Video editing question

[Suto the D.]

Is there a program whit I can change the background of a video while the moving objects remain the same. I want to change the background of a dance video but I do not want to change the dancer. Thank you very much for your help!

[paulears]

It depends so much on how clear the dancer is in front of the background. The usual ways of making it happens 'automatically' are by luminance (brightness) keying or Chroma (colour) keying. So a bright object against a dark background can be isolated as can a dark object against a bright background. Colour keying means the green or blue screen background. If you have a dancer against a random background, then it's much much more difficult, and although there are a few (quite expensive) plug-ins that can help - in most cases the process means you draw around the dancer, and delete the background, frame by frame. Some of the plug-ins let you set one frame like this, then they attempt to track through frame by frame - and if they get a little lost, you adjust the mask and keep going. Adobe has a nice way of doing this in a simplish manner - but it still takes time, and the result depends so much on how good your original footage is. Some backgrounds take almost forever to separate, others are nicer to the auto systems.

What editing software do you have - this is important as it gives us a guide as to what may work best for you.

[Suto the D.]

Thank you for your fast answer! I am using Sony Vegas pro 8 but i am willing to use anything else that can change my random background!

[paulears]

This shows you the basic idea of what you have to do - not a great video, but you get the picture - also have a read of this
Rotoscoping & Chroma Keying