Bitmap as mask

Question

I have a few imported images in my library I'd like to use as a mask to fit over a video but I can't get it to work. Here's how it works so far. The imported image is a photoshop .psd with some transparent layers.
import flash.display.Sprite;
import flash.media.Video;
import flash.display.MovieClip;
public class Main extends Sprite {
public function Main() {
     private var video:Video = new Video();
     private var dot:MovieClip = new Symbol1();
     video.width = 160;
     video.height = 90;
     video.x = 443; //Video position
     video.y = 190;
     addChild(video); //Add video to stage
     dot.x = video.x;
     dot.y = video.y;
     addChild(dot);
     video.mask = dot;
This doesn't work. The video just gets masked by the whole image, and not the shape with the trasparent layer.
So I figure I'd have to convert the psd to a bitmap, cause it sounds like you can only use bitmaps. So I just draged the psd image into flash to get a bitmapdata file in my library. But it still doesn't work. Here's the new code:
private var dot:BitmapData = new Bitmap6;
public function main {
          video.x = 443; //Video position
                                        video.y = 190;
                                        addChild(video); //Add video to stage
                                        dot.x = video.x;
                                        dot.y = video.y;
                                        addChild(dot);
                                        video.mask = dot;
but now I get these compiler errors:
1119: Access of possibly undefined property x through a reference with static type flash.display:BitmapData.
1119: Access of possibly undefined property y through a reference with static type flash.display:BitmapData.
1067: Implicit coercion of a value of type flash.display:BitmapData to an unrelated type flash.display:DisplayObject.
1067: Implicit coercion of a value of type flash.display:BitmapData to an unrelated type flash.display:DisplayObject.
So now I'm not sure what to do. Can anybody help me out?
Thanks, if anyone can help.

Answer 1

Nevermind, totally figured it out on my own. The image needs to be imported as a png or as a bitmap. Then:
public class Main extends Sprite {
public function Main() {
     private var video:Video = new Video();
     private var dot:BitmapData = new Symbol1();
     private var mymask:Bitmap = new Bitmap(dot);
     video.width = 160;
     video.height = 90;
     video.x = 443; //Video position
     video.y = 190;
     addChild(video); //Add video to stage
            video.cacheAsBitmap = true;  // this is pretty important
            mymask.cacheAsBitmap = true;
     mymask.x = video.x;
     mymask.y = video.y;
     addChild(mymask);
     video.mask = mymask;
Well... thanks anyway to anyone.