Using mobile front facing camera to animate lip sync of 3d model

Any advice on where to begin?

The detail does not have to great but i do need the data of a generated shape or two lines for top and bottom lips to do scripting with.

I have looked at plugins available but they seem expensive and overkill for what i need.

I would rather just do it with unity, the mobile camera/webcam and scripts if at all possible.

Thanks - Andy