Campaign for Digital Rights
Buying a new CD? Watch out for inferior imitations Thursday May 25, 2017

Overview of the situation

With the increasing use of digital technology to store and transfer all kinds of media works (music, books, films, video, etc), and the constantly increasing accessibility of the internet, the media distributing companies are facing a revolutionary change in their marketplace.

Unfortunately, they have not been keeping up with the technical possibilities, and so naturally other people have rushed to fill the empty space. This has lead to all kinds of new applications, such as MP3-swapping via Napster, on-line books (Project Gutenberg), and many other new ideas.

Because these new possibilities threaten the media distributors' tried and tested methods of generating revenue, even perhaps eliminating their place from the chain of supply in some cases, they have reacted defensively. Rather than expanding their operations into these new areas and embracing the new possibilities, they have started to use all their power and influence to restrict the possibilities as far as they can, so that they can maintain as much, or even more, control over digital media than they do at present in the world of physical media (books, CDs, video tapes). Only when they feel that they have complete control over the digital domain can they feel comfortable about expanding into this new marketplace.

Unfortunately, their fearful over-reaction is going to hurt everybody's freedoms. What they are trying to put in place is something many times more restrictive than what we are used to even in the domain of physical media.

This is not good for the internet, it is not good for the consumer, and it is not good even for the artists and producers of media works. Really, in an ideal world, this should only be a short-term issue until the media distributors have found a way to make a stable income from the new digital marketplace. However, unfortunately, that is not going to be the case, because in their fear of the new marketplace, they are putting in place exceptionally restrictive laws that will affect all of our lives in significant ways from here on.

In fact these laws are so extreme and unbalanced, that not only will they give the media companies the ability to completely control the distribution of works on the internet, but it will also give them much greater ability to control the distribution of works on the physical media that we are more familiar with.

The issue of copy-protected CDs is one of the first signs of this that has reached public attention, and we can take this as a sign of what is to come.

CD copy-protection mechanisms

The aim of copy-protecting CDs is to make it hard for people to copy them digitally (i.e. make perfect copies). This means stopping people from doing CD-to-CD copies using audio CD recorders, and stopping people from reading the CDs into their computers, from which they could create MP3s and store the music on their hard drives.

The following copy-protection mechanisms have been encountered so far (these are from my research to date -- many more articles and references to these techniques can be found by doing related searches on Google or other search engines):

  • Early attempts were made by corrupting the TOC (table-of-contents) on the CD, which most CD players ignored, but that significantly confused computer CD readers. CDs with this type of protection were released in Germany and Italy. However, it was found that these CDs would not work in 2-3% of normal CD players, so this method was abandoned.
  • Another attempt was tried in the USA, based on technology from SunnComm. The Charley Pride CD "A Tribute to Jim Reeves" was released with a form of protection that completely stops a computer from reading it. Instead the computer directs the user to register at an internet web-site and download replacement audio files in an encrypted format. Many people were upset about this, for one thing because this was not indicated on the CD cover, but also because of concerns about privacy since you are required to reveal personal information in order to listen to your CD. This has lead to a court case against both SunnComm and the record label:
  • Next came a form of protection known as SafeAudio by Macrovision. This is a much more severe form of copy-protection. Instead of corrupting the TOC, it corrupts the audio signal stored on the CD. Due to a CD player's built-in error correction, most of this is recoverable, which means that the CD still sounds okay. However, the corruption is so severe that some blocks of audio have to be completely fabricated by the CD player -- probably these are carefully chosen so that the CD player has a good chance of getting it more or less right. These errors cause a computer CD-ROM to reject the disk, or produce a recording full of pops and hiss. The biggest objection to this method of protection is that it affects all CD players in time, because error-correction was designed to take care of scratches, not intentional errors on the disk. These CDs will be much less tolerant to scratches, and thus less reliable. There have been several suspected SafeAudio CDs released in the USA, such as 2-Pac's "Until the End of Time", a Brad Mehldau CD and the Sopranos Soundtrack 2, to name a few. Once again, these CDs were on sale without any indication that protection had been applied.
  • The most recent format that's come to light is the Cactus Data Shield from Midbar. The earlier German tests also came under the name of Cactus, but it appears that Midbar's protection technology has developed since then. Like SafeAudio, this new method corrupts the audio signal on the CD. However, the method used is different. In this case blocks of audio are replaced with blocks of control data. A normal CD player ignores the control data and fabricates the sound of that block using its error recovery circuitry. Once again, the blocks must have been carefully chosen so that the sound is not disrupted significantly. Again, reliability of the CD will be affected. When the CD is copied using a computer or CD-to-CD copier, the control blocks are interpreted as audio, which means that the manufacturer can insert whatever sounds they wish into a copied recording, even sounds designed to damage speakers. The New Scientist ran an article on this copy-protection mechanism, based on research into the original patents, but it was forced to withdraw the article under pressure from Midbar. The link below only shows the replacement text, but in itself it says a lot, indicating that Midbar have been testing their format on a wide scale, and specifically in the Czech Republic and Slovakia.

You might ask why there are so many copy-protection formats. Well, the designers of these formats are trying to find a balance between consumer rejection and protection for the audio data. The technical details of these protection mechanisms show that they are not concerned about effects that these formats might have on the longevity of the CD, especially as this wouldn't be apparent to the consumer immediately.

In any case, at present they cannot completely prevent people from copying their CDs, as a copy via an analogue connection (via phono leads, for instance) is still possible. However they do hope to make copying as difficult as possible in order to put people off.

In the medium- to long-term they do indeed hope to completely stop the copying of all media works through laws such as the SSSCA (currently proposed in the USA) which requires that every piece of equipment sold has copy-protection mechanisms included -- and that includes your CD player, video, computer, tape recorder and so on. These would recognise 'watermarks' inserted into copyright materials and would refuse to copy them.

The most unfortunate thing for hi-fi buffs is that audio quality is no longer a primary motivation for the media distributors. They have already shown that they are quite willing to sacrifice the purity of audio quality, and even the reliability of CD media, in order to install copy-protection mechanisms.

As to how many CDs in these formats are being released, reports vary. Recent newspaper articles stated that one million protected CDs were being released into the market by five big recording companies (Universal, Warner, EMI, BMG and Sony). Information from Midbar indicates that a million CDs in their Cactus format have already been released across Europe.

In both cases, the distributors have clearly shown their intention to release CDs in these formats, without informational labels for consumers, and without any other specific warnings about which titles or artists are affected. They have also shown their intention to try new untested copy-protection formats, without warning, on individual countries before releasing them into larger markets.

Future directions

The possible future direction that this may take can only be speculation, due to the fact that the media distributors are not revealing their plans publically. All we have to go on are the laws that they are trying to put through.

The most extreme law proposed is the SSSCA, backed by Disney. The natural extension of this law would be that all devices in your home or office would have copy protection mechanisms built in. All freedom in the use of information would be eliminated. You would constantly find impediments in the things you do as a matter of course. Copying a CD to tape or to a portable MP3 player would be completely impossible, even via analogue leads. It might even be impossible to cut-and-paste text if it was marked as copyright (in fact this has already been put in place in Adobe's eBook format, based on the DMCA laws).

The SSSCA is so extreme that it could not possibily get through in its current form, because it would forbid things which are legal rights in the USA -- unless those rights were also revoked. However, even in a modified form, it would require every action that you make to be checked to see if it is legal. This doesn't necessarily mean a "big brother" style central form of monitoring, but rather that devices all around your home would be saying "I can't do that because so-and-so law doesn't permit it" whenever you try and use a media work in some slightly different way to its pre-designed usage pattern. (warning: technical, some strong language)

Taking the DMCA and EUCD as slightly less extreme cases, the consequences are still severe. If you have a CD that is copy-protected, not only would it be illegal to copy that CD (as it is at present, due to copyright laws), but it would also be illegal to tell anyone how you did it. Even passing on a hint or a tip like this could land you in jail. Compared to the SSSCA, it wouldn't be your machines stopping you doing things -- rather it would be the fear of prosecution or jail for doing anything that might upset a media distributor. The number of activities that could be covered under these laws is surprising. In the USA where the DMCA is already law, several academics have been taken to court or jailed due to revealing information in the course of their research which upset the commercial interests of media distributors. These researchers were doing things that are in the public interest, and they certainly should not be punished for that work.

This is all very unfortunate, to say the least. It would be a very bad sign for the coming decades if these laws or laws like them were to be allowed to stay in place.

Author: Jim Peters <>, dated 6-Oct-2001