encoding with VBR

Hi,

I have made 2 x 73min films I would like to put onto one DVD. I cut them in Avid and exported 2 high res H.264 files as masters.

I have then used Apple Compressor to make MPEG2 files. I used the setting 'DVD Nest Quality 150min'

The quality isn't great. I have heard you can encode it VBR so it gives more data to complex parts of the film and less to others to maximise overall quality. I can not work out how to do this with Compressor. Does anyone know how and what settings I would have to use?

Thank you in advance.

Steve