DVD Studio Pro includes an Alpha Transition feature. Alpha Transitions make it possible for you to create customized transitions for use in your menus, tracks, and slideshows. Creating an Alpha Transition requires from one to three QuickTime movies, depending on the type of transition you want to create.
- Do you want any kind of video other than the start and end frames to appear during the transition? For example, if you want a spinning DVD to fly across the screen during the transition, you must have an asset movie providing the flying DVD image.
- Do you want to see the start and end frames on the screen at the same time during the transition? In the example with the spinning DVD, maybe you want to see the start frame around the outside edge of the DVD and the end frame in the DVD’s center. To see the start and end frames at the same time, you must have a background matte movie.
- Do you want a simple wipe transition that uses a custom shape? You can use a background matte movie to create a wipe transition with hard or soft edges in any shape you like.
All transitions have a start and end frame, based on where the transition is being used. The standard transitions are able to transform the start and end frame video, providing the ability to have a variety of effects, such as rotating or blurring, directly applied to the video. An Alpha Transition does not directly transform the start and end frame video—it simply transitions from the start to the end based on QuickTime movies you create.
There are several components to an Alpha Transition:
Asset matte movie
Background matte movie
Start frame (red in this example)
End frame (blue in this example)
The DVD image is from the asset movie, with an asset matte movie controlling where the background video appears.
Motion projects and movies used as Alpha Transitions within DVD Studio Pro are handled differently than Motion projects and movies used in menus and tracks. When opened, DVD Studio Pro checks for transition asset folders located in specific areas of your hard disk. Any folders it finds that contain appropriate Motion projects or movies are automatically added as Alpha Transitions, and become available for use in any DVD projects you author.
In addition to containing the movies that make up the Alpha Transition, the name of the asset folder becomes the name of the transition. All files within the folder must also be named the same as the folder, with “matte” added to asset matte movies and “backgroundMatte” added to background matte movies to distinguish between them.
The asset movie is required if you want any kind of video other than the start and end frames to appear during the transition. For example, if you want a spinning DVD to fly across the screen during the transition, it is the asset movie that provides the flying DVD image.
The asset movie must have the same name as the asset folder and can have an extension. For example, if the asset folder’s name is Spinning DVD, the asset movie could be named Spinning DVD.mov.
There are two optional aspects to the asset movie: an alpha channel and a switch point.
In the above example with the spinning DVD flying by, you would most likely want to be able to see the start or end frame video through the DVD’s hole and around its edges. For this to happen, there must be an alpha channel for DVD Studio Pro to know which parts of the asset movie video should appear and which should be ignored.
The background matte movie must have the same name as the transition asset folder, followed by “backgroundMatte,” and can have an extension. For example, if the transition asset folder’s name is Spinning DVD, the background matte movie could be named Spinning DVD-backgroundMatte.mov.
The background matte movie needs to be monochrome, with white identifying where the start frame video appears, and black identifying where the end frame video appears. As a general rule, the background matte movie should start with a full white screen and end with a full black screen. You can also use levels in between white and black to set transparency and add soft edges.
Related Post of Create and Import a Motion Project as an Alpha Transition with DVD Studio Pro