How to keep the Alpha Over Node spit out a picture after input sequence has finished?

Hi there
I’m comping some image sequences together with masks and animated backgrounds as transitions.
Now, once the input file range of the first part has stopped, the Alpha Over Node doesn’t have an input anymore, which gives me a blank output, which is the input for the following sequences. How can I fix this?

Thanks for any help

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If you want to stop using a node at a certain frame you could use a switch node to bypass that node. Just keyframe when the switch node changes the input

thanks Ritchard, but the switch node doesn’t seem to help here. My problem is, that once the range of input files has finished feeding the alpha over node, there is no output out of the AlphaONode, which is bad for the input of the following Mix/Add Node.

Of course I could make the feeding image sequence as long as the whole time range, but since this is several thousands of frames, this way seems clumsy to me.

Maybe I’m doing something wrong here in general. Simply put, my question is:
How does one link different sequences with their various compositing nodes to one big linear string over time?

Ok, so here a simpler formulation of the question:

Input 1) is a image sequence with alpha of a cube over 10 frames
Input 2) is the same, but a sphere.
Compositing the two Inputs together with an AlphaOverNode, all fine.
Now I offset the sphere-Input by 10 frames: The sphere disappears in the backdrop, as expected.
But moving forward by a couple of frames, the input of the cube (Frames 1-11) into the AlphaOverNode stops, and with it the Output as well.
So any ideas how I can offset an image sequence and still have a picture as a result??




Richard, I gave your tip with the switch Node another try and - taraa - found the solution.
Of course the switch needs another input in order to replace the finished sequence when it stops. Set key, and voilà.

Thanks a lot for the help!