Dear Massimo, First of all... by the way... if anyone wants to contribute, I would be glad. I would probably publish it as GPL.
> can you explain in details what this mixer2 is supposed to do? It compares track A and track B. Copies track B to output D and sets D[alpha] to transparent whenever A and B are "equal". I am a professor of mathematics. I have recorded some classes I edited with Kdenlive. I know nothing about video editing. :-) For example: https://www.youtube.com/playlist?list=PLMG2ETzS-iy80kspoqaE2bgLWvZFf9i3u I am recording a new set of lectures for a different subject. Now, that I am a little savier, I want to be able to erase my background. I have asked a question here https://video.stackexchange.com/questions/34264/kind-of-chroma-key-using-a-key-frame on how to do that, but I got like 7 views in a few days. So, I decided to write a plugin. :-( I realized it would be easy to implement a simple version of that but that would not work very well due to already known issues with "chroma keying". I got it working roughly some 8 hours ago. Shadows are the biggest problem right now. But maybe I can fix it with better illumination. It is not really usable, but much better than I expected. I used "melt" to test it. I can share the resulting video if you want. Not a Kdenlive issue... but now I realize it would be better to write an MLT plugin, so I could use a better color scheme, and also chain some other processing. I can publish my code, if you want. The method to determine if two pixels are the same needs to be improved. I have thought of a dozen things that could be done, but I think it would have to be an MLT plugin to do more advanced processing. I will also need to "erase" the ink on the whiteboard. Also, a different version of the plugin could be an "MLT filter" instead of a "mixer2". It could compare to a specific keyframe, instead of comparing to a track. But I would probably not be able to do it with frei0r, and I am not really confident there is a GUI for the "keyframe" value. So, by now, it is a "mixer2". I would be a nice approach, and the image to be compared with could "evolve/adapt" for the next keyframes. > BTW: to add a frei0r plugin to Kdenlive, you have to add it to the > frei0r plugin folder and create an xml ui file for it. I have read a lot since I made this question. Following an advice I got on MLT mailing list, I have added it to ~/.frei0r-1/lib/ I guess I need to provide an XML as described here: https://invent.kde.org/multimedia/kdenlive/-/tree/master/data/effects And I should probably put it in here: ~/.local/share/kdenlive/effects/ Cheers, André Caldas.
