The UMSMonitorMClass metaclass is an Ultimedia Services Version 2 feature and does not apply to Ultimedia Services Version 1.2.1.
The UMSMonitorMClass metaclass constructs a monitor object based on the display and the video format required. Since all monitor implementations are contained within UMSVideoIn (and UMSVideoOut) objects, this metaclass returns one of those objects cast as a UMSMonitor object. This is an example of polymorphism. The UMSMonitorMClass contains the following method:
UMSVideoMonitor make_a_w
This method accepts a string that describes the monitor and a display pointer.
The UMSVideoInMClass constructs a UMSVideoIn device-specific class based on an alias. The alias corresponds to an entry in the configuration file for a particular video device. The UMSVideoInMClass contains the following method:
UMSVideoIn make_from_alias
This method returns a pointer to a VideoIn object or NULL. It tries to construct the object based on the given alias.
For introductory information, see Programming with MetaClass Objects.