How are local commercials put in national television broadcasts?

Question

How are local commercials put in national television broadcasts?

In: Technology

Answer 1

Assuming that you mean ‘how do local stations play local commercials during a national broadcast’ it is pretty simple. The local affiliate is told, for each part of the broadcast, “From this time to this time, you must let the national commercials play; from this time to this time, you may play local commercials.” The broadcaster then ‘overrides’ the national broadcast with their local video during the times they are allowed to play commercials.

Sometimes, they don’t override perfectly, which is why sometimes you’ll see a fraction of a second of other video right before a program starts – that is the tail end of the national broadcast that was overridden.