How to overlay images on video frames?

[vace117]

Hello. I am very new to video editing, so this is hopefully a very easy question. I have done some simple video editing with transitions and effects in Cinelerra, but nothing as serious as this, so I need help.

As a matter of fact, I am such a noob that I don't even know the proper name for the operation I want to perform, so that makes googling for it difficult .

What I would like to do is find video editing software that would allow me "draw" on my video. I know how to overlay text onto a video with Cinelerra (there is a video effect for that), but I don't see how I can also draw such things as arrows and mathematical formulas on my video. So I guess my questions are as follows:

1) What is the name for the operation I am trying to do?
2) Is it possible in Cinelerra?
3) Is it possible on Linux at all?
4) Ok, if I *have* to install Windows for this task, I will. What video editing software do I need?

Thank you for your help.

[guns1inger]

It can be done in Cinelerra, but it would take a bit of planning. Basically you would have to create your arrows, formula etc as still images, and overlay them onto the video as needed. By animating masks you could make it look like things were appearing character at a time, or that lines were being drawn, but it would be time consuming.

Another way to approach the problem would be to screen capture a video of you drawing the shapes etc, then overlay the video using keying so you can position it where ever you need to. I don't know what screen capture options you have in the Linux world to do this.

[vace117]

Thanks, guns1inger. I suspected that I might have to create still images first, but that's ok. Since I don't actually need any animation (i.e. my "annotations" should just appear and stay on the screen in their entirety for some number of frames), it shouldn't be too hard.

However, I am having difficulty finding a Cinelerra tutorial that would explain how to overlay images (although I admit, I haven't yet just tried it myself, b/c I am not at home right now). Would you happen to have a link to some material that would make the process clear?

Thanks.

[guns1inger]

Simplest would be the chromakey effect : http://cinelerra.org/docs/split_manual_en/cinelerra_cv_manual_en_14.html#SEC179

Choose a suitable background colour (green or blue depending on your needs) and put the text on top.

[vace117]

Wow, it turned out to be much simpler than using the chromakey effect (although it was useful to learn about it).

In Cinelerra you can overlay an image with an alpha channel over your movie by simply creating another video track, dropping the image into it and then middle-click-dragging the image to the correct length. That's it. It was too simple to be obvious