4x3 and 16x9: can the 16x9 automtically assign a "letterbox"

Hi All.
We have about 200 video clips sized to 4x3 playing in a player sized to 480x320 pixels.
It looks great.
We also have 50+ (and growing) videos shot in 16x9 that are set to play in the same player. They too look great, however the player skin “jumps” up to meet the bottom of the flv file. I would like to avoid this “jumpiness” and have the player itself always stay at a fixed size loading the flv in the center and placing a black background, or letterbox effect, behind the flv upon load of a video shot in 16x9.
Do any of you know how to do this dynamically? Please help!
I was thinking that flash’s levels might come in handy in resolving this, but have had no luck.
any thoughts?:fight: