Several effects already support additional keyframe interpolation modes (curve, discrete) besides the traditional linear interpolation. In addition these effects also support attaching keyframes to the end to make them relative to the end of a clip (region).

Please add support for these additional keyframe interpolation modes to keyframable transitions, in particular, Affine and Composite (probably also to their cairoblend cousins as well). This will greatly enhance the versatility of these transitions.

For instance, a typical use of an affine/composite transition is to fade in and out a title clip. At this time the current keyframe interface for these transitions lacks these two useful functions:

• smoothly fading in and out instead of linear fading,
• attaching the two fade out keyframes (start and end of fade-out) to the end of the clip so that these keyframes automatically adapt correctly whenever the title clip with its transition has been resized. At this time, this always needs careful manual labor to correctly update the fade-out keyframes.