Connecting Systems To Displays: Plugging (Away At) The Analog Hole
This blog post references my cover story 'Connecting Systems To Displays: What We Got Here Is A Failure To Communicate' in EDN's January 4, 2007 edition.
HDCP is the latest in a long line of technology attempts to encrypt the digital link spanning source and destination, thereby precluding (or at minimum controlling) the ability to copy data coming from that source. Other legacy DRM examples, off the top of my head, include the SCMS system at the heart of S/PDIF-inclusive DAT and music CD-Rs, and the abhorrent (at least to me) Broadcast Flag. Generally speaking, analog interfaces have engendered less industry scrutiny than their digital peers, especially if the content source is digital in nature.
The fundamental belief underlying the more temperate historical stance on analog interconnect, I think, is that the consecutive D/A and A/D conversions required to transform a digital source to a digital destination via an analog intermediary will create enough quality degradation that any resultant copy wouldn't notably harm the market opportunity for that digital source. With that said, the industry approach to analog interconnect hasn't been entirely hands-off; one needs only look at the Macrovision copy-suppressing (albeit not absolutely preventing) scheme present in most VCRs and DVD players, or the not-yet-implemented resolution-limiting Image Constraint Token which Blu-ray and HD DVD players support. And the analog scrutiny is ever-increasing.
Hollywood, in cahoots with friendly members of the U.S. government, has several times in recent years (most recently in late 2005) attempted to legislate far-reaching Analog Hole-plugging regulations. Put simply, the ambition of such proposals would be to include, in each multimedia source, a D/A converter that would determine and pass along over the analog link (via watermarking, out-of-band encoding or some other means) the allowable-copy provisions of a particular piece of content. The companion A/D converter in the multimedia destination would detect this copy-defining coding and would appropriately respond. If a multimedia source detected that the connected destination didn't include the necessary circuitry, it would refuse to activate its outputs.
I have strong and, you may have already guessed, disapproving views of any proposal that:
- Cost-burdens systems and
- Increases the probability that users will have problems operating the systems (see the HDCP issues outlined at the end of the HDMI section of my article, and extrapolate….), including breaking compatibility with users' existing equipment, but
- Won't, at the end of the day, do anything to reduce organized piracy, thereby leading me to conclude that the Analog Hole legislation actually is
- A thinly veiled (aptly-named) attempt to further restrict consumers' access to content, thereby acting as another strike against Fair Use Doctrine.
Instead of continuing on at length, at least at this time, I'm instead going to provide some links to chronologically-ordered additional reading suggestions on this issue. I welcome your comments.
- MPAA looks to bolster its dominance by plugging the analog hole
- New Bill Threatens to Plug "Analog Hole"
- Congress discusses broadcast flag, analog hole proposals
- "Analog hole" legislation introduced
- Analog Hole Legislation Formally Introduced
- The Clicker: DTCSA — A whole lot of analog holes are being plugged
- Analog watermark: both secret and poorly designed?
- Forcing the analog sunset: the ugly side of the HD revolution (note this one in particular: even in the absence of legislation forcing a lock-down of analog interfaces, technology developers and their chip, software and system implementation partners are in effect making analog 'vulnerabilities' a non-issue by phasing out analog connections)
- DRM and the Myth of the Analog Hole
