Handling of information already known to the characters but which the reader might not know and needs to be told is a tricky item to handle in writing. There are right ways of dealing with such a situation and a wrong way - and the use of "As you know" being a bad one should always be one avoided like the plague. (Just heard the phrase again a few days ago while watching the remake of The Day the Earth Stood Still - sigh...) It's a crutch, and not a good one, which can be avoided with a little effort or difused enough that the reader won't realize it's information being offered for their benefit and not one the characters would actually bring up and voice otherwise.
In TV regurgitating info for the audience's benefit is a little more restricting than for writing, but doable all the same. Let me see if I can work up an example.
Not so good way: "As you know, General, the enemy is at the border. We may have to use the gamma weapon sooner than anticipated."
Better way: "With the enemy at the border, General, we may have no choice but to use the gamma weapon sooner than anticipated."
In a written medium, you have the added option of the information never actually being said out loud but the character imparting the information instead by their thoughts or reactions.
Another way: As the colonel hurried down the hallway to the breifing, he realized that with the enemy already at the border, they might not have any choice but to use the gamma weapon sooner than anticipated.
You can mix dialogue with character thoughts/reactions to break up info dumps or add data that again would be known to those speaking and not the reader and do it in such a way that it does not disrupt the story but enhances it.
For example: "We may have to deplay the gamma weapon." Colonel Barns felt his stomach clench as he made the suggestion, only too aware of the weapon's theorized capabilities. With a range of up to two miles, once fired, it would create an ever widening zone of destruction unlike any other weapon ever used up to this point in the history of man.
Okay, I went a little over the top with the melodrama, but you get the point. Heh. While everyone at the briefing is probably already aware of the weapon's potential for destruction, and would not therefore mention it, I still got that information across to the reader. There are many ways to forward information yet not detract from the writing and characters themselves, you just need to get creative. Crutches may be quick fixes but won't satisfy anywhere near as much if you take the extra time and effort.
Keep your ears open and see how many time you can catch or stumble over the dreaded "As you know, Bob..." Steer clear of it in your own efforts! For all our sakes! Heh heh.