I would like to suggest a great feature that I used very often in another open video editor: the option to use keyframes in every filter as well as in transitions so that we can create more customized effects. In addition to this, it would be really nice to include some predefined effect/filter/transition curves such as sine, exponential, round, cubic, etc. to smooth entry and/or exit of the effects, filters or transitions.
These already exist. The advanced keyframes for these control position and size together because this parameter is of a type called “rect,” which is short for rectangle: https://www.mltframework.org/doxygen/structmlt__rect.html
Ah, okay! The Advanced Keyframes button being on the line for the Position parameter made me think this entire time that there was only Advanced Keyframes available for it and not Size. May I suggest moving the Advanced Keyframe button slightly lower so that it’s in between Position and Size that way it’s made clearer that advanced mode is available for both?