SubPicture Effects Technical Details
The purpose of this page is to further explain details of each of the effects since our example
is merely intended to show you how to add the most common effects.
As mentioned in the example, the delay or start time of the effect can be a negative
value to start the effect a certain number of frames prior to the end of presentation. The code generator will ensure
that delay <= -duration. In other words the duration will not be cut short if the start time
is too late, rather the effect will be started earlier in order to run the entire duration.
Not mentioned in the example, this effect simply sets new color and contrast values for the entire screen.
The fade effect changes only the contrast, the colors remain the same. However the contrast values are independant
and do not have to have the same values or direction of change. Most commonly PA, E1, and E2 will go from 0 to 15
or 15 to 0, while BG remains at 0. But fades can also be made with different starting or ending values such
as PA 0 -> 15, E1 0 -> 14, E2 0 -> 12. And channels can be cross faded, as PA 0 -> 15, E1 15 -> 0.
This effect is very flexible, even though only 18 pre-defined wipes are included. Wiping moves evenly from one rectangle
to the other. For the vertical and horizontal wipes the starting "rectangle" is a line, the ending rectangle
is the entire screen.
the center-out wipe starts as a point in the screen center and ends again with a full screen rectangle.
the edges-in wipe is unusual in that it starts with a full rectangle and ends as a point. For this
wipe (and any user defined wipe that begins full screen) the two color/contrast values get switched at the start as the old values are on the inside of the rectangle -
the reverse of all the other wipes.
you can design your own wipes by modifying the project file, and in the future the effect editor will
allow a free-style wipe with the two rectangles entered graphically.
- free-style wipe pattern
- partitioning the screen for more than 4 colors
- multiple effect channels operating in screen partitions
- chaining - eg wiping from one fade to another
- animation effect - looping through a sequence of effects
- last but not least - scrolling (the only effect to move text instead of color indirection)