EAC... how perfect? How does it work?, Redundant, but more detailed questions Options

[Radetzky]

I've been reading HydrogenAudio for a couple of weeks now and think
this place is a real gem for audio nuts.

I am about ready to proceed to backup about 250 CDs of mine on a
RAID-1 setup. I plan to rip all the CDs using a LGE HL-DT-ST RW/DVD
GCC-4240N drive and EAC 0.9b4.

Though, before doing do, I would love to have your input regarding a
couple of points I have a hard time with. I hope you won't find these
questions redundant. I know some, or most, have already been asked
but I never was satisfied with the answers (*not* that I think anybody
_has_ to provide an answer I will be happy with...).

So here goes for the questions :

1. Is it true that (at minimum) in any of the Secure modes EAC will
read at least twice every thing it reads? I ask so because there
are no confirmation anywhere in the software that it is doing so.
It would be nice if during the rip process a little string saying
"currently reading each sector twice" or something would appear.

When, if ever, does EAC perform only one read of the audio?

2. Exactly what does it read twice? How big is the chunk of data that
is being read? 10x2352 bytes? 2352 bytes? 1 bit?

3. I know this has already been asked at digital-inn.de, but I don't
think I understood the answer fully. How sure can we be that EAC
really does detect and "correct" errors?

I mean, lets say there is a minor scratch on one of my CDs. My
drive reads through the scratch.. the returned data is, say 0x2431.
It reads again and the data is still 0x2431. EAC thinks this is
fine. But the scratch is done in such a way that the reflected
information is always the same, AND wrong. How could EAC deal with
this physical anomaly?

I remember Andre (the author of EAC) said something like it was
very unlikely that the same data could be read from a scratch or
spot (or whatever damage there is) on the CD. But how sure are we
of that?

4. If I intend to keep all the ripped music on my computer and not
duplicate it on, say, CD-R media, should I go nuts with the
offsets?

I did tests myself and I tried to inject a -10000 offset and then a
+10000 offset and it didn't mater at all sound wise. I checked
with a WAV editor (Audacity) and the difference (the time-offset)
was really minimal and only cutting or adding silence (haven't
found a CD that starts with music too soon).

If I want to extract all the tracks as one big WAV file, am I right
to say that the digital extraction is successful anyway, that the
offset only induces a time-shift (a very, very small one)? Or is
there a subtlety I didn't grasp?

5. A very important (to me) question. When EAC commands the drive to
read whatever amount it has to during its rip process, what error
correction is performed by the drive? Is it using the Reed Salomon
ECC error codes from the disc?

In DAE mode (... is it a 'mode' ?), if the drive detects a problem
on the disc (scratch, etc.) will it try to interpolate between two
points or will it just send the data back unmodified?

Asked differently, in DAE mode does the drive treat the audio data
as audio or as data?

Reading http://www.roxio.com/en/support/cdr/cderrors.html leads one
to believe there are many more problems to deal with that "only"
scratches and finger prints. The actual CD might have errors
injected during its pressing (!).

6. I have a HL-DT-ST RW/DVD GCC-4240N drive. It is a low-profile
combo (DVD + CD-RW) drive. When I perform a rip using EAC and this
drive, will it be of the same quality from a rip performed from,
say, a Plextor Ultraplex drive?

7. Last question... what is the ETA for the next release of EAC?

Thanks for your time and patience ! :-)

[Pio2001]

EAC will have received 12, 13, 15 both times but it will be from
an interpolated value.

Right.

if the drive always provide the same value
from it's interpolation technique... we have a problem, no?

if I extract a track with a
cheap drive and the same track with the best DAE capable drive and
EAC reports that the extraction went by without any error, will I have the _exact_ same .wav file on my
hdd ?

When I asked this very question in the EAC forum ( http://www.digital-inn.de/showthread.php?t...?threadid=15838 ), Andre didn't seem to understand what the hell I meant by "returning the erroneous value unchanged". For him, a wrong value, interpolated or muted, was always the same when reread.
Anyway, when I got my drives (Teac e540, Sony DDU1621, Memorex DVDMaxx1648) that all interpolate, thus return always the same value when an error occurs, I tested them in secure mode (I lost the logs), and saw, for at least one of them, but I think it was for the three of them, that reading twice, on CD with lots of errors, but all correctable, could sometimes return same CRC where C2 could not.
But it might have been twice the same wrong CRC. Here, all we can rely on is the reports about same wrong CRC, that occur much less than different CRC with no errors occured in C2 mode. See my first post.
Note that a different CRC with no errors occured is nothing more than different matching CRC for a tiny bit of track (the zone that was wrongly corrected).

When you talked about the 'quality', you were referring to the way the
drive interpolates between points if an error is detected?

Not at all

If not, what did you mean

Bad drive :
Millions of errors detected, barely 10 % of them correctable, speed falls to 0x.

Good drive :
Same CD, 32x secure mode, no error detected, quality 100%, CRC OK.

and how would the sucessfully reported extraction from EAC differ when it is performed from a el-cheapo CD-ROM drive from a top of the line, made for DAE, CD-ROM drive?

This is not what I meant, this question is entierly about the secure mode performance as discussed previously (C2 accuracy, possibility of having wrong matching CRCs...)

will "Burst Mode" will be better than "Fast Mode" in any case, or also depends on the drive?

We must test.

And for interesting threads about secure mode, don't forget to browse the secure mode section of the HydrogenAudio FAQ