action is passed to plugins, when the host requires them to render an output frame.
All calls to the
are bracketed by a pair of
actions. This is to allow plugins to prepare themselves for rendering long sequences by setting up any tables etc.. it may need.
will indicate the frame range that is to be renderred, and whether this is purely a single frame render due to interactive feedback from a user in a GUI.
The render action is used in conjunction with the optional
If an effect does nothing to its input clips (for example a blur with blur size set to '0') it can indicate that it is an identity function via the
action. The plugin indicates which input the host should use for the region in question. This allows a host to short circuit the processing of an effect.