| 摘要 |
A video special effects generator for producing a wiped effect between two video signals uses presettable counters to define the boundary between the wiped and the wiping picture portions. Each counter, which is clocked with pulses synchronized with the horizontal or vertical synchronizing signal depending on whether the picture is being wiped horizontally or vertically, is loaded with a preset count during each horizontal or vertical period as appropriate and produces a signal defining the boundary of the wipe when it overflows. Arrangements for both horizontal and vertical wiping are disclosed; the vertical presettable counter may be used to load the horizontal presettable counter to achieve diagonal wiping of the picture. Keying may be accomplished by storing fixed values of preset count for the horizontal and/or vertical axes. |
