Safeaudio - The end of CD?
Posted by: P on 05 August 2001
I just read about this -
Quote:-
In what is intended to have the biggest impact yet on the thriving "rip, mix, burn" lifestyle, Macrovision has revealed that several record labels have been secretly putting its copy protection system onto new CD releases since around March of this year. The process, called SafeAudio, is a Macrovision registered trademark and is intended to prevent the copying of CDs,
or tracks from CDs, onto CD-R discs and computer hard drives. The technology was developed jointly by Macrovision and TTR Technologies.
While it is not intended to completely prevent copying, Macrovision claims that the SafeAudio process adds a special type of distortion to the CD during the mastering process at CD manufacturing facilities, which then reveals itself as periodic "clicks and pops" in the digital copy.
TTR's patents reveal that in the SafeAudio system, "grossly erroneous values," or bursts of digital noise, are added to the signal, forcing a regular CD player, whose error correction can't usually handle such extreme digital hash, to cover the gaps of bad data with data from before and after where the distortion occurs. But when copying the audio file to another device, like a PC's hard disc, the extreme digital values are said to overwhelm the computer's ability to transfer the data properly, leaving annoying noises in place of music.
Which labels are involved in the testing is still a mystery since the company cites non-disclosure agreements when asked to reveal specific names and CDs. Macrovision's Miao Chang says that "they [the labels] don't want to influence the listener's potential experience." Macrovision claims that during the last several months of testing on an unsuspecting public, there have been no significant reports of complaints from consumers, even though, the company reports, one title has so far seen sales in excess of 100,000 units.
Unquote
Any thoughts?
Pete
Posted on: 05 August 2001 by Martin Payne
According to New Scientist a company called Cactus has come up with a further variant on this theme.
By embedding control codes into the SubCodes in the CD certain blocks are marked as non-music.
When copying via PC, etc, the subcodes are not read, thus these blocks are then treated as part of the music on the copy.
By embedding very high frequency square waves into the 'hidden' data they reckon they can blow up your tweeters.
For details, see New Scientist, 4-6-01, page 19.
Martin
Posted on: 05 August 2001 by Jez Quigley
Greedy arseholes. Still I expect CloneCD and plextor will still do the business.
Posted on: 05 August 2001 by Mike Hanson
If the CD players are smart enough to deal with this, then the software that copies CDs will do just as well. Already many packages have the ability to customize their response to errors on the CD. I expect this to continue.
As to that square wave thing, I find it really hard to believe that any signal delivered by my amp at "acceptable" volumes is going to blow up my tweeters. What silliness. Both of these reports above seem to be fearmongering, and probably have no foundation in reality.
-=> Mike Hanson <=-
Posted on: 05 August 2001 by Martin Payne
Mike,
the absolute level of upper treble frequencies in any normal recording are much lower than those at mid & bass frequencies.
The power handling of tweeters are only engineered to handle this. By recording treble transients at high levels the tweeters can be overdriven.
My dealer reckons that a single accidental 'squeal' from plugging in a phono source to your preamp can noticeably degrade a pair of tweeters.
The Cactus system could only be bypassed if a CD-ROM is actually able to read the sub-code data which co-exists with the audio. A program could then correctly interpret it, and blank out the offending blocks.
I'm not sure if any protocols exist for CD-ROMs to read sub-codes, although if CD-Text is also encoded in this way then it must obviously be possible.
However, companies such as Macrovision & Cactus normally go to some lengths to devise every way to break their schemes, and then patent them also. It then becomes illegal to create an unlicensed device or program that uses these means.
Don't expect help from any of the major software suppliers on this one!
Martin
Posted on: 05 August 2001 by Mike Hanson
quote:
the absolute level of upper treble frequencies in any normal recording are much lower than those at mid & bass frequencies....
My dealer reckons that a single accidental 'squeal' from plugging in a phono source to your preamp can noticeably degrade a pair of tweeters.
There's a difference between an accidental electrical faux pas (like plugging the wrong thing into the wrong place at the wrong time), and a limited-by-definition signal from a CD player. There is no such thing as "louder treble" when you're talking about CDs. The loudest possible sound from a CD is "all 16 bits on". It's only the speed at which the levels change than makes it seem like treble or bass.
-=> Mike Hanson <=-
Posted on: 05 August 2001 by Justin
If you want to own music, just buy it. I have no problems with whatever the record lables come up with to prevent the theft of thier IP. I'd hate it if every time I drafted a contract or a will for somebody, that person scanned it into thier computer and started distributing them to all of thier friends.
Judd
Posted on: 05 August 2001 by JohnS
and its got intentional error blocks coded into it that my CD firmware is going to interpolate? Oh yes, I'm absolutely over the moon about that.
Also, I believe that I pay the royalty once so I can listen to the music whenever, and in whatever format, I choose. It's none of the record companies business if I want to listen to it on my portable mp3 player or minidisk - I could have used a portable CD player but they're too bulky.
-John
Posted on: 05 August 2001 by Gromit
If someone is smart enough to come up with codes that prevent copying, wouldn't someone else be smart enough to come up with a system that would bypass it? Be it MD, CD-RW, CD-R, DAT, etc. they do need to sell their recorders, right?
Posted on: 06 August 2001 by Frank Abela
Judd
I agree that I want to buy music to support the whole music industry. The problem with the above (which I read yesterday) is that historically, the schemes that have been put forward by various companies thus far have been quite discernable.
You can hear the difference pre and post protection, and this is usually detrimental to the music. Therefore, there is consternation whenever anything is put forward as a fait accompli, as in this case.
The problem is that the developers of these schemes are in such competition that they work in secrecy and generally do not have true and representative test-hearings with large samples of people on lots of kit. Their stats, therefore, are useless, or open to disbelief at the least!
The audiophile community is even more at pains to get this right since those people have spent what seem like insane amounts of money (to others) to achieve the best fidelity. If the 'undiscernable' system reduces the musicality of the piece, this will have a direct effect on the enjoyment of their hard-won fidelity.
I'm all for an undiscernable copy protection system, but not at the expense of musicality.
Regards,
Frank.
All opinions are my own and do not reflect the opinion of any organisations I work for, except where this is stated explicitly.
Posted on: 07 August 2001 by Martin Payne
quote:
The loudest possible sound from a CD is "all 16 bits on". It's only the speed at which the levels change than makes it seem like treble or bass.
Mike,
it's my understanding that any normal musical signal has a much lower average signal level in the treble than lower frequencues.
cheers, Martin
Posted on: 07 August 2001 by Mike Hanson
quote:
it's my understanding that any normal musical signal has a much lower average signal level in the treble than lower frequencues.
I don't believe that is pertinent to this case. Let's look at an extreme example. CDs are sampled at 44.1KHz. Let's say that every second reading is changed to be all-bits-on (i.e. 1111111111111111). This would represent a "pure" square wave at 22.05KHz. This is theoretically super sonic, and therefore should not impact the sound. However, any CD player filters out signals at this frequency, so it's never going to get through to the speakers.
If they put it at a lower frequency, so that it sneaks past the filter, then it's going to be audible. That's why it's not going to work as a copy protection scheme. This is a bit of an oversimplification, but I think you understand my point.
-=> Mike Hanson <=-
Posted on: 07 August 2001 by Mike Hanson
quote:
By embedding control codes into the SubCodes in the CD certain blocks are marked as non-music.When copying via PC, etc, the subcodes are not read, thus these blocks are then treated as part of the music on the copy.
If you're making a straight copy of a CD (i.e. CD-to-CDR), then all codes will be read as-is. If there is a marker stating it's non-music, then the copy will have the same marker.
I'm not sure that the same applies when ripping into invidividual tracks. However, I would think that the software would be aware of the same non-music block issue as the music player.
-=> Mike Hanson <=-
Posted on: 07 August 2001 by Martin M
Mike, I know you are taking a bashing today so I don't want to add to your misery but something you have written here and before is bothering me!
Sound with frequency above the threshold of hearing are Ultrasonic.
Sounds with frequency below the threhold of hearing are Infrasonic.
Thanks!!! 
Posted on: 07 August 2001 by Mike Hanson
Actually, both are correct. Ultrasonic is a bit more specific than supersonic, which could be misinterpreted as "faster than the speed of sound". Considering where we're hanging out, though, I don't think that will happen.
Subsonic and infrasonic are better synonyms, although subsonic could also be interpreted as relating to the speed of sound, rather than the frequency.
quote:
Mike, I know you are taking a bashing today so I don't want to add to your misery
Don't worry. It's quite obviously of my own design, and I'm having a hoot.
-=> Mike Hanson <=-
Posted on: 07 August 2001 by Martin Payne
quote:
Ultra vs. Super and Sub vs. Infra. ... Actually, both are correct. ... Considering where we're hanging out, though, I don't think that will happen.
Mike,
sorry, I have to disagree with this.
Ultra-, Super-, Infra- & Sub- sonic are all words with precisely defined meanings, unless you're the Queen Of Hearts. Super- & Sub- sonic definately refer to speed of an object relative to that of sound in that medium, rather than frequency.
Mike "Queeny" Hanson - explains a lot.
quote:
I'm not sure that the same applies when ripping into invidividual tracks. However, I would think that the software would be aware of the same non-music block issue as the music player.
The article stated specifically that this would affect any attempt to copy the audio, including use of a CD player & domestic CD recorder connected digitally. This latter is pretty unnecessary, since you could just set the appropriate control bit so that the SCMS circuitry will refuse to make the copy.
quote:
If they put it at a lower frequency, so that it sneaks past the filter, then it's going to be audible
The stated aim of this scheme is to make any copies unlistenable. It is merely a "fortunate" by-product that it can be used to get revenge on your HiFi as well.
cheers, Martin
[This message was edited by Martin Payne on TUESDAY 07 August 2001 at 22:13.]
Posted on: 07 August 2001 by Mike Hanson
quote:
Ultra-, Super-, Infra- & Sub- snic are all words with precisely defined meanings, unless you're the Queen Of Hearts. Super- & Sub- sonic definately refer to speed of an object relative to that of sound in that medium, rather than frequency.
Check www.dictionary.com:
supersonic - Of or relating to sound waves beyond human audibility.
subsonic - Of less than audible frequency.
BTW, I recognize that "ultra" and "infra" are better, but "super" and "sub" are not wrong.
Regarding the coping, if you make a bit-for-bit copy of the entire CD, then the copy protection would be ineffective. It's only if you run in "interpretive" mode that bad things could start to happen (depending on how the copying software refers to your block markers). If they can skip over them the same way that the player does for the original CD, then it's probably not an issue.
-=> Mike Hanson <=-
Posted on: 07 August 2001 by Andrew L. Weekes
quote:
As to that square wave thing, I find it really hard to believe that any signal delivered by my amp at "acceptable" volumes is going to blow up my tweeters. What silliness. Both of these reports above seem to be fearmongering, and probably have no foundation in reality.
The problem with this is that 'acceptable' volume for a treble signal is, as suggested by others, much lower than the full volume your system is capable of, and relative to the mid and low frequqency ranges much lower than either.
If you were to take a test CD with a 16kHz or higher 0dB reference signal and play it at full volume for any significant period (numbers of seconds) I'd guarantee you'd blow your tweeters. You'd probably damage them at much lower levels, they're just not designed to cope with 'non-musical' signals at high levels for significant time.
Square waves are a nightmare as the extended harmonic structure of the signal will deliver an enormous amount of power to the drive units, across a huge bandwidth.
The situation will be exacerbated by speakers that use simple, first order, filter networks to the HF units (e.g. Royd) since more low frequency energy reaches the tweeter.
Andy.
Posted on: 14 August 2001 by Tony L
