Hello there
I was wondering if there is a way in blender to use a video as a background (like you can do with images), so as to use it as reference to “build” something on it (for example effects for captured footage from a camcorder). I tried to load an avi as a background and though blender loaded it with no errors, as expected there was nothing in the background.

Yes you can!
But instead of image load a texture.

click F6.
For texture type select image.
Enable the movie button
Click Load image and select avi file.
On your left menu define how many Frames you want used.

Now of course this will not make the image in the background render. For that you need to either apply this texture on a plane in the background or use the sequence editor. If you want me to go into detail how to use the sequence editor and actually have the image render in the background, just ask.

Oh what the heck, open up sequence editor.
Click Add, Movie. Place the movie into the first slot.
Click Add, Scene. Place the Scene into the second slot.
Select the Movie, Followed by shift selecting the Scene.
Click Add, Effect, Alpha over.

Click F10, Under the big ANIM button, enable the “Do Sequence” (This will make the settings in the Sequencer rendered, instead of the scene alone)
Under Render, enable the “Premul” button (this will kill the sky, we don’t want anything in the back since we are adding a movie in the background)

Great! Thanks a lot man, you rule :slight_smile: