I have a video clip on the timeline that is scaled down to a 50% size and I have used a mask to crop down a certain area of the video. When I apply an effect the video the effect is applied to the entire video and will not stay with in the mask area only. In other words, I want the effect only to affect within the masked off part of the footage and not spill outside the mask. This seems like an error in the program to me.

Try adding the effect first then the mask.

I tried this but still the same error? It will crop the video fine but not the effect appleid to the video.
I am having to render the effect on the video on another timeline and then reload the file with the new video footage with the effect renderd to it.
This is a timely workaround and unsatisfactory.

I'm assuming you use After Effects, if not, ignore:

Unfortunately, masks and effects don't react to one another in order of application. The look you achieve also depends on the effect you use.

A simple way to get it done most of the time would be to use a masked or small adjustment layer (mask if you want complex shapes or small if you just want a square) over the layer you want to affect. Usually works

Alternatively, instead of rendering the video out then re-importing, try nesting the comp, in comp 1 add the effect to the layer. put comp 1 into comp 2, then apply the mask.

ooohh, That would work. I should have thought of that. I do the same thing in Premiere pro all the time but not in AFX.

And an Adjustment layer might work. I have never really used an Adjustment layer casue I didnt know what they did.

Thanks Conor. I had been waiting a week for a new idea.

No probs, sorry it took so long.