Buttons that play motion track only when selected

Question

I'd like to create a chapter menu such that as the chapter buttons are selected, a short loop of motion video (or audio+video) track plays somewhere on the screen, When focus moves away from the button, the track either goes away entirely or freezes at its start frame.
A good example of what I'm talking about would be the chapter menus of any of the Lord Of The Rings Extended Editions.
Is this possible with DSP?

Answer 1

The other way to achieve the effect is to use overlay shapes as masks which you make transparent when selected. You composite the motion areas as part of the background and then make an overlay to cover them. Set the overlay shape to be large enough and make it fully opaque when not selected/activated. You can then reveal the video underneath as you move from button to button.
This will work much faster than moving from menu to menu but there are some issues to consider...
Firstly, when you click on a button, your player may remove ALL overlay masks momentarily which will reveal all background videos. Similarly, when returning to the menu you may have a slight delay when the menu first appears, so that all video is again visible for a fraction of a second. This effect is not seen on every player, but some are worse for it than others.
Secondly, there is no way of controlling where abouts you start the video clip as the mask is removed - it will simply loop in the background and each time the mask is removed the clip will show from where it currently is.
However, if these are not major issues for you, then this technique will give you faster responses to your button selection and activation than moving between menus. If you want to have finer control over things then the multi-menu approach is the only one to consider!