Abstract: The present invention provides methods and apparatus for representing visual images in compressed digital form. A series of digital images is provided to a random access memory and compressed one frame at a time. The compressor of the present invention divides a frame into a predefined number of blocks. Each block is tested to determine whether the block has a homogeneous color distribution. If the block has a homogeneous color distribution as defined by a selected homogeneity test, each pixel in that block is encoded with a single color value. If the block does not have a homogeneous color distribution, the block is split into two distributions, one distribution with a greater luminance than the average luminance of the first distribution and one distribution with a smaller luminance than the average luminance of the first distribution. These distributions are separately tested for homogeneity and the same process is repeated until the region has been resolved into homogeneous distributions.

Abstract: The system of the present invention provides a mechanism for executing a script sequence containing a plurality of commands and associated time for executing the commands. The system allows a user of the script sequence to specify an arbitrary time, either forward or backward from a current time, and the result of the execution reflects the cumulative effects of executing the script sequence from the beginning up to the arbitrary time. The system provides for a skip ahead mechanism in which commands are executed without waiting for the occurrence of their associated time. The system also provides for rewind and key-frame features.

Abstract: A media player and the clock which controls it are integrated into a single object. This integration may be achieved by the construct of inheritance between objects in an object oriented programming environment. A software class for player objects is established which inherits from a software class for clock objects. In this way, a player "is a" clock. This integration provides improved synchronization among different media, and simplifies design of applications which employ player objects and clock objects. Each object is synchronized to a RootClock object which operates at the speed of the fastest media player in the system. The RootClock may be separated into "low" order and "high" order components and a compare register in order to reduce interrupt overhead.

Abstract: The present invention provides a method and apparatus for event handling which addresses the problems associated with the prior art, including those problems discussed above, by delegating, for example to the system software, the task of determining whether particular combinations of events and other conditions have occurred. The present invention provides applications with a mechanism for establishing a template, called an event qualifier network, which monitors the occurrence of an event or specific combination of events, along with virtually any other qualifying condition specified by the application. In response to the occurrence of such events and conditions, the event qualifier network notifies the application that its "desired event" has occurred, whereupon the application may then take the appropriate action. Event qualifier networks can be quickly and simply built to monitor for arbitrarily complex combinations of events.