Friday, April 13, 2007

Black Screen of Torture

This morning I came across yet another patent application (20070081560; 'Method and system for fast channel change in a communication device') that addresses ways to reduce the duration of the black screen when you change TV channels.

I'm shocked that Scientific Atlanta hasn't already used Bayesian probability and a sensor to solve this problem.

The only way to really eliminate the black screen is to have the selected channel spooled and ready to go before you select it. That usually means using additional memory or bandwith in the set-top box to stream multiple channels simultaneously. The goal is to accomplish this task using the smallest memory and bandwith possible.

Let's look at the role of the sensor in the remote. You can't change the channel using the remote unless you touch it; so an embedded proximity sensor determines whether you are about to touch a button or if you are holding the remote. Once the sensor detects your presence, the remote sends a signal to the set-top box to start streaming since you're likely to change channels.

Good. We've minimized the time that the set-top box streams, now let's see if we can reduce the bandwith by pre-selecting the likely channels based on past viewing habits.

You can only change channels a few different ways using your remote:
  • channel up/down
  • last
  • favorite
  • enter channel directly
  • 'Select' channel using electronic program guide
Since each of us uses these buttons in a different way and with different frequencies, the set-top box should be able to learn how you use the remote and be able to guess which method you'll most likely use.

That's fine if you usually press channel up/down, last or favorite. All of those buttons have preset operations (with associated channels) and the set-top box can stream these channels. But what if you enter the channels directly?

Actually, it's not too much of a problem.

You probably already know about these research results that were published two weeks ago:
According to a new report from NeilsenMedia, The number of television channels that the average U.S. home receives has reached a record high of 104.2 TV channels, an increase of almost eight channels since 2005. In 2006, the average household tuned to 15.7, or 15.1% of the 104.2 channels available for at least 10 minutes per week.
That's good news since it means the set-top box doesn't need to stream every channel.

But we can do better than that. Let's say you that you usually watch 16 channels. I'm sure you don't watch them equally. You might watch HBO more than Food Network. At the very least the set-top box should be able to track these difference in probabilities for overall viewing. If this probability is above a certain threshold — you're more than 20% likely to enter the channel — then the set-top box streams that channel.

That's just the first step. If there really is a need and the method works, the set-top box can use joint probabilities to include the effects of time of day and which show is currently airing on that particular channel. Maybe you watch "Scrubs" at 7PM and "The Daily Show" at 11PM most days on Comedy Central but no other Comedy Central shows. Your set-top box should know this and do everything it can to make the transition seamless when you change channels.


Anonymous said...

the sensor part is does it detect your hand tho, humidity, heat?

dr. tv (mike vicic) said...

maybe even a few other ways. short-range motion sensor. accelerometer. electrical conductivity.

really any inexpensive sensor/chipset that returns a binary response: zero (don't record, remote not being used) or one (record since remote is being used or about to be used).