Compositing two layers with transparency and chroma key
I want to achieve the following animation: - Track 1: the CGI animation, it has transparency and a chroma layer - Track 2: Video the animation runs over - Track 3: the CGI animation transitions to Track 1 + 2 = the default operation, this works when stacking the animation on top of the video. But *without rendering twice*, how am I able to mask out the chroma key in the animation, so track 3 becomes visible under it? -- Stefan
Lets do something nice and answer myself. How to achieve this? Tracks from top to bottom: - VIDEO transparent CGI animation, no extra chroma key layers - VIDEO transitioning FROM (Overlay Mode > PorterDuff > DstAtop) - VIDEO transitioning TO (Overlay Mode > PorterDuff > SrcAtop) - VIDEO mask layer (what to enable will be white) Now there is a bug, once a transition to black is added to the transitioning TO video layer, the video will black out at some point. And obviously to celebrate our working website and git repo a tutorial on YouTube! https://youtu.be/RCZuS4gy4BE Op 16-11-2025 om 6:12 p.m. schreef Stefan de Konink:
I want to achieve the following animation:
- Track 1: the CGI animation, it has transparency and a chroma layer - Track 2: Video the animation runs over - Track 3: the CGI animation transitions to
Track 1 + 2 = the default operation, this works when stacking the animation on top of the video.
But *without rendering twice*, how am I able to mask out the chroma key in the animation, so track 3 becomes visible under it?
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!DSPAM:1,691a060996561354169715!
-- Stefan
Stefan, I had to laugh at your answering yourself. I was hoping IgorBeg had an answer too. Very nice youtube video. Thanks, Phyllis On Sun, Nov 16, 2025 at 12:53 PM Stefan de Konink <stefan@konink.de> wrote:
Lets do something nice and answer myself.
How to achieve this?
Tracks from top to bottom: - VIDEO transparent CGI animation, no extra chroma key layers - VIDEO transitioning FROM (Overlay Mode > PorterDuff > DstAtop) - VIDEO transitioning TO (Overlay Mode > PorterDuff > SrcAtop) - VIDEO mask layer (what to enable will be white)
Now there is a bug, once a transition to black is added to the transitioning TO video layer, the video will black out at some point.
And obviously to celebrate our working website and git repo a tutorial on YouTube!
Op 16-11-2025 om 6:12 p.m. schreef Stefan de Konink:
I want to achieve the following animation:
- Track 1: the CGI animation, it has transparency and a chroma layer - Track 2: Video the animation runs over - Track 3: the CGI animation transitions to
Track 1 + 2 = the default operation, this works when stacking the animation on top of the video.
But *without rendering twice*, how am I able to mask out the chroma key in the animation, so track 3 becomes visible under it?
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!DSPAM:1,691a060996561354169715!
-- Stefan _______________________________________________ Cin mailing list -- cin@lists.cinelerra-gg.org To unsubscribe send an email to cin-leave@lists.cinelerra-gg.org
Stefan, I am seeing your good video tutorial. A good job! I tested here on my UbuntuStudio_16.04 using "CinGG-20250630-alternative_shortcuts.AppImage" version. To simulate your tracks I use my two mov video instead of your "drone.mp4" and "DSC5774.MOV". For the Mask, your "kessel24-mask.mkv" on the bottom track, I use the Foreground Effect (Plugin) creating a mask in it with the Mask Tool (you find in the Compositor Window); the mask is moved animating the mask with two keyframes. In my case the transition to black, like your, works right. It is strange. I don't know if it depends by CinGG version: I use the version for old OS. Have you tried using another video instead of your MOV? My Project Format is RGBA-8bit. IgorBeg Il 16/11/2025 20:53, Stefan de Konink ha scritto:
Now there is a bug, once a transition to black is added to the transitioning TO video layer, the video will black out at some point.
On Mon, 17 Nov 2025, Igor BEGHETTO wrote:
In my case the transition to black, like your, works right. It is strange. I don't know if it depends by CinGG version: I use the version for old OS. Have you tried using another video instead of your MOV? My Project Format is RGBA-8bit.
Il 16/11/2025 20:53, Stefan de Konink ha scritto:
Now there is a bug, once a transition to black is added to the transitioning TO video layer, the video will black out at some point.
Could you try to cut out that small piece of video (all the tracks) where your video gets unwanted blacked out? _______________________________________________________________________________ Georgy Salnikov NMR Group Novosibirsk Institute of Organic Chemistry Lavrentjeva, 9, 630090 Novosibirsk, Russia Phone +7-383-3307864 Email sge@nmr.nioch.nsc.ru _______________________________________________________________________________
Op 17-11-2025 om 12:02 p.m. schreef Georgy Salnikov:
Could you try to cut out that small piece of video (all the tracks) where your video gets unwanted blacked out? If you want the source project, I can provide that too.
-- Stefan
On Mon, 17 Nov 2025, Stefan de Konink wrote:
Op 17-11-2025 om 12:02 p.m. schreef Georgy Salnikov:
Could you try to cut out that small piece of video (all the tracks) where your video gets unwanted blacked out?
Stefan, I meant the following peculiarity. In CinGG, it can happen that two consecutive pieces of footage in a video track are not exactly adjacent to each other in timeline, so that in between there is a tiny (narrower than one single frame) empty segment in the track where there is no video at all. This happens when the next piece of footage is attached to the preceding one, in which the lengts of audio (quantified in units of audio samples, at let's say, 48000 Hz) is slightly more than the length of video (quantified in frames, at 30 Hz). If this is the case, CinGG can blink with a black frame at this position. If the user sets Settings -> Align cursor on frames in the CinGG menu and cuts out this tiny empty segment, two footage segments become exactly adjacent and black blinking disappears. _______________________________________________________________________________ Georgy Salnikov NMR Group Novosibirsk Institute of Organic Chemistry Lavrentjeva, 9, 630090 Novosibirsk, Russia Phone +7-383-3307864 Email sge@nmr.nioch.nsc.ru _______________________________________________________________________________
participants (4)
-
Georgy Salnikov -
Igor BEGHETTO -
Phyllis Smith -
Stefan de Konink