not enabled, the last track will be cut short by the size of your offset correction when offset samples are not filled with silence (assuming you've entered a positive value).

Any discrepancy you find with these two postulates is either due to an error in your process, a bug in the software (either on the ripping end or the analysis end), a problem with your drive, or the disc is simply giving an error as a result of either damage or defect.

FWIW, instead of EAC's wave compare feature, I always use Adobe Audition and either zoom in or subtract one file from the other and zoom in on the difference.

On a final note, EAC has a couple of error messages about which I've only read and of which I am completely ignorant. One of them is when it reports "Too many samples", the other is when it reports "Missing samples".

This post has been edited by greynol: Mar 18 2009, 06:31
Reason for edit: Trying to make my language more precise.


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eiko
post Mar 18 2009, 06:05
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Thank you! I will test this some more with my other drives tomorrow and see what results I get. smile.gif
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eiko
post Mar 18 2009, 06:26
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Beautiful... I probably couldn't sleep without resolving this so I tested 2 CDs again and you are right, I must have made some mistake the first time.

/solved smile.gif
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