[LAU] CDRDAO speed, CRC errors, blah

[Ken Restivo]

So I'm trying to burn this masterpeice to a CD.

$ crdao write tofile.toc

... ok here we go. It works, but then when I try to read the disk back, i get tons of CRC errors.

"5 Q sub-channels with CRC errors" .. etc etc.

Someone On The Internet (tm) said thusly:
http://linux.derkeiler.com/Mailing-Lists/Debian/2005-04/1370.html

OK, so I try to write at a lower speed.

$ cdrdao write --speed 4 tofile.toc
Starting write at speed 8...
Pausing 10 seconds - hit CTRL-C to abort.

No no no no, I said speed 4!

$ cdrdao write --speed 2 tofile.toc
Starting write at speed 8...
Pausing 10 seconds - hit CTRL-C to abort.

Arrgggh...

$ cdrdao write --speed 1 tofile.toc
Starting write at speed 8...
Pausing 10 seconds - hit CTRL-C to abort.

Hey, cdrdao, are you even listening to me!??

So, two questions:
1) Is there any reason to burn an audio CD at a speed < maximum, or is this the dreaded digital voodoo?

2) Why is cdrdao refusing to do what I tell it to do?

Thanks, all.

-ken

[Roberto]

Post by Ken Restivo
OK, so I try to write at a lower speed.
$ cdrdao write --speed 4 tofile.toc
Starting write at speed 8...
Pausing 10 seconds - hit CTRL-C to abort.
No no no no, I said speed 4!
$ cdrdao write --speed 2 tofile.toc
Starting write at speed 8...
Pausing 10 seconds - hit CTRL-C to abort.
Arrgggh...
$ cdrdao write --speed 1 tofile.toc
Starting write at speed 8...
Pausing 10 seconds - hit CTRL-C to abort.
Hey, cdrdao, are you even listening to me!??

Oh nice, so it was not my computer :) It seems it is not limited to
cdrdao, I noticed recently that growisofs (the tool that I use to write
my DVDs) also ignores the -speed=X setting. If I recall correctly, it
was previously working as expected with the same drive...

[Fons Adriaensen]

Post by Ken Restivo
Hey, cdrdao, are you even listening to me!??
1) Is there any reason to burn an audio CD at a speed < maximum, or is this the dreaded digital voodoo?
2) Why is cdrdao refusing to do what I tell it to do?

AFAIK there's no voodoo about this (yet). It probably depends on
your system if it can support the highest speed of your drive
(scheduling latencies, disk read speed, etc.).

OTOH, speed 8 is already quite slow, and it may well be the
lowest one supported by your drive (just guessing this).

If results at that speed are not as expected, you may have
to select a different driver, see man cdrdao. In my limited
experience and IIRC the generic-mmc didn't work for me, and
I had to use generic-mmc-raw. YMMV.

Ciao,

[Bob van der Poel]

Post by Fons Adriaensen
OTOH, speed 8 is already quite slow, and it may well be the
lowest one supported by your drive (just guessing this).

Sort of off topic ... but I had some older 2x DVD-RW discs that I
tried to burn on my current system. No way. I tossed the discs, my
assumption being that the drive could not go slow enough for the disc.
If I recall, I tired all the various speed= commands with growisofs,
cdrdao, etc. They would report back 8 or 4x (don't recall). I find it
somewhat odd that a drive will not slow down and am wondering if that
is due to the linux drivers or the actual drives. I'm not completely
sure, but I'm sure that the drives used to work with the dvds. Finding
better things to do with my time, I did toss the discs ... but it's a
wonderment.

[Fons Adriaensen]

Post by Bob van der Poel

Post by Fons Adriaensen
OTOH, speed 8 is already quite slow, and it may well be the
lowest one supported by your drive (just guessing this).

Sort of off topic ... but I had some older 2x DVD-RW discs that I
tried to burn on my current system. No way. I tossed the discs, my
assumption being that the drive could not go slow enough for the disc.
If I recall, I tired all the various speed= commands with growisofs,
cdrdao, etc. They would report back 8 or 4x (don't recall). I find it
somewhat odd that a drive will not slow down and am wondering if that
is due to the linux drivers or the actual drives.

It's very probably not a matter of slowing down the rotation
of the disk - it has to work at normal read speeds anyway.

The limiting factor could well be the minimum power at which
the write laser can operate - lower write speed requires less
power.

Ciao,

[Ken Restivo]

Post by Fons Adriaensen

Post by Bob van der Poel

Post by Fons Adriaensen
OTOH, speed 8 is already quite slow, and it may well be the
lowest one supported by your drive (just guessing this).

Sort of off topic ... but I had some older 2x DVD-RW discs that I
tried to burn on my current system. No way. I tossed the discs, my
assumption being that the drive could not go slow enough for the disc.
If I recall, I tired all the various speed= commands with growisofs,
cdrdao, etc. They would report back 8 or 4x (don't recall). I find it
somewhat odd that a drive will not slow down and am wondering if that
is due to the linux drivers or the actual drives.

It's very probably not a matter of slowing down the rotation
of the disk - it has to work at normal read speeds anyway.
The limiting factor could well be the minimum power at which
the write laser can operate - lower write speed requires less
power.

Makes sense; next time I'll try it with speed > 8 and see if it obeys.

But that raises the other question: does it even make sense to burn an audio CD at < maximum anyway? Are there errors introduced by burning RedBook CD's at higher speeds?

-ken

[Fons Adriaensen]

Post by Ken Restivo
But that raises the other question: does it even make sense to burn an audio CD at < maximum anyway? Are there errors introduced by burning RedBook CD's at higher speeds?

You'll have to try it. Since write speed is a marketing
point the official value can't be trusted. Half that
speed is probably reliable. For the rest, AFAIK, it's
a matter of your system being able to provide the data
in time. There's some buffering the drive, but that
can only handle so much delay.

Ciao,

[Scott]

Post by Fons Adriaensen
You'll have to try it. Since write speed is a marketing
point the official value can't be trusted. Half that
speed is probably reliable. For the rest, AFAIK, it's
a matter of your system being able to provide the data
in time. There's some buffering the drive, but that
can only handle so much delay.

I recall a study where they spun disks at speeds faster than 52x. The
result was that they disintegrated. It's probable that they set 52x as
the max due to the structural integrity of the disks, not due to other
limitations while writing.

Google is not being friendly so I can't find it, but it was on slashdot
ages ago.

-Scott

[Ken Restivo]

Post by Fons Adriaensen

Post by Ken Restivo
But that raises the other question: does it even make sense to burn an audio CD at < maximum anyway? Are there errors introduced by burning RedBook CD's at higher speeds?

You'll have to try it. Since write speed is a marketing
point the official value can't be trusted. Half that
speed is probably reliable. For the rest, AFAIK, it's
a matter of your system being able to provide the data
in time. There's some buffering the drive, but that
can only handle so much delay.

I didn't phrase my question properly.

I don't mean issues of buffering or keeping up with data; at maximum speed the buffer is 100% full the whole time.

What I meant was the sounds-like-voodoo stuff that the guy on that mailing list link was talking about: the drive being MODE2 and not having error correction and thus there being analog writing errors introduced by the laser when spinning the disc at maximum speed, and the pits being more reliable and having fewer errors when written at slower speed.

-ken

[Fons Adriaensen]

Post by Ken Restivo

Post by Fons Adriaensen

Post by Ken Restivo
But that raises the other question: does it even make sense to burn an audio CD at < maximum anyway? Are there errors introduced by burning RedBook CD's at higher speeds?

You'll have to try it. Since write speed is a marketing
point the official value can't be trusted. Half that
speed is probably reliable. For the rest, AFAIK, it's
a matter of your system being able to provide the data
in time. There's some buffering the drive, but that
can only handle so much delay.

I didn't phrase my question properly.
I don't mean issues of buffering or keeping up with data; at maximum speed the buffer is 100% full the whole time.
What I meant was the sounds-like-voodoo stuff that the guy on that mailing list link was talking about: the drive being MODE2 and not having error correction and thus there being analog writing errors introduced by the laser when spinning the disc at maximum speed, and the pits being more reliable and having fewer errors when written at slower speed.

Mode 1/2 is YellowBook, CD-ROM. Aren't you making an *Audio* CD ?

Anyway, if the pits are less reliable when written at high speed,
that really means that the drive doesn's support that speed except
in marketing terms.

Ciao,

[Niels Mayer]

-tao Write disk in TAO mode.

-dao Write disk in SAO mode.

-sao Write disk in SAO mode.


I've found that wodim seems to "do the right thing" -- also turning on
verbose mode lets you know what it's "thinking" -- including what speed it
thinks it can write at.

Niels
http://nielsmayer.com

[Jörn Nettingsmeier]

Post by Niels Mayer

-tao Write disk in TAO mode.

-dao Write disk in SAO mode.
-sao Write disk in SAO mode.
I've found that wodim seems to "do the right thing" -- also turning on
verbose mode lets you know what it's "thinking" -- including what speed it
thinks it can write at.

you shouldn't talk about computers as if they were people - they really
hate that.

/me runs...

[Paul Davis]

Post by Jörn Nettingsmeier
you shouldn't talk about computers as if they were people - they really
hate that.

right. Because Robots Have Feelings Too!

[Ken Restivo]

Post by Jörn Nettingsmeier

Post by Niels Mayer

-tao Write disk in TAO mode.

-dao Write disk in SAO mode.
-sao Write disk in SAO mode.
I've found that wodim seems to "do the right thing" -- also turning on
verbose mode lets you know what it's "thinking" -- including what speed it
thinks it can write at.

you shouldn't talk about computers as if they were people - they really
hate that.

Yeah, but what they really hate.. is BATHS. They're worse then cats that way.

-ken

[Roberto]

Oops, sorry, it was meant to be sent to the list :P


----- Forwarded message from Roberto <***@zenvoid.org> -----

Date: Sat, 24 Apr 2010 14:55:18 +0200
From: Roberto <***@zenvoid.org>
To: Fons Adriaensen <***@kokkinizita.net>
Subject: Re: [LAU] CDRDAO speed, CRC errors, blah

Post by Fons Adriaensen
The limiting factor could well be the minimum power at which
the write laser can operate - lower write speed requires less
power.

Hey, I found it! Is not the drive limits as I have used my drive to
write at very low speeds in the past (not because better recordings but
just to avoid annoying drive noise). It's medium limits: writable DVD
and CD have a minimum write speed, and software will refuse to select
slower speeds. Try this (with the blank medium loaded in the drive):

for DVD:
dvd+rw-mediainfo /dev/dvd1

for CD:
wodim -prcap

Ken, it is very likely that 8x is already the slowest that you can get
with those CD, I'm afraid.

----- End forwarded message -----

[Ken Restivo]

Post by Roberto
Oops, sorry, it was meant to be sent to the list :P
Date: Sat, 24 Apr 2010 14:55:18 +0200
Subject: Re: [LAU] CDRDAO speed, CRC errors, blah

Post by Fons Adriaensen
The limiting factor could well be the minimum power at which
the write laser can operate - lower write speed requires less
power.

Hey, I found it! Is not the drive limits as I have used my drive to
write at very low speeds in the past (not because better recordings but
just to avoid annoying drive noise). It's medium limits: writable DVD
and CD have a minimum write speed, and software will refuse to select
dvd+rw-mediainfo /dev/dvd1
wodim -prcap
Ken, it is very likely that 8x is already the slowest that you can get
with those CD, I'm afraid.

Awesome. This is why I love the Internet :-)

Makes sense: at slower speeds, the laser could burn a hole in the media. So at slowest possible speed, I should get the deepest possible pits, and thus the most reliable-to-read CD, I guess.

I will go now burn CD's with impunity. Thanks again.

-ken

[Fons Adriaensen]

Post by Ken Restivo
Makes sense: at slower speeds, the laser could burn a hole
in the media. So at slowest possible speed, I should get
the deepest possible pits, and thus the most reliable-to-read CD,
I guess.

No that's not how it works. Simplifying things as bit, on a
real 'stamped' CD the pits should be 1/4 wavelength deep,
so that the reflection of the bottom is in antiphase with
the one from the surface, this provides the best 'contrast'.

Writeable CDs don't have pits, either the color or the
reflectivity of the surface is modified by heating it.
Both require the laser power to be controlled in function
of write speed.

So the slowest allowed speed is not necessarily the best
one.

Ciao,

[Arnold Krille]

Post by Fons Adriaensen
Writeable CDs don't have pits, either the color or the
reflectivity of the surface is modified by heating it.
Both require the laser power to be controlled in function
of write speed.

Afaik writeable CDs _do_ use pits. They are created when the laser heats up
the colour-bubbles so they expand and raise the reflective layer.


Disclaimer: I've been found wrong in the past...

Arnold

[david]

Post by Arnold Krille

Post by Fons Adriaensen
Writeable CDs don't have pits, either the color or the
reflectivity of the surface is modified by heating it.
Both require the laser power to be controlled in function
of write speed.

Afaik writeable CDs _do_ use pits. They are created when the laser heats up
the colour-bubbles so they expand and raise the reflective layer.

[david]

Post by Arnold Krille

Post by Fons Adriaensen
Writeable CDs don't have pits, either the color or the
reflectivity of the surface is modified by heating it.
Both require the laser power to be controlled in function
of write speed.

Afaik writeable CDs _do_ use pits. They are created when the laser heats up
the colour-bubbles so they expand and raise the reflective layer.

Also, the Sidux website recommends burning ISOs at no faster than 8x
speeds, even for DVD images. (Hard for me to do that, my DVD burner
won't burn slower than 16x.) I don't think it's because of media
problems. I think it's because of the uneven quality of CD/DVD drive
mechanisms.

[Roberto]

Post by Ken Restivo
Awesome. This is why I love the Internet :-)
Makes sense: at slower speeds, the laser could burn a hole in the media. So at slowest possible speed, I should get the deepest possible pits, and thus the most reliable-to-read CD, I guess.

It seems that the material needs a certain time to change its
properties. Using faster speed but more laser power should give the same
result, but sometimes is not exactly equivalent (like cooking food with
much higher temperature but less time or something like that XD ), and
probably the same can be said when using slow than optimal speeds, I
guess.

Many people everywhere recommends using very slow speeds, but I must say
that personally I never noticed significant improvements with any speed.
Some drives perform much better that other when extracting data. In
practice is very difficult to get perfect tracks from audio cd, though
tools like cdparanoia do a nice job.

Digital media that can degrade the sound when dust or fingerprints are
present is a nice emulation of analog media when feeling nostalgic ;)
Today I just tend to write data CD or usb memories with flac files
inside.

[Philipp]

Post by Ken Restivo
So I'm trying to burn this masterpeice to a CD.
$ crdao write tofile.toc
... ok here we go. It works, but then when I try to read the disk back, i get tons of CRC errors.
"5 Q sub-channels with CRC errors" .. etc etc.
http://linux.derkeiler.com/Mailing-Lists/Debian/2005-04/1370.html
OK, so I try to write at a lower speed.
$ cdrdao write --speed 4 tofile.toc
Starting write at speed 8...
Pausing 10 seconds - hit CTRL-C to abort.
No no no no, I said speed 4!
$ cdrdao write --speed 2 tofile.toc
Starting write at speed 8...
Pausing 10 seconds - hit CTRL-C to abort.
Arrgggh...
$ cdrdao write --speed 1 tofile.toc
Starting write at speed 8...
Pausing 10 seconds - hit CTRL-C to abort.
Hey, cdrdao, are you even listening to me!??
1) Is there any reason to burn an audio CD at a speed < maximum, or is this the dreaded digital voodoo?
2) Why is cdrdao refusing to do what I tell it to do?
Thanks, all.
-ken

I'm not sure it helps anything but you could try to install cdrtools
instead of cdrkit.

Regards,
Philipp