Cable Boxes and Persistence of Vision

Our DVR remote control has a button you can push that will automatically rewind the show 15 seconds, so if you were having trouble hearing an actor, you can hit the 15-second rewind button and listen to it again. If you fast forward too much when skipping a commercial, you can hit the 15-second rewind button and go back.

But the remotes do not have a 15-second fast forward button. The reason? They don’t want to give you a convenient way to cleanly skip commercials, which are typically multiples of 15 or 30 seconds in length. You can still fast forward through the commercials, but you have to pay attention. TV networks would be very, very unhappy with cable companies if they gave their customers a simple way to skip commercials.

Since many of the networks hate DVRs, they have tried to get agreements with cable companies to not allow fast forwarding. They have also tried to get agreements with cable box manufacturers to allow them (the networks) to broadcast a special signal along with a TV show that tells the cable box that it may not allow fast forwarding during a certain program. For example, if they didn’t want you to be able to fast forward through “The Simpsons”, they would broadcast a special signal that the cable box would have to obey, and the cable box would disallow fast forwarding for that show. They could also add a signal that indicates that the show may not be recorded at all, or a signal that limits the number of times a show may be watched, or a signal that indicates that the show may only be watched in the 24 hours following the original broadcast. Pay-per-view movies already have limits like these, and I'm sure it would be no trouble for them to apply them to regular TV shows.

Instead of fighting fast forwarding, the networks could devise a way to take advantage of it. One way is to sell an advertisement in a long strip at the bottom of the screen, like the tickers on some news channels. It would be set up to display a message very slowly when watching the commercials at normal speed, but will show a legible message during fast forwarding. They could even time it somehow to show a legible message regardless of the speed the commercials are being fast forwarded. By knowing the standard fast forward speeds of the major cable boxes, they could use a computer to calculate a way to show messages that will be legible at different speeds, perhaps by using different colors.

Using persistence of vision (see some links below) you could arrange a series of colored dots or other shapes to produce messages that display correctly at different speeds. A common persistence of vision object is a clock, which consists of a thin arm covered with LED lights which protrudes from a base. The arm waves back and forth like the arm of a metronome. As it moves back and forth, the lights go on and off in a controlled way, and your brain sorts out the lights that are displayed and combines them into numbers. It's kind of like writing a letter with a sparkler - you see the light for a brief time after the sparkler has already moved to another position, because your brain sees it that way. For the clock, the lights "stay" long enough that you can read the time, or the message that it displays.

Some people have applied this idead to bicycle wheels -when you pedal the bike, strips of LEDs on the spokes will turn on and off and appear to draw a picture.

Persistence of vision clock
http://www.innovatoys.com/xp3.htm

Same idea in a mechanical form - a Zoetrope.
http://en.wikipedia.org/wiki/Zoetrope

Bicycle wheel persistence of vision.
http://4north.no-ip.com:8080/micro/