Back in
June 2005, Macrovision
sued Sima Products for making video processors that made it easy for
consumers to circumvent Macrovision's analogue copy protection (ACP), such as
that used in DVDs and certain pre-recorded VHS tapes. Early this year, the
court issued a preliminary injunction against Sima earlier this year, however this was later upheld in June.
ACP works by inserting noise into the vertical
blanking interval, which causes havoc with the automatic gain control of most
VCR's, thus resulting in a poor quality recording. Sima's product is
actually nothing more than a digital video signal processor, which takes in the
analogue picture, converts it to digital, processes the image and converts it
back to analogue. However as the blanking interval is not part of the
visible picture, this is simply left out during the analogue to digital
conversion as with most other video capture devices, thus leaving out the
analogue copy protection. As a result, this copy protection is no longer
present even after the processed picture is converted back to analogue
again.
The Consumer Electronics Association is now
concerned that if Sima loses this appeal, it would effectively make analogue to
digital video devices violate the DMCA unless they are also designed to capture
or analyse the vertical blanking signal to preserve ACP in the captured
signal. The injunction is currently being considered by the Court of
Appeals for the Federal Circuit and an amicus (friend of the court) brief has
been filed in support of Sima by several consumer groups, including the Consumer
Electronics Association and the
EFF. As ACP does not actually stop a VCR from making a copy, but
instead weakens the picture quality, the main argument is that ACP is not
actually a technological anti-piracy measure since most existing analogue
recording equipment will not look out for ACP to stop the recording taking
place. It is also ineffective against digital capture devices since these
do not make use of the vertical blanking. Thanks to GristyMcFisty for
letting us know
about this news:
The brief makes the point that Congress has already addressed this issue quite explicitly in Section 1201(k) of the copyright code, which prevents analog VCR manufacturers from ignoring automatic gain control copy protection. The coalition notes that this only applies to analog products, and they quote Senator Orrin Hatch's comments to the same effect. But the main argument is that ACP is not a technological measure that "effectively protects a right of the copyright owner" because ACP does not actually prevent making copies at all. It simply makes it difficult to get good copies. Furthermore, ACP is really a "flag," not a "measure," since it can be either read or ignored without problems. Finally, it is not an effective protection measure because it does nothing to stop digital copying (digital video signals do not require blanking intervals, so digital copies simply do not use the information in the blanking interval at all), The brief also argues that Sima is not "circumventing" anything'”the stripping of the ACP is just a necessary byproduct of digital conversion. "Circumventing" suggests a much more active process. |
While DVD recorders do not need to make use of the vertical blanking in the
video signal in order to capture the video, we can already see the effect
Macrovision has caused with DVD recorder makers. Pretty much every DVD
recorder on the market is configured to specifically look out for the tell-tale
ACP noise in the vertical blanking and prevent recording should this be
detected. So even though most DVD recorders are technically capable of
capturing video with ACP, the makers are protecting themselves from possible
legal action by deliberately preventing its customers from making recordings of
video with ACP present.
Unfortunately as old / worn out tapes may develop noise in the vertical
blanking, detecting ACP does have its side effects in that some DVD recorders
can be fooled into thinking that noise in the VHS picture's vertical blanking is
a form of copy protection and thus stops the recording process. Some
Lite-On models were notorious for false detection, thus resulting in
consumers risking hacked firmware on their DVD recorders just to back-up
their camcorder footage and old tapes.
Source: Ars Technica
