October 22, 2020

Macrovision Tries Passive Anti-Copying Technology for DVDs

Macrovision is introducing a new DRM technology for DVDs, apparently based on passive changes to the data encoded on the disc, according to a news.com article by John Borland. (The article is entitled “New Copy-Proof DVDs on the way?” The answer to that question is “no.”)

The new technology, called RipGuard, tries to code the DVD data on the disc in a way that triggers bugs in popular DVD ripping programs, while remaining readable on ordinary DVD players:

Macrovision’s new product takes a different approach to antipiracy than it has taken for analog or audio CDs. Gervin said Macrovision engineers have spent several years looking at how various DVD-copying software packages work and have devised ways to tweak the encoding of a DVD to block most of them.

That means the audio and video content itself requires no new hardware and isn’t scrambled anew, as is the case with most rights-management techniques. Someone using one of the ripping tools on a protected DVD might simply find their software crashing, or be presented with error messages instead of a copy.

As when used on CDs, this passive approach will only work against some ripping programs, and in any case will become useless as the bugs in ripping programs are fixed. If the goal is to keep protected DVD content off the P2P nets, then this product will fail.

The article argues that RipGuard can be updated over time, which is true, but not very helpful for copyright owners, for two reasons. First, there is a limited supply of disc-reading bugs in ripping programs, and each version of RipGuard will cause some of them to be fixed, making it harder to find bugs to exploit in the next RipGuard version. Second, although users can update their ripping software, there is no way to update RipGuard on DVDs that have already been sold. Once a version of RipGuard becomes useless, all of the discs produced with that version will be copyable forever after.

This is yet another anti-copying technology that will have no effect on P2P availability of content. It will make ripping somewhat more difficult for people who don’t use P2P; but how does that help the studios?

Comments

  1. > how does that help the studios?

    It helps the studios when their boards have to answer to the shareholders: “We’re losing money because we’re producing a substandard product^W^W^W^W^W p2p pirates are stealing our movies and posting them on the internets. To combat that, we instituted RipGard!!!!111”

  2. I can’t even begin to imagine how this will work, and even if it functions “as advertised” the 3% of rippers (and is this measured by number of users of a particular program, or as a percentage of the different programs available?) will become 100% of rippers in no time at all (either by the non-working programs being patched, or everyone switching to the working ones). If I find DVD Decrypt no longer serves my “put my DVDs on to my server so I can watch them on any PC in the house” needs I’ll switch to one that does. (And 97% is a suspicious looking figure…)

  3. Two points. First, it is important to understand the structure of the ripping market. End users are not the ones ripping these disks and putting them out on the net. These tasks are performed by people who are de facto professionals. You discussed this at http://www.freedom-to-tinker.com/archives/000746.html. The number of people who are positioned and equipped so as to get these rips into widespread distribution is relatively small. And there’s a lot more to it than just ripping. As the Wired article you link to describes, there’s a whole art form to tweaking the compression to get a clean, shareable file. The popular stereotype of end users ripping and sharing DVDs is an utter fabrication with no connection to reality.

    So what does this mean? Well, if only a small percentage of people have DVD software that works, and none of them happen to be the top rippers, then the measure could be effective for a while. In my experience, these kinds of communities tend to be inbred and most people will copy each other in terms of which software package they use for ripping. So they’re probably all using the same thing. But on the other hand, the people at the top of the pyramid are highly motivated and well funded. If there is software out there that will do the job, they will find it. So it is less clear how much these techniques will slow them down.

    Second, all the manufacturers want is a time window. They are looking for the infamous speed bump that you discussed last year. Your writeup today is almost a perfect discription of speed bump technology. Everything you have written would suggest that this new approach is going to do exactly what the content owners want and need it to do.

  4. Cypherpunk, it won’t create any kind of a speedbump. At all. If (and that’s a big if) the pros have any problems, they will work around it within milliseconds. Writing a program to rip a dvd is quite literally trivial, and the Macrovision process can’t interfere with the transcoding once the dvd is ripped.

  5. Even given a mythical “copy-proof” DVD technology, there are still plenty of chances for unencrypted originals to leak out. I am willing to bet that “professional” rippers have infiltrated DVD mastering and replication companies where they can access unencrypted masters.

  6. “I am willing to bet that “professional” rippers have infiltrated DVD mastering and replication companies where they can access unencrypted masters.”

    Currently a large proportion of DVD rips produced by “professionals” come from internal screener DVDs (most of which don’t even have CSS or “regular” Macrovision on them) or screeners provided for review purposes, and generally start appearing on P2P networks pretty close to the theatrical release date. (Read http://www.waxy.org/archive/2005/02/07/pirating.shtml for a good analysis of this.)

    As per usual, it’s only the normal consumer who’s going to have to put up with the added layer of irritation, but judging by the current state-of-the-art in the DVD ripper/transcoder market (both commercial and freeware tools) it’s going to produce at most a day or two’s inconvenience before updated versions appear. Tools such as AnyDVD (which removes CSS, Macrovision, RCE, a variety of passive schemes, etc., at the driver level, allowing a DVD to be ripped simply by dragging the files via Explorer) are also bound to be patched fairly rapidly, and given that they cope with existing passive schemes may already defeat RipGuard.

  7. It may work:

    Firstly: there is a premium on freshness. Old DVDs are worth less on the market anyway. So by the time a bug is fixed in the ripper, the DVD could probably be picked up in the discount shelves for a few dollars.

    Secondly: it increases development costs. Rippers would have to have extensive trace/log facilities in order to report back the source of the error. Some of these might be in the DVD driver itself.

    Thirdly: unstable rippers give rippers a bad name. People may just decide it is not worth the trouble.

  8. Chui,

    If “RipGuard” has anything to do with bugs in DVD drivers, it’s probably going to interfere with playback as well… which won’t stand well with consumers and will just create a bigger incentive to circumvent it.

  9. “Firstly: there is a premium on freshness. Old DVDs are worth less on the market anyway. So by the time a bug is fixed in the ripper, the DVD could probably be picked up in the discount shelves for a few dollars.”

    This is only slightly true — most of the DVD rips on P2P networks fall in to two categories: pre-release screeners made my “professionals” (in which case RipGuard probably won’t even be an issue) or ordinary common-or-garden DVDs you can buy in the store that an individual has ripped for the heck of it. I’m fairly certain the lead-time required to fix a ripping tool to counter a particular flavour of RipGuard is going to be a lot shorter than the full price to bargain price delay. As DVDs also tend to have staggered release, even if it takes a month to rip a US-released DVD it’s still liable to be available on P2P netwroks before it goes on sale in Europe.

    “Secondly: it increases development costs. Rippers would have to have extensive trace/log facilities in order to report back the source of the error. Some of these might be in the DVD driver itself. ”

    As Mason points out, if this exploits driver errors it’s most likely going to stop it working altogether, something that Macrovision claim to have avoided. If your DVD playing software can read it, your ripping software should also be able to read it.

    “Thirdly: unstable rippers give rippers a bad name. People may just decide it is not worth the trouble.”

    In the early days of ripping/transcoding software people still used it, even when the process was “rip contents with DeCSS, split audio/video streams with VirtualDub, encode streams seperately, remux with VirtualDub”.

    I think there’s probably going to be a short period where ripping gets harder, but as soon as it becomes widely known which tools still work and which ones don’t it’s all going to go back to “business as usual”. As 3% of rippers still work I presume that they’re *always* going to work, otherwise Macrovision would have made darned sure that the first iteration of RipGuard also broke those tools. If this is the case then either everyone will switch to the working tools or the non-working ones will be modified accordingly…

  10. DVD decrypter already checks for and defeats existing structure protection. Assuming the existing anti-protection code doesn’t catch what Macrovision does it will be updated very quickly. I wouldn’t be suprised if DVD Decrypter is in the 3% of rippers that are already immune.

  11. Where is Halderman to “analyze” this new technology from Macrovision? Those at Macrovision are making some fairly lofty claims that need looking into. Come on Johnny do your magic on this technology, all in the name of fairness of course.