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IDProjectCategoryView StatusLast Update
0000571Cinelerra-GG[All Projects] Featurepublic2021-06-02 07:50
Reporterpallium Assigned ToPhyllisSmith  
PrioritynormalSeverityminorReproducibilityhave not tried
Status acknowledgedResolutionopen 
Product Version 
Target VersionFixed in Version 
Summary0000571: Overlay : Alpha
DescriptionCan you add the plugin of frei0r : alphaatop. ->
Keep the alpha of the track above and remplace the pixels of the track above with the track below. Maybe with an example, it's more clear (video and picure below).
TagsNo tags attached.




2021-06-02 07:50

reporter   ~0004776

I am glad you have seen other things in my demo. This was my goal.
When I do a demo I try to add other things that an User might think useful.

About the 3 my demo, I guess you would like to have their with subtitles or am I wrong?
Let's see. (I am getting lazy,... sorry)


2021-06-02 00:48

reporter   ~0004773

Hooo we need to do a "sandwich overlay". Very good!!! Thanks @IgorBeg. You also solved another of my problem: I didn't know to import a transition in black and white. Now it's possible with overlay and chromakey.

import-transition.png (835,831 bytes)
transition-overlay-chromakey.webm (752,198 bytes)


2021-06-01 20:37

manager   ~0004772

[@IgorBeg; OT]
Any chance you'd like to turn these 2 videos on alpha mode and the other on copying effects keyframes into video tutorials?


2021-06-01 18:34

reporter   ~0004771

Cinelerra[--] can do that!

Like @Andrea_Paz said you can use Overlay Mode,... or Overlay plugin (this one is more "flexible").
Of course your "Color Model" in Settings-> Format...-> Video section have to be RGBA or YUVA (with Alpha Channel).

For Overlay plugin you can see my demo at:
For Overlay Mode you can see my demo at:


2021-05-31 15:27

reporter   ~0004770

I just suggest. I don't want to stress someone. Cinelerra is a great surprise and I just want to help the project with my experience in video editing.

I tried all the overlays of Cinelerra 3 times and I don't get a similar result.


2021-05-31 14:59

manager   ~0004769

I don't know much about Overlays. Probably what you are looking for is "Dsatop" or its opposite "Srcatop", which are among the Porter-Duff Overlays. see:


2021-05-31 14:07

manager   ~0004768

That would be a good addition. It is not as easy as just "adding it". A whole new plugin program has to be
written in C++ code to create the desired effect.
Is there another plugin already that would get similar results?


2021-05-31 11:40


overlay-alpha.webm (190,805 bytes)
kdenlive-alphaatop.png (26,124 bytes)
kdenlive-alphaatop.png (26,124 bytes)

Issue History

Date Modified Username Field Change
2021-05-31 11:40 pallium New Issue
2021-05-31 11:40 pallium File Added: overlay-alpha.webm
2021-05-31 11:40 pallium File Added: kdenlive-alphaatop.png
2021-05-31 14:07 PhyllisSmith Assigned To => PhyllisSmith
2021-05-31 14:07 PhyllisSmith Status new => acknowledged
2021-05-31 14:07 PhyllisSmith Note Added: 0004768
2021-05-31 14:59 Andrea_Paz Note Added: 0004769
2021-05-31 15:27 pallium Note Added: 0004770
2021-06-01 18:34 IgorBeg Note Added: 0004771
2021-06-01 20:37 Andrea_Paz Note Added: 0004772
2021-06-02 00:48 pallium File Added: import-transition.png
2021-06-02 00:48 pallium File Added: transition-overlay-chromakey.webm
2021-06-02 00:48 pallium Note Added: 0004773
2021-06-02 07:50 IgorBeg Note Added: 0004776