Re: Commercial killers

At 1:00 AM 8/1/95, Robert Hettinga wrote:
>God help me, all of this reminds me of a Carl Sagan book, of all things.
>One of his science fiction characters was said to have made his first
>fortune by building a commercial zapping chip for VCRs.
>
>Butthead Astronomer, indeed...

There have been _billions and billions_ of proposals for commercial
zappers. (Actually, not such a saganesque number, but dozens at least.)

Harry Bartholomew was telling me a year or so ago about some ideas for
detecting volume changes. I think, however, the problem of distinguishing
commercial from non-commercial signal is, I think, a tough one.

My point earlier was not to actually do this, but to suggest that if the
V-chip is to code various kinds of content, then the logic is strong for
commercial content to be similarly coded. (For example, schools often show
taped broadcasts...they might claim that it would be harmful and improper
for children to be exposed to beer commercial during school hours...)

This would gore the ox of the advertisers, so they might quietly have the
whole V-chip thing killed.

--Tim May

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| Harry Bartholomew was telling me a year or so ago about some ideas for
| detecting volume changes. I think, however, the problem of distinguishing
| commercial from non-commercial signal is, I think, a tough one.

	Yes, but the tv stations put in a short period of black &
silence before returning to the show.  I'm pretty confident that this
is what the 'zip through commercials' vcrs cue on.


Adam

-- 
"It is seldom that liberty of any kind is lost all at once."
					               -Hume

Adam Shostack <adam@bwh.harvard.edu> writes:

>	Yes, but the tv stations put in a short period of black &
>silence before returning to the show.  I'm pretty confident that this
>is what the 'zip through commercials' vcrs cue on.

Darned close.  The article I saw said it detects the period of black
and silence and puts a `notch' on the tape at each such switch.  The
notch can be detected at fast-forward speeds.  My question is - what
happens if there is black/silence *between commercials*?  How does
the VCR know that what follows a mark is show or merely the next
commercial?
-- 
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