Hi I'm new here so please be patient with me ...

I have an image composited over a set of background layers using an Affine transition, all composited to black. I want to make this image disappear in an interesting way. I worked out how to use the Affine transition to make it fade by reducing its opacity. However I would like to make it disappear using a wipe effect. So far my attempts have made it wipe to black, so that it scrubs the background during the wipe. I want the background to remain visible.

A more general question. I've been making videos with kdenlive but I would like try some more adventurous things such as the above but I can't find any good tutorials. Is there any explanation of the compositing model anywhere? How do the layers combine especially when you have multiple layers subject to transitions? Currently I just use trial and error but I would like a more rigorous explanation of how they work if there's one available.

Your problem seems to be more involved, so a concrete example of your tracks and transitions may help helping you. Did you already investigate into how to set up the composition tree for your transitions? If not, maybe this series of Kdenlive blog posts may be of some help to you: http://thediveo-e.blogspot.de/2014/07/k ... art-1.html

Thanks for the link. I'll have a look at it, it looks like it could be helpful.

Yes I realized after I posted that I should have given some specifics. My tracks are currently something like:

1. title tracks (affine transition, with black)
2. image, some pixels opaque some transparent (affine transition, with black)
3. artwork track, some pixels opaque some transparent (affine transition, with black)
4. fully opaque background track (affine transition, with black)
5. sound track

All the video tracks have some degree of animation to them.

Specifically I want the image to disappearwith a wipe, e.g., horizontal blinds, and reappear at a different pan/zoom. I'm currently using the affine transition for the pan/zoom but I can sort of figure out how to use a pan/zoom effect for that and change the transition to a wipe. The problem is that I can't get the wipe to make the image vanish/reappear on top of the background tracks. E.g., if ". . ." is the background artwork and "! ! !" is the image, I would like it to wipe away in a series of frames like this:

. . . . . . . . . .
. . . ! ! ! ! . . .
. . . ! ! ! ! . . .
. . . ! ! ! ! . . .
. . . . . . . . . .

. . . . . . . . . .
. . . . . . . . . .
. . . ! ! ! ! . . .
. . . ! ! ! ! . . .
. . . . . . . . . .

. . . . . . . . . .
. . . . . . . . . .
. . . . . . . . . .
. . . ! ! ! ! . . .
. . . . . . . . . .

. . . . . . . . . .
. . . . . . . . . .
. . . . . . . . . .
. . . . . . . . . .
. . . . . . . . . .


PS Sorry for long post. Here is an example of what I can do now: https://youtu.be/rhJO2RQrEJE?t=34s

But I'd like, instead of the boy fading out and the girl fading in, for the boy to disappear and the girl to appear with wipes.

I think I figured it out. You use a Composite transition instead of a Wipe transition!

Wipe seems to only work properly between fully opaque frames and replaces transparent pixels with black. With Composite you have the option of specifying a wipe but it wasn't obvious at first since you have to animate the opacity channel in the transition to make the wipe actually work.

Composite transitions are also buggy and thus take some patience.

Glad you found it yourself! Yes, you're correct: only the composite transition handles transparency. There are also now the cairoblend transitions that also do the job -- albeit be careful as there is still an unfixed bug in many distributions in frei0r that bugs cairoblend transitions with transparency.

On a sidenote, I sometimes didn't get the desired composition results when using the implicit Black track. I thus regularly simply put in a bottom video track that is either mostly empty or has a black color clip in certain composition situations.