I am not a great user of Fx other than for grading and filmic look but i need to do mask compiste thing with some footage I have. Talking head to side of a big apple monitor as he talks i want to run stuff up on the monitor. I can do it easily until he leans forward and his head gets chopped off as he comes into the mask. The background around him isnt clean i.e. backdrop of office items.I ahd a scour of some internet tutorials but most are rubbish or dont apply. Anybody on here today able to help me through this. Im in the Uk but i do have Skype.

Hey Simon,
Its pretty easy to do in Vegas,
Just go to the Pan Crop window of your text/pictures (whatever you have running up the monitor) track,
When he leans in front of the monitor, you just use the pen tool to draw a subtracting mask on your text to match the shape of the subjects head, and animate the mask as he moves into the text and then away.
Apply maybe 2 or 3 pixels of feather to make a softened edge.
If you have to do this numerous times, when he clears the text, keyframe the whole mask out of the shot and have it waiting for the next time you need it, then keyframe the position back to 1 frame b4 he encroaches on the text again. Clear as mud :)
It will be crystal once you do it once or twice.
Good luck.