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Pre-emphasis detection in EAC
kikonenko
post Dec 5 2013, 21:42
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Hi, i'm concerned about EAC's pre-emphasis detection reliability. I've made a few rips of my cd collection and some came up pre-emphasized in EAC rightmost column. Also the generated cue sheet has FLAGS PRE. This confirms that EAC has some kind of pre-emphasis detection going. Problem is i read on some other threads that pre-emphasis info may be located in two different places (TOC and subcode) and worse, as one user suggested in a thread, they may contradict each other. As an example: a cdda2wav was posted which found pre-emphasized CD that EAC(1.03) couldn't detect (emphasis logs). A little search shows more cdda2wav log results that back up that claim. Now i'd like to keep using EAC but would hope someone here can explain where exactly EAC looks for pre-emphasis (subcode? TOC? both? why is it missing pre-emp while cdda2wav detects it? the wiki says something about a TOC detection feature that could detect pre-emphasis and copyright in the subcode was discontinued in 0.95 due to European law but that paragraph is rather confusing and i don't really get what it says). I really like EAC but missing pre-emphasis on some of my rips is a huge loss i'm not willing to take.

Thanks in advance for any help smile.gif
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DVDdoug
post Dec 5 2013, 22:13
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QUOTE
I really like EAC but missing pre-emphasis on some of my rips is a huge loss i'm not willing to take.
If there is pre-emphasis, you should hear a difference between the rip and the played CD. If the rip sounds OK, you've got nothing to worry about. wink.gif If the rip is overly bright, you'll need to de-emphasize.

As far as I know EAC doesn't apply de-emphasis, so it's just a warning flag and it's not going to affect the sound in either case.
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pdq
post Dec 5 2013, 22:28
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Are you sure that any of your CDs actually have pre-emphasis? AFAIK there are virtually no discs less than 25 years old that have it.
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greynol
post Dec 5 2013, 22:53
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EAC detects pre-emphasis in TOC only. Whether manual TOC "detection" will find it in the sub-channel data on a per-track basis has been left for user experimentation:
http://www.digital-inn.de/threads/pre-emph...e-in-eac.19034/


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kikonenko
post Dec 5 2013, 22:57
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Hi, yeah it's just that i have a moderately large collection (think few hundreds) and i don't really have the time to listen to them all at the time of ripping. I'm doing this for archival purposes and i'd like my rips to accurately reflect the album's audio contents. Pre emphasis might be noticeable on some albums, but not all. I find joy in analysing more thoroughly the albums i like the most with a good audio analysis app but i wouldn't like this to become an habit for every album i rip. A good ripping program should be able to accurately report what albums have this feature. Actually i don't deemphasize them because that's a lossy process and i want to keep it exactly like it was on cd. Instead i use the F2K de-emphasize addon which does it on the go.

Yeah my albums are quite old wink.gif but pre-emphasis isn't a thing from the past, at least not for some labels who consistently use it in their issues. Besides i read some reissues of old albums have it.

Basically i'd like to know how exactly does EAC (1.03) detect pre-emphasis and why it might be missing the flags for some.

Thanks smile.gif
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kikonenko
post Dec 5 2013, 23:04
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Sorry was typing while you posted. Thanks exactly what i was looking for. I notice the thread you linked is a bit old. I read about 0.95 dropping some TOC reading support.

"Removed features: EAC 0.9 beta 1 (21 Jan 2001) through 0.95 beta 3 (30 Aug 2005) had manual TOC detection as an option, useful if a CD is defective and displays wrong track positions or data tracks instead of audio; EAC will try to detect the CD structure by analysis." This could also be used to detect pre-emphasis and copyright flags in the subcode, since they're sometimes missing from the TOC. The manual TOC detection feature was removed in 0.95 beta 4 (21 Feb 2006) due to European legislation which would outlaw software capable of circumventing a certain type of CD copy protection involving erroneous TOC data."

Do you know if as of 1.03 EAC still reads that TOC data accurately? Thanks a bunch.

This post has been edited by kikonenko: Dec 5 2013, 23:08
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greynol
post Dec 5 2013, 23:11
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Post-0.95b3 reads from TOC only. Determining whether any previous versions could read from the sub-channel data on a per-track basis is left as an exercise for the user. By V0.95b4, the final alternate means of attempting to get a TOC that matches the proper structure of the audio portion of a disc was removed in an attempt to comply with laws prohibiting the circumvention of copyright protection

Anyway, if you're paranoid, use cdda2wav. If you're more paranoid use both.

If you wish to improve the knowledge base rather than just leech from it, do both and report your findings.

PS:
Here's a screenshot of V0.95b3 showing the last remaining TOC alteration option:
Attached Image


Some earlier versions had additional TOC detection options, though I already quoted the author as saying he didn't know they would work. Perhaps EAC could only ever detect pre-emphasis data from the TOC. Does anyone have any information to the contrary?

This post has been edited by greynol: Jul 30 2014, 20:45
Reason for edit: edited for clarity. It was never my intention to imply that I believe any versions of EAC can detect pre-emphasis information from subcode.


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kikonenko
post Dec 6 2013, 00:16
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Thanks, i'll make sure to post regularly with my findings. I'd hope TOC pre-emphasis data matches the subcode data for most cd's, but just to be safe i'll try cdda2wav.

This post has been edited by kikonenko: Dec 6 2013, 00:17
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edwardar
post Dec 6 2013, 10:18
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I use Cueripper, which detects pre-emphasis in the TOC or subcode.

It's frustrating that EAC dropped this feature. I believe it was over issues of copy protection, but I don't see why the pre-emphasis detection function couldn't have been left in.

Anyway, there is an interesting thread on SteveHoffman forums where people list CDs with pre-emphasis:
http://forums.stevehoffman.tv/threads/pre-...16#post-9713720
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greynol
post Dec 6 2013, 13:54
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The link I provided makes it evident that the feature was never intended to detect pre emphasis in what Andre was deeming an incorrectly authored disc (be uses the term illegal). It is readily apparent (to me at least) that Andre doesn't even know if the detection routine would even work.

Regardless, thanks for suggesting another alternative. I found CUERipper to be painfully slow with caching drives, even worse than EAC with the bone-headed monkey-see, monkey-do settings/ripping method.


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Porcus
post Dec 6 2013, 21:00
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Re detection software: dBpoweramp does only detect TOC, just like (recent) EACs.

Re the claim that no-one applies pre-emphasis anymore:
-> For classical music, old recordings are routinely repackaged by some (budget?) label: http://www.hydrogenaudio.org/forums/index....rt=#entry796949
-> Even a few new recordings: http://www.hydrogenaudio.org/forums/index....&pid=793938

Re whether TOC and subchannel agree ... and are correct:
-> The flag need not be correctly set. There could be false positives. And once the pre-emphasis EQ curve is applied, there is no sure guarantee against someone putting it on disc without setting the flag. And it need not be that EQ curve either - a Dolby'ed mastering is blamed for the sound on some early CD version of Skinny Puppy's "Rabies".
-> Another thread here: http://www.hydrogenaudio.org/forums/index....howtopic=100678
-> Here is one release claimed to be flagged only in subcode. http://www.discogs.com/Pink-Floyd-The-Dark.../release/667546
-> In connection to the thread mentioned by the OP, here are three samples of "Money":
http://www.hydrogenaudio.org/forums/index....showtopic=97318


Have a listen at the third - a release I have not stated any identification on - what do you think?


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Lazlo Nibble
post Feb 1 2014, 22:41
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Unfortunately it's not uncommon for discs to have the PRE flag set in the subcodes but not the TOC. My ripping workflow includes a cdrdao pass to check TOC data against the subcodes and so far I've uncovered a half-dozen or more examples in my collection, including titles mastered as late as 1989 (The Blue Nile's Hats) and pressed well into the mid-'90s (my copy of Sandra's The Long Play, which has an IFPI mould SID). If you want to know for sure, you have to check the subcodes.

I maintain a list of discs known to have pre-emphasis here, based largely on information from the Hoffman forums thread. It includes matrix code and TOC-vs.-subcode flag information where I've been able to get it.
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drSeehas
post Jul 29 2014, 19:21
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QUOTE (greynol @ Dec 5 2013, 23:11) *
Post-0.95b3 reads from TOC only. ...

I have a version 0.95 beta 3 from 26. August 2005 with a file date of 30 ‎August ‎2005, ‏‎00:07:48 on my machine running and there is no "Manually Detect TOC".
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mjb2006
post Jul 29 2014, 22:24
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I don't have 0.95 beta 3, so I can't confirm, but from the 0.95 beta 4 News.rtf:

CODE
What’s new in version 0.95 beta 4
===========================

Removed “Retrieve native TOC”
Several bug fixes, mainly bug on creation of CD images not showing the file dialog
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drSeehas
post Jul 29 2014, 22:59
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QUOTE (mjb2006 @ Jul 29 2014, 22:24) *
... What’s new in version 0.95 beta 4
===========================

Removed “Retrieve native TOC” ...

So nothing was left in "TOC Alterations".
In 0.95 prebeta 4 "Detect TOC Manually" was removed.
It should read "Post-0.95pb3 reads from TOC only". The "p" (for pre) is missing.
0.95pb3 (May 11, 2003) != 0.95b3
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mjb2006
post Jul 30 2014, 08:29
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Hmm, well, I'm not sure what you are trying to say, but to clarify:

It is not "Manually Detect TOC" or "Detect TOC Manually". The name of the action is "Retrieve Native TOC" and it was available in all versions of EAC from 0.9 beta 1 (21 Jan 2001) through 0.95 beta 3 (30 Aug 2005). This includes 0.95pb3 and 0.95b3. See greynol's screenshot above.

(By default, EAC's main window shows track boundaries, gaps, flags, etc. as read from the disc's TOC data in the lead-in area at the beginning of the disc. When you select "Retrieve Native TOC", the data in the main window is replaced with the results of scanning the CD's subcode for what may be better information.)
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drSeehas
post Jul 30 2014, 10:32
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QUOTE (mjb2006 @ Jul 30 2014, 09:29) *
... It is not "Manually Detect TOC" or "Detect TOC Manually".

So we disagree.
AFAIR only "Manually Detect TOC" or "Detect TOC Manually" could be used to detect pre-emphasis in subcode in cases where the PE flag is missing in the TOC.
And this was removed definitively in 0.95 pb4 (and wasn't hence in 0.95 beta 3 either).

QUOTE
The name of the action is "Retrieve Native TOC" and it was available in all versions of EAC from 0.9 beta 1 (21 Jan 2001) through 0.95 beta 3 (30 Aug 2005). This includes 0.95pb3 and 0.95b3. See greynol's screenshot above.

Correct, we agree. :-)
But AFAIR with "Retrieve Native TOC" you couldn't detect pre-emphasis in subcode.

Unfortunately the latest? version 1.0 beta 3 from 29. August 2011 is installed here, which misses both. So I can't verify this case anymore. Indeed I still have CDs with pre-emphasis but I can't remember anyway which one of these are missing the pre-emphasis flag in the TOC.
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mjb2006
post Jul 30 2014, 12:38
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OK, clearly I need to research this further...
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Lazlo Nibble
post Jul 31 2014, 00:30
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FWIW, I verified it by running v0.95pb3 and drSeehas is right: Detect TOC Manually is the command that pulls (pulled) the flag information from the subcodes, and which was removed in 0.95pb4 (without a corresponding note in the News or What's New files). Retrieve Native TOC re-reads the TRACK 00 TOC as if you were reloading the disc, but without clearing things like track and artist names. I assume Retrieve Native TOC was kept around for a while after Detect TOC Manually was removed because it can also be used to clear the Gap column back to "Unknown" after you manually run Detect Gaps.

Unforunately the other values returned by Detect TOC Manually are all over the map; repeated runs on the same disc in the same drive with the same gap detection settings can return completely different TRACK and INDEX values. So it's really only useful for double-checking the pre-emphasis flag.
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Lazlo Nibble
post Jul 31 2014, 04:07
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Supporting information, as requested by greynol:

I validated EAC's error handling using the original Japanese release of Wynton Marsalis' self-titled debut album (1982, CBS/Sony 35DP 33, pressed by CBS/Sony, matrix 35DP-33 11C4). On initial load, EAC v0.95pb3 shows "No" for all tracks in the Pre-Emphasis column and includes no flag information in the cuesheet:

CODE
PERFORMER "Wynton Marsalis"
TITLE "Wynton Marsalis"
FILE "Range.wav" WAVE
TRACK 01 AUDIO
TITLE "Father Time"
PERFORMER "Wynton Marsalis"
INDEX 01 00:00:00
TRACK 02 AUDIO
TITLE "I'll Be There When The Time Is Right"
PERFORMER "Wynton Marsalis"
INDEX 01 08:12:50
TRACK 03 AUDIO
TITLE "RJ"
PERFORMER "Wynton Marsalis"
INDEX 01 10:48:00
TRACK 04 AUDIO
TITLE "Hesitation"
PERFORMER "Wynton Marsalis"
INDEX 01 14:39:25
TRACK 05 AUDIO
TITLE "Sister Cheryl"
PERFORMER "Wynton Marsalis"
INDEX 00 20:19:00
INDEX 01 20:24:00
TRACK 06 AUDIO
TITLE "Who Can I Turn To (When Nobody Needs Me)"
PERFORMER "Wynton Marsalis"
INDEX 01 27:47:50
TRACK 07 AUDIO
TITLE "Twilight"
PERFORMER "Wynton Marsalis"
INDEX 01 32:27:00


After running a Detect TOC Manually the Pre-Emphasis column shows "Yes" for all tracks and each track in the cuesheet has a FLAGS PRE line (and bad INDEX 00s for all tracks):

CODE
PERFORMER "Wynton Marsalis"
TITLE "Wynton Marsalis"
FILE "Range.wav" WAVE
TRACK 01 AUDIO
TITLE "Father Time"
PERFORMER "Wynton Marsalis"
FLAGS PRE
INDEX 00 00:00:00
INDEX 01 00:00:07
TRACK 02 AUDIO
TITLE "I'll Be There When The Time Is Right"
PERFORMER "Wynton Marsalis"
FLAGS PRE
INDEX 00 00:00:00
INDEX 01 08:12:61
TRACK 03 AUDIO
TITLE "RJ"
PERFORMER "Wynton Marsalis"
FLAGS PRE
INDEX 00 00:00:00
INDEX 01 10:48:09
TRACK 04 AUDIO
TITLE "Hesitation"
PERFORMER "Wynton Marsalis"
FLAGS PRE
INDEX 00 00:00:00
INDEX 01 14:39:40
TRACK 05 AUDIO
TITLE "Sister Cheryl"
PERFORMER "Wynton Marsalis"
FLAGS PRE
INDEX 00 00:00:00
INDEX 01 20:24:11
TRACK 06 AUDIO
TITLE "Who Can I Turn To (When Nobody Needs Me)"
PERFORMER "Wynton Marsalis"
FLAGS PRE
INDEX 00 00:00:00
INDEX 01 27:47:63
TRACK 07 AUDIO
TITLE "Twilight"
PERFORMER "Wynton Marsalis"
FLAGS PRE
INDEX 00 00:00:00
INDEX 01 32:27:13


This is consistent with the disc having the PRE flag in the subcodes but not the TRACK 00 TOC, which CDRDAO confirms:

CODE
PQ sub-channel reading (audio track) is supported, data format is BCD.
Raw P-W sub-channel reading (audio track) is supported.
Cooked R-W sub-channel reading (audio track) is supported.
Analyzing track 01 (AUDIO): start 00:00:00, length 08:12:50...
WARNING: Pre-emphasis flag of track differs from TOC - toc file contains TOC setting.
Analyzing track 02 (AUDIO): start 08:12:50, length 02:35:25...
WARNING: Pre-emphasis flag of track differs from TOC - toc file contains TOC setting.
Analyzing track 03 (AUDIO): start 10:48:00, length 03:51:25...
WARNING: Pre-emphasis flag of track differs from TOC - toc file contains TOC setting.
Analyzing track 04 (AUDIO): start 14:39:25, length 05:44:50...
WARNING: Pre-emphasis flag of track differs from TOC - toc file contains TOC setting.
Analyzing track 05 (AUDIO): start 20:24:00, length 07:23:50...
Found pre-gap: 00:05:00
WARNING: Pre-emphasis flag of track differs from TOC - toc file contains TOC setting.
Analyzing track 06 (AUDIO): start 27:47:50, length 04:39:25...
WARNING: Pre-emphasis flag of track differs from TOC - toc file contains TOC setting.
Analyzing track 07 (AUDIO): start 32:27:00, length 08:42:00...
WARNING: Pre-emphasis flag of track differs from TOC - toc file contains TOC setting.


The CDRDAO TOC file indicates no pre-emphasis:


CODE
CD_DA


// Track 1
TRACK AUDIO
NO COPY
NO PRE_EMPHASIS
TWO_CHANNEL_AUDIO
FILE "data.wav" 0 08:12:50


// Track 2
TRACK AUDIO
NO COPY
NO PRE_EMPHASIS
TWO_CHANNEL_AUDIO
FILE "data.wav" 08:12:50 02:35:25


// Track 3
TRACK AUDIO
NO COPY
NO PRE_EMPHASIS
TWO_CHANNEL_AUDIO
FILE "data.wav" 10:48:00 03:51:25


// Track 4
TRACK AUDIO
NO COPY
NO PRE_EMPHASIS
TWO_CHANNEL_AUDIO
FILE "data.wav" 14:39:25 05:39:50


// Track 5
TRACK AUDIO
NO COPY
NO PRE_EMPHASIS
TWO_CHANNEL_AUDIO
FILE "data.wav" 20:19:00 07:28:50
START 00:05:00


// Track 6
TRACK AUDIO
NO COPY
NO PRE_EMPHASIS
TWO_CHANNEL_AUDIO
FILE "data.wav" 27:47:50 04:39:25


// Track 7
TRACK AUDIO
NO COPY
NO PRE_EMPHASIS
TWO_CHANNEL_AUDIO
FILE "data.wav" 32:27:00 08:42:00
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drSeehas
post Jul 31 2014, 07:29
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QUOTE (Lazlo Nibble @ Jul 31 2014, 01:30) *
... running v0.95pb3 and drSeehas is right: Detect TOC Manually is the command that pulls (pulled) the flag information from the subcodes, and which was removed in 0.95pb4 ...

Thank you!
So my memory isn't too bad...
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mjb2006
post Jul 31 2014, 08:45
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Thanks guys. I updated the Removed features section of the EAC article in our wiki.
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drSeehas
post Jul 31 2014, 08:57
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QUOTE (mjb2006 @ Jul 31 2014, 09:45) *
... I updated the Removed features section of the EAC article in our wiki.

Thank you.
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2Bdecided
post Jul 31 2014, 09:03
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QUOTE (Lazlo Nibble @ Feb 1 2014, 22:41) *
I maintain a list of discs known to have pre-emphasis here, based largely on information from the Hoffman forums thread. It includes matrix code and TOC-vs.-subcode flag information where I've been able to get it.
Lazlo Studio Nibble: how would I add an entry to that list?

HA mods: do you think we should/could have a semi-openly editable list in the HA wiki? The paranoid person in me thinks it would be helpful to have the cdda2wav output linked on file to prove which discs have been checked properly. And/or it would be helpful to have direct links to posts/threads where a particular release had been discussed.

I know each of us can check ourselves, but doing that when ripping is an extra step (even in programs that do it automatically, it's an extra bit of time when you put the disc in).

Cheers,
David.
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Lazlo Nibble
post Aug 7 2014, 01:36
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QUOTE (2Bdecided @ Jul 31 2014, 02:03) *
Lazlo Studio Nibble: how would I add an entry to that list?

Email or PM me, preferably with as much detail as you see for other entries in the list. Matrix codes are particularly important.
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