defective by design question.

[svyr]

I have 2 audio-cds that crackle, when played or ripped on a computer, but play without defects on a hi-fi deck (since the cds aren't scratched, I assume it's some sort of copy protection, although neither CDs say anything about that on the covers and are both marked 'compact disc digital audio')

For now, I've tried about a dozen different rippers and analogue modes on them (yes, the cable from the cd-rom to the sound card is connected and yes, the 'digital audio' checkbox was removed in device manager), but they don't seem to work.

The new mode in R13 doesn't help - with C2 errors interpolated, the resulting rip is extremely poor in quality, with about 1/4 of the volume and still substantial crackling. With c2 errors turned off, the rip is the same as a normal rip (i.e extreme crackling)

The questions is: is it possible to implement a defective cd read mode, where cdgrab to reads the audio frames, and does reed-solomon interleaving style correction (which is what cd players do) instead of interpolating C2?

p.s http://www.cdfreaks.com/reviews/Defe...opy-Protection might explain what I mean I bit better

[Spoon]

Re: defective by design question.

>and does reed-solomon interleaving style correction

All CD drives do this, it is done automatically.

IF there are intentional errors on the CD then interpolation is the only recourse (which is exactly what a normal cd player does).

[Spoon]

Re: defective by design question.

What are the disc titles? and which country are you in? which CD drive do you have?

[svyr]

Re: defective by design question.

What are the disc titles? and which country are you in? which CD drive do you have?

Hi Spoon,

One is 'Ghost in the Shell SAC 1, MIYA records MICA-0142', the other is 'Tchaikovsky - Nutcracker Ballet Suite, op.71a (Excerpts From The Ballet), Overture by Georgian SIMI Festival Orchestra DDD' (apparently a 20-bit recording).

The country is Australia (as the IP suggests), but not sure if or how that's relevant.

Not sure if there's any significance, but only the last few tracks (about 1/4 or 1/3 of the cd) are crackling on cd-roms.

You can get the first one off ebay (from http://myworld.ebay.com.au/atv888rad or more specifically http://cgi.ebay.com/GHOST-IN-THE-SHE...QQcmdZViewItem). BTW, It's my 2nd copy, (i.e I've requested a replacement, since I initially thought it was a defective CD), so it's definitely a copy protection feature. Doubt you'd be able to find the second CD though.

The problem with the crackle is present on my 2 pcs and laptops (all with different dvd-roms/rws/cd-roms from different brands, and neither analog, nor digital ripping work), while the cd plays perfectly on a sony microhifi system, and a really cheap huindai portable mp3/cd player and in an in-car one.

>All CD drives do this, it is done automatically.
IF there are intentional errors on the CD then interpolation is the only recourse (which is exactly what a normal cd player does).

ah, I see. Is there any way you could replicate an interpolation algorithm from a CD-player then?


BTW, this could have a nice side effect with the feature if it's implemented - ripping of damaged/scratched CDs . I'm sure there are a lot of people who want to try their luck with that, if the CD isn't ripping on their PC, but still plays in a cd player.

[svyr]

Re: defective by design question.

The main pc's cd drive is a fairly old 'lite-on dvdrw sohw-1673s'
The other pc's is a fairly new dual layer 'asus drw-1608P3S'

[Spoon]

Re: defective by design question.

When writing these routines we have never had access to a drive + cd combination which gave these results, all our drives with discs we believe employ this kind of copyprotection self interpolate! so our work was best guess.

Work on these kind of discs progresses at a slow rate (copy protection as a whole has been abandoned).

It would also seem strange that a classical cd would employ any kind of protection, what you been able to verify (on the internet) that those 2 discs do have protection?

There is also 2 types of protection that could be at play:

Deliberate errors to upset CD-Roms,
Discs contained a 'sony rootkit' type program, once installed this program will interrupt the audio data for that one cd.

[svyr]

Re: defective by design question.

When writing these routines we have never had access to a drive + cd combination which gave these results, all our drives with discs we believe employ this kind of copyprotection self interpolate! so our work was best guess.

Work on these kind of discs progresses at a slow rate (copy protection as a whole has been abandoned).

It would also seem strange that a classical cd would employ any kind of protection, what you been able to verify (on the internet) that those 2 discs do have protection?

There is also 2 types of protection that could be at play:

Deliberate errors to upset CD-Roms,
Discs contained a 'sony rootkit' type program, once installed this program will interrupt the audio data for that one cd.

I see.

Hopefully the work on deliberate error type audio cd protection from labels really was abandoned, but there are quite a few still floating around from the tests. And perhaps if you do work out a way to overcome (for the deliberate errors type) it it would help with scratched cds as I mentioned above...

This is the deliberate error type. The cd has no data on it all, just the audio tracks (and obviously nothing autoruns since there is no data, not to mention that I've disabled autorun a while ago, and the other pc never had any cds but these 2 ripped on it, and a test rip of other cds runs fine)

I do see your point about the classical cd having protection being strange, however as it's a small and fairly unknown orchestra, perhaps the labels were just testing it...

Anyway, hope you do pursue the matter further, since you can actually acquire the CD in question and play around with it if you are interested.

[svyr]

Re: defective by design question.

When writing these routines we have never had access to a drive + cd combination which gave these results, all our drives with discs we believe employ this kind of copyprotection self interpolate! so our work was best guess.

Work on these kind of discs progresses at a slow rate (copy protection as a whole has been abandoned).

It would also seem strange that a classical cd would employ any kind of protection, what you been able to verify (on the internet) that those 2 discs do have protection?

There is also 2 types of protection that could be at play:

Deliberate errors to upset CD-Roms,
Discs contained a 'sony rootkit' type program, once installed this program will interrupt the audio data for that one cd.

in regards to confirming on the net that they're copy protected, it's virtually impossible, since most people either don't care or can't be bothered/don't have a place to whine about such things... not to mention both cds seem to have a rather small number in circulation.

btw, both of the cd drives use the latest firmware, and are by fairly reputable manufacturers (I'm implying that I don't really see what else could it be but a copy protection).

also, the asus drive is a rebadge of a PIONEER DVR-111, which should increase the chances of you getting a hold of one, if you really do need the exact drive after you get the cd.

oh, btw, tried the cds on my dse dvd player, with the same problem occurring (the dvd player uses a pc cd drive inside, afaik)

C'moooon, just buy the cd and have a look :teufel8:, please?