Hi there
Ok i want to change the colour of wall (to white) in my clip. (its 4-6 sec)
what should i do. thanks

In order for us to help you, you really need to tell us what program you are using, it doesn't really matter what color the wall is presently, just as long as you don't have something of the same color in front of the wall. If your editing app has this feature, then its 'colour keyer' you want

thanks for the reply.

I am using Premier pro and Affter Effects Cs3
thats the problem i have an object in front and it is moving a little bit.
so i was wondering whats the best way to change the colour of wall.
and there is more my wall is damaged from someplace.

Duplicate the layer in AE. Then mask out the wall for the length of your clip, and use the colour correction tools (Hue + saturation + contrast and brightness I would guess) on the layer of video with your wall mask.

Yeah, follow Luke's ideas. Getting it to pure white might be tough though. Any 'real' colour and you can just mask off the wall and apply AE's tint to it. Not sure how well that works for a changing a dark colour into white. Worth a try though.

If it doesn;t work so well then dupliate the layer, mask off the wall, desaturate it to get the wall to black of dark grey and then invert it.

Might help. Without more info that's all I have right now.

__________________
I'm not young enough to know everything!

Only other thing i have though of, is using the threshold tool on the masked out layer.