Sunday, April 1, 2012

A is for Analog Sunset and the CopyCop in your Blu-Ray player

For April I'm going to try the ambitious (for me) effort of posting something every day, running through the alphabet. We'll start at 'A', with the analog sunset.
So much analog has gone away in terms of video. No more analog cable or satellite broadcasts. No more VGA outputs on new computers. It's been years since  I've seen Y-C (S-Video) encoded video on anything. But analog isn't quite gone, is it? Your TV still has some component inputs (YPbPr, for example), and your old blu-ray player and set-top box still has component outputs, right? So if you don't want to spring for an HDMI cable or your HDMI inputs are all in use, you can still play high-definition moves through the good old analog component input, right? Right?

Well, not so fast. There are other parts of the analog sunset that happened quietly, where many of us might not have noticed. They aren't as splashy as the end of broadcast analog TV, but speak to bigger and, to some observers, scarier trends.

As part of the "analog sunset" to urge in the digital era, content providers can put an "image constraint token" on a disc. This means that it could force your high-definition display to show your high-definition content in standard definition. Why? Because analog signals are hard to encrypt. Once you encode video in an analog format (from composite video all the way up to RGBHV), what you're creating, in a nutshell,  is a varying voltage level representing individual colors. You could take this voltage and split it in multiple directions, record it, boost the level to enhance it, recreate it, etc. A digitally encoded signal, on the other hand, is a stream of zeroes and ones which in this case, thanks to the magic of  HDCP (High-Bandwidth Digital Content Protection) can be encoded with the private keys hiding in your blu-ray player or HDCP-compliant display. Absent a key to decode it, you have what for any practical effect is a stream of random numbers.

Why should we care about this? In the short term, it could be an inconvenience to people with older equipment; most new displays have plenty of HDMI inputs and very few analog inputs, so it's only those nursing along five-year old monitors who will run into an issue. In the mediu-term, it's not that big an issue to anybody. Sure, there might be the occaisonal home-theater enthusiast with a Blu-Ray player in an equipment closet connected through an AV-reveiver to TVs in his living room, bedroom, and kitchen. If he manages to get HDMI everywhere he might find himself running out of keys (another note - for another entry - is that per-session decryption keys are limitted in quantity. Your Blu-ray player might only want to hand out 3 keys, for example. Your TV takes one of them. The surround-sound receiver between the player and TV also takes one. So, two down.. not many left. But I digress). So medium-term, who cares if analog video goes away? Modern displays are digital anyway; they are made up of pixels which are either on or off. Zero or one. Why should we care about losing the chance to turn the digital recording on our blu-ray disc analog only to redigitize it at the other end?

Perhaps we shouldn't. However, I worry that by giving studios the right to stop our technology from working the way it could we've let the camel's nose into the tent, with the rest of the camel to follow. There are those who believe that we own our technology, we own whatever content we choose to view on it, and we should be able to do what we will with it. While I'll agree that "I can open my own TV station and  broadcast it to the whole world" might be a step too far, "I'll convert it to a different format so I can back it up or do some video editting on it for my own amusement and that of my close friends" seems perfectly reasonable. We can't do this today because of how digital rights are being  managed. If this goes on, what will we lose tomorrow in the name of protecting corporate profits?

No comments:

Post a Comment