Here's what you do. Compressor can automatically fit large projects on a DVD, regardless of their capacity when exported. Take your highest quality export, and make that your Target in a blank project in Compressor. Under the "Disc Burning" presets, you want MPEG-2 encoding, and Dolby Digital Professional for audio. Drag them one at a time onto your "Target". Select the MPEG-2, and go under "Quality" and set to 2 Pass VBR Best. Leave the Dolby Digital Professional alone. Then click on your target in Compressor (the space outside of the MPEG-2 and Dolby but within that whole rectangular space of the object) and in the inspector, go to Job Action. Select Create DVD. You can put in a title, and choose whether to "Play Automatically" or "Go To Menu" when the disc is put in a DVD player. Compressor will fit your 12GB file onto the DVD using the best quality compression while getting it within the 4.7GB capacity.