flash doesn't have a good memory and every time your use this, _parent or _root, flash has to look up the reference. if you use a variable to reference your timeline, flash will always know were to look.
we create two place holders. one for your external movie clip and one so that we can check if your .swf is loaded.
begin loading your file...
oe_mc.onEnterFrame = function ()
if (video_mc._width > 0)
video_mc._width = 640;
video_mc._height = 480;
video_mc._x = (Stage.width / 2) - (video_mc._width / 2);
video_mc._y = (Stage.height / 2) - (video_mc._height / 2);
initiate a loop onto our movieclip. as it continues to loop, onEnterFrame in an endless loop unless stopped, we want to check if the width of the video_mc is greater than 0; An empty movie clip's width is 0, once any data is loaded, its width is adjusted to the contents
Once the width has chanced, we want to remove the oe_mc movieclip, remvoing stops the loop automatically, and then you can treating the video_mc movieclip like any other movieclip... change its properties, add properties, adjust its alpha, add funcations etc. etc.