What is the purpose of the 5 (?) second delay during news broadcasts?

The delays are usually due to long distance hops over satellite links, which takes time, but is usually less than 5 secs.

 

http://en.wikipedia.org/wiki/Broadcast_delay

 

I'm not sure that's the same thing the OP means, though I could be wrong...

 

I agree with your original assessment, but as you stated it's not nearly the 5 seconds the OP mentioned.

 

So...you discount my explanation?

 

I think Deesky has the correct explanation for this.

 

It is indeed the lag cause by satellite communication (and/or other things in that chain). This is, I think, why sometimes talking to someone on another continent results in an even longer lag.

I laugh when someone on TV, whose job is to appear on TV, still after all these years doesn't seem to be used to this lag and talks over the other person.

 

Actually, the request need to turn down the radio is for reasons similar to what you asked about. If a caller to a radio station left their volume up and was put on the air live, it could possibly create a feedback loop, and at the very least make the caller sound like they were in an echo chamber.

If a pre-taped person had their radio up in the background, that may be irritating, but not a technical issue.

EDIT : Actually, they probably would have someone turn down their radio in both cases. With a five-second delay, the echo of the radio would be delayed long enough to not be immediately identifiable, but it would still be unusual and irritating.

 

There's definitely a delay introduced by satellite and/or some type of codec at each end. Occasionally, there'll be a "now we turn to our reporter in Iraq" segment and the conversation seems to flow very well, but I'm reasonably convinced those are pre-produced and the delay has been edited out.

 

The delay has become even more commonplace as local TV reporters now relay their live shots via bonded cellular instead of microwave.

 

There are two scenarios for a delay. One like the OP mentioned is in a live show like Howard Stern, where they want a delay so they can bleep out cuss words and other inappropriate comments. The other is a satellite delay. The signal is bounced from earth to a satellite in geosynchronous orbit and then back down to earth. This causes a delay of a few seconds.

I was working at a TV station and we were trying to get the satellite link working. I was talking to the other people who were only 100 or so miles away on the telephone. I could also hear the person I was talking too on the satellite feed. His audio was coming in a few seconds after I heard him on the phone. It was very confusing.

Chad

 

...instructions on how to manipulate the story to their benefit?

 

Glad to help! The bonded cellular delay is a relatively new phenomenon; only recently has mobile broadband increased in speed enough to support broadcast-quality video.

 

Yes, the traditional satellites are about 22,000 miles up, more or less orbiting above Mexico City, which they figured out is about the right place to blanket a signal over most of the continental United States. (At least, that's what I was told.) The electronic delay from the time the signal leaves the earth and goes up to the satellite, then comes back down to earth where it gets received, is about 2 seconds. So when the news anchor says, "we go now live to our correspondent in North Korea. Joe, can you tell us about the current state of the government?", they cut to the reporter who stands there silently, not talking until he or she gets their cue, and that takes about 2 seconds.

This has been a known problem for about 40 years, and what they've been doing more and more lately is have an assistant director count down the reporter on a wireless link so they can start talking about 2 seconds earlier. This only works if the news anchor sticks to the script and doesn't ask any unexpected questions. I've seen them do this fairly well on NBC in the last year, so somebody is paying attention to this annoying timing issue.

But generally, we just have to accept the audio/video delay. 45,000 miles is a long way to travel, even for digital signals. When NASA talked to the astronauts on the moon, the delay was about 6 times longer, because the distance (240,000 miles) is six times greater.

 

Yup, the universe's maximum speed limit is way too slow.

 

Yes, I see that could explain it. So much is actually pre-produced.

 

Just an aside, but I wish video clips were date stamped as to when made. It's so irritating to watch a clip of uncertain date and relevance looped many times while the talking head drones on.

 

Latency is an ingredient to all the processes described above.
Processing takes time. Be it satellite hops, fiber transmission or back hauls, format or frame rate conversion, frame syncing, etc.
It all adds up to delay. It is the sum of all of the components mentioned that determines how much delay is added.