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XLD - checking pregap


NotRick

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I'm using XLD on a macbook Pro 2.6 Core i7 OS/X 10.9.4 retina

 

I've used both an Apple external and a samsung external drive.

 

Every time in put in a cd to rip - XLD goes though a very time consuming process of measuring pre gap - I haven't actually timed it but, it's probably in the neighborhood of a minute or more - feels like several minutes.

 

Is that normal? Is there a setting I have screwed up?

 

EAC doesn't do this - but EAC drives me nuts. (What is it with programmers who create 1000 setup options and document 6 of them. Sorry, been programming since 1973, it's a pet peeve)

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I'm using XLD on a macbook Pro 2.6 Core i7 OS/X 10.9.4 retina

 

I've used both an Apple external and a samsung external drive.

 

Every time in put in a cd to rip - XLD goes though a very time consuming process of measuring pre gap - I haven't actually timed it but, it's probably in the neighborhood of a minute or more - feels like several minutes.

 

Is that normal? Is there a setting I have screwed up?

 

EAC doesn't do this - but EAC drives me nuts. (What is it with programmers who create 1000 setup options and document 6 of them. Sorry, been programming since 1973, it's a pet peeve)

 

Screen Shot 2014-08-17 at 6.18.31 PM.png

 

That said, I always leave this setting unchecked (i.e., I let it detect pregap). On my MacBook Pro, it only takes about 5-10 seconds / disc, so it's not an issue.

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[ATTACH=CONFIG]14155[/ATTACH]

 

That said, I always leave this setting unchecked (i.e., I let it detect pregap). On my MacBook Pro, it only takes about 5-10 seconds / disc, so it's not an issue.

 

 

 

It took just over 4 minutes with

Screen Shot 2014-08-17 at 4.49.33 PM.png

Using a [h=1]Samsung USB 2.0 Ultra Portable External DVD Writer Model SE-218CB/RSBS[/h]

about the same with the apple drive. If my understanding of pre gap is correct - then I probably need to have it on if I want to use accuraterip

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[ATTACH=CONFIG]14155[/ATTACH]

 

That said, I always leave this setting unchecked (i.e., I let it detect pregap). On my MacBook Pro, it only takes about 5-10 seconds / disc, so it's not an issue.

 

I agree with my esteemed colleague from Texas.

Silver Circle Audio | Roon | Devialet | Synology | Vivid Audio | Stillpoint Aperture | Auralic | DH Labs

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I agree with my esteemed colleague from Texas.

 

Sure, the only difference between mine and his is the auto start and eject. Changing either of those have no effect on my 4 minute "measuring pre gap" time.

 

So what kind of disc reader are you using? I wonder if it's a USB 2.0 speed issue? seems unlikely but I'm kinda stumped.

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My settings under Preferences-CD Rip have "Don't detect pregap, ISRC, and MCN" enabled. "Scan replaygain" disabled. "Verify suspicious sectors" disabled. I am using an external Apple USB Superdrive. So I don't think it is a USB 2.0 issue.

Silver Circle Audio | Roon | Devialet | Synology | Vivid Audio | Stillpoint Aperture | Auralic | DH Labs

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My settings under Preferences-CD Rip have "Don't detect pregap, ISRC, and MCN" enabled. "Scan replaygain" disabled. "Verify suspicious sectors" disabled. I am using an external Apple USB Superdrive. So I don't think it is a USB 2.0 issue.

 

Apparently you don't agree with your college from TX :) he allows the detect pre gap. As do I, so still something else.

 

I'm curious - my understanding (limited at best) is that checking pre gap allows the calculation of checksums to match the accuraterip database. When you run with it Checked (disabled) what kind of result do you get from accurate rip and do you know of any other consequences?

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Guilty as charged. ;)

 

My understanding of pre gap, which is limited, and happy to have someone prove me wrong, is that it has no impact when using the AccurateRip database.

 

When reviewing the log files (don't have one handy to look at right now) it did indicate which tracks ripped successfully without errors.

 

Maybe an expert will pipe in, I "googled" it as well and the answers are all over the place as to whether it makes a difference or not.

Silver Circle Audio | Roon | Devialet | Synology | Vivid Audio | Stillpoint Aperture | Auralic | DH Labs

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Guilty as charged. ;)

 

My understanding of pre gap, which is limited, and happy to have someone prove me wrong, is that it has no impact when using the AccurateRip database.

 

When reviewing the log files (don't have one handy to look at right now) it did indicate which tracks ripped successfully without errors.

 

Maybe an expert will pipe in, I "googled" it as well and the answers are all over the place as to whether it makes a difference or not.

 

I disabled the pre gap, ISRC and MCN. Seems to work fine - no 4 minute delay, accuaterip still works. Makes me wonder what that heck it really does - still searching web for an answer that makes some sort of sense. Most of the answers I've found seem to say - it does everything it needs to do when you rip the track before hand, then does it again while you're ripping the track - which means - it just waists time - I'd say that can't be right since it makes no sense, but then, I've been doing software since 73, so I've seen more than my share of code that makes no sense.

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I never found a good explanation of that setting either, but I did find that by disabling it my rips went a lot faster.

 

You might have an easier time solving the Big Bang Theory.

Silver Circle Audio | Roon | Devialet | Synology | Vivid Audio | Stillpoint Aperture | Auralic | DH Labs

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In my experience, the setting that grossly slows the initial scanning is the first one: Use C2 Error Pointers. Try turning that off but leaving Pre-Gap on.

 

I suspect that the purpose of Pre-Gap is to compare the duration of each track with the Accurate Rip database. I suspect the Pre-Gap is an offset in the measured duration.

HQPlayer (on 3.8 GHz 8-core i7 iMac 2020) > NAA (on 2012 Mac Mini i7) > RME ADI-2 v2 > Benchmark AHB-2 > Thiel 3.7

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  • 1 month later...
I disabled the pre gap, ISRC and MCN. Seems to work fine - no 4 minute delay, accuaterip still works. Makes me wonder what that heck it really does - still searching web for an answer that makes some sort of sense. Most of the answers I've found seem to say - it does everything it needs to do when you rip the track before hand, then does it again while you're ripping the track - which means - it just waists time - I'd say that can't be right since it makes no sense, but then, I've been doing software since 73, so I've seen more than my share of code that makes no sense.

Pregap (countdown between tracks on CD players) detection makes sense only if you intend to burn a CD. No part of the TOC of the CD, is manually read by the drive-software; so the process is slow. The information is stored in the cuesheet (like the ISRC and MCN - stored in the subchannels CD).

Pregap: index 00 in the cuesheet.

Beginning of the track is the index 01 (contained in the CD TOC)

AccurateRip only takes into account the information of the individual tracks [starting at index 01 and include audio content (or silence) of pregap of the next track] The pregap not exist as independent in the PCM data stream.

[...] "Do fathers always know more than sons?" and the father said, "yes". The next question was, "Daddy, who invented the steam engine?" and the father said, "James Watt." And then the son came back with "- but why didn't James Watt's father invent it?"

Gregory Bateson

Steps to an Ecology of Mind (...)

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Every time in put in a cd to rip - XLD goes though a very time consuming process of measuring pre gap - I haven't actually timed it but, it's probably in the neighborhood of a minute or more - feels like several minutes.
FWIW, I have the same issue with a Samsung SE-208 I bought after the internal drive of my Macbook died. Pre-gap detection can take minutes. Very annoying. I suspect that the problem is in the Samsung (firmware?). I don't rip that much, so I can live with the waiting, but it's not normal.
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  • 3 weeks later...
FWIW, I have the same issue with a Samsung SE-208 I bought after the internal drive of my Macbook died. Pre-gap detection can take minutes. Very annoying. I suspect that the problem is in the Samsung (firmware?). I don't rip that much, so I can live with the waiting, but it's not normal.

 

 

I will provide some recent experience that will add to the mystery - or confusion - depending on your POV.

 

I've ripped hundreds of discs with Macpro 13" retina ( new ) with Mavericks ( installed version) using XLD - no problems.

 

Then.... same problems identified by others re: slow pre-gap.... and slow to rip.

 

1. Changed the settings in XLD - still SLOW

 

2. Tested on my OLD system - with appropriate XLD setting NO PROBLEMS ; old system, 2008 macbook pro

with snow leopard.

 

3. Bought a brand new OWC external drive ... used it with new system - macpro retina ... XLD Still SLOW

 

4. working backwards ..... problems with XLD started when my mac did an auto update with most recent

os to 10.9.4

 

Conclusion........ ??????????

 

Any/all thoughts welcome.....

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I'm pretty sure it's an external drive thing. I used to have a late 2009 24" iMac, switched to a brand new 27" iMac, they both were using the same version OS. The new 27" does not have an internal drive like the old one, so I had to buy an external one. On my old 24" it would take like 30 seconds to read the pregap. With the new 27" and Apple Super drive it now takes several minutes. Actual ripping speeds are comparable.

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I'm pretty sure it's an external drive thing. I used to have a late 2009 24" iMac, switched to a brand new 27" iMac, they both were using the same version OS. The new 27" does not have an internal drive like the old one, so I had to buy an external one. On my old 24" it would take like 30 seconds to read the pregap. With the new 27" and Apple Super drive it now takes several minutes. Actual ripping speeds are comparable.

 

The reason I don't think it's the drive is that BOTH the owc drive and apple superdrive run fine w/ itunes.

OWC at lightning speed ( aiff) .... several discs ripped last night with owc/itunes in about 2 minutes.

 

and BOTH drives run slow with XLD. very very very slow.

 

so I'm stymied.

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The reason I don't think it's the drive is that BOTH the owc drive and apple superdrive run fine w/ itunes.

OWC at lightning speed ( aiff) .... several discs ripped last night with owc/itunes in about 2 minutes.

 

and BOTH drives run slow with XLD. very very very slow.

 

so I'm stymied.

 

just clarifying that last comment - I know XLD will take longer to rip than itunes..... we are talking here specifically about the lag time for pregap checking.

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HELP!

 

If anyone has an external drive that does not take more than 10 seconds to "check pre-gap" in XLD, please let us know!

 

I just bought an LG GE24NU40 drive (USB2), which has a mechanism similar to the OWC, and it took almost 5 minutes to read the pre-gaps on a CD that only took 4 seconds in the internal drive of my 2010 Mini. Normally I have "C2 error pointers" turned off, but it doesn't seem to matter with the external drive.

 

This a serious issue because XLD needs the pre-gaps to use the Accurate Rip database.

HQPlayer (on 3.8 GHz 8-core i7 iMac 2020) > NAA (on 2012 Mac Mini i7) > RME ADI-2 v2 > Benchmark AHB-2 > Thiel 3.7

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This a serious issue because XLD needs the pre-gaps to use the Accurate Rip database.

 

XLD will rip the pre-gaps whether or not you first read them. There is no difference in the rip if you have the "Don't detect pre-gap" selected. Do not worry.

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XLD will rip the pre-gaps whether or not you first read them. There is no difference in the rip if you have the "Don't detect pre-gap" selected. Do not worry.

 

Axiom05 - thanks for that reply- good to know actually since that means I can turn it off.

It does raise a separate question - what function does "detect pre-gap" serve?

thx

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It does raise a separate question - what function does "detect pre-gap" serve?

thx

 

Look right here: #12

 

Sorry for my english

[...] "Do fathers always know more than sons?" and the father said, "yes". The next question was, "Daddy, who invented the steam engine?" and the father said, "James Watt." And then the son came back with "- but why didn't James Watt's father invent it?"

Gregory Bateson

Steps to an Ecology of Mind (...)

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XLD will rip the pre-gaps whether or not you first read them. There is no difference in the rip if you have the "Don't detect pre-gap" selected. Do not worry.

Thanks! I ripped a CD with and without ticking "Don't detect pre-gap". I confirmed that it has no effect on the AccurateRip database comparison or any other apparent aspect of the ripping process.

 

When burning a CD, XLD purports to replicate the hidden pre-gap tracks. (The pre-gap of a track is the extra period of silence that a CD player inserts before playing that track if the track is played continuously after the preceding track rather than by selecting it directly.)

 

When ripping a CD, I confirmed that XLD does not pad the duration of any track files by the pre-gap time. Therefore, I conclude that pre-gap has no apparent effect on the files ripped by XLD.

 

I did not investigate whether pre-gap information is stored somewhere in the ripped files for purposes of subsequently burning a CD or whether the pre-gap information is lost when you quit XLD. I don't really care because, as a computer audiophile, I have no intention of burning a CD!

HQPlayer (on 3.8 GHz 8-core i7 iMac 2020) > NAA (on 2012 Mac Mini i7) > RME ADI-2 v2 > Benchmark AHB-2 > Thiel 3.7

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Exactly. The only drawback: if the CD (unusual) contains HTOA (hidden track before track 1, index 0 track 1). AccurateRip does not analyze HTOA and not all drives can read...

 

The way to play it (on a CD player) : when playing track 1 (playback always starts at index 1) , rewind to the beginning of the hidden track

 

Sorry for my english

[...] "Do fathers always know more than sons?" and the father said, "yes". The next question was, "Daddy, who invented the steam engine?" and the father said, "James Watt." And then the son came back with "- but why didn't James Watt's father invent it?"

Gregory Bateson

Steps to an Ecology of Mind (...)

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Exactly. The only drawback: if the CD (unusual) contains HTOA (hidden track before track 1, index 0 track 1). AccurateRip does not analyze HTOA and not all drives can read...

 

The way to play it (on a CD player) : when playing track 1 (playback always starts at index 1) , rewind to the beginning of the hidden track

 

Sorry for my english

 

 

Thank you.

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