This tutorial is to demonstrate a use for a submixer.  It has a background image and a submixer containing a frame image and two other videos (in this case images) which falls off the wall.  The submixer keeps all its children together so you can rotate or move them all at the same time.  You can also move the children seperately in the submixer of course, which we do in this tutorial as well.

I'm just using pictures for this example which you can download in this zip file if you like.  In the demo video, at the end i did basically the same thing but with a combination of videos and pictures.

Step 1 - Import background.jpg and drag it onto the MediaMixer.

Step 2 - Get a submixer (sub-mixers) from the f/x tab and drop it onto the MediaMixer.

 
 
Step 3 - Import celtic.jpg, nudy.png, and frame.png, in that order, and drop them all onto the submixer track.

 
 
Step 4 - Now you have a subarrangement with 3 tracks inside it.  The frame.png should be at the top so that it covers the other two tracks.  If it isn't, go to the properties tab for frame.png and click the to top arrow.  You could also hover the mouse over the track and press the up arrow on your keyboard to move the track up one step at a time.

 
 
Step 5 - The celtic.jpg is hanging on the outside of the frame.png so you can shrink it a bit using the slider on the right side (drag it down).

 
 
Step 6 - The nudy.png also needs to be moved so that it is inside the frame.  You can use the left and top sliders to move it into the right spot.

 
 
Step 7 - Click on the submixers track (in the treeview) and then go to the current tab.  Under the picture there is a toggle which allows you to set the centre of the image.  The reason i want to change this is because i want the frame to rotate around the top left corner, as if it is in the process of falling off a wall.
So once you've pressed the toggle in, you can click at the top left corner of the frame to set the centre there.  The image adjusts its placement accordingly.

 
 
Step 8 - Now the sub-mixers track can be set to its proper location above the white strip.

 
 
Step 9 - Use the controls below the arrangement window (see screenshot) to move 1.5 seconds forward in time and give both the submixer track and the nudy.png a keyframe using the add key frame button.  This is just so they stay in the same spots for a bit at the beginning.

 
 
Step 10 - Go forward another 1.5 seconds, and give the sub-mixer another key frame.  Now click on the current tab in the arrangement area.  Select the angle tool, its the one with the line, and draw a line in the direction of the rotation.

 
 
Step 11 - Back to nudy.png, rectangle tab.  Move him over to the right side of the frame.

 
 
Step 12 - Move the time slider another 1 second to the right.  Go back to the submixer and set a key frame so it holds its position for a bit.

 
 
Step 13 - Move the time slider another 1 second to the right.  Move the submixer down in the destination (parent) rectangle.  If you want to see more area around the frame, move the slider at the bottom of the rectangle to the right.

 
This is the type of situation for which the quality slider on the export tab comes in handy.  If you want the rotated object (frame) to be anti-aliased, set the quality to around 30%.  Its a lot slower to export but looks better.