During an the effect's describe in context action an effect
define the clips mandated for that context, it can also define extra clips that it may need for that context. It does this using the
function, the property handle returned by this function is purely for definition purposes only. It has not persistance outside the describe in context action and is distinct to the clip property handles used by instances. The
parameter is how you can later access that clip in a plugin instance via the
During the describe in context action, the plugin sets properties on a clip to control its use. The properties that can be set during a describe in context call are...
kOfxPropLabelto give a user readable name to the clip (the host need not use this, for example in a transition it is redundant),
kOfxImageEffectPropSupportedComponentsto specify which components it is willing to accept on that clip,
kOfxImageClipPropOptionalto specify if the clip is optional,
kOfxImageClipPropFieldExtractionspecifies how to extract fielded images from a clip, see \ref ImageEffectsFieldRendering for more details on field and field rendering,
kOfxImageEffectPropTemporalClipAccesswhether the effect wants to access images from the clip at times other that the frame being renderred.
indicate which pixel depths they can process by setting the
on the plugin handle during the describe action.
Pixel Aspect Ratios, frame rates, fielding, components and pixel depths are constant for the duration of a clip, they cannot changed from frame to frame.
kOfxImageEffectPropSupportedPixelDepthsplugin property during its describe action
kOfxImageEffectPropSupportedComponentson an input clip during describe in context