[sci.electronics] automatic commercial deletion

inc@tc.fluke.COM (Gary Benson) (09/20/89)

Someone made the point that the broadcasters lifeblood in commercial
television are the commercial, a point I agree with and thought sure someone
would have made by this time in the discussion.

I am a little surprised that noone has asked about how networks time the
station breaks...after all, when you have hundreds of local affiliates all
"going to a commercial" simultaneously, you gotta believe there is some
signalling going on. I mean, every station in the nation doesn't have a
dedicated engineer sitting there watching a clock count down and then
pressing his "goto local" button!

I once toured the Public Broadcasting studios in Madison, WI. I seem to
recall that there is in fact a "blip" sent that studio equipment can detect,
(the human eye can, too, if you know where it is and when it will
be coming). It is about as fast as a half an eyeblink, and I believe it is
simply a small white circle (or target) in the lower right corner of the
screen. In my memory of all this, the blip was sent some precise interval
(one second or 5 seconds) before the changeover, and it occurred in the
program before the station break, and in the commercial prior to returning
to the program.

Does anyone know if this system is still in use? Is it only the public
network that uses it or do the commercial ones, too? Is it only for network
station breaks, or do they use it for timing national ads, too? Does it
maybe only occur on scans 526 through 550 or something, so ordinary gear
won't see it? Or maybe it's sent only during retrace and the studio gear
can turn on the beam during retrace if there's anything there? I really don't
recall any of the technical details, but I clearly remember thinking at the
time that *if* video recorders for the home ever became widely used, a
commercial-zapper built around this blip would have widespread appeal.

Does anyone who has ever worked in a studio care to comment? (or is your
non-disclosure agreement still in effect? ;-)




-- 
GaryBenson_-inc@tc.fluke.COM-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_
-_-_-_-_-_-_-_-_-_-_-_-_-_-_-Tell the girls to slice the ham thin -J.C. Penney

logajan@ns.network.com (John Logajan) (09/20/89)

inc@tc.fluke.COM (Gary Benson) writes:
> I mean, every station in the nation doesn't have a
> dedicated engineer sitting there watching a clock count down and then
> pressing his "goto local" button!

But that doesn't necessarily mean that such automatic signaling is
available on the outgoing video/audio signal.  It could either be
stripped off, or come over a completely independent channel.

I've often noticed, however, some touch-tone like sounds on cable
tv broadcasts, such as from WTBS Atlanta, CNN etc.  I don't know what
sort of information is being sent -- but it doesn't coorelated with
the time commercials appear.

-- 
- John M. Logajan @ Network Systems;  7600 Boone Ave; Brooklyn Park, MN 55428 -
- logajan@ns.network.com, john@logajan.mn.org, Phn 612-424-4888, Fax 424-2853 -

tell@oscar.cs.unc.edu (Stephen Tell) (09/20/89)

In article <11213@fluke.COM> inc@tc.fluke.COM (Gary Benson) writes:
>I once toured the Public Broadcasting studios in Madison, WI. I seem to
>recall that there is in fact a "blip" sent that studio equipment can detect,
>(the human eye can, too, if you know where it is and when it will
>be coming). It is about as fast as a half an eyeblink, and I believe it is
>simply a small white circle (or target) in the lower right corner of the
>screen. In my memory of all this, the blip was sent some precise interval
>(one second or 5 seconds) before the changeover, and it occurred in the
>program before the station break, and in the commercial prior to returning
>to the program.
.... stuff deleted ...
>GaryBenson_-inc@tc.fluke.COM-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_

This sounds suspiciously like the timing dots used on film to help
the projectionist switch over between reels.  I suppose it could
be generated electronicly and used for commercial insertion too,
but it seems a bit hard to detect, especialy if the picture is nearly
white in the area of the blip...

Anyway, about how the film thing works:  35mm film only fits about 20
minutes to a reel of ~15 inches, so every movie you watch in a theater
has several changeovers.

Before the movie opens at your theater,
someone watches the film and notes what scenes the dots occur in.
When the changeover comes around, the projectionist has the next reel
mounted on the other projector, and queued to a special 'start frame'
by hand.  He/She watches for the afforementioned scene, and when they see
the dot(s), usually in the upper right hand corner, they start the
second projector rolling.   Exactly five seconds later, more dots appear,
and the first reel is over.  The projectionist opens the shutter on
the second projector, and simultaneously cuts the sound over, usually
with a foot pedal.  The first reel's lead-out is black for a while, to
give them time to reach over and close the shutter before shutting down
the projector and removing the reel to make way for the next one.

I may have some of the details wrong, I never actually ran one of these,
but have hung out in the booth while this was going on.  I think some
theaters have some way of automating this, I think by metal clips attached to
the film at the point of the changeover.  
Before I was told this, I never saw the dots, but now I always do.  The
actual changeover comes at a cut between scenes, so it usualy isn't too
noticable.

Another note related to TV commercial insertion:
Has anyone tried decoding the audio tones that come just before ESPN cuts
to a commercial?  It sounds like 4 or 5 of them, and they sound a lot
like DTMF.  Do they identify which commerials are comming, or how long
the break is?  If I was watching the direct satelite feed, would there be
more tones announcing the resumption of the program?
I recall these mostly from watching live games; don't recall if they
are always there.  Anyone have any info?

--------------------------------------------------------------------
Steve Tell					tell@cs.unc.edu
CS Grad Student, UNC Chapel Hill.
Former video guy, Duke Union Community Television, Durham, NC.

jlemon@cory.Berkeley.EDU (Jonathan Lemon) (09/20/89)

In article <1680@ns.network.com> logajan@ns.network.com (John Logajan) writes:
]inc@tc.fluke.COM (Gary Benson) writes:
]> I mean, every station in the nation doesn't have a
]> dedicated engineer sitting there watching a clock count down and then
]> pressing his "goto local" button!
]
]But that doesn't necessarily mean that such automatic signaling is
]available on the outgoing video/audio signal.  It could either be
]stripped off, or come over a completely independent channel.

A few years ago, a friend who worked at a TV station explained it this way
to me:
   For most of the mainstream affilates (CBS,ABC,etc..) they pull their
   signal off the satellites, and there is a marker (I don't know what
   kind) in the signal indicating commercial breaks.  The station then
   re-broadcasts the signal a few seconds later, with local commercials
   included, but WITHOUT this marker.  Thus there is no definite marker
   in the signal you are receiving.  (I imagine that if there was, they
   would lose LOTS of advertising revenues.)  I have no idea if this is
   true for every station - possibly the independents do it another way.
   But one thing stuck in my mind - if you have a satellite reciever, you
   can (or should, or I am wrong. :-) ) get the complete program without
   any commercials.  Has anyone tried this?
--
Jonathan   ...ucbvax!cory!jlemon    or    jlemon@cory.Berkeley.EDU

mbutts@mentor.com (Mike Butts) (09/20/89)

From article <1680@ns.network.com>, by logajan@ns.network.com (John Logajan):
> inc@tc.fluke.COM (Gary Benson) writes:
>> I mean, every station in the nation doesn't have a
>> dedicated engineer sitting there watching a clock count down and then
>> pressing his "goto local" button!
> 
> But that doesn't necessarily mean that such automatic signaling is
> available on the outgoing video/audio signal.  It could either be
> stripped off, or come over a completely independent channel.
> 
> I've often noticed, however, some touch-tone like sounds on cable
> tv broadcasts, such as from WTBS Atlanta, CNN etc.  I don't know what
> sort of information is being sent -- but it doesn't coorelated with
> the time commercials appear.
> 
> -- 
> - John M. Logajan @ Network Systems;  7600 Boone Ave; Brooklyn Park, MN 55428 -
> - logajan@ns.network.com, john@logajan.mn.org, Phn 612-424-4888, Fax 424-2853 -
I'm pretty sure the tones are used to signal the local cable distributor when a
time for inserting a local commercial is upcoming.
-- 
Michael Butts, Research Engineer       KC7IT           503-626-1302
Mentor Graphics Corp., 8500 SW Creekside Place, Beaverton, OR 97005
!{sequent,tessi,apollo}!mntgfx!mbutts         mbutts@pdx.MENTOR.COM
Opinions are my own, not necessarily those of Mentor Graphics Corp.

mflawson@uokmax.ecn.uoknor.edu (Michael F Lawson) (09/21/89)

In article <1680@ns.network.com> logajan@ns.network.com (John Logajan) writes:
>
>I've often noticed, however, some touch-tone like sounds on cable
>tv broadcasts, such as from WTBS Atlanta, CNN etc.  I don't know what
>sort of information is being sent -- but it doesn't coorelated with
>the time commercials appear.
>

The signals being sent are ordinary DTMF codes (like you get on your touch-
tone phone).  Each network which uses them has its own code.  Their purpose
is to signal local cable companies' insertion equipment that a slot is
available.  Usually one or two slots per hour are available for local
insertion.  There is one code which signals the beginning of the slot,
and one which signals the end.  For example, on ESPN the start code is 048#
and the end code is 048* (from what I can remember).  The code transmissions
don't appear to be correlated with the commercials because the VCR's need
an eight second preroll time to get up to speed.  So the next time you hear
one, count eight seconds, and a commercial spot should begin.  Lots of the
time it is network promos or public service announcements that go here if
locals aren't inserting their commercials.  The preroll time is, I believe
the exact reason Headline News has their little (~8 sec) "around the world
in 30 minutes, this is Headline News" clip during the commercial breaks
at the end of each half hour.  Several networks, though, are now switching
to tones on a different audio channel (or inaudiable, I forget which).
That's why you don't hear the tones on several stations anymore (CNN and
Headline News, for instance). I suspect we will hear less and less DTMF
as the years go on.

Even if you built a circuit to intercept these codes, though, you would only
cut out maybe 4 minutes of commercials per hour, hardly worth the effort.

Mike Lawson
mflawson@uokmax.uucp

henryb@hpspdra.HP.COM (Henry Black) (09/21/89)

 [  ..  about automatic commercial deletion  ... ]

 If this point has already been raised, I apologise for repetition,

It seems to me that if an electronic method of automatic commercial
deletion is devised then the broadcasters will surely mount
countermeasures.   But, perhaps this is a business opportunity for
someone as follows:
Have an office with human operators watching the TV and sending out
commercial start/end signals to subscribers over a dedicated
distribution network.  People wanting the "Commercial Deletion Service"
would have to acquire equipment and subscribe.  But the bandwidth
requirements are low and the value added to the consumer (IMHO)
enormous.  Certainly technically viable,  is it commercially viable,
would the broadcasters find a way of hitting back?  Interesting but
not electronic problems, so please follow up elsewhere than
sci.electronics on this drift thread.
-----------------------------------------------------------------------------
Henry Black      My views, endorsement by my employer not intended.
G4NOC/W6   henryb@hpspd.HP.COM   +1 415 857 6655

crc@raider.MFEE.TN.US (Charles Cain) (09/22/89)

The way that most of the networks like ESPN, TNN, A&E, etc.,etc., use what
is called Monroe tones. These are tones that are transmitted over a subcarrier
over the satellite to the cable systems. Each cable operator has to buy their 
own decoders. The tones that you hear on ESPN whenever they go to a break is the
monroe tones being sent. TNN, for whom I work, sends out their tones 8 seconds
before going to black. This gives the cable system tape machines time to come upto speed and color lock before the MC switcher takes the machine online.

The big 3 networks do it somewhat differently. NBC has the capability to auto- 
mate the system by using a SCPC carrier that is broadcast along side the main
satellite signal. This carrier can switch receivers, move the dish, ANYTHING 
they at NBC Master Control want it to do. CBS and ABC are still doing it the
hard way. The way that they tell the affiliates to go to a break is by throwing
up a slide or still store and saying,, """""""""""", 'This is CBS' or 'This is ABC'. CBS is
working on a similar package as NBC but have not as yet implemented it nation-
wide.

But all of this is for naught if a station decides to block a network promo
or commercial with their own. In that case, their is no way that I can think
of that a 'commercial killer' could pick it up, unless it looked for a timing
shift from one signal to the other, or looked for compressed audio, which 
commercials are HIGHLY compressed to create the effect of louder and hence
get your attention. This last method would probably be the best way to have
something know it was receiving a commercial and do a backspace edit to last
black and pause the recorder.

I hope that this helps somewhat. I apologize for the length of the post. If
anyone has any more questions, please email you questions to me.

Randy Cain

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jb@aablue.UUCP (John B Scalia) (09/22/89)

In article <11213@fluke.COM> inc@tc.fluke.COM (Gary Benson) writes:
>Someone made the point that the broadcasters lifeblood in commercial
>television are the commercial, a point I agree with and thought sure someone
>would have made by this time in the discussion.
>
>I am a little surprised that noone has asked about how networks time the
>station breaks...after all, when you have hundreds of local affiliates all
>"going to a commercial" simultaneously, you gotta believe there is some
>signalling going on. I mean, every station in the nation doesn't have a
> [you get the idea...]

Having no access to local TV or any cable TV, I get all my programming off
satellites (Gee, just like the local stations :-). Every station does indeed
know EXACTLY when a station break will occur and whether it should be local
or if the network is just interrupting the program. AND, it's not some
magical device that lets them know this. Before the networks begin broad-
casting say for the prime time session, they display a chart showing when
and for how long a break will occur. Kind of like:

	Position 1:	18:12:05	35 seconds
	Position 2:	18:22:40	1:15 minutes
	...

Maybe what we need are VCR's, etc. with a lot better programming and timing
characteristics.

jb@aablue

goddard@aic.hrl.hac.com (09/23/89)

In article <137@raider.MFEE.TN.US> crc@raider.MFEE.TN.US (Charles Cain) writes:
>But all of this is for naught if a station decides to block a network promo
>or commercial with their own. In that case, their is no way that I can think
>of that a 'commercial killer' could pick it up, unless it looked for a timing
>shift from one signal to the other, or looked for compressed audio, which 
>commercials are HIGHLY compressed to create the effect of louder and hence
>get your attention. This last method would probably be the best way to have
>something know it was receiving a commercial and do a backspace edit to last
>black and pause the recorder.

Is this technique something one could hope to use online, i.e. as I
watch the TV, when a commercial break begins (or soon thereafter), have
the TV automatically muted?  How does one detect compressed audio?  What
is compressed audio?  Sorry if these questions are really naive.

Nigel Goddard

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wcurtiss@x102c.harris-atd.com (Curtiss WC 67625) (09/26/89)

In article <602@aablue.UUCP> jb@aablue.UUCP (Root) writes:
>
>Having no access to local TV or any cable TV, I get all my programming off
>satellites (Gee, just like the local stations :-). Every station does indeed
>know EXACTLY when a station break will occur and whether it should be local
>or if the network is just interrupting the program. AND, it's not some
>magical device that lets them know this. Before the networks begin broad-
>casting say for the prime time session, they display a chart showing when
>and for how long a break will occur. Kind of like:
>
>	Position 1:	18:12:05	35 seconds
>	Position 2:	18:22:40	1:15 minutes
>	...
>
>Maybe what we need are VCR's, etc. with a lot better programming and timing
>characteristics.
>
>jb@aablue

This morning (about 6:00 EST) as I was flicking through the channels,
A&E network was displaying a list like this.  It could've been that our
cable company was supposed to block this and didn't or didn't care.
They are quite famous for splitting channels between providers (i.e.
UNOVISION before 4pm, SUN after, except on Saturday, when its ...)

Anyway, there were 48 slots per day and they listed 12 at a time.  They
seemed to be placed mostly at xx:29 and xx:59, but some were off those
"standard" times by as much as 6 minutes.  The times were listed to the
second, and were given at least through next Thursday (10/5) (I got bored and
changed the channel).  I doubt this is all of A&E's commercial slots,
since I thought they had more than 2 per hour, but it would give you a
start.  Now you just have to syncronize your VCR with them :-).

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